Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 11/22/13
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1108 PM MST TUE NOV 19 2013
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 310 PM MST TUE NOV 19 2013
MOIST LOW AMPLITUDE SHORT WAVE RACES ACROSS NORTHWEST COLORADO
TONIGHT. RADAR SHOWING LOW DBZ RETURNS AS THE MOISTURE INCREASES
THIS AFTERNOON...SOME OF THIS PCPN IS REACHING THE GROUND AS KCAG
MEASURED A TRACE AND SUNLIGHT MOUNTAIN AWOS REPORTS LIGHT SNOW.
THE COMBINATION OF OROGRAPHICS AND WEAK DYNAMICAL FORCING WILL
RESULT IN WIDESPREAD LIGHT PCPN OVERNIGHT ACROSS NW COLORADO...POSSIBLY
EXTENDING AS FAR SOUTH AS THE ELK MOUNTAINS. ENHANCED CLOUD COVER
IN THE INFRARED IS SOMEWHAT FRAGMENTED AND UPSTREAM RADAR
OBSERVATIONS SHOW BROKEN AREAS OF PCPN. THE RAP MODEL SHOW PCPN
EXPANDING AS THE SHORT WAVE GETS LIFTED OVER THE DIVIDE...BUT
APPEARS THAT THE TIME DURATION DOES NOT LAST LONG ENOUGH FOR
ADVISORY CRITERIA SNOWFALL. APPEARS THE ELKHEADS AND PARK RANGE
MAY GET A FEW INCHES OF SNOW TONIGHT...BUT TAPERING OFF AFTER
MIDNIGHT. THE SRN HALF HALF GETS EXTENSIVE CLOUD COVER BUT THE
MOISTURE IS NOT AS DEEP...FLURRIES OR BRIEF LIGHT SNOW MAY OCCUR
OVER THE SAN JUAN MOUNTAINS AS THE SHORT WAVE DRAGS ACROSS WRN
COLORADO.
SATELLITE INFRARED AND WATER VAPOR CLEARLY SHOWS A STREAM OF
MOISTURE FROM NW OF THE HAWAIIAN ISLES TO THE CALIFORNIA COAST.
THE FORECAST AREA MAY GET ONLY ONE SHOT AT THIS MOISTURE AND THAT
OCCURS FROM WEDNESDAY AFTERNOON INTO THURSDAY. BUT SHORT WAVE
ENERGY ADVECTING THIS MOISTURE TO THE FOUR CORNERS REGION IS WEAK
AND FRAGMENTED (SIMILAR TO THE LEAD SHORT WAVE). NO SHORTAGE OF
MOISTURE AS 700 MB SPECIFIC HUMIDITY VALUES EXCEED 4 G/KG...BUT
OTHER FEATURES THAT ARE NEEDED FOR EFFICIENT RAIN OR SNOW PRODUCTION
ARE MISSING. LACKING ELEMENTS INCLUDE BAROCLINICITY AND
DYNAMICAL/OROGRAPHICAL FORCING AS 700 MB GRADIENT FLOW IS LESS
THAN 20 KNOTS. THE AREA OF PRECIPITATION WILL BE EXPANDING
WEDNESDAY AFTERNOON OVER SW COLORADO AND SPREADING NEWD...CURRENT
QPF PROJECTIONS SUGGEST SNOW POTENTIAL OF 4 TO 8 INCHES OVER THE
SAN JUAN AND WRN COLORADO CENTRAL MOUNTAINS. THE DEEPEST MOISTURE
WILL BE POSITIONED ACROSS THE REGION ON WEDNESDAY NIGHT BEFORE
SHIFTING DOWNSTREAM BY THURSDAY MORNING...NOT COINCIDING WITH THE
COLD FRONT SURGING SOUTHWARD NEAR THE WYOMING BORDER. SNOW LEVELS
A BIT TRICKY AND WILL BE FLUCTUATING DEPENDING ON TIME OF DAY. IN
GENERAL TERMS...SNOW LEVELS WILL RANGE FROM 7000 TO 8000 FEET.
DIABATIC COOLING PROCESSES COULD RESULT IN WET SNOW TO NEAR THE
VALLEY FLOORS LATE WEDNESDAY NIGHT. LATER SHIFTS MAY NEED TO
CONSIDER HOISTING WINTER WEATHER ADVISORIES.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 310 PM MST TUE NOV 19 2013
BY THU THE SPLIT IN THE FLOW WILL BECOME MORE DISTINCT AS THE LOW
BEGINS TO CLOSE OFF ROUGHLY OVER SOUTHERN CALIFORNIA. A MOIST AND
UNSETTLED SOUTHWEST FLOW AHEAD OF THE LOW WILL CONTINUE TO STREAM
OVER THE SOUTHWEST CORNER OF THE CONUS...AND ACROSS THE SOUTHERN
AND CENTRAL ROCKIES. IN ADDITION...A COLD FRONT ASSOCIATED WITH A
NORTHERN BRANCH SHORTWAVE WILL DROP INTO THE NORTHERN EDGE OF THE
CWA BY AROUND MIDDAY. WE CAN EXPECT MOUNTAIN SNOW AND THE CHANCE
FOR VALLEY RAIN TO CONTINUE THROUGH THU. MOST OF THE AREA WILL BE
DOMINATED BY THE MOIST UNSTABLE SOUTHWEST FLOW WITH SOUTH-
SOUTHWEST SLOPES FAVORED IN THIS REGIME. BUT THE OROGRAPHICS WILL
GENERALLY REMAIN ON THE WEAK SIDE AS THE SOUTHWEST FLOW IS NOT
EXPECTED TO BE OVERLY STRONG. OVER THE FAR NORTH HOWEVER...THE
AREA IMPACTED BY THE THE NORTHERN BRANCH COLD FRONT WILL SPREAD
SOUTH/SOUTHEAST. I EXPECT THAT THERE WILL BE A NICE ENHANCEMENT OF
THE PRECIPITATION IN THE VICINITY OF THE FRONT. BUT MODELS
INDICATE MUCH DRIER AIR WILL PUSH IN BEHIND THE FRONT. THIS WILL
BRING A DOWNTURN IN POPS OVER THE NORTHWEST CORNER BY LATE IN THE
AFTERNOON WITH THAT TREND EXTENDING SOUTH-SOUTHWEST THROUGH THE
EVENING. ALSO A LOCALIZED AREA OF STRONG NORTHERLY WINDS WILL
DEVELOP OVER WESTERN MOFFAT COUNTY INTO THE EASTERN UINTA BASIN
DURING THE EVENING. MUCH COLDER TEMPS WILL RESULT IN THIS DRIER
AIR BEHIND THE FRONT. MODELS DISAGREE ON JUST HOW FAR SOUTH THIS
FRONT WILL REACH BEFORE IT WASHES OUT IN THE SOUTHWEST FLOW AHEAD
OF THE SOUTHERN BRANCH LOW. BUT WE CAN CERTAINLY EXPECT MUCH
COLDER TEMPS OVER THE FAR NORTH...WITH LESS COOLING AS ONE TRAVELS
SOUTH.
MODELS AGREE THAT THE LOW WILL STALL IN THE VICINITY OF SAN DIEGO
BY EARLY FRIDAY...THEN PRETTY MUCH REMAIN STATIONARY UNTIL EARLY
SUNDAY. BY SUN AFTERNOON THE LOW BEGINS TO SLOWLY SHIFT
EAST...MAKING IT OVER NM/GFS...TO THE OK PANHANDLE/ECMWF ON
MONDAY. THIS KEEPS THE DESERT SOUTHWEST THROUGH THE SOUTHERN CO
MOUNTAINS UNDER A MOIST UNSETTLED FLOW AHEAD OF THIS LOW...AND
STILL UNSETTLED AS IT PASSES. OVER THE NORTH...MODELS SHOW A COL
AREA BETWEEN THE SOUTHERN BRANCH LOW AND THE NORTHERN BRANCH
NORTHWESTERLIES WILL MORE OR LESS SET UP OVER WY/NORTHERN CO...AND
EXTEND INTO NORTHEAST UT. THIS WILL KEEP THE NORTHERN HALF TO
TWO/THIRDS OF THE CWA ON THE DRY SIDE. BUT OUR SOUTHERN EDGE MAY
CONTINUE TO SEE PRECIPITATION TROUGH MONDAY. EXPECT THERE WILL BE
BREAKS AT TIMES. AND AS ANY EMBEDDED DISTURBANCES MOVE INTO THE
THE AREA... SHOWERS WILL BE ENHANCED.
MODELS ALL AGREE THAT BY TUE...A DRIER NORTH-NORTHWEST FLOW WILL
DOMINATE AREA-WIDE AS A LARGE AREA OF HIGH PRESSURE BUILDS TO OUR
WEST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1030 PM MST TUE NOV 19 2013
VFR EXPECTED IN MOST PLACES BUT THERE WILL BE AN AREA OF MVFR
SOUTH OF EEO BUT NORTH OF MTJ DUE TO SHOWERS MOVING THROUGH.
MOUNTAIN AREAS MAY BE PARTLY OBSCURED TONIGHT FROM LOW CEILINGS. SNOW
LEVELS WILL BE LOWERING TO NEAR THE VALLEY FLOORS OR AROUND 5500
FEET.
VFR ALL TAF SITES AFTER 12Z UNTIL ABOUT 00Z THURS WHEN DEEP MOISTURE
RETURNS ESPECIALLY IN SOUTHERN LOCATIONS...VISIBILITIES AND
CEILING REDUCING AT HIGHER LOCATIONS IN THE SAN JUANS THROUGHOUT
THE EVENING.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...PF
LONG TERM...EH
AVIATION...JAM
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
820 PM EST THU NOV 21 2013
.DISCUSSION...SEVERAL BANDS OF LIGHT TO MODERATE RAIN CONTINUE
ACROSS EAST CENTRAL FLORIDA THIS EVENING...OVER A MUCH LARGER AREA
AND FURTHER INLAND THAN WHAT WAS SEEN ON WEDNESDAY. WHILE OVERALL
RAIN RATES ARE LIGHTER THAN EARLIER TODAY...THERE REMAIN EMBEDDED
POCKETS OF HEAVY RAIN...PRIMARILY ACROSS INDIAN RIVER...SAINT
LUCIE...OSCEOLA...AND OKEECHOBEE COUNTIES.
THE CONTINUING FORECAST CONTINUES TO BE HOW LONG THE CURRENT RAIN
LASTS...AND WHERE AND HOW INTENSE ANY ADDITIONAL CONVERGENT RAIN
BANDS WILL BE.
LAST RUC ANALYSIS SHOWS A POCKET OF DRIER AIR OFF TO THE NORTHEAST
WHICH MODELS CONTINUE TO ADVECT INTO THE REGION OVERNIGHT. THIS WILL
SERVE TO KEEP THE BEST RAIN CHANCES IN THEIR CURRENT
LOCATIONS...SOUTH OF A MELBOURNE-LAKE KISSIMMEE LINE...WITH THE RAIN
NORTH OF THIS AREA DIMINISHING QUICKLY BY MIDNIGHT. THE THREAT WILL
REMAIN FOR LOCALLY HEAVY RAINFALL...PRIMARILY ALONG THE COAST SOUTH
OF THE CAPE...THROUGH THE OVERNIGHT HOURS.
MOSTLY CLOUDY SKIES EXPECTED WITH LOWS IN THE MID TO UPPER 60S OVER
MUCH OF THE REGION...EXCEPT LOW 70S ALONG COASTAL AREAS FROM THE
CAPE SOUTHWARD.
FRIDAY...HIGH PRESSURE NORTH OF THE AREA WILL BEGIN TO WEAKEN BUT
LOW LEVEL EASTERLY FLOW WILL ONLY DECREASE SLIGHTLY. DRIER AIR WILL
CONTINUE TO BUILD INTO DOWN INTO THE AREA WITH BEST CHANCE FOR
CONTINUED ONSHORE MOVING SHOWERS ALONG THE TREASURE COAST AND INTO
OKEECHOBEE COUNTY. THIS DRIER AIR SHOULD ALSO BEGIN TO DECREASE
CLOUD COVER ESPECIALLY OVER NORTH CENTRAL FLORIDA WITH SKIES
BECOMING PARTLY CLOUDY. WITH A LITTLE MORE SUNSHINE EXPECTED HIGHS
SHOULD BE ABLE TO REACH UP INTO THE LOW 80S OVER MUCH OF THE AREA.
&&
.AVIATION...ONGOING LIGHT-MODERATE RA WITH TEMPO IFR CIGS ACROSS
ORLANDO METRO AND LOCATIONS NORTH WILL DIMINISH AFTER 03Z...THOUGH
MVFR CIGS MAY LINGER FOR A FEW HOURS LATER. FURTHER SOUTH...IFR/MVFR
CONDS WILL OCCUR IN ONSHORE MOVING RAIN BANDS PRIMARILY SOUTH OF
KMLB-KISM OVERNIGHT WITH HIGHEST COVERAGE ALONG THE COAST.
DRIER AIR BUILDING SOUTHWARDS ON FRIDAY WILL LIMIT RAIN CHANCES
NORTH OF KMLB-KISM...HOWEVER ISOLD-SCT ONSHORE MOVING SHRA WILL
CONTINUE FURTHER SOUTH...ESPECIALLY VCNTY KOBE...KFPR...AND KSUA.
&&
.MARINE...WINDS AT LOCAL BUOYS CONTINUE TO RUN AROUND 20KTS WITH
SEAS AT LEAST 7-8FT...EVEN AT NEARSHORE SITES. NO CHANGES TO THE
ONGOING SMALL CRAFT ADVISORY WHICH CONTINUES THROUGH FRIDAY
AFTERNOON.
THE BRISK EASTERLY FLOW WILL BE SLOW TO SUBSIDE WITH WINDS AROUND
20KTS OVERNIGHT DIMINISHING TO 15 TO 20KTS BY FRI AFTERNOON. HOWEVER
THE ONSHORE FLOW WILL CONTINUE TO KEEP SEAS ELEVATED WITH UP TO 8-9
FEET OFFSHORE TONIGHT AND 7-8 FEET TOMORROW AND CHOPPY.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 4 PM FRIDAY FROM FLAGLER BEACH
TO JUPITER INLET OUT TO 60 NM.
$$
MOSES/KELLY
AREA FORECAST DISCUSSION
NWS MIAMI FL
939 AM EST WED NOV 20 2013
.UPDATE...
MAJOR CHANGES HAVE NOT BEEN MADE TO THE MORNING UPDATE. THERE
APPEARS TO BE A WEAK SURFACE TROUGH OFF THE EAST COAST WHICH IS
TRIGGERING CONVECTION OVER THE ATLANTIC WATERS BUT THE MAIN
SURFACE BOUNDARY IS STILL NORTH OF LAKE OKEECHOBEE. THE 12Z MFL
SOUNDING DOES SHOW SOME MODEST INSTABILITY WITH WEAK MID LEVEL
LAPSE RATES WITHIN THE WARM SECTOR ALONG WITH WELL ABOVE AVERAGE
PWAT FOR MID NOVEMBER. HOWEVER, THE LAST TWO RUNS OF THE HRRR HAVE
DECREASED THE AMOUNT OF AFTERNOON CONVECTION ACROSS THE PENINSULA AND
IF THIS TREND CONTINUES, WILL NEED TO SCALE BACK AT LEAST ON THE
TIMING OF THE HIGHER POPS.
KOB
&&
.PREV DISCUSSION... /ISSUED 552 AM EST WED NOV 20 2013/
AVIATION...
A STATIONARY FRONT WILL SLOWLY DISSIPATE THROUGH THURSDAY OVER
SOUTH CENTRAL FLORIDA. THIS WILL KEEP LOW LEVEL MOISTURE IN PLACE
OVER THE SOUTH FLORIDA TAF SITES TODAY INTO THURSDAY ALONG WITH
SCATTERED SHOWERS. THERE COULD EVEN BE A THUNDERSTORM OVER THE TAF
SITES THIS AFTERNOON...BUT THE COVERAGE WILL BE FEW AND FAR
BETWEEN. SO AT THIS TIME WILL CONTINUE TO CARRY VCSH IN THE TAF
SITES FOR TODAY.
THE CEILING AND VIS WILL REMAIN IN THE VFR CONDITIONS TODAY OVER
THE TAF SITES. HOWEVER...KTMB AND KAPF TAF SITES COULD SEE VIS
REDUCTION INTO THE MVFR CONDITIONS EARLY THIS MORNING AND AGAIN
LATE TONIGHT INTO EARLY THURSDAY MORNING DUE TO FOG FORMATION.
AVIATION...54/BNB
PREV DISCUSSION... /ISSUED 423 AM EST WED NOV 20 2013/
SHORT TERM (TODAY-FRIDAY)...
PLENTY OF DEEP LAYER MOISTURE COMBINED WITH A FRONTAL BOUNDARY
STALLING NEAR/OVER THE AREA WILL KEEP THE RAIN CHANCES UP THROUGH A
GOOD PORTION OF THE SHORT-TERM PERIOD. MODEL SOUNDINGS REFLECT THIS
MOIST ENVIRONMENT AND SHOW PRECIPITABLE WATER VALUES RANGING FROM
1.6-1.9" THROUGH THE PERIOD...WHICH IS ABOVE AVERAGE FOR THIS TIME
OF YEAR. THE EARLY MORNING SURFACE ANALYSIS SHOWED THE FRONTAL
BOUNDARY JUST NORTH OF OUR LOCAL AREA WITH A WEAK PRE-FRONTAL TROUGH
EXTENDING SOUTHWEST OUT AHEAD OF IT. THE LATEST WATER VAPOR LOOP
SHOWED MOSTLY ZONAL FLOW ACROSS THE REGION. A FEW RIPPLES OF ENERGY
TRANSLATING EWD WITHIN THE WESTERLY FLOW ALOFT COULD SLIGHTLY
ENHANCE THE RAINFALL ACTIVITY ALONG AND AHEAD OF THE BOUNDARY
PERIODICALLY OVER THE UPCOMING 24-48 HRS. UPPER HEIGHTS WILL THEN
BEGIN TO RISE THROUGH THE LATTER HALF OF THE PERIOD...WHICH MAY
INTRODUCE SOME SLIGHTLY DRIER CONDITIONS AND REDUCE THE TSTM CHANCES
BY FRIDAY. THE FLOW WILL REMAIN QUITE WEAK THROUGH THE LOWER
LEVELS...WHICH SHOULD ALLOW THE EAST/WEST COAST SEA BREEZES TO
DEVELOP THROUGH THE AFTERNOON HOURS. TEMPERATURES WILL REMAIN
SEVERAL DEGREES ABOVE AVERAGE WITH OVERNIGHT LOWS RANGING FROM THE
MID 60S INLAND TO THE LOWER 70S ALONG THE EAST COAST/METRO LOCATIONS
EACH NIGHT. AFTERNOON HIGHS ARE FORECAST TO REACH THE LOW TO MID 80S
EACH DAY. THIS COMBINED WITH DEWPOINTS REMAINING IN THE UPPER 60S
WILL KEEP THE HUMID CONDITIONS IN PLACE.
LONG TERM (SATURDAY-WEDNESDAY)...
THE LATEST GFS MEAN/GFS/ECMWF REMAIN IN DECENT AGREEMENT THROUGH THE
WEEKEND AND INDICATE UPPER HEIGHTS FALLING AS A STRONG SHORTWAVE
TROUGH DIGS SOUTHEAST DRIVING A COLD FRONT THROUGH THE LOCAL AREA
THROUGH THE DAY SUNDAY. THUNDERSTORM CHANCES WITH THIS BOUNDARY
SHOULD REMAIN LOW AS MOST OF THE UPPER FORCING REMAINS WELL TO THE
NORTH. THIS BOUNDARY WILL BE FOLLOWED BY GUSTY NNE WINDS SUNDAY
NIGHT INTO MONDAY WITH SOME DRIER/SLIGHTLY COOLER AIR SPREADING OVER
THE AREA. HOWEVER...TEMPERATURES ARE NOT EXPECTED TO CHANGE MUCH
WITH THIS BOUNDARY AS THE FLOW IF FORECAST TO QUICKLY VEER TO THE
ESE AHEAD OF ANOTHER DEVELOPING SYSTEM ALONG THE TEXAS COAST IN
RESPONSE TO A STRONG SHORTWAVE TROUGH. THIS FEATURE IS PROGGED TO
QUICKLY SWEEP FROM WEST TO EAST ALONG THE NORTHERN GULF COAST STATES
MONDAY THROUGH TUESDAY DRAGGING A SECOND COLD FRONT THROUGH THE AREA
BY THE END OF THE EXTENDED PERIOD.
AVIATION...
PATCHY FOG WILL REMAIN POSSIBLE THROUGH DAYBREAK...MAINLY
FOR TMB AND APF...WHICH MAY PERIODICALLY RESTRICT VSBY/CIGS. ANY
FOG SHOULD BURN OFF QUICKLY AFTER 13/14Z. LIGHT WINDS WILL PERSIST
THROUGH MUCH OF THE PERIOD AS A FRONTAL BOUNDARY REMAINS NEAR/OVER
THE LOCAL AREA. LIGHT WESTERLY WINDS ASSOCIATED WITH THE AFTERNOON
SEA BREEZE WILL REMAIN POSSIBLE AT APF TODAY. THE BEST CHANCE FOR
SHOWERS AND STORMS WILL REMAIN ALONG THE EAST COAST THROUGH THE
PERIOD AS PLENTY OF MOISTURE REMAINS IN PLACE. FOG WILL BECOME A
POSSIBILITY ONCE AGAIN LATE TONIGHT INTO THURSDAY MORNING...MAINLY
FOR TMB AND APF.
BNB/AG
MARINE...
LIGHT WINDS WILL REMAIN IN PLACE ACROSS THE LOCAL WATERS THROUGH
FRIDAY AS A FRONTAL BOUNDARY STALLS OVER THE AREA. THE BEST CHANCE
FOR SHOWERS AND STORMS WILL REMAIN ALONG THE ATLANTIC COAST THROUGH
THURSDAY. A SMALL NORTHERLY SWELL ASSOCIATED WITH FRESH TO STRONG
NORTHEAST WINDS NORTH OF THE FRONT WILL CONTINUE TO SPREAD SOUTH
OVER THE ATLANTIC WATERS THROUGH THE REMAINDER OF THE WEEK. A
STRONG COLD FRONT WILL PUSH THROUGH THE AREA BY THE END OF THE
WEEKEND WITH STRONG NORTHEAST WINDS AND BUILDING SEAS EXPECTED
SUNDAY NIGHT THROUGH MONDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 83 73 83 72 / 50 40 50 20
FORT LAUDERDALE 83 74 83 74 / 50 30 50 10
MIAMI 84 72 83 73 / 50 20 50 10
NAPLES 84 68 85 69 / 20 20 20 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
540 PM EST WED NOV 20 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 207 PM EST WED NOV 20 2013
HIGH PRESSURE TO THE EAST IS GOING TO RULE INDIANA WEATHER
OVERNIGHT. FROM THURSDAY INTO FRIDAY A COMBINED LOW PRESSURE SYSTEM
AND COLD FRONT SHOULD CROSS THE HOOSIER STATE FROM THE WEST. THE LOW
PRESSURE SYSTEM AND COLD FRONT WILL BE FOLLOWED BY A HUGE AREA OF
HIGH PRESSURE.
THE HIGH PRESSURE AREA IS FORECAST TO BE FOLLOWED BY ANOTHER
COMBINED LOW PRESSURE SYSTEM AND COLD FRONT. EXPECT MORE HIGH
PRESSURE TO ARRIVE ACROSS INDIANA BY WEDNESDAY.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 207 PM EST WED NOV 20 2013
PROBLEM IS WHETHER RAIN WILL START LATE TONIGHT.
MODELS CONCUR WARM ADVECTION CAUSING INCREASING CLOUDS AND
SATURATION TONIGHT. RACE WILL BE ON FOR WHICH HAPPENS FIRST...WATER
MAKING IT TO GROUND OR 12Z ARRIVING.
THE MAV IS HIGH WITH POPS COMPARED TO THE MET. LAST TIME
PRECIPITATION MOVED INTO STATE MET TIMING WAS BETTER. LATEST RAP IN
BUFKIT HAS LITTLE OR NO QPF IN CWA THROUGH 10Z. THAT DOES NOT LEAVE
MUCH OF A WINDOW FOR ANYTHING TO START BEFORE THURSDAY. GOING MET
PLUS 10 PERCENT...SO AS TO NOT COMPLETELY DISCOUNT MAV.
VERY LOW CONFIDENCE TEMPERATURE FORECAST. MINOR CHANGES IN
CLOUDS OR PCPN WOULD HAVE A BIG IMPACT. FOR NOW USING
GUIDANCE...WHICH IS ALMOST THE SAME BETWEEN MODELS. EVENING SHIFT
MAY BE ABLE TO MAKE SIGNIFICANT IMPROVEMENTS.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 207 PM EST WED NOV 20 2013
WITH MODELS AGREEING ABOUT WET THURSDAY AND THURSDAY NIGHT...MAIN
QUESTION IS WHEN RAIN WILL END.
FOR SOME REASON MAV POPS DROP SHARPLY FRIDAY. THIS MAKES NO SENSE
LOOKING AT ANY MODEL QPF. IT IS ALSO VERY DIFFERENT FROM EITHER THE
ECM OR NAM GUIDANCE. MAV HAD A SIMILAR PROBLEM DROPPING POPS FOR NO
APPARENT REASON WITH LAST SYSTEM. WILL USE THE MET.
GOING TO SLIGHTLY DAMPER MAV POPS FRIDAY NIGHT. PCPN WILL DEFINITELY
BE ON DOWNSWING. HOWEVER THAT FAR OUT I DONT WANT TO COMPLETELY RULE
OUT SOMETHING PAST 00Z. EVERYTHING POINTS TO CLEARING SATURDAY.
TEMPERATURES...GREAT UNCERTAINTY. THEY WILL BE HEAVILY IMPACTED BY
DETAILS IN TIMING OF PRECIPITATION...CLOUDS...AND A FRONTAL PASSAGE.
CONSENSUS BEST FOR SITUATIONS LIKE THIS. WILL TRY THAT BETWEEN MAV
AND MET. SIGNIFICANT FORECAST CHANGES MAY OCCUR AS NEW INFO ARRIVES.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 236 PM EST WED NOV 20 2013
BOTH THE EURO AND GFS ARE IN GOOD AGREEMENT WITH SPLIT FLOW ACROSS
THE U.S. AS MID/UPPER LEVEL FLOW WILL COME FROM THE NORTHERN
CANADIAN TERRITORIES SOUTHEAST INTO THE UPPER OHIO VALLEY DUE TO A
MID/UPPER LOW BLOCKING OVER THE SOUTHWESTERN U.S. THIS LEAVES AREAS
FROM THE UPPER GREAT LAKES AND OHIO VALLEY IN COLD AIR REGIME
THROUGH THE PERIOD. TEMPERATURES WILL BE IN THE 30S FOR HIGHS AND IN
THE TEENS TO THE MID 20S FOR LOWS.
A TROUGH WILL BE EMBEDDED WITHIN THE MID LEVEL FLOW BRINGING
RAIN/SNOW EARLY ON DURING THE SHORTENED WORK WEEK AS TEMPERATURES
WILL BE WARM ENOUGH FOR RAIN/SNOW POSSIBLE STARTING ON MONDAY
BECOMING LIGHT SNOW MONDAY NIGHT.
&&
.AVIATION /DISCUSSION FOR 210000Z TAF ISSUANCE/...
ISSUED AT 540 PM EST WED NOV 20 2013
VFR WITH SCATTERED LIGHT SHOWERS OVERNIGHT...GIVING WAY TO MVFR IN
RAIN DURING THE DAY THURSDAY.
SCATTERED LIGHT SHOWERS...MOST NUMEROUS AROUND KLAF...WILL CONTINUE
THIS EVENING. DO NOT THINK THERE WILL BE ANY RESTRICTIONS WITH THESE
SHOWERS...SO WILL COVER WITH VCSH AS NECESSARY. WINDS NOT FAR OFF
THE SURFACE WILL BE RELATIVELY STRONG OVERNIGHT...BUT NOT QUITE TO
LOW LEVEL WIND SHEAR CRITERIA.
RAIN WILL DEVELOP LATE TONIGHT NORTHWEST AND SLOWLY SPREAD SOUTHEAST
ACROSS THE TAF SITES ON THURSDAY. EXPECT CEILINGS AND VISIBILITIES
TO LOWER TO MVFR IN THE RAIN. CANNOT RULE OUT IFR BY THE END OF THE
PERIOD AT KLAF AND IN THE LATTER PART OF THE 30 HOUR TAF AT KIND.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JK
LONG TERM....DWM
AVIATION...50
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
352 PM EST WED NOV 20 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 207 PM EST WED NOV 20 2013
HIGH PRESSURE TO THE EAST IS GOING TO RULE INDIANA WEATHER
OVERNIGHT. FROM THURSDAY INTO FRIDAY A COMBINED LOW PRESSURE SYSTEM
AND COLD FRONT SHOULD CROSS THE HOOSIER STATE FROM THE WEST. THE LOW
PRESSURE SYSTEM AND COLD FRONT WILL BE FOLLOWED BY A HUGE AREA OF
HIGH PRESSURE.
THE HIGH PRESSURE AREA IS FORECAST TO BE FOLLOWED BY ANOTHER
COMBINED LOW PRESSURE SYSTEM AND COLD FRONT. EXPECT MORE HIGH
PRESSURE TO ARRIVE ACROSS INDIANA BY WEDNESDAY.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 207 PM EST WED NOV 20 2013
PROBLEM IS WHETHER RAIN WILL START LATE TONIGHT.
MODELS CONCUR WARM ADVECTION CAUSING INCREASING CLOUDS AND
SATURATION TONIGHT. RACE WILL BE ON FOR WHICH HAPPENS FIRST...WATER
MAKING IT TO GROUND OR 12Z ARRIVING.
THE MAV IS HIGH WITH POPS COMPARED TO THE MET. LAST TIME
PRECIPITATION MOVED INTO STATE MET TIMING WAS BETTER. LATEST RAP IN
BUFKIT HAS LITTLE OR NO QPF IN CWA THROUGH 10Z. THAT DOES NOT LEAVE
MUCH OF A WINDOW FOR ANYTHING TO START BEFORE THURSDAY. GOING MET
PLUS 10 PERCENT...SO AS TO NOT COMPLETELY DISCOUNT MAV.
VERY LOW CONFIDENCE TEMPERATURE FORECAST. MINOR CHANGES IN
CLOUDS OR PCPN WOULD HAVE A BIG IMPACT. FOR NOW USING
GUIDANCE...WHICH IS ALMOST THE SAME BETWEEN MODELS. EVENING SHIFT
MAY BE ABLE TO MAKE SIGNIFICANT IMPROVEMENTS.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 207 PM EST WED NOV 20 2013
WITH MODELS AGREEING ABOUT WET THURSDAY AND THURSDAY NIGHT...MAIN
QUESTION IS WHEN RAIN WILL END.
FOR SOME REASON MAV POPS DROP SHARPLY FRIDAY. THIS MAKES NO SENSE
LOOKING AT ANY MODEL QPF. IT IS ALSO VERY DIFFERENT FROM EITHER THE
ECM OR NAM GUIDANCE. MAV HAD A SIMILAR PROBLEM DROPPING POPS FOR NO
APPARENT REASON WITH LAST SYSTEM. WILL USE THE MET.
GOING TO SLIGHTLY DAMPER MAV POPS FRIDAY NIGHT. PCPN WILL DEFINITELY
BE ON DOWNSWING. HOWEVER THAT FAR OUT I DONT WANT TO COMPLETELY RULE
OUT SOMETHING PAST 00Z. EVERYTHING POINTS TO CLEARING SATURDAY.
TEMPERATURES...GREAT UNCERTAINTY. THEY WILL BE HEAVILY IMPACTED BY
DETAILS IN TIMING OF PRECIPITATION...CLOUDS...AND A FRONTAL PASSAGE.
CONSENSUS BEST FOR SITUATIONS LIKE THIS. WILL TRY THAT BETWEEN MAV
AND MET. SIGNIFICANT FORECAST CHANGES MAY OCCUR AS NEW INFO ARRIVES.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 236 PM EST WED NOV 20 2013
BOTH THE EURO AND GFS ARE IN GOOD AGREEMENT WITH SPLIT FLOW ACROSS
THE U.S. AS MID/UPPER LEVEL FLOW WILL COME FROM THE NORTHERN
CANADIAN TERRITORIES SOUTHEAST INTO THE UPPER OHIO VALLEY DUE TO A MID/UPPER
LOW BLOCKING OVER THE SOUTHWESTERN U.S. THIS LEAVES AREAS FROM THE
UPPER GREAT LAKES AND OHIO VALLEY IN COLD AIR REGIME THROUGH THE
PERIOD. TEMPERATURES WILL BE IN THE 30S FOR HIGHS AND IN THE TEENS
TO THE MID 20S FOR LOWS.
A TROUGH WILL BE EMBEDDED WITHIN THE MID LEVEL FLOW BRINGING
RAIN/SNOW EARLY ON DURING THE SHORTENED WORK WEEK AS TEMPERATURES
WILL BE WARM ENOUGH FOR RAIN/SNOW POSSIBLE STARTING ON MONDAY
BECOMING LIGHT SNOW MONDAY NIGHT.
&&
.AVIATION /DISCUSSION FOR 202100Z TAF UPDATE/...
ISSUED AT 352 PM EST WED NOV 20 2013
KIND TAF LOOKS GOOD. ONLY MINOR TWEAKS MADE.
PREVIOUS DISCUSSION FOLLOWS...
VFR CONDITIONS IN PLACE FOR THIS AFTERNOON AND EARLY TONIGHT AS HIGH
PRESSURE WILL BE OVER THE EASTERN GREAT LAKES AND NEW ENGLAND.
THIS HIGH PRESSURE WILL MOVE MOVE OFF TO THE EAST AND NORTHEAST AS
LOW PRESSURE DEVELOPS OVER SOUTHEAST COLORADO TONIGHT AND A COLD FRONT
DRIFTS IN FROM THE NORTHWEST THURSDAY AFTERNOON. SOUTHERLY WINDS
WILL BRING MOISTURE NORTHWARD DURING THE EARLY HALF OF THURSDAY
AND WILL BE EXPECTING SOME LIGHT RAIN BY LATE MORNING BECOMING
MORE STEADY WITH MVFR/IFR CONDITIONS AT MOST TAF SITES BY THURSDAY
AFTERNOON.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JK
LONG TERM....DWM
AVIATION...DWM/50
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
252 PM EST WED NOV 20 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 207 PM EST WED NOV 20 2013
HIGH PRESSURE TO THE EAST IS GOING TO RULE INDIANA WEATHER
OVERNIGHT. FROM THURSDAY INTO FRIDAY A COMBINED LOW PRESSURE SYSTEM
AND COLD FRONT SHOULD CROSS THE HOOSIER STATE FROM THE WEST. THE LOW
PRESSURE SYSTEM AND COLD FRONT WILL BE FOLLOWED BY A HUGE AREA OF
HIGH PRESSURE.
THE HIGH PRESSURE AREA IS FORECAST TO BE FOLLOWED BY ANOTHER
COMBINED LOW PRESSURE SYSTEM AND COLD FRONT. EXPECT MORE HIGH
PRESSURE TO ARRIVE ACROSS INDIANA BY WEDNESDAY.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 207 PM EST WED NOV 20 2013
PROBLEM IS WHETHER RAIN WILL START LATE TONIGHT.
MODELS CONCUR WARM ADVECTION CAUSING INCREASING CLOUDS AND
SATURATION TONIGHT. RACE WILL BE ON FOR WHICH HAPPENS FIRST...WATER
MAKING IT TO GROUND OR 12Z ARRIVING.
THE MAV IS HIGH WITH POPS COMPARED TO THE MET. LAST TIME
PRECIPITATION MOVED INTO STATE MET TIMING WAS BETTER. LATEST RAP IN
BUFKIT HAS LITTLE OR NO QPF IN CWA THROUGH 10Z. THAT DOES NOT LEAVE
MUCH OF A WINDOW FOR ANYTHING TO START BEFORE THURSDAY. GOING MET
PLUS 10 PERCENT...SO AS TO NOT COMPLETELY DISCOUNT MAV.
VERY LOW CONFIDENCE TEMPERATURE FORECAST. MINOR CHANGES IN
CLOUDS OR PCPN WOULD HAVE A BIG IMPACT. FOR NOW USING
GUIDANCE...WHICH IS ALMOST THE SAME BETWEEN MODELS. EVENING SHIFT
MAY BE ABLE TO MAKE SIGNIFICANT IMPROVEMENTS.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 207 PM EST WED NOV 20 2013
WITH MODELS AGREEING ABOUT WET THURSDAY AND THURSDAY NIGHT...MAIN
QUESTION IS WHEN RAIN WILL END.
FOR SOME REASON MAV POPS DROP SHARPLY FRIDAY. THIS MAKES NO SENSE
LOOKING AT ANY MODEL QPF. IT IS ALSO VERY DIFFERENT FROM EITHER THE
ECM OR NAM GUIDANCE. MAV HAD A SIMILAR PROBLEM DROPPING POPS FOR NO
APPARENT REASON WITH LAST SYSTEM. WILL USE THE MET.
GOING TO SLIGHTLY DAMPER MAV POPS FRIDAY NIGHT. PCPN WILL DEFINITELY
BE ON DOWNSWING. HOWEVER THAT FAR OUT I DONT WANT TO COMPLETELY RULE
OUT SOMETHING PAST 00Z. EVERYTHING POINTS TO CLEARING SATURDAY.
TEMPERATURES...GREAT UNCERTAINTY. THEY WILL BE HEAVILY IMPACTED BY
DETAILS IN TIMING OF PRECIPITATION...CLOUDS...AND A FRONTAL PASSAGE.
CONSENSUS BEST FOR SITUATIONS LIKE THIS. WILL TRY THAT BETWEEN MAV
AND MET. SIGNIFICANT FORECAST CHANGES MAY OCCUR AS NEW INFO ARRIVES.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 236 PM EST WED NOV 20 2013
BOTH THE EURO AND GFS ARE IN GOOD ARGEEMENT WITH SPLIT FLOW ACROSS
THE U.S. AS MID/UPPER LEVEL FLOW WILL COME FROM THE NORTHERN
CANADIAN TERRITORIES SOUTHEAST INTO THE UPPER OHIO VALLEY DUE TO A MID/UPPER
LOW BLOCKING OVER THE SOUTHWESTERN U.S. THIS LEAVES AREAS FROM THE
UPPER GREAT LAKES AND OHIO VALLEY IN COLD AIR REGIME THROUGH THE
PERIOD. TEMPERATURES WILL BE IN THE 30S FOR HIGHS AND IN THE TEENS
TO THE MID 20S FOR LOWS.
A TROUGH WILL BE EMBEDDED WITHIN THE MID LEVEL FLOW BRINGING
RAIN/SNOW EARLY ON DURING THE SHORTENED WORK WEEK AS TEMPERATURES
WILL BE WARM ENOUGH FOR RAIN/SNOW POSSIBLE STARTING ON MONDAY
BECOMING LIGHT SNOW MONDAY NIGHT.
&&
.AVIATION /DISCUSSION FOR 201800Z TAF ISSUANCE/...
ISSUED AT 1153 AM EST WED NOV 20 2013
VFR CONDITIONS IN PLACE FOR THIS AFTERNOON AND EARLY TONIGHT AS
HIGH PRESSURE WILL BE OVER THE EASTERN GREAT LAKES AND NEW
ENGLAND.
THIS HIGH PRESSURE WILL MOVE MOVE OFF TO THE EAST AND NORTHEAST AS
LOW PRESSURE DEVELOPS OVER SOUTHEAST COLORADO TONIGHT AND A COLD FRONT
DRIFTS IN FROM THE NORTHWEST THURSDAY AFTERNOON. SOUTHERLY WINDS
WILL BRING MOISTURE NORTHWARD DURING THE EARLY HALF OF THURSDAY
AND WILL BE EXPECTING SOME LIGHT RAIN BY LATE MORNING BECOMING
MORE STEADY WITH MVFR/IFR CONDITIONS AT MOST TAF SITES BY THURSDAY
AFTERNOON.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JK
LONG TERM....DWM
AVIATION...DWM
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
207 PM EST WED NOV 20 2013
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 207 PM EST WED NOV 20 2013
HIGH PRESSURE TO THE EAST IS GOING TO RULE INDIANA WEATHER
OVERNIGHT. FROM THURSDAY INTO FRIDAY A COMBINED LOW PRESSURE SYSTEM
AND COLD FRONT SHOULD CROSS THE HOOSIER STATE FROM THE WEST. THE LOW
PRESSURE SYSTEM AND COLD FRONT WILL BE FOLLOWED BY A HUGE AREA OF
HIGH PRESSURE.
THE HIGH PRESSURE AREA IS FORECAST TO BE FOLLOWED BY ANOTHER
COMBINED LOW PRESSURE SYSTEM AND COLD FRONT. EXPECT MORE HIGH
PRESSURE TO ARRIVE ACROSS INDIANA BY WEDNESDAY.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 207 PM EST WED NOV 20 2013
PROBLEM IS WHETHER RAIN WILL START LATE TONIGHT.
MODELS CONCUR WARM ADVECTION CAUSING INCREASING CLOUDS AND
SATURATION TONIGHT. RACE WILL BE ON FOR WHICH HAPPENS FIRST...WATER
MAKING IT TO GROUND OR 12Z ARRIVING.
THE MAV IS HIGH WITH POPS COMPARED TO THE MET. LAST TIME
PRECIPITATION MOVED INTO STATE MET TIMING WAS BETTER. LATEST RAP IN
BUFKIT HAS LITTLE OR NO QPF IN CWA THROUGH 10Z. THAT DOES NOT LEAVE
MUCH OF A WINDOW FOR ANYTHING TO START BEFORE THURSDAY. GOING MET
PLUS 10 PERCENT...SO AS TO NOT COMPLETELY DISCOUNT MAV.
VERY LOW CONFIDENCE TEMPERATURE FORECAST. MINOR CHANGES IN
CLOUDS OR PCPN WOULD HAVE A BIG IMPACT. FOR NOW USING
GUIDANCE...WHICH IS ALMOST THE SAME BETWEEN MODELS. EVENING SHIFT
MAY BE ABLE TO MAKE SIGNIFICANT IMPROVEMENTS.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 207 PM EST WED NOV 20 2013
WITH MODELS AGREEING ABOUT WET THURSDAY AND THURSDAY NIGHT...MAIN
QUESTION IS WHEN RAIN WILL END.
FOR SOME REASON MAV POPS DROP SHARPLY FRIDAY. THIS MAKES NO SENSE
LOOKING AT ANY MODEL QPF. IT IS ALSO VERY DIFFERENT FROM EITHER THE
ECM OR NAM GUIDANCE. MAV HAD A SIMILAR PROBLEM DROPPING POPS FOR NO
APPARENT REASON WITH LAST SYSTEM. WILL USE THE MET.
GOING TO SLIGHTLY DAMPER MAV POPS FRIDAY NIGHT. PCPN WILL DEFINITELY
BE ON DOWNSWING. HOWEVER THAT FAR OUT I DONT WANT TO COMPLETELY RULE
OUT SOMETHING PAST 00Z. EVERYTHING POINTS TO CLEARING SATURDAY.
TEMPERATURES...GREAT UNCERTAINTY. THEY WILL BE HEAVILY IMPACTED BY
DETAILS IN TIMING OF PRECIPITATION...CLOUDS...AND A FRONTAL PASSAGE.
CONSENSUS BEST FOR SITUATIONS LIKE THIS. WILL TRY THAT BETWEEN MAV
AND MET. SIGNIFICANT FORECAST CHANGES MAY OCCUR AS NEW INFO ARRIVES.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ISSUED AT 305 AM EST WED NOV 20 2013
MODELS ARE IN BETTER AGREEMENT ON TIMING OF EXIT OF SYSTEM ON
SATURDAY. ONLY KEEPING A SLIGHT CHANCE IN THE FAR EAST IN THE
MORNING WITH THE UPPER TROUGH AXIS MOVING THROUGH. WITH SOME LAKE
EFFECT POSSIBILITY IN THE FAR NORTHEAST HAVE CARRIED A SLIGHT CHANCE
OF SNOW THERE ALL DAY. BY SATURDAY NIGHT HIGH PRESSURE STARTS
BUILDING IN AND BRINGS IN DRY WEATHER THROUGH MONDAY. BY MONDAY
NIGHT THE SURFACE HIGH IS OFF TO THE SOUTHEAST AND AN UPPER LOW
FORMING OVER THE PLAINS ALLOWS SOME MOISTURE TO WORK IT/S WAY BACK
NORTH ON THE BACK SIDE OF THE SURFACE HIGH. THIS WILL BRING SMALL
CHANCES FOR SNOW MONDAY NIGHT INTO TUESDAY. TEMPERATURES WILL RUN
WELL BELOW NORMAL THROUGH THE LONG TERM.
&&
.AVIATION /DISCUSSION FOR 201800Z TAF ISSUANCE/...
ISSUED AT 1153 AM EST WED NOV 20 2013
VFR CONDITIONS IN PLACE FOR THIS AFTERNOON AND EARLY TONIGHT AS
HIGH PRESSURE WILL BE OVER THE EASTERN GREAT LAKES AND NEW
ENGLAND.
THIS HIGH PRESSURE WILL MOVE MOVE OFF TO THE EAST AND NORTHEAST AS
LOW PRESSURE DEVELOPS OVER SOUTHEAST COLORADO TONIGHT AND A COLD FRONT
DRIFTS IN FROM THE NORTHWEST THURSDAY AFTERNOON. SOUTHERLY WINDS
WILL BRING MOISTURE NORTHWARD DURING THE EARLY HALF OF THURSDAY
AND WILL BE EXPECTING SOME LIGHT RAIN BY LATE MORNING BECOMING
MORE STEADY WITH MVFR/IFR CONDITIONS AT MOST TAF SITES BY THURSDAY
AFTERNOON.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JK
LONG TERM....CP
AVIATION...DWM
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1204 PM CST WED NOV 20 2013
.UPDATE...
ISSUED AT 1200 PM CST WED NOV 20 2013
THE DRY AIR IS SLOWLY LOSING GROUND AS THE WAA PRECIPITATION
SLOWLY MOVES ACROSS THE CWFA. THE OVERALL TIMING HAS BEEN ADJUSTED
SLIGHTLY BUT THOSE AREAS THAT WERE DRY THIS MORNING SHOULD SEE
RAIN DEVELOPING THIS AFTERNOON. IF CURRENT RADAR TRENDS CONTINUE
THEN THE FAR WESTERN PARTS OF THE AREA MAY SEE AN END TO THE RAIN
THIS AFTERNOON.
UPDATE ISSUED AT 951 AM CST WED NOV 20 2013
BASED ON REPORTS OF SLEET IN THE KIIB AREA...THE FORECAST HAS BEEN
UPDATED TO ADD MENTION OF SLEET IN THE FAR NORTHWEST PART OF THE
AREA.
THE SLEET APPEARS TO BE THE RESULT OF EVAPORATIVE COOLING WITH
SURFACE DEW POINTS BELOW 30 DEGREES. BASED ON RAP TRENDS...THE
LOWEST PART OF THE ATMOSPHERE WILL SLOWLY SATURATE THE REMAINDER
OF THE MORNING AND SHOULD PUSH THE PRECIPITATION OVER TO ALL
RAIN. ANY SLEET ACCUMULATIONS ARE EXPECTED TO BE MINOR WITH AMOUNTS
BRIEFLY BEING NO MORE THAN 0.1 OR 0.2 INCHES.
UPDATE ISSUED AT 904 AM CST WED NOV 20 2013
ADJUSTMENTS HAVE BEEN MADE TO THE FORECAST TO BETTER REFLECT
PRECIPITATION TRENDS ON RADAR AND THE OVERALL TIMING AS IT
MOVES/DEVELOPS NORTHEAST. KIIB CURRENTLY SHOWS SNOW BUT A WEB CAM
IS INCONCLUSIVE ON PRECIPITATION TYPE. IT IS POSSIBLE THAT A BRIEF
MIX MAY OCCUR IN THE FAR NORTHWEST UNTIL THE ATMOSPHERE SATURATES
BUT NO ACCUMULATION IS EXPECTED DUE TO THE STILL WARM GROUND.
&&
.SYNOPSIS...
ISSUED AT 250 AM CST WED NOV 20 2013
A WEAK SHORT WAVE RIDGE AND SURFACE HIGH PRESSURE ARE SLIDING EAST
OF THE AREA WHILE A MODEST STORM SYSTEM PULLS OUT OF THE ROCKIES
INTO THE CENTRAL AND NORTHERN PLAINS. MOISTURE AHEAD OF THIS
SYSTEM IS APPARENT VIA ECHOS ON THE 88D...BUT OTHER THAN A FEW
SPOTS OF SLEET...MOST OF THE RETURNS ARE ALOFT. MORE SUBSTANTIAL
PRECIP IN NORTHWEST MISSOURI IS ASSOCIATED WITH THUNDER DUE TO SUPPORT
FROM THE LOW-LEVEL JET.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 250 AM CST WED NOV 20 2013
MAIN CONCERN IN THE SHORT TERM IS THE IMPACT OF THE TROUGH AS IT
PASSES ACROSS THE AREA TODAY AND THIS EVENING.
SHORT AND LONG TERM MODELS ARE IN GOOD AGREEMENT IN MOVING PRECIP
INTO THE CWA DURING THE MORNING...THEN OUT OF THE CWA DURING THE
EVENING. QPFS ARE FAIRLY CONSISTENT BETWEEN 1/5 AND 1/3 INCH...NOT
SUFFICIENT TO HAVE A NOTABLE IMPACT IN AREAS WHERE DROUGHT
PERSISTS. THE GFS QPF IS AN OUTLIER AND SEEMS TOO WET WHICH MAY
RELATE TO A LARGE AREA OF SEVERELY OVER ANALYZED AND FORECAST
SURFACE DEW POINTS IN THE SOUTH CENTRAL U.S. ON THE 00Z INITIAL.
CLOUDS ARE INCREASING AND WITH RAIN DEVELOPING...TEMPS WILL
STRUGGLE TO CLIMB TODAY. LOOKS LIKE GUIDANCE CAUGHT UP TO THE COOL
VALUES WE HAVE BEEN FORECASTING...SO MADE NO SIGNIFICANT CHANGE TO
MAX TEMPS. AS THE SYSTEM DEPARTS THE AREA...LOW-LEVEL FLOW
BECOMES WEAK AS AN INVERTED TROUGH DEVELOPS. MOISTURE HANGS IN SO
CLOUDS WILL PERSIST AHEAD OF THE NEXT SYSTEM IN LINE...WHICH
SHOULD HOLD UP MIN TEMPS TONIGHT. WOLF
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 250 AM CST WED NOV 20 2013
THE MAIN FORECAST CONCERN CONTINUE TO BE PRECIPITATION TYPE THURSDAY
NIGHT INTO FRIDAY AND TEMPERATURES AFTER SATURDAY. MODELS ARE IN
DECENT OVERALL AGREEMENT THROUGH THE PERIOD WITH SOME TIMING
DIFFERENCES WITH THE ARCTIC AIR FOR THIS WEEKEND.
A WAVE WILL RIDE ALONG A STRONG BAROCLINIC ZONE THAT SETS UP ACROSS
THE REGION DURING THE DAY ON THURSDAY. TEMPERATURES WILL BE WARM
ENOUGH THAT PRECIPITATION WILL FALL AS ALL RAIN THROUGH 06 UTC ON
FRIDAY. A SECOND SHORTWAVE TROUGH WILL DIVE SOUTHEASTWARD OUT OF
SOUTHERN CANADA AFTER 00 UTC ON FRIDAY BRINGING ANOTHER ROUND OF
PRECIPITATION TO THE REGION AND PUSHING A STRONG COLD FRONT EASTWARD. GFS
AND NAM BUFR SOUNDINGS INDICATE THAT PRECIPITATION WILL START OUT AS
RAIN AT MOST LOCATIONS AND BEGIN TO CHANGE OVER TO SNOW VERY SLOWLY
FROM NORTHWEST TO SOUTHEAST AFTER 06 UTC ON FRIDAY. PRECIPITATION
WILL BEGIN TO CHANGE OVER TO THE SOUTHERN HALF OF THE CWA AFTER 12
UTC ON FRIDAY ABOUT THE TIME DRIER AIR BEGINS TO COME SOUTHWARD
CUTTING THE PRECIPITATION OFF. ACCUMULATIONS SHOULD BE LESS THAN A
HALF AN INCH IN THE NORTHWEST.
A SECOND REINFORCING SURGE OF ARCTIC AIR ARRIVES AFTER 00 UTC ON
SATURDAY WITH A SECONDARY COLD FRONT. THERE ARE SOME TIMING DIFFERENCES
BETWEEN THE 00 UTC GFS AND ECMWF WITH THE ARCTIC AIR ARRIVING A
LITTLE MORE SLOWLY WITH THE ECWMF. MODELS SHOW A 1050 MB HIGH DROPPING
SOUTHWARD INTO THE PLAINS WITH A VERY TIGHT PRESSURE GRADIENT OVER
IOWA DURING THE DAY ON SATURDAY. THERE WILL BE LITTLE REBOUND IN
TEMPERATURES DURING THE DAY ON SATURDAY WITH STRONG COLD ADVECTION
AND GUSTY NORTHWEST WINDS. SATURDAY NIGHT WILL BE VERY COLD WITH
HIGH PRESSURE CENTERED OVER CENTRAL AND EASTERN IOWA WITH CLEAR
SKIES AND DEWPOINTS IN THE SINGLE DIGITS WHICH WILL ALLOW
TEMPERATURES TO DROP VERY QUICKLY AS THE WINDS BECOME CALM THROUGH
SUNDAY MORNING. LOW TEMPERATURES MAY VERY WELL NEED TO BE LOWER A
COUPLE MORE DEGREES FOR SUNDAY MORNING. THE SURFACE HIGH
SHIFTS TO THE SOUTHEAST OF THE REGION DURING THE DAY ON SUNDAY
ALLOWING FOR RETURN FLOW TO SETUP AND PULL WARMER AIR NORTHWARD FOR
THE BEGINNING OF NEXT WEEK.
A CLOSED UPPER LEVEL OVER THE SOUTHWESTERN US WILL BEGIN TO LUMBER
EASTWARD EARLY NEXT WEEK WITH MODELS NOW INDICATING PRECIPITATION
ASSOCIATED WITH THIS SYSTEM MOVING TO THE SOUTH OF HIGHWAY 34 DURING
THE DAY ON MONDAY. TEMPERATURES WILL STILL BE COLD ENOUGH ON MONDAY
THAT PRECIPITATION WOULD FALL AS A RAIN SNOW MIX.
AFTER MONDAY ANOTHER CLIPPER SYSTEM WILL DROP SOUTHWARD OUT OF
CANADA AND SWING A COLD FRONT THROUGH THE REGION ALLOWING FOR
TEMPERATURES A COUPLE OF DEGREES FOR THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1200 PM CST WED NOV 20 2013
MVFR TO VFR CONDITIONS EXIST ACROSS EASTERN IOWA AND NORTHERN
ILLINOIS AS AN AREA OF RAIN SLOWLY MOVES NORTHEAST. CONDITIONS
WILL DETERIORATE TO MVFR ONCE THE RAIN BEGINS AND THEN IMPROVE TO
VFR WHEN THE RAIN ENDS. HOWEVER...MVFR CIGS ARE DEVELOPING BEHIND
THE RAIN WHICH MAY RESULT IN MVFR CONDITIONS PERSISTING. AFT
06Z/21 A WEAK FRONT WILL MOVE INTO THE AREA CAUSING WIDESPREAD
MVFR CONDITIONS WITH A GOOD PROBABILITY OF IFR CONDITIONS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...WOLF
SHORT TERM...WOLF
LONG TERM...COUSINS
AVIATION...08
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
955 AM CST WED NOV 20 2013
.UPDATE...
ISSUED AT 951 AM CST WED NOV 20 2013
BASED ON REPORTS OF SLEET IN THE KIIB AREA...THE FORECAST HAS BEEN
UPDATED TO ADD MENTION OF SLEET IN THE FAR NORTHWEST PART OF THE
AREA.
THE SLEET APPEARS TO BE THE RESULT OF EVAPORATIVE COOLING WITH
SURFACE DEW POINTS BELOW 30 DEGREES. BASED ON RAP TRENDS...THE
LOWEST PART OF THE ATMOSPHERE WILL SLOWLY SATURATE THE REMAINDER
OF THE MORNING AND SHOULD PUSH THE PRECIPITATION OVER TO ALL
RAIN. ANY SLEET ACCUMULATIONS ARE EXPECTED TO BE MINOR WITH AMOUNTS
BRIEFLY BEING NO MORE THAN 0.1 OR 0.2 INCHES.
UPDATE ISSUED AT 904 AM CST WED NOV 20 2013
ADJUSTMENTS HAVE BEEN MADE TO THE FORECAST TO BETTER REFLECT
PRECIPITATION TRENDS ON RADAR AND THE OVERALL TIMING AS IT
MOVES/DEVELOPS NORTHEAST. KIIB CURRENTLY SHOWS SNOW BUT A WEB CAM
IS INCONCLUSIVE ON PRECIPITATION TYPE. IT IS POSSIBLE THAT A BRIEF
MIX MAY OCCUR IN THE FAR NORTHWEST UNTIL THE ATMOSPHERE SATURATES
BUT NO ACCUMULATION IS EXPECTED DUE TO THE STILL WARM GROUND.
&&
.SYNOPSIS...
ISSUED AT 250 AM CST WED NOV 20 2013
A WEAK SHORT WAVE RIDGE AND SURFACE HIGH PRESSURE ARE SLIDING EAST
OF THE AREA WHILE A MODEST STORM SYSTEM PULLS OUT OF THE ROCKIES
INTO THE CENTRAL AND NORTHERN PLAINS. MOISTURE AHEAD OF THIS
SYSTEM IS APPARENT VIA ECHOS ON THE 88D...BUT OTHER THAN A FEW
SPOTS OF SLEET...MOST OF THE RETURNS ARE ALOFT. MORE SUBSTANTIAL
PRECIP IN NORTHWEST MISSOURI IS ASSOCIATED WITH THUNDER DUE TO SUPPORT
FROM THE LOW-LEVEL JET.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 250 AM CST WED NOV 20 2013
MAIN CONCERN IN THE SHORT TERM IS THE IMPACT OF THE TROUGH AS IT
PASSES ACROSS THE AREA TODAY AND THIS EVENING.
SHORT AND LONG TERM MODELS ARE IN GOOD AGREEMENT IN MOVING PRECIP
INTO THE CWA DURING THE MORNING...THEN OUT OF THE CWA DURING THE
EVENING. QPFS ARE FAIRLY CONSISTENT BETWEEN 1/5 AND 1/3 INCH...NOT
SUFFICIENT TO HAVE A NOTABLE IMPACT IN AREAS WHERE DROUGHT
PERSISTS. THE GFS QPF IS AN OUTLIER AND SEEMS TOO WET WHICH MAY
RELATE TO A LARGE AREA OF SEVERELY OVER ANALYZED AND FORECAST
SURFACE DEW POINTS IN THE SOUTH CENTRAL U.S. ON THE 00Z INITIAL.
CLOUDS ARE INCREASING AND WITH RAIN DEVELOPING...TEMPS WILL
STRUGGLE TO CLIMB TODAY. LOOKS LIKE GUIDANCE CAUGHT UP TO THE COOL
VALUES WE HAVE BEEN FORECASTING...SO MADE NO SIGNIFICANT CHANGE TO
MAX TEMPS. AS THE SYSTEM DEPARTS THE AREA...LOW-LEVEL FLOW
BECOMES WEAK AS AN INVERTED TROUGH DEVELOPS. MOISTURE HANGS IN SO
CLOUDS WILL PERSIST AHEAD OF THE NEXT SYSTEM IN LINE...WHICH
SHOULD HOLD UP MIN TEMPS TONIGHT. WOLF
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 250 AM CST WED NOV 20 2013
THE MAIN FORECAST CONCERN CONTINUE TO BE PRECIPITATION TYPE THURSDAY
NIGHT INTO FRIDAY AND TEMPERATURES AFTER SATURDAY. MODELS ARE IN
DECENT OVERALL AGREEMENT THROUGH THE PERIOD WITH SOME TIMING
DIFFERENCES WITH THE ARCTIC AIR FOR THIS WEEKEND.
A WAVE WILL RIDE ALONG A STRONG BAROCLINIC ZONE THAT SETS UP ACROSS
THE REGION DURING THE DAY ON THURSDAY. TEMPERATURES WILL BE WARM
ENOUGH THAT PRECIPITATION WILL FALL AS ALL RAIN THROUGH 06 UTC ON
FRIDAY. A SECOND SHORTWAVE TROUGH WILL DIVE SOUTHEASTWARD OUT OF
SOUTHERN CANADA AFTER 00 UTC ON FRIDAY BRINGING ANOTHER ROUND OF
PRECIPITATION TO THE REGION AND PUSHING A STRONG COLD FRONT EASTWARD. GFS
AND NAM BUFR SOUNDINGS INDICATE THAT PRECIPITATION WILL START OUT AS
RAIN AT MOST LOCATIONS AND BEGIN TO CHANGE OVER TO SNOW VERY SLOWLY
FROM NORTHWEST TO SOUTHEAST AFTER 06 UTC ON FRIDAY. PRECIPITATION
WILL BEGIN TO CHANGE OVER TO THE SOUTHERN HALF OF THE CWA AFTER 12
UTC ON FRIDAY ABOUT THE TIME DRIER AIR BEGINS TO COME SOUTHWARD
CUTTING THE PRECIPITATION OFF. ACCUMULATIONS SHOULD BE LESS THAN A
HALF AN INCH IN THE NORTHWEST.
A SECOND REINFORCING SURGE OF ARCTIC AIR ARRIVES AFTER 00 UTC ON
SATURDAY WITH A SECONDARY COLD FRONT. THERE ARE SOME TIMING DIFFERENCES
BETWEEN THE 00 UTC GFS AND ECMWF WITH THE ARCTIC AIR ARRIVING A
LITTLE MORE SLOWLY WITH THE ECWMF. MODELS SHOW A 1050 MB HIGH DROPPING
SOUTHWARD INTO THE PLAINS WITH A VERY TIGHT PRESSURE GRADIENT OVER
IOWA DURING THE DAY ON SATURDAY. THERE WILL BE LITTLE REBOUND IN
TEMPERATURES DURING THE DAY ON SATURDAY WITH STRONG COLD ADVECTION
AND GUSTY NORTHWEST WINDS. SATURDAY NIGHT WILL BE VERY COLD WITH
HIGH PRESSURE CENTERED OVER CENTRAL AND EASTERN IOWA WITH CLEAR
SKIES AND DEWPOINTS IN THE SINGLE DIGITS WHICH WILL ALLOW
TEMPERATURES TO DROP VERY QUICKLY AS THE WINDS BECOME CALM THROUGH
SUNDAY MORNING. LOW TEMPERATURES MAY VERY WELL NEED TO BE LOWER A
COUPLE MORE DEGREES FOR SUNDAY MORNING. THE SURFACE HIGH
SHIFTS TO THE SOUTHEAST OF THE REGION DURING THE DAY ON SUNDAY
ALLOWING FOR RETURN FLOW TO SETUP AND PULL WARMER AIR NORTHWARD FOR
THE BEGINNING OF NEXT WEEK.
A CLOSED UPPER LEVEL OVER THE SOUTHWESTERN US WILL BEGIN TO LUMBER
EASTWARD EARLY NEXT WEEK WITH MODELS NOW INDICATING PRECIPITATION
ASSOCIATED WITH THIS SYSTEM MOVING TO THE SOUTH OF HIGHWAY 34 DURING
THE DAY ON MONDAY. TEMPERATURES WILL STILL BE COLD ENOUGH ON MONDAY
THAT PRECIPITATION WOULD FALL AS A RAIN SNOW MIX.
AFTER MONDAY ANOTHER CLIPPER SYSTEM WILL DROP SOUTHWARD OUT OF
CANADA AND SWING A COLD FRONT THROUGH THE REGION ALLOWING FOR
TEMPERATURES A COUPLE OF DEGREES FOR THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 532 AM CST WED NOV 20 2013
MOISTURE SURGE AHEAD OF THE STORM SYSTEM MOVING INTO THE MIDWEST
THIS MORNING IS RESULTING IN VIRGA AND SPOTTY RAIN SHOWERS AND ICE
PELLETS. AS THE ATMOSPHERE MOISTENS...RAIN WILL BECOME MORE
WIDESPREAD BY MID MORNING...THEN CONTINUE THROUGH THE DAY INTO THE
EVENING HOURS. VFR CONDITIONS WILL DETERIORATE TO MVFR DURING THE
DAY. IT IS A LITTLE LESS CLEAR HOW THINGS WILL EVOLVE LATER THIS
EVENING AND OVERNIGHT...BUT MVFR CONDITIONS ARE LIKELY TO CONTINUE
WITH A LOW PROBABILITY OF IFR CONDITIONS IF LINGERING MOISTURE
LEADS TO THE FORMATION OF FOG. WOLF
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...WOLF
SHORT TERM...WOLF
LONG TERM...COUSINS
AVIATION...WOLF
AREA FORECAST DISCUSSION...UPDATED
NWS TOPEKA KS
545 PM CST Thu Nov 21 2013
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Friday)
Issued at 256 PM CST THU NOV 21 2013
.Synopsis...
Water vapor imagery shows a shortwave trough over the northern
plains propagating east towards the great lakes, while energy
begins to cut off over central CA. At the surface, a strong cold
front has pushed through the entire forecast area with
temperatures continuing to fall in response to strong cold air
advection.
.Short Term... (Tonight)
For tonight the forcing for continued precipitation looks to be
mainly driven by mid level frontogenesis. The NAM and RAP progs
show weakening isentropic upglide early in the evening as the 850
front continues to push south. Then by the late evening and
overnight mid level drying near the better mid level
frontogenetical forcing suggests that precip could come to an end
since there is no lift within the low level cloud from isentropic
features for light freezing drizzle. With this in mind have
trended POPs down for most areas overnight. The latest
HRRR/RAP13/NAM12 continue to show this band of precip currently
from Minneapolis to Hiawatha, associated with some mid level
frontogenesis, to lift northeast into northwest MO. Therefore have
some likely pops for the early evening across far northeast KS.
Otherwise the forecast will only have some chance pops through the
rest of tonight. Did not feel confident enough to lower pops any
further since there will be some mid level frontogenesis through
the night. Also will not make any major changes to the advisory
other than to end it earlier in the day Friday. It is one of those
situations that with the advisory already out it doesn`t make
sense to cancel it early since there remains the potential for
some light frozen precip with reports of slick roads coming in.
Since forcing is weak and moisture will continue to lessen through
the night, additional precipitation is anticipated to be on the
light side with accumulations generally around a tenth of an inch in
water equivalent. The mid level drying will also make it difficult
for snow to occur since the dendritic growth zone is not expected to
be saturated. Because of this there shouldn`t be any ice crystals
for snow. So think freezing rain and sleet will be the primary
precip type through the night if precip does fall. Continued cold
air advection should cause temperatures to fall into the teens and
mid 20s for the forecast area by sunrise Friday.
.LONG TERM...(Friday Night through Thursday)
Issued at 256 PM CST THU NOV 21 2013
Friday...Becomes a race with the incoming drier air as to how much
precipitation can fall on Friday as high pressure continues to surge
into the southern plains through the day. Back to the west an upper
low advances into Baja, lifting a lobe of moisture into southern
Kansas in the mid levels. Frontogenesis gets some further
enhancement from northern trof dropping energy into the area mid to
late day. Isentropic charts indicate downglide in the lower levels,
with 700mb chart showing some broad convergence in the wind field
through the noon hour. With lack of strong lift and incoming drier
air have pulled back on precip chances and amounts but not ready to
remove entirely for the southern counties just yet. Enough
consensus in incoming dry air from north to end the advisory earlier
for generally the I70 counties, but will hang onto it through noon
for those south of I70. Temperature profiles are finally cold enough
for all snow along the northern edge but hold onto a weak warm nose
across the SE and will keep a S/IP mix for these areas. Went colder
on both highs and lows given current reflection in observations with
highs upper 20s to near freezing and dropping overnight into the
upper teens.
Saturday and Sunday... Continue to go on the cool side of guidance
on Saturday with high pressure still on the move to the south. Have
highs near freezing and lows in the lower to middle teens. Incoming
clouds from the southwest on Sunday plus a return to southerly
surface low on the wrn side of the high should bring highs back into
the middle 30s on Sunday.
Monday: An upper level trough forming out of the Four Corners region
will propagate to the east. The 12Z ECMWF/GFS are in reasonable
agreement pertaining to the location of the trough. A jet streak of
up to 100kt winds associated with this trough should eject
additional moisture into Oklahoma and Kansas. Southerly winds in
this region should help support moisture transfer over eastern
Kansas. This additional moisture, along with freezing temperatures,
could support light snow over eastern Kansas.
By Tuesday, the trough should pivot to the south due to a ridging
stream wave over the western CONUS. The trough should stay further
south into Texas and Oklahoma. Winds shift from southerly to
northerly as the trough moves south. The ridging pattern over the
western CONUS will translate towards the east by Wednesday, bringing
quiet weather to the region. Lows will be in the 20s overnight and
highs will be in the upper 30s/lower 40s for the rest of the week.
&&
.AVIATION...(For the 00Z TAFs through 00Z Friday Evening)
Issued at 527 PM CST THU NOV 21 2013
Stronger forcing now coming through the Taf sites with an IFR mixture
of freezing drizzle...sleet and snow. Expect this precip to
gradually diminish through 04z but with mvfr cigs in its wake. As
drier air aloft moves in...still some potential for light freezing
drizzle but confidence remains too low to insert into Tafs at
this point. North winds will gust to 25 kts overnight...but
steadily decrease through the day Friday. MVFR cigs should scatter
to vfr in the 19-21Z time frame.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until 6 AM CST Friday FOR KSZ008>012-
020>024-026-034>036-038-039.
WINTER WEATHER ADVISORY until 6 AM CST Friday FOR KSZ040.
WINTER WEATHER ADVISORY until Noon CST Friday FOR KSZ037.
WINTER WEATHER ADVISORY until Noon CST Friday FOR KSZ054>056-058-
059.
&&
$$
SHORT TERM...67/Wolters
LONG TERM...67/JTS
AVIATION...63
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
418 PM EST WED NOV 20 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 416 PM EST WED NOV 20 2013
THE OVERALL WEATHER PATTERN WILL REMAIN QUITE MESSY...MAKING THE
OVERALL FORECAST TRICKY OVER THE NEXT DAY. A LIGHT WET SNOW IS
EXPECTED ACROSS THE INTERIOR WEST THIS EVENING BEFORE A COLD FRONT
PUSHES INTO THE WESTERN CWA THURSDAY AFTERNOON.
LATE THIS AFTERNOON AND TONIGHT...MID-LEVEL SW FLOW AHEAD OF DEEP
TROUGHING DEVELOPING ACROSS CENTRAL CANADA WILL CONTINUE THROUGH
THURSDAY. AN ASSOCIATED SFC TROUGH ORIENTED ACROSS THE UPPER MS
VALLEY BETWEEN LOW PRESSURE OVER HUDSON BAY AND DEVELOPING LOW
PRESSURE ACROSS THE SOUTHERN HIGH PLAINS WILL SLOWLY PUSH EAST. A
WELL-DEFINED MID-LEVEL SHORTWAVE TROUGH CURRENTLY CENTERED NEAR
SIOUX FALLS WILL CONTINUE ITS NORTHEASTWARD PROGRESSION THIS EVENING
AND BE THE MAIN PLAYER IN PRECIPITATION.
MANY CONVOLUTED FORCING MECHANISMS WILL BE AT WORK THIS EVENING. A
COMPLICATED LOW-LEVEL FGEN PATTERN SLOPING TO THE SE WITH HEIGHT AND
A WEAK UPPER-LEVEL JET STREAK MERGING WITH THE POLAR JET WILL IMPOSE
CONFLICTING OMEGA FIELDS ON EACH OTHER. THIS WEAK UPPER JET STREAK
APPEARS TO BE SOME CONVECTIVE FEEDBACK TIED TO A CLUSTER OF
PERSISTENT STORMS OVER IA AND MO. MEANWHILE...WEAK ISENTROPIC ASCENT
ON THE 290-295K SFCS WILL ASSIST SOME MID-LEVEL PRECIP DEVELOPMENT
THIS EVENING. OVERALL...PRECIP LOOKS TO BE CONTROLLED BY THE
ISENTROPIC ASCENT AND Q-VECTOR CONV WITH THE MID-LEVEL WAVE.
A BROKEN SHIELD OF RAIN AND SNOW SHOWERS HAS DEVELOPED ACROSS
WESTERN WI OVER THE PAST SEVERAL HOURS. THIS HAS EASED SOME CONCERNS
THAT THE MIXED OMEGA FIELD WOULD SUPPRESS PRECIP. THE RAP HAS
MAINTAINED A DECENT HANDLE ON THE PRECIP EVOLUTION...SO HAVE
FOLLOWED IT FOR THE OVERALL PRECIP PATTERN WHILE EMPLOYING THE NAM
FOR THE SYNOPTIC EVOLUTION. PRECIP HAS JUST STARTED TO SPREAD INTO
THE INTERIOR WEST NEAR WI AND WILL CONTINUE NORTHWARD INTO THE
EVENING. THERE IS GOOD AGREEMENT THAT THE GREATEST COVERAGE WILL BE
MID TO LATE EVENING ACROSS MUCH OF THE WEST HALF OF THE CWA BEFORE
PRECIP SPREADS EASTWARD OVERNIGHT WITH THE WAVE.
PTYPE LOOKS TO BE MOSTLY WET SNOW FOR ALL BUT THE NEAR LAKE SUPERIOR
SHORELINE AS WETBULB ZERO LEVELS WILL BE WELL BELOW 1KFT. A SUB
700MB DRY LAYER MAY INHIBIT PRECIP INITIALLY...BUT GIVEN CURRENT
RADAR RETURNS IN WI...PRECIP RATES SHOULD BE HIGH ENOUGH TO OVERCOME
THE DRY AIR IN A HOUR OR SO. SNOW RATIOS SHOULD BE QUITE
LOW...GENERALLY 8-10:1 AS MOST LIFT WILL BE W/IN TEMPS HIGHER THAN
THE DGZ. SOME AGGREGATION COULD BE POSSIBLE THROUGH A DEEP
ISOTHERMAL LAYER BETWEEN -3 AND -5C...SO LARGER WET FLAKES ARE
POSSIBLE. TOTAL SNOWFALL THROUGH TONIGHT IS FORECAST TO BE 0.5-1.5
INCHES FOR THE INTERIOR WEST HALF...HIGHEST FROM IRON RIVER TO
CHAMPION. WOULD NOT BE SURPRISED IF SOME LOCATIONS TOP 2 INCHES
GIVEN THE HEAVIER SHOWER ACTIVITY EXPECTED. SHORELINE LOCATIONS WILL
SEE MINIMAL ACCUMULATION AS A RESULT OF LOWER ELEVATION AND
DOWNSLOPING WITH A GENERAL SOUTH WIND.
OVERALL PRECIP COVERAGE WILL DIMINISH SLOWLY AS THE SHIELD
PROGRESSES EASTWARD. HOWEVER...CONTINUED SOUTH TO SSW FLOW OFF LAKE
MI SHOULD YIELD A LAKE-ENHANCED BAND OF RAIN AND SNOW SHOWERS
ACROSS EASTERN DELTA INTO SCHOOLCRAFT COUNTIES. MEANWHILE...MINIMAL
FZDZ WILL BE POSSIBLE ACROSS THE FAR WEST LATE TONIGHT AS SOME
MID-LEVEL DRYING BEHIND THE SHORTWAVE LIMITS LIFT TO THE BARELY
SUB-FREEZING LOW-LEVELS.
THURSDAY...AN OVERALL LULL IN PRECIP IS EXPECTED THROUGH THURSDAY
MORNING BEHIND THE MID-LEVEL WAVE...BUT THE SFC TROUGH WILL BEGIN TO
TRACK ACROSS THE CWA DURING THE AFTERNOON ACROSS THE WEST. HIGH
TEMPS WILL BE FAIRLY EARLY IN THE DAY FOR THE WEST HALF...WITH
FALLING TEMPS THROUGHOUT THE AFTERNOON. HIGHER MOISTURE WITH THE
FRONT AND DROPPING TEMPS WILL INCREASE SNOW SHOWER COVERAGE
WEST...ESPECIALLY FOR THE HIGHER TERRAIN.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 416 PM EST WED NOV 20 2013
SPLIT FLOW PATTERN PERSISTS THROUGH LATE THIS WEEK THEN FLOW PATTERN
BECOMES PHASED THIS WEEKEND INTO INTO FIRST PART OF NEXT WEEK WHICH
ALLOWS COLDEST AIR OF THE SEASON TO ARRIVE. COUPLE OF SHORTWAVES AND
SMALLER JET STREAKS LIFT ACROSS THURSDAY NIGHT INTO FRIDAY. BEST
CHANCE OF SYNOPTIC PRECIPITATION OCCURS THURSDAY NIGHT...ESPECIALLY
OVER THE SOUTH AND EAST. THOUGH THERE COULD BE SOME MIXED RAIN AND
SNOW EARLY THURSDAY EVENING IN THE EAST...SOUNDINGS AND THICKNESSES
BEYOND THAT TIME INDICATE COLD AIR WILL STAY IN PLACE LEADING TO SNOW
AS ONLY PTYPE THROUGH THE THANKSGIVING HOLIDAY.
MAY SEE ENHANCEMENT TO SNOW OVER THE WEST AND NORTH THURSDAY NIGHT
AS TEMPS AT INVERSION TOP OR H85 FALL TO -8C TO -10C GIVING A DELTA
T TO AROUND 13C. MORE SIGNIFICANT CONTRIBUTION FROM THE LAKE
ENHANCEMENT MAY BE OVER HIGHER TERRAIN OF NCNTRL AS LARGER SCALE
FORCING FOR SNOW PERSISTS INTO DAYBREAK ON FRIDAY. A FEW INCHES OF
SNOW MAY OCCUR OVER THURSDAY NIGHT FOR HIGHER TERRAIN OF MARQUETTE
COUNTY AND FOR FAVORED INLAND SNOWBELTS OF WESTERN ALGER COUNTY.
ELSEWHERE SNOW AMOUNTS OF AN INCH OR TWO ARE POSSIBLE.
ARCTIC FRONT WILL BE BLASTING SOUTH ACROSS MANITOBA AND NORTHERN
ONTARIO ON FRIDAY BUT WILL NOT ARRIVE OVER UPR LAKES UNTIL FRIDAY
EVENING. SO...FRIDAY MAY END UP A FAIRLY QUIET BTWN SYSTEMS DAY AS
CWA WILL BE IN WAKE OF THURSDAY NIGHT WAVE AND STILL AHEAD OF ARCTIC
FRONT/STRONG COLD AIR ADVECTION/LK EFFECT SNOWS FOR LATER FRIDAY
NIGHT INTO THE WEEKEND. PARTIAL CLEARING MAY OCCUR BUT WITH LIMITED
WARM AIR ADVECTION AHEAD OF THE FRONT...TEMPS WILL SILL END UP IN
THE 20S. WINDS WILL BE ON THE LIGHTER SIDE COMPARED TO THE WINDY
CONDITIONS COMING FOR THE WEEKEND.
ARCTIC FRONT SWEEPS THROUGH ON FRIDAY NIGHT. TEMPS STARTING OUT THE
EVENING IN THE UPR 20S WILL BE SOLIDLY IN THE TEENS OVER THE WEST BY
DAYBREAK ON SATURDAY AND GOING NOWHERE FAST. TEMPS WILL STAY STEADY
OR FALL SLIGHTLY ON SATURDAY AS PLUNGE OF COLD AIR AT H85 AND H7
DRIVES ACROSS THE GREAT LAKES REGION. EXPECT LK EFFECT SNOWS TO RAMP
UP SIGNIFICANTLY. INTITAL BURST OF SNOW OCCURS FRIDAY EVENING OVER
THE KEWEENAW WITH SUFFICIENT OVERWATER INSTABILITY COMBINING WITH
LOW-LEVEL CONVERGENCE ALONG FRONT. SOUNDINGS INDICATE FAVORABLE
MOISTURE AND LOCATION OF DGZ INTERSECTING PROJECTED UVM. SLR/S
SHOULD INCREASE TO MORE OF A FLUFFY 15-20:1 WITH STRONG NW WINDS IN
BLYR ONLY THING PROHIBITING SLR/S WELL OVER 20:1. ONCE BURST OF
HEAVIER SNOW SLIDES ACROSS CWA WITH THE ARCTIC FRONT...EXPECT
PERIOD OF HEAVY NNW FLOW LK EFFECT THROUGH THE DAY. NNW WINDS IN
BLYR AND A STILL OPEN LK NIPEGON COULD LEAD TO HEAVIEST SNOW
SHOWERS SETTING UP BTWN MQT AND MUNISING. SNOW TOTALS LATER
FRIDAY NIGHT THROUGH SATURDAY WILL BE AT LEAST ADVY ALONG MUCH OF
LK SUPERIOR WITH SOME AREAS SEEING WARNING AMOUNTS OF 10 INCHES IN
12 HOURS. STRONG WINDS WITH THE FLUFFIER SNOW WILL RESULT IN AREAS
OF BLOWING SNOW/REDUCED VSBY. PRETTY CONFIDENT HEADLINES FOR THIS
EVENT WILL BE COMING IN THE NEXT COUPLE DAYS. FOR NOW...WILL KEEP
GRAPHICAL MENTION IN THE EHWO AND A MENTION IN HAZARDOUS WEATHER
OUTLOOK.
DEPARTING DEEPER MOISTURE AND LOWERING INVERSIONS/INCREASING
ANTICYCLONIC FLOW WITH ARRIVAL OF SFC RIDGE WILL PUT A CRIMP IN LK
EFFECT BY SATURDAY NIGHT. STILL MAY SEE ADVY AMOUNTS OVER THE EAST
THOUGH AS OVERWATER INSTABILITY REMAINS MORE THAN SUFFICIENT AND
THERE WILL LIKELY BE SOME UPTICK OF LOW-LEVEL CONVERGENCE AS WINDS
BACK MORE WESTERLY OVR LAND WITH THE ARRIVAL OF THE SFC RIDGE TOWARD
WESTERN UPR MICHIGAN. TRANSITION ON SUNDAY AS SFC RIDGE CROSSES.
COULD BE TRICKY SINCE COLD AIR LINGERS AND WINDS BECOME FAVORABLE
FOR LK EFFECT OFF LK MICHIGAN. INITIALLY WINDS HAVE ENOUGH SOUTHERLY
COMPONENT TO INCLUDE HIGHER POPS OVER MUCH OF SCHOOLCRAFT AND LUCE
COUNTIES...THEN EVENTUALLY ON SUNDAY NIGHT THE WINDS HAVE ENOUGH OF
A WESTERLY COMPONENT TO PUSH MOST OF MORE SIGNIFICANT LK EFFECT
FARTHER TO THE EAST. HOWEVER...CLIPPER LOW PRESSURE SYSTEM DROPPING
TO NORTH OF LK SUPERIOR WILL SPREAD ADDITIONAL SNOW ACROSS NORTHERN
AND EASTERN UPR MICHIGAN.
ANOTHER BOUT OF COLD AIR AND LK EFFECT LIKELY IN WAKE OF THAT
CLIPPER TUESDAY AND WEDNESDAY. ONCE AGAIN AREAS FAVORED BY NNW
FLOW OVER CNTRL AND EASTERN CWA WILL SEE THE BEST SHOT AT HEAVIER
SNOW. PLENTY OF TIME TO ASSESS THIS POTENTIAL ONCE WE GET PAST THE
WEEKEND LK EFFECT SNOWS. PEEK AHEAD TO THANKSGIVING SHOWS THE COLD
AIR PERSISTS WHILE LINGERING LK EFFECT RUNS ITS COURSE. SO...AT
LEAST AT THIS POINT...NO LARGE SCALE LOW PRESSURE SYSTEM/WIDESPREAD
SNOW EXPECTED FOR THE THANKSGIVING TIME FRAME. PROBABLY GOES WITHOUT
SAYING...BUT OBVIOUSLY THERE IS PLENTY OF TIME FOR THIS TO CHANGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1251 PM EST WED NOV 20 2013
MAIN IMPACTS AT ALL SITES WILL DEVELOP THROUGH THIS EVENING AS
PRECIP SPREADS OVER THE AREA. EXCEPT ELEVATED -SHRA TO FALL THROUGH
A DRY NEAR-SFC LAYER AND CHANGE TO -SN THIS EVENING...MAINLY AT IWD
AND CMX. FORECAST GUIDANCE HAS BEEN CONSISTENTLY UNCLEAR AS TO HOW
HEAVY -SN WILL BE. EXPECTATIONS ARE THAT -SN AT CMX AND IWD WILL
ONLY LOWER VIS AND CIGS TO LOW-END MVFR. THOUGH MOISTURE WILL BE
INCREASING AT ALL SITES AS PRECIP PASSES THROUGH...DOWNSLOPING WITH
GENERALLY SOUTH WINDS SHOULD KEEP CIGS MVFR THROUGH THE EVENING. IFR
CIGS SHOULD THEN DEVELOP AT IWD AND SAW OVERNIGHT AS WINDS BECOME
MORE SSW AND LOW-LEVEL MOISTURE INCREASES BEHIND THE PRECIP. ALL
SITES SHOULD SEE SOME CIG IMPROVEMENT THURSDAY MORNING WITH SOME
LOW-LEVEL DRYING AND MINIMAL LIFT. THE EXCEPTION WILL BE CMX...WHERE
AN APPROACHING COLD FRONT WILL BRING NW WINDS AND INCREASINGLY
UPSLOPE FLOW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 416 PM EST WED NOV 20 2013
SOUTHERLY WINDS OF UP TO 30 KNOTS FOR EASTERN LAKE SUPERIOR LATE
THIS AFTERNOON WILL DIMINISH TO LESS THAN 20 KNOTS BY THURSDAY
MORNING AS A COLD FRONT NEARS WESTERN LAKE SUPERIOR. THE COLD FRONT
IS EXPECTED TO CROSS LAKE SUPERIOR BEGINNING FAR WEST MID-THURSDAY
MORNING...AND REACHING THE FAR EAST THURSDAY EVENING. WINDS WILL
QUICKLY VEER TO THE NW AROUND 30 KNOTS FOR MUCH OF LAKE SUPERIOR
BEHIND THE FRONT. EXPECT THESE WINDS TO CONTINUE THROUGH THURSDAY
EVENING BEFORE DIMINISHING ON FRIDAY.
STRONG HIGH PRESSURE BUILDING ACROSS CENTRAL CANADA WILL BEGIN TO
IMPINGE ON LOW PRESSURE DEVELOPING OVER THE LOWER GREAT LAKES FRIDAY
AFTERNOON AND EVENING. WEST WINDS OF 20-30 KNOTS ACROSS WESTERN LAKE
SUPERIOR FRIDAY EVENING WILL BECOME NW GALES TO 35 KNOTS WEST TO NW
GALES TO 45 KNOTS EAST SATURDAY MORNING. THE WINDS WILL GRADUALLY
DIMINISH TO UNDER 20 KNOTS BY SUNDAY MORNING. WITH ARCTIC AIR MOVING
OVER THE LAKE...THERE IS A POTENTIAL FOR WIDESPREAD FREEZING SPRAY
SATURDAY AND SATURDAY NIGHT. THEN AN APPROACHING LOW PRESSURE FROM
CANADA WILL BACK WINDS SW TO 20-30 KNOTS BY MONDAY MORNING. ANOTHER
COLD FRONT WILL FOLLOW MONDAY AFTERNOON WITH 20-30 KNOTS NW WINDS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM LATE FRIDAY NIGHT THROUGH LATE SATURDAY NIGHT
FOR LSZ264>267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KLUBER
LONG TERM...JLA
AVIATION...KLUBER
MARINE...KLUBER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1253 PM EST WED NOV 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 441 AM EST WED NOV 20 2013
UPPER MICHIGAN IS BETWEEN SURFACE FEATURES THIS MORNING...WITH A
1036MB HIGH MOVING EAST FROM THE LOWER GREAT LAKES AND A 996MB LOW
BETWEEN LAKE WINNIPEG AND HUDSON BAY. A COLD FRONT STRETCHES
SOUTHWEST FROM THIS LOW THROUGH NORTHWEST MINNESOTA AND THROUGH THE
DAKOTAS. THE PRESSURE GRADIENT BETWEEN THESE THREE FEATURES HAS
LEAD TO BREEZY CONDITIONS EARLY THIS MORNING...ESPECIALLY OVER LAKE
SUPERIOR AND THE DOWNSLOPE AREAS OF CENTRAL UPPER MICHIGAN. KMQT VAD
WIND DATA SHOWS 45KT WINDS AT 2KFT AND THAT MATCHES UP WELL WITH
THE 46KT GUST RECORDED AT STANNARD ROCK LAST HOUR. THE REST OF
THE UPPER MICHIGAN HAS BEEN GUSTING TO 15-30KTS OVER THE LAST
COUPLE OF HOURS. EXPECT THE GUSTY WINDS TO CONTINUE THROUGH A GOOD
PORTION OF THE DAY TODAY AT VALUES SIMILAR TO WHAT WAS SEEN
OVERNIGHT. WITH A LITTLE BETTER MIXING...THE HIGHER GUSTS WILL
LIKELY BE MORE WIDESPREAD THAN THE SPORADIC VALUES SEEN OVERNIGHT.
FORTUNATELY...THE 40-50KT 925MB WINDS SHOULD STAY ABOVE THE SURFACE
DUE TO THE INVERSION INDICATED JUST BELOW THAT LEVEL. WITH THE
GRADIENT WEAKENING OVER THE AREA FROM WEST TO EAST THIS AFTERNOON
AND EVENING...ALONG THE WITH PRESSURE FALLS NORTH OF LAKE SUPERIOR
EXITING THIS MORNING...EXPECT A DIMINISHING TREND IN THE WINDS THIS
AFTERNOON/EVENING.
THE REST OF THE WEATHER FORECAST WILL DEPEND ON TWO FEATURES...THE
COLD FRONT TO THE WEST OF THE AREA THAT WILL MOVE THROUGH TONIGHT
AND THURSDAY AND A SHORTWAVE CURRENTLY PULLING OUT OF COLORADO.
THIS SHORTWAVE WILL SLIDE NORTHEAST TODAY AND ACROSS UPPER MICHIGAN
THIS EVENING AND EARLY OVERNIGHT HOURS. AS THIS OCCURS...THE COLD
FRONT WILL BE MOVING ACROSS WESTERN LAKE SUPERIOR. MID LEVEL
SOUTHWESTERLY FLOW AHEAD OF THIS WAVE HAS PRODUCED WIDESPREAD MID
CLOUDS FROM THE CENTRAL PLAINS INTO ONTARIO AND EXPECT THAT TO
CONTINUE THROUGH MUCH OF THE DAY TODAY. RADAR HAS BLOSSOMED OVER THE
LAST COUPLE OF HOURS FROM LAKE SUPERIOR THROUGH EASTERN IOWA AND ALL
ASSOCIATED WITH THE MID CLOUDS. THUS...THERE IS PROBABLY SOME PRECIP
FALLING OUT OF THOSE CLOUDS...BUT THE DRIER AIR IS EVAPORATING THE
PRECIP BEFORE REACHING THE SURFACE (NO OBS INDICATING RAIN). MODELS
INDICATING THERE COULD BE A FEW SHOWERS OVER CENTRAL LAKE SUPERIOR
AND THE KEWEENAW TODAY...BUT HAVE MAINLY LEFT AS SLIGHT CHANCES
SINCE THE DRIER LOW LEVELS WILL LIKELY EVAPORATE MUCH OF THE PRECIP.
THERE WAS A BRIEF PERIOD OF 2-3KFT RETURNS JUST NORTHEAST OF
MARQUETTE (WHICH HAD BEEN HINTED AT IN THE ECMWF AND A COUPLE OTHER
MODELS OVER THE LAST COUPLE OF DAYS)...BUT IT QUICKLY DISSIPATED.
THE DRY AIR INDICATED OVER THE AREA ON INITIAL RAP SOUNDINGS
(DEWPOINT DEPRESSIONS OF 15-20C BETWEEN 900-800MB) WILL CONTINUE
THROUGH MUCH OF THE DAY AND WILL PLAY A ROLE IN THE PRECIP TYPE
FORECAST FOR LATE THIS AFTERNOON AND TONIGHT.
MODELS SEEM TO HAVE DECENT AGREEMENT WITH THE PRECIPITATION TIMING
AND LOCATION FOR TONIGHT...AS THE LOWER LEVELS MOISTEN FROM TOP DOWN
WITH THE ARRIVAL OF THE SHORTWAVE. BEST FORCING FROM THE
SHORTWAVE...ALONG WITH 700-500 Q-VECTOR CONVERGENCE AND ISENTROPIC
ASCENT ON 280-290K SFCS TRACKS ACROSS THE MUCH OF THE CWA...WITH THE
GREATEST FOCUS OVER THE CENTRAL AND EAST THIS EVENING. THINK THAT
LAYER IS WHERE MUCH OF THE PRECIPITATION WILL INITIATE LATE THIS
AFTERNOON OVER NORTHERN WISCONSIN AND THEN LIFT NORTHEAST INTO UPPER
MICHIGAN. LOOKING UPSTREAM...THERE IS NOT MUCH FOR LOWER LEVEL
MOISTURE...AND THINK THAT IT WILL TAKE A LITTLE BIT FOR THE
PRECIPITATION TO COOL AND MOISTEN THE LOWER LEVELS. THIS CAN
SOMEWHAT BE SEEN ON MODEL QPF FIELDS WITH THEIR BLOTCHY NATURE AT
TIMES ALONG WITH 280-285K THETA-E SURFACES COND PRESS DEF VALUES
INDICATING SIGNIFICANT LIFT NEEDED TO MOISTEN THE CENTRAL/EASTERN
CWA DURING THE LATE AFTERNOON/EVENING. IN ADDITION...THE HIGHER
RESOLUTION RUNS ARE ALSO SHOWING SOME OF THE DOWNSLOPE FLOW OVER THE
NORTH CENTRAL EATING AWAY AT QPF AMOUNTS. THEREFORE...ALTHOUGH THE
CONFIDENCE IS HIGH ON TIMING/LOCATION...QPF AMOUNTS ARE MORE
UNCERTAIN DUE TO THE DRY AIR AND WILL LIKELY COME DOWN TO HOW
QUICKLY THINGS MOISTEN. THINK WE WILL GET PRECIPITATION...BUT
WONDERING IF THE DRY AIR WILL LOWER QPF AMOUNTS MORE THAN SOME OF
THE MODELS ARE INDICATING. ALSO...THERE ARE SOME HINTS ON THE 06Z
MODEL RUNS THAT THE MAIN PIECE OF SHORTWAVE ENERGY (NOTED BY THE PV
ANOMALY) WILL SLIDE SOUTH OF THE AREA (THROUGH CENTRAL WISCONSIN
AND LOWER MICHIGAN). AS THE SHORTWAVE SLIDES EAST OVERNIGHT...HAVE
DIMINISHED POPS FROM SOUTHWEST TO NORTHEAST.
AS FOR PRECIP TYPE...HAVE FOLLOWED THE WETBULB0 VALUES FOR MUCH OF
THE FORECAST...AS IT HANDLES WHERE THE THERMAL FIELDS WILL GO AS
EVAPORATIVE COOLING AND MOISTENING OCCURS. THIS LEADS TO MUCH OF
THE INTERIOR (HIGHER TERRAIN) WEST/CENTRAL TO QUICKLY TRANSITION TO
OR START AS SNOW. WITH THE UNCERTAINTY ON QPF...HAVE WENT WITH A
MIDDLE GROUND OF 0.1-0.18IN OF QPF OVER THE CENTRAL CWA WITH
LOWER AMOUNTS WEST AND EAST. WITH THAT AREA SHOWING MAINLY
SNOW...WOULD EXPECT AROUND AN INCH OF ACCUMULATION DURING THE
EVENING HOURS. OF COURSE...IF THE HIGHER QPF SHOWN IN THE 00Z
NAM/GFS IS CORRECT...COULD SEE AMOUNTS AROUND OR A LITTLE OVER 2
INCHES AROUND IRON/DICKINSON COUNTY BUT NOT COMPLETELY BUYING THEIR
QUICK 0.2-0.3IN OF QPF LATE THIS AFTERNOON. DID CONTINUE RAIN/SNOW
IN THE DOWNSLOPE WARMED AREAS NEAR LAKE SUPERIOR AND ALSO OVER THE
EAST. AS DEEPER MOISTURE PULLS OUT OF THE WEST OVERNIGHT...MUCH OF
THE REMAINING CLOUD ENDS UP BEING WARMER THAN -5C. THUS...IF ANY
PRECIPITATION DOES OCCUR...WOULD EXPECT IT TO BE AS FREEZING
DRIZZLE. PREVIOUS SHIFT HAD A GOOD HANDLE ON THIS IDEA AND HAVE
ONLY MADE MINOR ADJUSTMENTS TO PUSH IT A LITTLE TO THE WEST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 513 AM EST WED NOV 20 2013
ALTHOUGH A FAIRLY ACTIVE PATTERN WILL BE THE RULE THRU THE LONG
TERM...NO SIGNIFICANT PCPN EVENTS ARE ANTICIPATED AS NW FLOW WILL
BECOME THE PREVAILING REGIME FROM THIS WEEKEND THRU AT LEAST THE
MIDDLE OF NEXT WEEK. ACTIVE PATTERN WILL COME IN THE FORM OF A
NUMBER OF SHORTWAVES PRODUCING MOSTLY LIGHT PCPN...THOUGH LAKE
SUPERIOR WILL PROVIDE ENHANCEMENT. THE NW FLOW REGIME WILL SET IN
THIS WEEKEND AS A MEAN RIDGE DEVELOPS ALONG THE W COAST WITH
DOWNSTREAM TROF GENERALLY FROM THE MISSISSIPPI VALLEY TO THE E
COAST. INITIAL SURGE OF COLD AIR THIS WEEKEND ASSOCIATED WITH
DEEPENING TROF WILL BE THE COLDEST OF THE SEASON SO FAR. SOURCE
REGION OF THE AIR MASS IS THE YUKON WHERE A NUMBER OF SITES HAVE
BEEN RECORDING TEMPS IN THE -25 TO -35F RANGE OVER THE LAST DAY OR
SO. SHOT OF ARCTIC AIR WILL BE BRIEF AS TROF TEMPORARILY DEAMPLIFIES
LATE WEEKEND AHEAD OF THE NEXT SHORTWAVE THAT DROPS SE. THAT WAVE
WILL THEN REAMPLIFY THE TROF EARLY NEXT WEEK...BRINGING MORE COLD
AIR INTO THE AREA...THOUGH PROBABLY NOT QUITE AS COLD AS THE AIR
MASS THIS WEEKEND. FARTHER DOWN THE LINE INTO LATE NEXT WEEK...THERE
ARE SOME HINTS THAT THE FLOW PATTERN WILL DEAMPLIFY SOME...
SUGGESTING NO SIGNIFICANT PCPN EVENTS ALONG WITH TEMPS RETURNING TO
AROUND NORMAL.
BEGINNING THU...SHORTWAVE LEADING TO PCPN TONIGHT WILL BE EXITING TO
THE NE. MAY SEE LINGERING PCPN OVER THE E IN THE MORNING AND ALSO IN
THE UPSLOPE AREAS OF THE W. WITH DEEPER MOISTURE PULLING OUT...THERE
COULD BE A LITTLE DZ/FZDZ OVER THE FAR W EARLY...THOUGH THERE IS A
FAIR AMOUNT OF UNCERTAINTY IN HOW MUCH DRYING OCCURS ALOFT.
OTHERWISE...A COLD FRONT WILL BE MOVING ACROSS THE FCST AREA THU.
CAA IS NOT ESPECIALLY STRONG...SO THERE SHOULD STILL BE SOME TEMP
RISE OVER THE W IN THE MORNING BEFORE TEMPS BEGIN FALLING IN THE
AFTN. TEMPS OVER THE E SHOULD RISE TO THE LWR 40S UNDER DELAYED CAA.
IN THE AFTN...WELL BEHIND SFC COLD FRONT...IT APPEARS A BAND OF -SN
MAY ORGANIZE ACROSS ROUGHLY THE W HALF OF THE FCST AREA WITHIN A
ZONE OF LOW/MID LEVEL FRONTOGENESIS UNDERNEATH RIGHT ENTRANCE OF
UPPER JET FROM THE NRN PLAINS TO HUDSON BAY AND LEFT EXIT OF JET
EXTENDING FROM THE SW STATES TO THE MIDWEST.
WITH STRENGTHENING FRONTOGENESIS/UPPER DIVERGENCE TRANSLATING ACROSS
THE UPPER LAKES THU NIGHT AHEAD OF NEXT SHORTWAVE SWINGING ACROSS
THE NRN PLAINS/UPPER MISSISSIPPI VALLEY...EXPECT A PERIOD OF PCPN
ACROSS THE FCST AREA. PER FCST SOUNDINGS AND WETBULB ZERO HEIGHTS
ABOVE 1500FT...PCPN SHOULD START AS MAINLY RA OVER THE E BEFORE IT
CHANGES TO SNOW. SNOW WILL BE THE RULE OVER THE W. WITH NOT MUCH IN
THE WAY OF ISENTROPIC ASCENT NOTED...PCPN SHOULD REMAIN ON THE LIGHT
SIDE. CONSENSUS OF MODEL GUIDANCE SHOWS PCPN AMOUNTS IN THE 0.10 TO
0.20 INCH RANGE. WITH A HIGH DGZ GENERALLY BTWN 11K AND 15KFT AND
MOSTLY ABOVE THE BEST UPWARD MOTION...SNOW TO WATER RATIOS WILL BE
ON THE LOW SIDE...PROBABLY 10-15 TO 1. SO...RIGHT NOW IT LOOKS LIKE
A GENERAL 1-2 TO MAYBE 3 INCH SNOW ACCUMULATION ACROSS THE AREA THU
NIGHT INTO FRI MORNING. WITH 850MB TEMPS FALLING TO -8 TO -10C
DURING THE PERIOD OF -SN...THERE WILL BE SOME LAKE ENHANCEMENT UNDER
NRLY LOW-LEVEL FLOW...AND THAT SHOULD LEAD TO GREATEST ACCUMULATIONS
OVER THE HIGHER TERRAIN NEAR LAKE SUPERIOR. HOWEVER...WITH HIGH
DGZ...ENHANCEMENT SHOULDN`T ADD MUCH TO SYNOPTIC SNOW AMOUNTS.
-SN WILL END FROM W TO E FRI IN THE WAKE OF SHORTWAVE...THOUGH A FEW
-SHSN MAY LINGER THRU THE AFTN OFF LAKE SUPERIOR OVER THE ERN FCST
AREA UNDER 850MB TEMPS AROUND -10C.
ATTENTION THEN TURNS TO THE NEXT SHORTWAVE DROPPING SE AND LEADING
TO THE AFOREMENTIONED WEEKEND TROF AMPLIFICATION AND ARCTIC AIR.
BRIEF PERIOD OF VIGOROUS DEEP LAYER FORCING PER QVECTORS OVERTOP
MORE THAN ADEQUATE OVERWATER INSTABILITY WILL YIELD THE TYPICAL
BURST OF MDT/HVY LAKE ENHANCED SNOW SWEEPING OFF LAKE SUPERIOR ALONG
THE ASSOCIATED ARCTIC COLD FRONT FRI NIGHT/EARLY SAT. IN THE WAKE OF
THE FRONT...850MB TEMPS FALL TO -18 TO -21C SAT...RESULTING IN
VIGOROUS NW/NNW FLOW ORIENTED LAKE CONVECTION. CONSENSUS OF GUIDANCE
IS FOR DEEP MOISTURE TO LINGER LONGEST OVER THE ERN FCST AREA. GFS
FCST SOUNDINGS SHOW MOISTURE UP TO 10KFT OR SO. COMBINED WITH LAKE
NIPIGON PRECONDITIONING AND DGZ LIKELY WELL CENTERED WITHIN THE
UPWARD MOTION ZONE...A SIGNIFICANT LAKE EFFECT EVENT LOOKS TO BE
SETTING UP FOR ALGER/LUCE/NRN SCHOOLCRAFT. GUSTY WINDS OF 30-40MPH
WILL ALSO LEAD TO INCREASING BLSN ISSUES AS SNOW ACCUMULATES. OUT
W...SHORTER FETCH...LOWER DGZ AND MOISTURE EXTENDING TO AROUND 6KFT
WILL WORK TO LIMIT SNOW ACCUMULATIONS COMPARED TO THE E.
HOWEVER...TERRAIN ENHANCEMENT PLAYS A BIGGER ROLE OVER THE W THAN
THE E...AND BOUNDARY LAYER WINDS LOOK SUPPORTIVE OF THE TYPICAL
ENHANCED CONVERGENCE AREA FOR GOGEBIC/ONTONAGON INTO CNTRL HOUGHTON
COUNTIES. AS A RESULT...SIGNIFICANT SNOW MAY ALSO OCCUR IN THAT AREA
AS WELL. ANTICIPATE AT LEAST SOLID ADVY FOR THE KEWEENAW...AND THERE
MAY BE A PERIOD WITH WINDS HAVING ENOUGH NRLY COMPONENT FOR
BARAGA/MARQUETTE COUNTIES TO SEE ADVY AMOUNTS AS WELL. ALL OF THESE
DETAILS WILL BE SORTED OUT ONCE THE EVENT MOVES INTO THE SHORT TERM.
OTHERWISE...IT WILL SEEM LIKE MID WINTER CONDITIONS ACROSS THE AREA
SAT/SAT NIGHT WITH GUSTY WINDS/COLD AIR AND WIND CHILLS FALLING TO
ZERO OR BLO.
LES WILL END SUN FROM W TO E AS WINDS BACK TO THE SW AHEAD OF THE
NEXT SHORTWAVE DIVING SE THRU SCNTRL CANADA. HOWEVER...DEVELOPING
STRONG WAA PATTERN MAY LEAD TO AN AREA OF -SN STREAKING SE INTO THE
AREA SUN AFTN/NIGHT. ANOTHER PERIOD OF LAKE EFFECT SNOW SHOULD SET
UP BEHIND THIS SYSTEM EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1251 PM EST WED NOV 20 2013
MAIN IMPACTS AT ALL SITES WILL DEVELOP THROUGH THIS EVENING AS
PRECIP SPREADS OVER THE AREA. EXCEPT ELEVATED -SHRA TO FALL THROUGH
A DRY NEAR-SFC LAYER AND CHANGE TO -SN THIS EVENING...MAINLY AT IWD
AND CMX. FORECAST GUIDANCE HAS BEEN CONSISTENTLY UNCLEAR AS TO HOW
HEAVY -SN WILL BE. EXPECTATIONS ARE THAT -SN AT CMX AND IWD WILL
ONLY LOWER VIS AND CIGS TO LOW-END MVFR. THOUGH MOISTURE WILL BE
INCREASING AT ALL SITES AS PRECIP PASSES THROUGH...DOWNSLOPING WITH
GENERALLY SOUTH WINDS SHOULD KEEP CIGS MVFR THROUGH THE EVENING. IFR
CIGS SHOULD THEN DEVELOP AT IWD AND SAW OVERNIGHT AS WINDS BECOME
MORE SSW AND LOW-LEVEL MOISTURE INCREASES BEHIND THE PRECIP. ALL
SITES SHOULD SEE SOME CIG IMPROVEMENT THURSDAY MORNING WITH SOME
LOW-LEVEL DRYING AND MINIMAL LIFT. THE EXCEPTION WILL BE CMX...WHERE
AN APPROACHING COLD FRONT WILL BRING NW WINDS AND INCREASINGLY
UPSLOPE FLOW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 441 AM EST WED NOV 20 2013
SOUTHERLY GALES TO 35-40KTS WILL CONTINUE THROUGH MOST OF THE
DAYLIGHT HOURS TODAY OVER EASTERN LAKE SUPERIOR AHEAD OF
A COLD FRONT MOVING THROUGH MINNESOTA TODAY. TIMING OF THE ONGOING
GALE WARNING LOOKS GOOD AND WON/T MAKE ANY CHANGES AT THIS TIME. AS
THE FRONT NEARS LATE THIS AFTERNOON AND EVENING...EXPECT THE WINDS
TO DIMINISH FROM WEST TO EAST THROUGH THE NIGHT. THE FRONT WILL
SLOWLY MOVE EAST ACROSS LAKE SUPERIOR TONIGHT AND THURSDAY...WHICH
WILL SHIFT THE WINDS TO THE NORTHWEST 20-30KTS ON THURSDAY. A HIGH
PRESSURE RIDGE MOVING OVER THE LAKE ON THURSDAY NIGHT WILL SHIFT
WINDS TO THE NORTH AND DIMINISH THEM THURSDAY NIGHT THROUGH FRIDAY.
A WEAK LOW TRACKING FROM THE SOUTHERN PLAINS THROUGH THE LOWER GREAT
LAKES ON FRIDAY WILL KEEP THE NORTHERLY WINDS IN PLACE DUE TO A WEAK
TROUGH SETTING UP OVER UPPER MICHIGAN. THIS TROUGH WILL DIVE SOUTH
ON FRIDAY NIGHT AND WHEN COMBINED WITH A STRONG HIGH BUILDING INTO
THE NORTHERN PLAINS...EXPECT NORTHWESTERLY WINDS TO INCREASE TO
GALES TO 35-40KTS ON SATURDAY AND CONTINUE INTO SATURDAY NIGHT. THIS
EVENT WILL BE SHORT LIVED...AS A RIDGE FROM THAT STRONG HIGH SHIFTS
EAST OVER THE UPPER GREAT LAKES ON SUNDAY AND BRINGS WINDS BELOW
25KTS BY SUNDAY AFTERNOON.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LSZ266-267.
GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ249>251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...KLUBER
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
644 AM EST WED NOV 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 441 AM EST WED NOV 20 2013
UPPER MICHIGAN IS BETWEEN SURFACE FEATURES THIS MORNING...WITH A
1036MB HIGH MOVING EAST FROM THE LOWER GREAT LAKES AND A 996MB LOW
BETWEEN LAKE WINNIPEG AND HUDSON BAY. A COLD FRONT STRETCHES
SOUTHWEST FROM THIS LOW THROUGH NORTHWEST MINNESOTA AND THROUGH THE
DAKOTAS. THE PRESSURE GRADIENT BETWEEN THESE THREE FEATURES HAS
LEAD TO BREEZY CONDITIONS EARLY THIS MORNING...ESPECIALLY OVER LAKE
SUPERIOR AND THE DOWNSLOPE AREAS OF CENTRAL UPPER MICHIGAN. KMQT VAD
WIND DATA SHOWS 45KT WINDS AT 2KFT AND THAT MATCHES UP WELL WITH
THE 46KT GUST RECORDED AT STANNARD ROCK LAST HOUR. THE REST OF
THE UPPER MICHIGAN HAS BEEN GUSTING TO 15-30KTS OVER THE LAST
COUPLE OF HOURS. EXPECT THE GUSTY WINDS TO CONTINUE THROUGH A GOOD
PORTION OF THE DAY TODAY AT VALUES SIMILAR TO WHAT WAS SEEN
OVERNIGHT. WITH A LITTLE BETTER MIXING...THE HIGHER GUSTS WILL
LIKELY BE MORE WIDESPREAD THAN THE SPORADIC VALUES SEEN OVERNIGHT.
FORTUNATELY...THE 40-50KT 925MB WINDS SHOULD STAY ABOVE THE SURFACE
DUE TO THE INVERSION INDICATED JUST BELOW THAT LEVEL. WITH THE
GRADIENT WEAKENING OVER THE AREA FROM WEST TO EAST THIS AFTERNOON
AND EVENING...ALONG THE WITH PRESSURE FALLS NORTH OF LAKE SUPERIOR
EXITING THIS MORNING...EXPECT A DIMINISHING TREND IN THE WINDS THIS
AFTERNOON/EVENING.
THE REST OF THE WEATHER FORECAST WILL DEPEND ON TWO FEATURES...THE
COLD FRONT TO THE WEST OF THE AREA THAT WILL MOVE THROUGH TONIGHT
AND THURSDAY AND A SHORTWAVE CURRENTLY PULLING OUT OF COLORADO.
THIS SHORTWAVE WILL SLIDE NORTHEAST TODAY AND ACROSS UPPER MICHIGAN
THIS EVENING AND EARLY OVERNIGHT HOURS. AS THIS OCCURS...THE COLD
FRONT WILL BE MOVING ACROSS WESTERN LAKE SUPERIOR. MID LEVEL
SOUTHWESTERLY FLOW AHEAD OF THIS WAVE HAS PRODUCED WIDESPREAD MID
CLOUDS FROM THE CENTRAL PLAINS INTO ONTARIO AND EXPECT THAT TO
CONTINUE THROUGH MUCH OF THE DAY TODAY. RADAR HAS BLOSSOMED OVER THE
LAST COUPLE OF HOURS FROM LAKE SUPERIOR THROUGH EASTERN IOWA AND ALL
ASSOCIATED WITH THE MID CLOUDS. THUS...THERE IS PROBABLY SOME PRECIP
FALLING OUT OF THOSE CLOUDS...BUT THE DRIER AIR IS EVAPORATING THE
PRECIP BEFORE REACHING THE SURFACE (NO OBS INDICATING RAIN). MODELS
INDICATING THERE COULD BE A FEW SHOWERS OVER CENTRAL LAKE SUPERIOR
AND THE KEWEENAW TODAY...BUT HAVE MAINLY LEFT AS SLIGHT CHANCES
SINCE THE DRIER LOW LEVELS WILL LIKELY EVAPORATE MUCH OF THE PRECIP.
THERE WAS A BRIEF PERIOD OF 2-3KFT RETURNS JUST NORTHEAST OF
MARQUETTE (WHICH HAD BEEN HINTED AT IN THE ECMWF AND A COUPLE OTHER
MODELS OVER THE LAST COUPLE OF DAYS)...BUT IT QUICKLY DISSIPATED.
THE DRY AIR INDICATED OVER THE AREA ON INITIAL RAP SOUNDINGS
(DEWPOINT DEPRESSIONS OF 15-20C BETWEEN 900-800MB) WILL CONTINUE
THROUGH MUCH OF THE DAY AND WILL PLAY A ROLE IN THE PRECIP TYPE
FORECAST FOR LATE THIS AFTERNOON AND TONIGHT.
MODELS SEEM TO HAVE DECENT AGREEMENT WITH THE PRECIPITATION TIMING
AND LOCATION FOR TONIGHT...AS THE LOWER LEVELS MOISTEN FROM TOP DOWN
WITH THE ARRIVAL OF THE SHORTWAVE. BEST FORCING FROM THE
SHORTWAVE...ALONG WITH 700-500 Q-VECTOR CONVERGENCE AND ISENTROPIC
ASCENT ON 280-290K SFCS TRACKS ACROSS THE MUCH OF THE CWA...WITH THE
GREATEST FOCUS OVER THE CENTRAL AND EAST THIS EVENING. THINK THAT
LAYER IS WHERE MUCH OF THE PRECIPITATION WILL INITIATE LATE THIS
AFTERNOON OVER NORTHERN WISCONSIN AND THEN LIFT NORTHEAST INTO UPPER
MICHIGAN. LOOKING UPSTREAM...THERE IS NOT MUCH FOR LOWER LEVEL
MOISTURE...AND THINK THAT IT WILL TAKE A LITTLE BIT FOR THE
PRECIPITATION TO COOL AND MOISTEN THE LOWER LEVELS. THIS CAN
SOMEWHAT BE SEEN ON MODEL QPF FIELDS WITH THEIR BLOTCHY NATURE AT
TIMES ALONG WITH 280-285K THETA-E SURFACES COND PRESS DEF VALUES
INDICATING SIGNIFICANT LIFT NEEDED TO MOISTEN THE CENTRAL/EASTERN
CWA DURING THE LATE AFTERNOON/EVENING. IN ADDITION...THE HIGHER
RESOLUTION RUNS ARE ALSO SHOWING SOME OF THE DOWNSLOPE FLOW OVER THE
NORTH CENTRAL EATING AWAY AT QPF AMOUNTS. THEREFORE...ALTHOUGH THE
CONFIDENCE IS HIGH ON TIMING/LOCATION...QPF AMOUNTS ARE MORE
UNCERTAIN DUE TO THE DRY AIR AND WILL LIKELY COME DOWN TO HOW
QUICKLY THINGS MOISTEN. THINK WE WILL GET PRECIPITATION...BUT
WONDERING IF THE DRY AIR WILL LOWER QPF AMOUNTS MORE THAN SOME OF
THE MODELS ARE INDICATING. ALSO...THERE ARE SOME HINTS ON THE 06Z
MODEL RUNS THAT THE MAIN PIECE OF SHORTWAVE ENERGY (NOTED BY THE PV
ANOMALY) WILL SLIDE SOUTH OF THE AREA (THROUGH CENTRAL WISCONSIN
AND LOWER MICHIGAN). AS THE SHORTWAVE SLIDES EAST OVERNIGHT...HAVE
DIMINISHED POPS FROM SOUTHWEST TO NORTHEAST.
AS FOR PRECIP TYPE...HAVE FOLLOWED THE WETBULB0 VALUES FOR MUCH OF
THE FORECAST...AS IT HANDLES WHERE THE THERMAL FIELDS WILL GO AS
EVAPORATIVE COOLING AND MOISTENING OCCURS. THIS LEADS TO MUCH OF
THE INTERIOR (HIGHER TERRAIN) WEST/CENTRAL TO QUICKLY TRANSITION TO
OR START AS SNOW. WITH THE UNCERTAINTY ON QPF...HAVE WENT WITH A
MIDDLE GROUND OF 0.1-0.18IN OF QPF OVER THE CENTRAL CWA WITH
LOWER AMOUNTS WEST AND EAST. WITH THAT AREA SHOWING MAINLY
SNOW...WOULD EXPECT AROUND AN INCH OF ACCUMULATION DURING THE
EVENING HOURS. OF COURSE...IF THE HIGHER QPF SHOWN IN THE 00Z
NAM/GFS IS CORRECT...COULD SEE AMOUNTS AROUND OR A LITTLE OVER 2
INCHES AROUND IRON/DICKINSON COUNTY BUT NOT COMPLETELY BUYING THEIR
QUICK 0.2-0.3IN OF QPF LATE THIS AFTERNOON. DID CONTINUE RAIN/SNOW
IN THE DOWNSLOPE WARMED AREAS NEAR LAKE SUPERIOR AND ALSO OVER THE
EAST. AS DEEPER MOISTURE PULLS OUT OF THE WEST OVERNIGHT...MUCH OF
THE REMAINING CLOUD ENDS UP BEING WARMER THAN -5C. THUS...IF ANY
PRECIPITATION DOES OCCUR...WOULD EXPECT IT TO BE AS FREEZING
DRIZZLE. PREVIOUS SHIFT HAD A GOOD HANDLE ON THIS IDEA AND HAVE
ONLY MADE MINOR ADJUSTMENTS TO PUSH IT A LITTLE TO THE WEST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 513 AM EST WED NOV 20 2013
ALTHOUGH A FAIRLY ACTIVE PATTERN WILL BE THE RULE THRU THE LONG
TERM...NO SIGNIFICANT PCPN EVENTS ARE ANTICIPATED AS NW FLOW WILL
BECOME THE PREVAILING REGIME FROM THIS WEEKEND THRU AT LEAST THE
MIDDLE OF NEXT WEEK. ACTIVE PATTERN WILL COME IN THE FORM OF A
NUMBER OF SHORTWAVES PRODUCING MOSTLY LIGHT PCPN...THOUGH LAKE
SUPERIOR WILL PROVIDE ENHANCEMENT. THE NW FLOW REGIME WILL SET IN
THIS WEEKEND AS A MEAN RIDGE DEVELOPS ALONG THE W COAST WITH
DOWNSTREAM TROF GENERALLY FROM THE MISSISSIPPI VALLEY TO THE E
COAST. INITIAL SURGE OF COLD AIR THIS WEEKEND ASSOCIATED WITH
DEEPENING TROF WILL BE THE COLDEST OF THE SEASON SO FAR. SOURCE
REGION OF THE AIR MASS IS THE YUKON WHERE A NUMBER OF SITES HAVE
BEEN RECORDING TEMPS IN THE -25 TO -35F RANGE OVER THE LAST DAY OR
SO. SHOT OF ARCTIC AIR WILL BE BRIEF AS TROF TEMPORARILY DEAMPLIFIES
LATE WEEKEND AHEAD OF THE NEXT SHORTWAVE THAT DROPS SE. THAT WAVE
WILL THEN REAMPLIFY THE TROF EARLY NEXT WEEK...BRINGING MORE COLD
AIR INTO THE AREA...THOUGH PROBABLY NOT QUITE AS COLD AS THE AIR
MASS THIS WEEKEND. FARTHER DOWN THE LINE INTO LATE NEXT WEEK...THERE
ARE SOME HINTS THAT THE FLOW PATTERN WILL DEAMPLIFY SOME...
SUGGESTING NO SIGNIFICANT PCPN EVENTS ALONG WITH TEMPS RETURNING TO
AROUND NORMAL.
BEGINNING THU...SHORTWAVE LEADING TO PCPN TONIGHT WILL BE EXITING TO
THE NE. MAY SEE LINGERING PCPN OVER THE E IN THE MORNING AND ALSO IN
THE UPSLOPE AREAS OF THE W. WITH DEEPER MOISTURE PULLING OUT...THERE
COULD BE A LITTLE DZ/FZDZ OVER THE FAR W EARLY...THOUGH THERE IS A
FAIR AMOUNT OF UNCERTAINTY IN HOW MUCH DRYING OCCURS ALOFT.
OTHERWISE...A COLD FRONT WILL BE MOVING ACROSS THE FCST AREA THU.
CAA IS NOT ESPECIALLY STRONG...SO THERE SHOULD STILL BE SOME TEMP
RISE OVER THE W IN THE MORNING BEFORE TEMPS BEGIN FALLING IN THE
AFTN. TEMPS OVER THE E SHOULD RISE TO THE LWR 40S UNDER DELAYED CAA.
IN THE AFTN...WELL BEHIND SFC COLD FRONT...IT APPEARS A BAND OF -SN
MAY ORGANIZE ACROSS ROUGHLY THE W HALF OF THE FCST AREA WITHIN A
ZONE OF LOW/MID LEVEL FRONTOGENESIS UNDERNEATH RIGHT ENTRANCE OF
UPPER JET FROM THE NRN PLAINS TO HUDSON BAY AND LEFT EXIT OF JET
EXTENDING FROM THE SW STATES TO THE MIDWEST.
WITH STRENGTHENING FRONTOGENESIS/UPPER DIVERGENCE TRANSLATING ACROSS
THE UPPER LAKES THU NIGHT AHEAD OF NEXT SHORTWAVE SWINGING ACROSS
THE NRN PLAINS/UPPER MISSISSIPPI VALLEY...EXPECT A PERIOD OF PCPN
ACROSS THE FCST AREA. PER FCST SOUNDINGS AND WETBULB ZERO HEIGHTS
ABOVE 1500FT...PCPN SHOULD START AS MAINLY RA OVER THE E BEFORE IT
CHANGES TO SNOW. SNOW WILL BE THE RULE OVER THE W. WITH NOT MUCH IN
THE WAY OF ISENTROPIC ASCENT NOTED...PCPN SHOULD REMAIN ON THE LIGHT
SIDE. CONSENSUS OF MODEL GUIDANCE SHOWS PCPN AMOUNTS IN THE 0.10 TO
0.20 INCH RANGE. WITH A HIGH DGZ GENERALLY BTWN 11K AND 15KFT AND
MOSTLY ABOVE THE BEST UPWARD MOTION...SNOW TO WATER RATIOS WILL BE
ON THE LOW SIDE...PROBABLY 10-15 TO 1. SO...RIGHT NOW IT LOOKS LIKE
A GENERAL 1-2 TO MAYBE 3 INCH SNOW ACCUMULATION ACROSS THE AREA THU
NIGHT INTO FRI MORNING. WITH 850MB TEMPS FALLING TO -8 TO -10C
DURING THE PERIOD OF -SN...THERE WILL BE SOME LAKE ENHANCEMENT UNDER
NRLY LOW-LEVEL FLOW...AND THAT SHOULD LEAD TO GREATEST ACCUMULATIONS
OVER THE HIGHER TERRAIN NEAR LAKE SUPERIOR. HOWEVER...WITH HIGH
DGZ...ENHANCEMENT SHOULDN`T ADD MUCH TO SYNOPTIC SNOW AMOUNTS.
-SN WILL END FROM W TO E FRI IN THE WAKE OF SHORTWAVE...THOUGH A FEW
-SHSN MAY LINGER THRU THE AFTN OFF LAKE SUPERIOR OVER THE ERN FCST
AREA UNDER 850MB TEMPS AROUND -10C.
ATTENTION THEN TURNS TO THE NEXT SHORTWAVE DROPPING SE AND LEADING
TO THE AFOREMENTIONED WEEKEND TROF AMPLIFICATION AND ARCTIC AIR.
BRIEF PERIOD OF VIGOROUS DEEP LAYER FORCING PER QVECTORS OVERTOP
MORE THAN ADEQUATE OVERWATER INSTABILITY WILL YIELD THE TYPICAL
BURST OF MDT/HVY LAKE ENHANCED SNOW SWEEPING OFF LAKE SUPERIOR ALONG
THE ASSOCIATED ARCTIC COLD FRONT FRI NIGHT/EARLY SAT. IN THE WAKE OF
THE FRONT...850MB TEMPS FALL TO -18 TO -21C SAT...RESULTING IN
VIGOROUS NW/NNW FLOW ORIENTED LAKE CONVECTION. CONSENSUS OF GUIDANCE
IS FOR DEEP MOISTURE TO LINGER LONGEST OVER THE ERN FCST AREA. GFS
FCST SOUNDINGS SHOW MOISTURE UP TO 10KFT OR SO. COMBINED WITH LAKE
NIPIGON PRECONDITIONING AND DGZ LIKELY WELL CENTERED WITHIN THE
UPWARD MOTION ZONE...A SIGNIFICANT LAKE EFFECT EVENT LOOKS TO BE
SETTING UP FOR ALGER/LUCE/NRN SCHOOLCRAFT. GUSTY WINDS OF 30-40MPH
WILL ALSO LEAD TO INCREASING BLSN ISSUES AS SNOW ACCUMULATES. OUT
W...SHORTER FETCH...LOWER DGZ AND MOISTURE EXTENDING TO AROUND 6KFT
WILL WORK TO LIMIT SNOW ACCUMULATIONS COMPARED TO THE E.
HOWEVER...TERRAIN ENHANCEMENT PLAYS A BIGGER ROLE OVER THE W THAN
THE E...AND BOUNDARY LAYER WINDS LOOK SUPPORTIVE OF THE TYPICAL
ENHANCED CONVERGENCE AREA FOR GOGEBIC/ONTONAGON INTO CNTRL HOUGHTON
COUNTIES. AS A RESULT...SIGNIFICANT SNOW MAY ALSO OCCUR IN THAT AREA
AS WELL. ANTICIPATE AT LEAST SOLID ADVY FOR THE KEWEENAW...AND THERE
MAY BE A PERIOD WITH WINDS HAVING ENOUGH NRLY COMPONENT FOR
BARAGA/MARQUETTE COUNTIES TO SEE ADVY AMOUNTS AS WELL. ALL OF THESE
DETAILS WILL BE SORTED OUT ONCE THE EVENT MOVES INTO THE SHORT TERM.
OTHERWISE...IT WILL SEEM LIKE MID WINTER CONDITIONS ACROSS THE AREA
SAT/SAT NIGHT WITH GUSTY WINDS/COLD AIR AND WIND CHILLS FALLING TO
ZERO OR BLO.
LES WILL END SUN FROM W TO E AS WINDS BACK TO THE SW AHEAD OF THE
NEXT SHORTWAVE DIVING SE THRU SCNTRL CANADA. HOWEVER...DEVELOPING
STRONG WAA PATTERN MAY LEAD TO AN AREA OF -SN STREAKING SE INTO THE
AREA SUN AFTN/NIGHT. ANOTHER PERIOD OF LAKE EFFECT SNOW SHOULD SET
UP BEHIND THIS SYSTEM EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 643 AM EST WED NOV 20 2013
GUSTY WINDS WILL CONTINUE AT ALL THREE SITES THROUGH MID AFTERNOON
AHEAD OF A COLD FRONT MOVING THROUGH MINNESOTA. IN ADDITION...A
SMALL POCKET OF MVFR CEILINGS IS AFFECTING PORTIONS OF
CENTRAL/EASTERN UPPER MICHIGAN THIS MORNING AND WILL LIKELY
CONTINUE OFF AN ON OVER THE FIRST COUPLE OF THE TAF PERIOD AT KSAW.
OTHERWISE...10KFT CEILINGS WILL CONTINUE TODAY AND THEN LOWER LATER
THIS AFTERNOON AHEAD OF AN APPROACHING DISTURBANCE.
THIS DISTURBANCE/SHORTWAVE WILL LEAD TO THE POTENTIAL FOR RAIN/SNOW
SHOWERS INITIALLY AND THEN QUICKLY TRANSITIONING TO ALL SNOW.
THERE IS SOME UNCERTAINTY ON THE EXACT LOCATION OF THE HEAVIEST
SHOWERS...BUT CURRENT THINKING IS THAT IT WILL BRUSH KIWD/KCMX AND
LARGELY AFFECT KSAW. THEREFORE...HAVE THE LOWEST VISIBILITIES AT
KSAW. THIS UNCERTAINTY ALSO AFFECTS CEILINGS AT KCMX/KIWD THIS
EVENING...AS IF THE PRECIPITATION IS FARTHER WEST...THE CEILINGS
WILL BE LOWER. THIS DISTURBANCE WILL SHIFT NORTHEAST OVERNIGHT AND
BRING AN END TO THE SNOW...BUT STILL EXPECT MVFR/IFR CEILINGS TO
REMAIN IN PLACE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 441 AM EST WED NOV 20 2013
SOUTHERLY GALES TO 35-40KTS WILL CONTINUE THROUGH MOST OF THE
DAYLIGHT HOURS TODAY OVER EASTERN LAKE SUPERIOR AHEAD OF
A COLD FRONT MOVING THROUGH MINNESOTA TODAY. TIMING OF THE ONGOING
GALE WARNING LOOKS GOOD AND WON/T MAKE ANY CHANGES AT THIS TIME. AS
THE FRONT NEARS LATE THIS AFTERNOON AND EVENING...EXPECT THE WINDS
TO DIMINISH FROM WEST TO EAST THROUGH THE NIGHT. THE FRONT WILL
SLOWLY MOVE EAST ACROSS LAKE SUPERIOR TONIGHT AND THURSDAY...WHICH
WILL SHIFT THE WINDS TO THE NORTHWEST 20-30KTS ON THURSDAY. A HIGH
PRESSURE RIDGE MOVING OVER THE LAKE ON THURSDAY NIGHT WILL SHIFT
WINDS TO THE NORTH AND DIMINISH THEM THURSDAY NIGHT THROUGH FRIDAY.
A WEAK LOW TRACKING FROM THE SOUTHERN PLAINS THROUGH THE LOWER GREAT
LAKES ON FRIDAY WILL KEEP THE NORTHERLY WINDS IN PLACE DUE TO A WEAK
TROUGH SETTING UP OVER UPPER MICHIGAN. THIS TROUGH WILL DIVE SOUTH
ON FRIDAY NIGHT AND WHEN COMBINED WITH A STRONG HIGH BUILDING INTO
THE NORTHERN PLAINS...EXPECT NORTHWESTERLY WINDS TO INCREASE TO
GALES TO 35-40KTS ON SATURDAY AND CONTINUE INTO SATURDAY NIGHT. THIS
EVENT WILL BE SHORT LIVED...AS A RIDGE FROM THAT STRONG HIGH SHIFTS
EAST OVER THE UPPER GREAT LAKES ON SUNDAY AND BRINGS WINDS BELOW
25KTS BY SUNDAY AFTERNOON.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LSZ244-245-266-
267.
GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LSZ264.
GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ249>251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
514 AM EST WED NOV 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 441 AM EST WED NOV 20 2013
UPPER MICHIGAN IS BETWEEN SURFACE FEATURES THIS MORNING...WITH A
1036MB HIGH MOVING EAST FROM THE LOWER GREAT LAKES AND A 996MB LOW
BETWEEN LAKE WINNIPEG AND HUDSON BAY. A COLD FRONT STRETCHES
SOUTHWEST FROM THIS LOW THROUGH NORTHWEST MINNESOTA AND THROUGH THE
DAKOTAS. THE PRESSURE GRADIENT BETWEEN THESE THREE FEATURES HAS
LEAD TO BREEZY CONDITIONS EARLY THIS MORNING...ESPECIALLY OVER LAKE
SUPERIOR AND THE DOWNSLOPE AREAS OF CENTRAL UPPER MICHIGAN. KMQT VAD
WIND DATA SHOWS 45KT WINDS AT 2KFT AND THAT MATCHES UP WELL WITH
THE 46KT GUST RECORDED AT STANNARD ROCK LAST HOUR. THE REST OF
THE UPPER MICHIGAN HAS BEEN GUSTING TO 15-30KTS OVER THE LAST
COUPLE OF HOURS. EXPECT THE GUSTY WINDS TO CONTINUE THROUGH A GOOD
PORTION OF THE DAY TODAY AT VALUES SIMILAR TO WHAT WAS SEEN
OVERNIGHT. WITH A LITTLE BETTER MIXING...THE HIGHER GUSTS WILL
LIKELY BE MORE WIDESPREAD THAN THE SPORADIC VALUES SEEN OVERNIGHT.
FORTUNATELY...THE 40-50KT 925MB WINDS SHOULD STAY ABOVE THE SURFACE
DUE TO THE INVERSION INDICATED JUST BELOW THAT LEVEL. WITH THE
GRADIENT WEAKENING OVER THE AREA FROM WEST TO EAST THIS AFTERNOON
AND EVENING...ALONG THE WITH PRESSURE FALLS NORTH OF LAKE SUPERIOR
EXITING THIS MORNING...EXPECT A DIMINISHING TREND IN THE WINDS THIS
AFTERNOON/EVENING.
THE REST OF THE WEATHER FORECAST WILL DEPEND ON TWO FEATURES...THE
COLD FRONT TO THE WEST OF THE AREA THAT WILL MOVE THROUGH TONIGHT
AND THURSDAY AND A SHORTWAVE CURRENTLY PULLING OUT OF COLORADO.
THIS SHORTWAVE WILL SLIDE NORTHEAST TODAY AND ACROSS UPPER MICHIGAN
THIS EVENING AND EARLY OVERNIGHT HOURS. AS THIS OCCURS...THE COLD
FRONT WILL BE MOVING ACROSS WESTERN LAKE SUPERIOR. MID LEVEL
SOUTHWESTERLY FLOW AHEAD OF THIS WAVE HAS PRODUCED WIDESPREAD MID
CLOUDS FROM THE CENTRAL PLAINS INTO ONTARIO AND EXPECT THAT TO
CONTINUE THROUGH MUCH OF THE DAY TODAY. RADAR HAS BLOSSOMED OVER THE
LAST COUPLE OF HOURS FROM LAKE SUPERIOR THROUGH EASTERN IOWA AND ALL
ASSOCIATED WITH THE MID CLOUDS. THUS...THERE IS PROBABLY SOME PRECIP
FALLING OUT OF THOSE CLOUDS...BUT THE DRIER AIR IS EVAPORATING THE
PRECIP BEFORE REACHING THE SURFACE (NO OBS INDICATING RAIN). MODELS
INDICATING THERE COULD BE A FEW SHOWERS OVER CENTRAL LAKE SUPERIOR
AND THE KEWEENAW TODAY...BUT HAVE MAINLY LEFT AS SLIGHT CHANCES
SINCE THE DRIER LOW LEVELS WILL LIKELY EVAPORATE MUCH OF THE PRECIP.
THERE WAS A BRIEF PERIOD OF 2-3KFT RETURNS JUST NORTHEAST OF
MARQUETTE (WHICH HAD BEEN HINTED AT IN THE ECMWF AND A COUPLE OTHER
MODELS OVER THE LAST COUPLE OF DAYS)...BUT IT QUICKLY DISSIPATED.
THE DRY AIR INDICATED OVER THE AREA ON INITIAL RAP SOUNDINGS
(DEWPOINT DEPRESSIONS OF 15-20C BETWEEN 900-800MB) WILL CONTINUE
THROUGH MUCH OF THE DAY AND WILL PLAY A ROLE IN THE PRECIP TYPE
FORECAST FOR LATE THIS AFTERNOON AND TONIGHT.
MODELS SEEM TO HAVE DECENT AGREEMENT WITH THE PRECIPITATION TIMING
AND LOCATION FOR TONIGHT...AS THE LOWER LEVELS MOISTEN FROM TOP DOWN
WITH THE ARRIVAL OF THE SHORTWAVE. BEST FORCING FROM THE
SHORTWAVE...ALONG WITH 700-500 Q-VECTOR CONVERGENCE AND ISENTROPIC
ASCENT ON 280-290K SFCS TRACKS ACROSS THE MUCH OF THE CWA...WITH THE
GREATEST FOCUS OVER THE CENTRAL AND EAST THIS EVENING. THINK THAT
LAYER IS WHERE MUCH OF THE PRECIPITATION WILL INITIATE LATE THIS
AFTERNOON OVER NORTHERN WISCONSIN AND THEN LIFT NORTHEAST INTO UPPER
MICHIGAN. LOOKING UPSTREAM...THERE IS NOT MUCH FOR LOWER LEVEL
MOISTURE...AND THINK THAT IT WILL TAKE A LITTLE BIT FOR THE
PRECIPITATION TO COOL AND MOISTEN THE LOWER LEVELS. THIS CAN
SOMEWHAT BE SEEN ON MODEL QPF FIELDS WITH THEIR BLOTCHY NATURE AT
TIMES ALONG WITH 280-285K THETA-E SURFACES COND PRESS DEF VALUES
INDICATING SIGNIFICANT LIFT NEEDED TO MOISTEN THE CENTRAL/EASTERN
CWA DURING THE LATE AFTERNOON/EVENING. IN ADDITION...THE HIGHER
RESOLUTION RUNS ARE ALSO SHOWING SOME OF THE DOWNSLOPE FLOW OVER THE
NORTH CENTRAL EATING AWAY AT QPF AMOUNTS. THEREFORE...ALTHOUGH THE
CONFIDENCE IS HIGH ON TIMING/LOCATION...QPF AMOUNTS ARE MORE
UNCERTAIN DUE TO THE DRY AIR AND WILL LIKELY COME DOWN TO HOW
QUICKLY THINGS MOISTEN. THINK WE WILL GET PRECIPITATION...BUT
WONDERING IF THE DRY AIR WILL LOWER QPF AMOUNTS MORE THAN SOME OF
THE MODELS ARE INDICATING. ALSO...THERE ARE SOME HINTS ON THE 06Z
MODEL RUNS THAT THE MAIN PIECE OF SHORTWAVE ENERGY (NOTED BY THE PV
ANOMALY) WILL SLIDE SOUTH OF THE AREA (THROUGH CENTRAL WISCONSIN
AND LOWER MICHIGAN). AS THE SHORTWAVE SLIDES EAST OVERNIGHT...HAVE
DIMINISHED POPS FROM SOUTHWEST TO NORTHEAST.
AS FOR PRECIP TYPE...HAVE FOLLOWED THE WETBULB0 VALUES FOR MUCH OF
THE FORECAST...AS IT HANDLES WHERE THE THERMAL FIELDS WILL GO AS
EVAPORATIVE COOLING AND MOISTENING OCCURS. THIS LEADS TO MUCH OF
THE INTERIOR (HIGHER TERRAIN) WEST/CENTRAL TO QUICKLY TRANSITION TO
OR START AS SNOW. WITH THE UNCERTAINTY ON QPF...HAVE WENT WITH A
MIDDLE GROUND OF 0.1-0.18IN OF QPF OVER THE CENTRAL CWA WITH
LOWER AMOUNTS WEST AND EAST. WITH THAT AREA SHOWING MAINLY
SNOW...WOULD EXPECT AROUND AN INCH OF ACCUMULATION DURING THE
EVENING HOURS. OF COURSE...IF THE HIGHER QPF SHOWN IN THE 00Z
NAM/GFS IS CORRECT...COULD SEE AMOUNTS AROUND OR A LITTLE OVER 2
INCHES AROUND IRON/DICKINSON COUNTY BUT NOT COMPLETELY BUYING THEIR
QUICK 0.2-0.3IN OF QPF LATE THIS AFTERNOON. DID CONTINUE RAIN/SNOW
IN THE DOWNSLOPE WARMED AREAS NEAR LAKE SUPERIOR AND ALSO OVER THE
EAST. AS DEEPER MOISTURE PULLS OUT OF THE WEST OVERNIGHT...MUCH OF
THE REMAINING CLOUD ENDS UP BEING WARMER THAN -5C. THUS...IF ANY
PRECIPITATION DOES OCCUR...WOULD EXPECT IT TO BE AS FREEZING
DRIZZLE. PREVIOUS SHIFT HAD A GOOD HANDLE ON THIS IDEA AND HAVE
ONLY MADE MINOR ADJUSTMENTS TO PUSH IT A LITTLE TO THE WEST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 513 AM EST WED NOV 20 2013
ALTHOUGH A FAIRLY ACTIVE PATTERN WILL BE THE RULE THRU THE LONG
TERM...NO SIGNIFICANT PCPN EVENTS ARE ANTICIPATED AS NW FLOW WILL
BECOME THE PREVAILING REGIME FROM THIS WEEKEND THRU AT LEAST THE
MIDDLE OF NEXT WEEK. ACTIVE PATTERN WILL COME IN THE FORM OF A
NUMBER OF SHORTWAVES PRODUCING MOSTLY LIGHT PCPN...THOUGH LAKE
SUPERIOR WILL PROVIDE ENHANCEMENT. THE NW FLOW REGIME WILL SET IN
THIS WEEKEND AS A MEAN RIDGE DEVELOPS ALONG THE W COAST WITH
DOWNSTREAM TROF GENERALLY FROM THE MISSISSIPPI VALLEY TO THE E
COAST. INITIAL SURGE OF COLD AIR THIS WEEKEND ASSOCIATED WITH
DEEPENING TROF WILL BE THE COLDEST OF THE SEASON SO FAR. SOURCE
REGION OF THE AIR MASS IS THE YUKON WHERE A NUMBER OF SITES HAVE
BEEN RECORDING TEMPS IN THE -25 TO -35F RANGE OVER THE LAST DAY OR
SO. SHOT OF ARCTIC AIR WILL BE BRIEF AS TROF TEMPORARILY DEAMPLIFIES
LATE WEEKEND AHEAD OF THE NEXT SHORTWAVE THAT DROPS SE. THAT WAVE
WILL THEN REAMPLIFY THE TROF EARLY NEXT WEEK...BRINGING MORE COLD
AIR INTO THE AREA...THOUGH PROBABLY NOT QUITE AS COLD AS THE AIR
MASS THIS WEEKEND. FARTHER DOWN THE LINE INTO LATE NEXT WEEK...THERE
ARE SOME HINTS THAT THE FLOW PATTERN WILL DEAMPLIFY SOME...
SUGGESTING NO SIGNIFICANT PCPN EVENTS ALONG WITH TEMPS RETURNING TO
AROUND NORMAL.
BEGINNING THU...SHORTWAVE LEADING TO PCPN TONIGHT WILL BE EXITING TO
THE NE. MAY SEE LINGERING PCPN OVER THE E IN THE MORNING AND ALSO IN
THE UPSLOPE AREAS OF THE W. WITH DEEPER MOISTURE PULLING OUT...THERE
COULD BE A LITTLE DZ/FZDZ OVER THE FAR W EARLY...THOUGH THERE IS A
FAIR AMOUNT OF UNCERTAINTY IN HOW MUCH DRYING OCCURS ALOFT.
OTHERWISE...A COLD FRONT WILL BE MOVING ACROSS THE FCST AREA THU.
CAA IS NOT ESPECIALLY STRONG...SO THERE SHOULD STILL BE SOME TEMP
RISE OVER THE W IN THE MORNING BEFORE TEMPS BEGIN FALLING IN THE
AFTN. TEMPS OVER THE E SHOULD RISE TO THE LWR 40S UNDER DELAYED CAA.
IN THE AFTN...WELL BEHIND SFC COLD FRONT...IT APPEARS A BAND OF -SN
MAY ORGANIZE ACROSS ROUGHLY THE W HALF OF THE FCST AREA WITHIN A
ZONE OF LOW/MID LEVEL FRONTOGENESIS UNDERNEATH RIGHT ENTRANCE OF
UPPER JET FROM THE NRN PLAINS TO HUDSON BAY AND LEFT EXIT OF JET
EXTENDING FROM THE SW STATES TO THE MIDWEST.
WITH STRENGTHENING FRONTOGENESIS/UPPER DIVERGENCE TRANSLATING ACROSS
THE UPPER LAKES THU NIGHT AHEAD OF NEXT SHORTWAVE SWINGING ACROSS
THE NRN PLAINS/UPPER MISSISSIPPI VALLEY...EXPECT A PERIOD OF PCPN
ACROSS THE FCST AREA. PER FCST SOUNDINGS AND WETBULB ZERO HEIGHTS
ABOVE 1500FT...PCPN SHOULD START AS MAINLY RA OVER THE E BEFORE IT
CHANGES TO SNOW. SNOW WILL BE THE RULE OVER THE W. WITH NOT MUCH IN
THE WAY OF ISENTROPIC ASCENT NOTED...PCPN SHOULD REMAIN ON THE LIGHT
SIDE. CONSENSUS OF MODEL GUIDANCE SHOWS PCPN AMOUNTS IN THE 0.10 TO
0.20 INCH RANGE. WITH A HIGH DGZ GENERALLY BTWN 11K AND 15KFT AND
MOSTLY ABOVE THE BEST UPWARD MOTION...SNOW TO WATER RATIOS WILL BE
ON THE LOW SIDE...PROBABLY 10-15 TO 1. SO...RIGHT NOW IT LOOKS LIKE
A GENERAL 1-2 TO MAYBE 3 INCH SNOW ACCUMULATION ACROSS THE AREA THU
NIGHT INTO FRI MORNING. WITH 850MB TEMPS FALLING TO -8 TO -10C
DURING THE PERIOD OF -SN...THERE WILL BE SOME LAKE ENHANCEMENT UNDER
NRLY LOW-LEVEL FLOW...AND THAT SHOULD LEAD TO GREATEST ACCUMULATIONS
OVER THE HIGHER TERRAIN NEAR LAKE SUPERIOR. HOWEVER...WITH HIGH
DGZ...ENHANCEMENT SHOULDN`T ADD MUCH TO SYNOPTIC SNOW AMOUNTS.
-SN WILL END FROM W TO E FRI IN THE WAKE OF SHORTWAVE...THOUGH A FEW
-SHSN MAY LINGER THRU THE AFTN OFF LAKE SUPERIOR OVER THE ERN FCST
AREA UNDER 850MB TEMPS AROUND -10C.
ATTENTION THEN TURNS TO THE NEXT SHORTWAVE DROPPING SE AND LEADING
TO THE AFOREMENTIONED WEEKEND TROF AMPLIFICATION AND ARCTIC AIR.
BRIEF PERIOD OF VIGOROUS DEEP LAYER FORCING PER QVECTORS OVERTOP
MORE THAN ADEQUATE OVERWATER INSTABILITY WILL YIELD THE TYPICAL
BURST OF MDT/HVY LAKE ENHANCED SNOW SWEEPING OFF LAKE SUPERIOR ALONG
THE ASSOCIATED ARCTIC COLD FRONT FRI NIGHT/EARLY SAT. IN THE WAKE OF
THE FRONT...850MB TEMPS FALL TO -18 TO -21C SAT...RESULTING IN
VIGOROUS NW/NNW FLOW ORIENTED LAKE CONVECTION. CONSENSUS OF GUIDANCE
IS FOR DEEP MOISTURE TO LINGER LONGEST OVER THE ERN FCST AREA. GFS
FCST SOUNDINGS SHOW MOISTURE UP TO 10KFT OR SO. COMBINED WITH LAKE
NIPIGON PRECONDITIONING AND DGZ LIKELY WELL CENTERED WITHIN THE
UPWARD MOTION ZONE...A SIGNIFICANT LAKE EFFECT EVENT LOOKS TO BE
SETTING UP FOR ALGER/LUCE/NRN SCHOOLCRAFT. GUSTY WINDS OF 30-40MPH
WILL ALSO LEAD TO INCREASING BLSN ISSUES AS SNOW ACCUMULATES. OUT
W...SHORTER FETCH...LOWER DGZ AND MOISTURE EXTENDING TO AROUND 6KFT
WILL WORK TO LIMIT SNOW ACCUMULATIONS COMPARED TO THE E.
HOWEVER...TERRAIN ENHANCEMENT PLAYS A BIGGER ROLE OVER THE W THAN
THE E...AND BOUNDARY LAYER WINDS LOOK SUPPORTIVE OF THE TYPICAL
ENHANCED CONVERGENCE AREA FOR GOGEBIC/ONTONAGON INTO CNTRL HOUGHTON
COUNTIES. AS A RESULT...SIGNIFICANT SNOW MAY ALSO OCCUR IN THAT AREA
AS WELL. ANTICIPATE AT LEAST SOLID ADVY FOR THE KEWEENAW...AND THERE
MAY BE A PERIOD WITH WINDS HAVING ENOUGH NRLY COMPONENT FOR
BARAGA/MARQUETTE COUNTIES TO SEE ADVY AMOUNTS AS WELL. ALL OF THESE
DETAILS WILL BE SORTED OUT ONCE THE EVENT MOVES INTO THE SHORT TERM.
OTHERWISE...IT WILL SEEM LIKE MID WINTER CONDITIONS ACROSS THE AREA
SAT/SAT NIGHT WITH GUSTY WINDS/COLD AIR AND WIND CHILLS FALLING TO
ZERO OR BLO.
LES WILL END SUN FROM W TO E AS WINDS BACK TO THE SW AHEAD OF THE
NEXT SHORTWAVE DIVING SE THRU SCNTRL CANADA. HOWEVER...DEVELOPING
STRONG WAA PATTERN MAY LEAD TO AN AREA OF -SN STREAKING SE INTO THE
AREA SUN AFTN/NIGHT. ANOTHER PERIOD OF LAKE EFFECT SNOW SHOULD SET
UP BEHIND THIS SYSTEM EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1212 AM EST WED NOV 20 2013
EXPECT VFR CONDITIONS OVERNIGHT THROUGH WED MORNING AS THE LOW-LEVEL
AIR MASS REMAINS DRY. A TIGHT PRES GRADIENT BTWN STRENGTHENING
HIGH PRES TO THE E AND LOW PRES MOVING TOWARD HUDSON BAY WILL BRING
STRONG SOUTHERLY FLOW TO THE AREA TONIGHT. WITH SFC WINDS LARGELY
DECOUPLED DUE TO INVERSION... LLWS IS EXPECTED EXCEPT FOR AT IWD
WHERE DECOUPLING IS NOT STRONG ENOUGH TO KEEP WINDS FROM GUSTING TO
NEAR 30KT. WAA PCPN MOVING IN MID TO LATE AFTERNOON WILL DROP CIGS
TO AROUND MVFR WITH VSBY REMAINING MAINLY VFR. PCPN TYPE MAY START
OUT BRIEFLY AS RAIN AND THEN CHANGE TO SNOW TOWARD 00Z/THU. PCPN
CHANGING TO SNOW DURING THE EVENING WILL DROP CONDITIONS TOWARD THE
LOWER END MVFR WITH EVEN IFR CIGS POSSIBLE BY LATE EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 441 AM EST WED NOV 20 2013
SOUTHERLY GALES TO 35-40KTS WILL CONTINUE THROUGH MOST OF THE
DAYLIGHT HOURS TODAY OVER EASTERN LAKE SUPERIOR AHEAD OF
A COLD FRONT MOVING THROUGH MINNESOTA TODAY. TIMING OF THE ONGOING
GALE WARNING LOOKS GOOD AND WON/T MAKE ANY CHANGES AT THIS TIME. AS
THE FRONT NEARS LATE THIS AFTERNOON AND EVENING...EXPECT THE WINDS
TO DIMINISH FROM WEST TO EAST THROUGH THE NIGHT. THE FRONT WILL
SLOWLY MOVE EAST ACROSS LAKE SUPERIOR TONIGHT AND THURSDAY...WHICH
WILL SHIFT THE WINDS TO THE NORTHWEST 20-30KTS ON THURSDAY. A HIGH
PRESSURE RIDGE MOVING OVER THE LAKE ON THURSDAY NIGHT WILL SHIFT
WINDS TO THE NORTH AND DIMINISH THEM THURSDAY NIGHT THROUGH FRIDAY.
A WEAK LOW TRACKING FROM THE SOUTHERN PLAINS THROUGH THE LOWER GREAT
LAKES ON FRIDAY WILL KEEP THE NORTHERLY WINDS IN PLACE DUE TO A WEAK
TROUGH SETTING UP OVER UPPER MICHIGAN. THIS TROUGH WILL DIVE SOUTH
ON FRIDAY NIGHT AND WHEN COMBINED WITH A STRONG HIGH BUILDING INTO
THE NORTHERN PLAINS...EXPECT NORTHWESTERLY WINDS TO INCREASE TO
GALES TO 35-40KTS ON SATURDAY AND CONTINUE INTO SATURDAY NIGHT. THIS
EVENT WILL BE SHORT LIVED...AS A RIDGE FROM THAT STRONG HIGH SHIFTS
EAST OVER THE UPPER GREAT LAKES ON SUNDAY AND BRINGS WINDS BELOW
25KTS BY SUNDAY AFTERNOON.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LSZ244-245-266-
267.
GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LSZ264.
GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ249>251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...JLB
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
442 AM EST WED NOV 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 441 AM EST WED NOV 20 2013
UPPER MICHIGAN IS BETWEEN SURFACE FEATURES THIS MORNING...WITH A
1036MB HIGH MOVING EAST FROM THE LOWER GREAT LAKES AND A 996MB LOW
BETWEEN LAKE WINNIPEG AND HUDSON BAY. A COLD FRONT STRETCHES
SOUTHWEST FROM THIS LOW THROUGH NORTHWEST MINNESOTA AND THROUGH THE
DAKOTAS. THE PRESSURE GRADIENT BETWEEN THESE THREE FEATURES HAS
LEAD TO BREEZY CONDITIONS EARLY THIS MORNING...ESPECIALLY OVER LAKE
SUPERIOR AND THE DOWNSLOPE AREAS OF CENTRAL UPPER MICHIGAN. KMQT VAD
WIND DATA SHOWS 45KT WINDS AT 2KFT AND THAT MATCHES UP WELL WITH
THE 46KT GUST RECORDED AT STANNARD ROCK LAST HOUR. THE REST OF
THE UPPER MICHIGAN HAS BEEN GUSTING TO 15-30KTS OVER THE LAST
COUPLE OF HOURS. EXPECT THE GUSTY WINDS TO CONTINUE THROUGH A GOOD
PORTION OF THE DAY TODAY AT VALUES SIMILAR TO WHAT WAS SEEN
OVERNIGHT. WITH A LITTLE BETTER MIXING...THE HIGHER GUSTS WILL
LIKELY BE MORE WIDESPREAD THAN THE SPORADIC VALUES SEEN OVERNIGHT.
FORTUNATELY...THE 40-50KT 925MB WINDS SHOULD STAY ABOVE THE SURFACE
DUE TO THE INVERSION INDICATED JUST BELOW THAT LEVEL. WITH THE
GRADIENT WEAKENING OVER THE AREA FROM WEST TO EAST THIS AFTERNOON
AND EVENING...ALONG THE WITH PRESSURE FALLS NORTH OF LAKE SUPERIOR
EXITING THIS MORNING...EXPECT A DIMINISHING TREND IN THE WINDS THIS
AFTERNOON/EVENING.
THE REST OF THE WEATHER FORECAST WILL DEPEND ON TWO FEATURES...THE
COLD FRONT TO THE WEST OF THE AREA THAT WILL MOVE THROUGH TONIGHT
AND THURSDAY AND A SHORTWAVE CURRENTLY PULLING OUT OF COLORADO.
THIS SHORTWAVE WILL SLIDE NORTHEAST TODAY AND ACROSS UPPER MICHIGAN
THIS EVENING AND EARLY OVERNIGHT HOURS. AS THIS OCCURS...THE COLD
FRONT WILL BE MOVING ACROSS WESTERN LAKE SUPERIOR. MID LEVEL
SOUTHWESTERLY FLOW AHEAD OF THIS WAVE HAS PRODUCED WIDESPREAD MID
CLOUDS FROM THE CENTRAL PLAINS INTO ONTARIO AND EXPECT THAT TO
CONTINUE THROUGH MUCH OF THE DAY TODAY. RADAR HAS BLOSSOMED OVER THE
LAST COUPLE OF HOURS FROM LAKE SUPERIOR THROUGH EASTERN IOWA AND ALL
ASSOCIATED WITH THE MID CLOUDS. THUS...THERE IS PROBABLY SOME PRECIP
FALLING OUT OF THOSE CLOUDS...BUT THE DRIER AIR IS EVAPORATING THE
PRECIP BEFORE REACHING THE SURFACE (NO OBS INDICATING RAIN). MODELS
INDICATING THERE COULD BE A FEW SHOWERS OVER CENTRAL LAKE SUPERIOR
AND THE KEWEENAW TODAY...BUT HAVE MAINLY LEFT AS SLIGHT CHANCES
SINCE THE DRIER LOW LEVELS WILL LIKELY EVAPORATE MUCH OF THE PRECIP.
THERE WAS A BRIEF PERIOD OF 2-3KFT RETURNS JUST NORTHEAST OF
MARQUETTE (WHICH HAD BEEN HINTED AT IN THE ECMWF AND A COUPLE OTHER
MODELS OVER THE LAST COUPLE OF DAYS)...BUT IT QUICKLY DISSIPATED.
THE DRY AIR INDICATED OVER THE AREA ON INITIAL RAP SOUNDINGS
(DEWPOINT DEPRESSIONS OF 15-20C BETWEEN 900-800MB) WILL CONTINUE
THROUGH MUCH OF THE DAY AND WILL PLAY A ROLE IN THE PRECIP TYPE
FORECAST FOR LATE THIS AFTERNOON AND TONIGHT.
MODELS SEEM TO HAVE DECENT AGREEMENT WITH THE PRECIPITATION TIMING
AND LOCATION FOR TONIGHT...AS THE LOWER LEVELS MOISTEN FROM TOP DOWN
WITH THE ARRIVAL OF THE SHORTWAVE. BEST FORCING FROM THE
SHORTWAVE...ALONG WITH 700-500 Q-VECTOR CONVERGENCE AND ISENTROPIC
ASCENT ON 280-290K SFCS TRACKS ACROSS THE MUCH OF THE CWA...WITH THE
GREATEST FOCUS OVER THE CENTRAL AND EAST THIS EVENING. THINK THAT
LAYER IS WHERE MUCH OF THE PRECIPITATION WILL INITIATE LATE THIS
AFTERNOON OVER NORTHERN WISCONSIN AND THEN LIFT NORTHEAST INTO UPPER
MICHIGAN. LOOKING UPSTREAM...THERE IS NOT MUCH FOR LOWER LEVEL
MOISTURE...AND THINK THAT IT WILL TAKE A LITTLE BIT FOR THE
PRECIPITATION TO COOL AND MOISTEN THE LOWER LEVELS. THIS CAN
SOMEWHAT BE SEEN ON MODEL QPF FIELDS WITH THEIR BLOTCHY NATURE AT
TIMES ALONG WITH 280-285K THETA-E SURFACES COND PRESS DEF VALUES
INDICATING SIGNIFICANT LIFT NEEDED TO MOISTEN THE CENTRAL/EASTERN
CWA DURING THE LATE AFTERNOON/EVENING. IN ADDITION...THE HIGHER
RESOLUTION RUNS ARE ALSO SHOWING SOME OF THE DOWNSLOPE FLOW OVER THE
NORTH CENTRAL EATING AWAY AT QPF AMOUNTS. THEREFORE...ALTHOUGH THE
CONFIDENCE IS HIGH ON TIMING/LOCATION...QPF AMOUNTS ARE MORE
UNCERTAIN DUE TO THE DRY AIR AND WILL LIKELY COME DOWN TO HOW
QUICKLY THINGS MOISTEN. THINK WE WILL GET PRECIPITATION...BUT
WONDERING IF THE DRY AIR WILL LOWER QPF AMOUNTS MORE THAN SOME OF
THE MODELS ARE INDICATING. ALSO...THERE ARE SOME HINTS ON THE 06Z
MODEL RUNS THAT THE MAIN PIECE OF SHORTWAVE ENERGY (NOTED BY THE PV
ANOMALY) WILL SLIDE SOUTH OF THE AREA (THROUGH CENTRAL WISCONSIN
AND LOWER MICHIGAN). AS THE SHORTWAVE SLIDES EAST OVERNIGHT...HAVE
DIMINISHED POPS FROM SOUTHWEST TO NORTHEAST.
AS FOR PRECIP TYPE...HAVE FOLLOWED THE WETBULB0 VALUES FOR MUCH OF
THE FORECAST...AS IT HANDLES WHERE THE THERMAL FIELDS WILL GO AS
EVAPORATIVE COOLING AND MOISTENING OCCURS. THIS LEADS TO MUCH OF
THE INTERIOR (HIGHER TERRAIN) WEST/CENTRAL TO QUICKLY TRANSITION TO
OR START AS SNOW. WITH THE UNCERTAINTY ON QPF...HAVE WENT WITH A
MIDDLE GROUND OF 0.1-0.18IN OF QPF OVER THE CENTRAL CWA WITH
LOWER AMOUNTS WEST AND EAST. WITH THAT AREA SHOWING MAINLY
SNOW...WOULD EXPECT AROUND AN INCH OF ACCUMULATION DURING THE
EVENING HOURS. OF COURSE...IF THE HIGHER QPF SHOWN IN THE 00Z
NAM/GFS IS CORRECT...COULD SEE AMOUNTS AROUND OR A LITTLE OVER 2
INCHES AROUND IRON/DICKINSON COUNTY BUT NOT COMPLETELY BUYING THEIR
QUICK 0.2-0.3IN OF QPF LATE THIS AFTERNOON. DID CONTINUE RAIN/SNOW
IN THE DOWNSLOPE WARMED AREAS NEAR LAKE SUPERIOR AND ALSO OVER THE
EAST. AS DEEPER MOISTURE PULLS OUT OF THE WEST OVERNIGHT...MUCH OF
THE REMAINING CLOUD ENDS UP BEING WARMER THAN -5C. THUS...IF ANY
PRECIPITATION DOES OCCUR...WOULD EXPECT IT TO BE AS FREEZING
DRIZZLE. PREVIOUS SHIFT HAD A GOOD HANDLE ON THIS IDEA AND HAVE
ONLY MADE MINOR ADJUSTMENTS TO PUSH IT A LITTLE TO THE WEST.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 435 PM EST TUE NOV 19 2013
A SOMEWHAT ACTIVE AND MESSY START TO THE LONG TERM WILL BE FOLLOWED
BY THE COLDEST AIRMASS OF THE SEASON. A SERIES OF WEAK WAVES ARE
EXPECTED TO BRING PRECIP CHANCES WEDNESDAY NIGHT...AND POSSIBLY
AGAIN THURSDAY NIGHT INTO FRIDAY. ARCTIC AIR WILL THEN USHER IN FOR
THE WEEKEND...BRINGING BLUSTERY CONDITIONS FOR SATURDAY AND A PERIOD
OF LAKE EFFECT SNOW FOR N TO NW WINDS BELTS.
WEDNESDAY NIGHT AND THURSDAY...A BROAD MID-LEVEL TROUGH ACROSS
CENTRAL CANADA WILL BE IMPINGING ON A DEPARTING SHARP MID-LEVEL
RIDGE ACROSS THE NE CONUS AND ST LAWRENCE VALLEY. AN ASSOCIATED SFC
LOW OVER SOUTHERN HUDSON BAY WILL EXTEND SOUTHWESTWARD ACROSS THE
UPPER MS VALLEY TO A DEVELOPING LOW OVER THE SW STATES. THE FIRST OF
A SERIES OF SHORTWAVE TROUGHS WILL ROUND THE BASE OF THE BROAD
CANADIAN TROUGH BEGINNING WEDNESDAY NIGHT. MODELS ARE IN FAIRLY GOOD
AGREEMENT THAT A WEAK SFC LOW WILL DEVELOP ALONG THE TROUGH OVER
WESTERN LAKE SUPERIOR WEDNESDAY NIGHT.
PRECIP ON WAA AHEAD OF THE DEVELOPING LOW WILL BE ONGOING ACROSS THE
CENTRAL CWA AT THE START OF THE PERIOD. MUCH OF THIS PRECIP WILL BE
FORCED BY WEAK ISENTROPIC LIFT ON THE 285K TO 295K SFCS AND WEAK
MID-LEVEL Q-VECTOR CONVERGENCE AHEAD OF THE SHORTWAVE. DID NOT
CHANGE MUCH IN THE GENERAL PRECIP COVERAGE OTHER THAN SLOW THE
EASTWARD PROGRESSION BY A FEW HOURS. THE MAIN QUESTION REVOLVES
AROUND PRECIP TYPE. WITH RATHER DRY AIR BELOW 5KFT...WETBULB ZERO
HEIGHTS WILL BE UNDER 1KFT FOR NEARLY THE ENTIRE CWA...KEEPING
PRECIP ALL SNOW. AS NOTED BY THE PREVIOUS SHIFT...DOWNSLOPE
INFLUENCE AND SLIGHTLY HIGHER WETBULB ZERO HEIGHTS/TEMPS SHOULD KEEP
PRECIP RAIN TO A MIX OF RAIN/SNOW ALONG LAKE SUPERIOR. VERY POOR
SNOW GROWTH WILL KEEP RATIOS QUITE LOW. WITH THAT...AND WITH OVERALL
WEAK FORCING...ONLY EXPECT UP TO AN INCH OF SNOW INTERIOR WEST.
THE ASSOCIATED COLD FRONT WILL PUSH ACROSS THE CWA FROM WEST TO EAST
THURSDAY. CAA ACROSS THE WEST WILL KEEP TEMPS STEADY IN THE MORNING
BEFORE DROPPING DURING THE AFTERNOON. THE EAST MAY SEE A TOUCH OF
CLEARING AHEAD OF THE FRONT...SO TWEAKED TEMPS UP A DEGREE OR SO FOR
THURSDAY. DRY AIR WORKING IN AND LOWERING INVERSION AT AND BEHIND
THE FRONT MAY RESULT IN SOME PATCHY FREEZING DRIZZLE FOR SOME
LOCATIONS ACROSS THE WEST HALF WED NIGHT INTO THURSDAY MORNING. ONLY
PUT A SLIGHT MENTION IN ATTM...BUT FELT CONDITIONS WARRANTED SOME
PLACEMENT OF FZDZ IN THE FORECAST. EXPECT AN OVERALL BREAK IN
PRECIP...BUT NOT CLOUDS...THURSDAY AS COLD AIR CONTINUES TO FILTER
INTO THE AREA AND SUBSIDENCE INCREASES BEHIND THE TROUGH.
THURSDAY NIGHT AND FRIDAY...THE FORECAST BECOMES QUITE CHALLENGING
AT THIS POINT AS MODEL SPREAD AND RUN-TO-RUN CONSISTENCY BECOMING
QUITE POOR. AGREEMENT IS DECENT...HOWEVER...THAT A REINFORCING
SHORTWAVE TROUGH DIGGING OUT OF WESTERN CANADA WILL TRACK ACROSS THE
BASE OF THE BROAD CANADIAN TROUGH. THE GFS HAS BEEN PERSISTENT FOR
OVER A DAY NOW WITH DEVELOPING A STRONG SFC LOW OVER LOWER MI INTO
FAR EASTERN ONTARIO ON FRIDAY. THE ECMWF...NAM...AND GEM WERE ALL IN
AGREEMENT THAT A WEAKER LOW WOULD REMAIN SOUTH OF THE REGION.
HOWEVER...THE 12Z ECMWF HAS TRENDED NORTHWARD AND STRONGER WITH THE
SYSTEM...THUS INTRODUCING MORE MODEL SPREAD. HAVE TRENDED NORTHWARD
WITH CHANCE POPS A SLIGHT BIT ACROSS THE SOUTH CENTRAL AND EASTERN
CWA...BUT DO NOT WANT TO JUMP ON THE ECMWF TREND QUITE YET. IF THE
ECMWF DOES COME IN LINE WITH THE GFS...A BREEZY FRIDAY WITH LIGHT TO
MODERATE LAKE ENHANCED SNOW COULD OCCUR. FOR NOW...HAVE MAINTAINED A
MOSTLY DRY FORECAST FOR FRIDAY WITH GENERALLY LIGHT WINDS.
SATURDAY THROUGH TUESDAY...GUIDANCE COMES A BIT MORE IN LINE ONCE
THE LOW PASSES SATURDAY. A POTENT ARCTIC FRONT WITH A POCKET OF H8
AIR LESS THAN -20C WILL ADVECT CROSS THE CWA WITH A VERY STRONG
1050MB SFC BUILDING IN BEHIND THE FRONT...RESULTING IN LES AND
STRONG NORTHWESTERLY WINDS. LOCATIONS EXPOSED TO NW WINDS ALONG LAKE
SUPERIOR COULD SEE GUSTS OVER 40MPH ON SATURDAY. COMBINED WITH THE
COLDER TEMPS ONLY IN THE UPPER TEENS...WIND CHILLS WILL FALL TO
AROUND 0F...IF NOT A BIT LOWER FOR SATURDAY. OVERALL...IT WILL BE A
TRUE UPPER MICHIGAN WINTER DAY. DRY AIR SHOULD CUT OFF REMAINING LES
ON SUNDAY.
DEEP TROUGHING WILL CONTINUE ACROSS EASTERN CANADA INTO EARLY NEXT
WEEK WITH SIGNS OF A CLIPPER SYSTEM TRACKING ACROSS THE CWA ON
MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1212 AM EST WED NOV 20 2013
EXPECT VFR CONDITIONS OVERNIGHT THROUGH WED MORNING AS THE LOW-LEVEL
AIR MASS REMAINS DRY. A TIGHT PRES GRADIENT BTWN STRENGTHENING
HIGH PRES TO THE E AND LOW PRES MOVING TOWARD HUDSON BAY WILL BRING
STRONG SOUTHERLY FLOW TO THE AREA TONIGHT. WITH SFC WINDS LARGELY
DECOUPLED DUE TO INVERSION... LLWS IS EXPECTED EXCEPT FOR AT IWD
WHERE DECOUPLING IS NOT STRONG ENOUGH TO KEEP WINDS FROM GUSTING TO
NEAR 30KT. WAA PCPN MOVING IN MID TO LATE AFTERNOON WILL DROP CIGS
TO AROUND MVFR WITH VSBY REMAINING MAINLY VFR. PCPN TYPE MAY START
OUT BRIEFLY AS RAIN AND THEN CHANGE TO SNOW TOWARD 00Z/THU. PCPN
CHANGING TO SNOW DURING THE EVENING WILL DROP CONDITIONS TOWARD THE
LOWER END MVFR WITH EVEN IFR CIGS POSSIBLE BY LATE EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 441 AM EST WED NOV 20 2013
SOUTHERLY GALES TO 35-40KTS WILL CONTINUE THROUGH MOST OF THE
DAYLIGHT HOURS TODAY OVER EASTERN LAKE SUPERIOR AHEAD OF
A COLD FRONT MOVING THROUGH MINNESOTA TODAY. TIMING OF THE ONGOING
GALE WARNING LOOKS GOOD AND WON/T MAKE ANY CHANGES AT THIS TIME. AS
THE FRONT NEARS LATE THIS AFTERNOON AND EVENING...EXPECT THE WINDS
TO DIMINISH FROM WEST TO EAST THROUGH THE NIGHT. THE FRONT WILL
SLOWLY MOVE EAST ACROSS LAKE SUPERIOR TONIGHT AND THURSDAY...WHICH
WILL SHIFT THE WINDS TO THE NORTHWEST 20-30KTS ON THURSDAY. A HIGH
PRESSURE RIDGE MOVING OVER THE LAKE ON THURSDAY NIGHT WILL SHIFT
WINDS TO THE NORTH AND DIMINISH THEM THURSDAY NIGHT THROUGH FRIDAY.
A WEAK LOW TRACKING FROM THE SOUTHERN PLAINS THROUGH THE LOWER GREAT
LAKES ON FRIDAY WILL KEEP THE NORTHERLY WINDS IN PLACE DUE TO A WEAK
TROUGH SETTING UP OVER UPPER MICHIGAN. THIS TROUGH WILL DIVE SOUTH
ON FRIDAY NIGHT AND WHEN COMBINED WITH A STRONG HIGH BUILDING INTO
THE NORTHERN PLAINS...EXPECT NORTHWESTERLY WINDS TO INCREASE TO
GALES TO 35-40KTS ON SATURDAY AND CONTINUE INTO SATURDAY NIGHT. THIS
EVENT WILL BE SHORT LIVED...AS A RIDGE FROM THAT STRONG HIGH SHIFTS
EAST OVER THE UPPER GREAT LAKES ON SUNDAY AND BRINGS WINDS BELOW
25KTS BY SUNDAY AFTERNOON.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LSZ244-245-266-
267.
GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LSZ264.
GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ249>251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KLUBER
AVIATION...JLB
MARINE...SRF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1210 PM CST WED NOV 20 2013
.UPDATE...
ISSUED AT 1122 AM CST WED NOV 20 2013
MINOR ADJUSTMENTS MADE TO EXISTING GRIDS/FCSTS. DECREASED SKY
COVER OVER WRN CWA AND TRENDED DOWNWARD THIS AFTERNOON OVER CTRL
CWA BASED ON LATEST SAT IMAGERY/RAP13 FCST OF MID LVL MOISTURE.
CHANGED PTYPE TO MORE MIXED RAIN/SNOW IN ERN CWA BASED ON
INCREASED POTENTIAL FOR DIABATIC COOLING. LOCATIONS TO THE SOUTH
ALREADY REPORTING SN/IP AT TIMES AND LATEST NAM BUFR SNDGS. HOPWRF
SHOWS ALL SNOW WITH INCREASING ACC POTENTIAL. THIS IS POSSIBLE
CONSIDERING THE USUAL PATTERN OF ALL SNOW OCCURRING IN BULLSEYE OF
GREATEST UVV. ADDED SOME MINOR ACCUMULATIONS FOR NOW. HOWEVER WILL
WATCH SOUTH OF REGION NEXT FEW HRS FOR ANY INDICATIONS OF MORE
ORGANIZED/SUSTAINED POTENTIAL.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST WED NOV 20 2013
EARLY MORNING WATER VAPOR IMAGERY TOGETHER WITH GFS20.00 500MB
HEIGHTS AND WINDS SHOWS SPLIT FLOW ACROSS NORTH AMERICA...WITH THE
NORTHERN STREAM SET UP ACROSS SOUTHERN CANADA...WHILE THE ZONAL
SOUTHERN STREAM WAS POSITIONED FROM SOUTHERN CALIFORNIA TO GEORGIA.
A LOW AMPLITUDE SOUTHERN STREAM SHORTWAVE CURRENTLY LOCATED ACROSS
EASTERN COLORADO WILL TRACK NORTHEASTWARD TODAY...AND THIS WILL
PROVIDE THE LARGE SCALE FORCING FOR A FEW LIGHT RAIN/SNOW SHOWERS IN
WESTERN WISCONSIN AND FAR EASTERN MINNESOTA. RAP FORECAST SOUNDINGS
FOR EAU CLAIRE SHOW AROUND 15UB/S OF LIFT CENTERED AROUND THE 600MB
LAYER..WITH AN ISOTHERMAL LAYER IN THE LOWEST 4000FT HOVERING AROUND
0C. THE WARM NEAR SURFACE TEMPERATURES SHOULD MELT THE PRECIP DURING
THE AFTERNOON...BUT EXPECT A TRANSITION TO A RAIN/SNOW MIX DURING
THE EVENING AND OVERNIGHT HOURS. ANY SNOW ACCUMULATIONS SHOULD BE
CONFINED TO GRASSY SURFACES...AND RANGE FROM A TRACE TO A HALF INCH.
MEANWHILE A STRONGER NORTHERN STREAM SHORTWAVE WILL MOVE ACROSS
SOUTHERN CANADA AND DRIVE A COLD FRONT THROUGH THE DAKOTAS INTO
NORTHWEST MN. A BAND OF POST FRONTAL SNOW WILL GIVE A QUICK 2-3
INCHES OF SNOW UP THERE...BUT THIS WILL WEAKEN AS IT APPROACHES WEST
CENTRAL MN. THEREFORE JUST HAVE CHANCE POPS IN...WITH LITTLE IF ANY
ACCUMULATION. THE MOST NOTICEABLE CHANGE IN THE WEATHER WILL BE
STRONG OVERNIGHT NORTHWEST WINDS OF 25MPH...WITH GUSTS NEAR 35MPH
ASSOCIATED WITH THE COLD AIR ADVECTION BEHIND THE SURFACE FRONT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 340 AM CST WED NOV 20 2013
THE BIG WEATHER STORY OVER THE COMING DAYS IS THE SNOW EVENT
EXPECTED THURSDAY AFTERNOON - THURSDAY NIGHT. THE FEATURE EXPECTED
TO BRING MN/WI SNOW THIS WEEK IS CURRENTLY LOCATED IN THE PACIFIC
NORTHWEST AND NORTHERN ROCKIES THIS MORNING...BUT REALLY DOESN`T
SHOW MUCH AMPLIFICATION THIS MORNING. HOWEVER...THERE IS A WELL
DEFINED ARCTIC BOUNDARY NEAR THE US/CANADIAN BORDER IN
MT/ND...WITH COLD AIR ALREADY SPILLING ACROSS THE BORDER. THIS
WAVE WILL DROP SOUTHEAST OVER THE NEXT COUPLE DAYS...BECOME A
LITTLE SHARPER/WELL-DEFINED AND PASS THROUGH THE FORECAST AREA
BETWEEN 21Z THURSDAY AND 12Z FRIDAY. A SW/NE ORIENTATED BAND OF
600-700MB FGEN WILL SWING THROUGH THE FORECAST THIS AREA DURING
THIS TIME...YIELDING A 3-6 HR WINDOW WITH LIGHT TO MODERATE SNOW.
THE 20.00-06Z NAM HAVE A SHARPER WAVE AND STRONGER FGEN. AS A
RESULT...THE NAM HAS HIGHER TOTALS ACROSS A LARGER PORTION OF THE
FORECAST AREA /A LOT OF 3-4" TOTALS/. THE GEM/GFS/ECMWF ARE A
LITTLE MORE DIFFUSE WITH THE BOUNDARY AND HAVE THE HIGHER TOTALS
/2-3"/ ACROSS MAINLY SOUTH CENTRAL MN. THE LAST 3 RUNS OF THE SREF
HAVE MAINTAINED AROUND 1" FOR MSP...THE NAM HAS SHOWN
1-3.5"...OVER THE LAST FEW RUNS...AND THE GFS HAS BEEN THE
STEADIEST WITH RIGHT AROUND 2". THE QPF ISN`T OVERLY IMPRESSIVE
/NOT SURPRISING GIVEN THIS IS A NORTHWEST FLOW EVENT/ BUT THE SNOW
RATIOS SHOULD EXCEED 12:1 GIVEN THE COLD PROFILE. HOWEVER...THE
COMBINATION OF STRONG SURFACE WINDS AND UNCERTAINTY IN OVERLAP OF
BEST OMEGA AND THE DENDRITE GROWTH ZONE SUGGESTS RATIOS SHOULD NOT
BE AS THEY COULD BE...PERHAPS 13-15:1. WE HAVE TRACE AMOUNTS IN
THE NORTHERN FORECAST AREA OF CENTRAL MN TO AROUND 3" IN OUR
SOUTH. AT THIS POINT...THE EVENT LOOKS JUST SHY OF NEEDING A
WINTER WEATHER ADVISORY...ESPECIALLY SINCE MOST OF THE ACTIVITY
WILL FALL BETWEEN THE EVENING AND MORNING COMMUTES.
NONETHELESS...THURSDAY NIGHT WILL FEEL MORE LIKE DECEMBER OR
JANUARY WITH FALLING TEMPS...BRISK NORTHERLY WINDS...AND BANDS OF
SNOW.
THE THURSDAY SYSTEM IS THE FIRST OF TWO ARCTIC BOUNDARIES EXPECTED
OVER THE NEXT 7 DAYS. THE WIND AND COLD TEMPS BEHIND THE THURSDAY
SYSTEM WILL DROP WIND CHILLS NEAR OR BELOW ZERO FOR MUCH OF THE
FORECAST AREA...FOR MOST OF THE WEEKEND. ANOTHER...POTENTIALLY
MORE POTENT /IN TERMS OF COLD/ ARCTIC BOUNDARY IS EXPECTED TO
ARRIVE ON TUESDAY. THIS WOULD BE THE COLDEST AIR OF THE SEASON IF
THE GFS/ECMWF PAN OUT. AS A RESULT...MINUS A BRIEF WARM UP ON
MONDAY...MN/WI WILL SEE HIGHS IN THE TEENS AND 20S AND LOWS IN THE
SINGLE DIGITS ABOVE OR BELOW ZERO FROM SATURDAY-WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1207 PM CST WED NOV 20 2013
SOUTHERLY WINDS WILL CONTINUE AHEAD OF AN APPROACHING COLD FRONT
THAT WILL MOVE THROUGH THE REGION LATE TONIGHT. BEHIND THE FRONT
EXPECT MVFR/IFR CIGS AND NORTHWEST WINDS. AFTER APPROX 15Z WINDS
TO INCREASE AND GUST IN EXCESS OF 20KTS AT TIMES. TODAY MOISTURE
WILL SURGE UP FROM THE SOUTH AND BRING SOME MVFR/IFR CONDITIONS
ACROSS WESTERN WI. AS FRONT MOVES INTO THIS EXISTING AREA OF
MVFR/IFR CIGS TONIGHT SOME DRIZZLE AND FOG POSSIBLE...BUT HAVE
LEFT OUT FOR NOW WITH LOW CONFIDENCE.
KMSP...
LATEST HIRES MODELS HAVE THE LOW CIGS JUST TO THE SOUTH AND EAST OF
THE METRO AREA THIS EVENING/ EARLY OVERNIGHT...SO HAVE TRENDED IN
THAT DIRECTION. CONFIDENCE MUCH HIGHER IN MVFR/IFR CIGS THURSDAY
MORNING AS THE COLD FRONT MOVES IN FROM THE NORTHWEST.
/OUTLOOK FOR KMSP/
FRI...MVFR/IFR AND -SN ENDING. THEN VFR. WINDS NNW AT 10KTS.
SAT...VFR/MVFR. WINDS NW AT 15G25KTS.
SUN...VFR. WINDS SW AT 10-15KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
UPDATE...99
SHORT TERM...JRB
LONG TERM...CLF
AVIATION...99
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
ISSUED BY NATIONAL WEATHER SERVICE DULUTH MN
1137 AM CST WED NOV 20 2013
.UPDATE...
ISSUED AT 1122 AM CST WED NOV 20 2013
MINOR ADJUSTMENTS MADE TO EXISTING GRIDS/FCSTS. DECREASED SKY
COVER OVER WRN CWA AND TRENDED DOWNWARD THIS AFTERNOON OVER CTRL
CWA BASED ON LATEST SAT IMAGERY/RAP13 FCST OF MID LVL MOISTURE.
CHANGED PTYPE TO MORE MIXED RAIN/SNOW IN ERN CWA BASED ON
INCREASED POTENTIAL FOR DIABATIC COOLING. LOCATIONS TO THE SOUTH
ALREADY REPORTING SN/IP AT TIMES AND LATEST NAM BUFR SNDGS. HOPWRF
SHOWS ALL SNOW WITH INCREASING ACC POTENTIAL. THIS IS POSSIBLE
CONSIDERING THE USUAL PATTERN OF ALL SNOW OCCURRING IN BULLSEYE OF
GREATEST UVV. ADDED SOME MINOR ACCUMULATIONS FOR NOW. HOWEVER WILL
WATCH SOUTH OF REGION NEXT FEW HRS FOR ANY INDICATIONS OF MORE
ORGANIZED/SUSTAINED POTENTIAL.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST WED NOV 20 2013
EARLY MORNING WATER VAPOR IMAGERY TOGETHER WITH GFS20.00 500MB
HEIGHTS AND WINDS SHOWS SPLIT FLOW ACROSS NORTH AMERICA...WITH THE
NORTHERN STREAM SET UP ACROSS SOUTHERN CANADA...WHILE THE ZONAL
SOUTHERN STREAM WAS POSITIONED FROM SOUTHERN CALIFORNIA TO GEORGIA.
A LOW AMPLITUDE SOUTHERN STREAM SHORTWAVE CURRENTLY LOCATED ACROSS
EASTERN COLORADO WILL TRACK NORTHEASTWARD TODAY...AND THIS WILL
PROVIDE THE LARGE SCALE FORCING FOR A FEW LIGHT RAIN/SNOW SHOWERS IN
WESTERN WISCONSIN AND FAR EASTERN MINNESOTA. RAP FORECAST SOUNDINGS
FOR EAU CLAIRE SHOW AROUND 15UB/S OF LIFT CENTERED AROUND THE 600MB
LAYER..WITH AN ISOTHERMAL LAYER IN THE LOWEST 4000FT HOVERING AROUND
0C. THE WARM NEAR SURFACE TEMPERATURES SHOULD MELT THE PRECIP DURING
THE AFTERNOON...BUT EXPECT A TRANSITION TO A RAIN/SNOW MIX DURING
THE EVENING AND OVERNIGHT HOURS. ANY SNOW ACCUMULATIONS SHOULD BE
CONFINED TO GRASSY SURFACES...AND RANGE FROM A TRACE TO A HALF INCH.
MEANWHILE A STRONGER NORTHERN STREAM SHORTWAVE WILL MOVE ACROSS
SOUTHERN CANADA AND DRIVE A COLD FRONT THROUGH THE DAKOTAS INTO
NORTHWEST MN. A BAND OF POST FRONTAL SNOW WILL GIVE A QUICK 2-3
INCHES OF SNOW UP THERE...BUT THIS WILL WEAKEN AS IT APPROACHES WEST
CENTRAL MN. THEREFORE JUST HAVE CHANCE POPS IN...WITH LITTLE IF ANY
ACCUMULATION. THE MOST NOTICEABLE CHANGE IN THE WEATHER WILL BE
STRONG OVERNIGHT NORTHWEST WINDS OF 25MPH...WITH GUSTS NEAR 35MPH
ASSOCIATED WITH THE COLD AIR ADVECTION BEHIND THE SURFACE FRONT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 340 AM CST WED NOV 20 2013
THE BIG WEATHER STORY OVER THE COMING DAYS IS THE SNOW EVENT
EXPECTED THURSDAY AFTERNOON - THURSDAY NIGHT. THE FEATURE EXPECTED
TO BRING MN/WI SNOW THIS WEEK IS CURRENTLY LOCATED IN THE PACIFIC
NORTHWEST AND NORTHERN ROCKIES THIS MORNING...BUT REALLY DOESN`T
SHOW MUCH AMPLIFICATION THIS MORNING. HOWEVER...THERE IS A WELL
DEFINED ARCTIC BOUNDARY NEAR THE US/CANADIAN BORDER IN
MT/ND...WITH COLD AIR ALREADY SPILLING ACROSS THE BORDER. THIS
WAVE WILL DROP SOUTHEAST OVER THE NEXT COUPLE DAYS...BECOME A
LITTLE SHARPER/WELL-DEFINED AND PASS THROUGH THE FORECAST AREA
BETWEEN 21Z THURSDAY AND 12Z FRIDAY. A SW/NE ORIENTATED BAND OF
600-700MB FGEN WILL SWING THROUGH THE FORECAST THIS AREA DURING
THIS TIME...YIELDING A 3-6 HR WINDOW WITH LIGHT TO MODERATE SNOW.
THE 20.00-06Z NAM HAVE A SHARPER WAVE AND STRONGER FGEN. AS A
RESULT...THE NAM HAS HIGHER TOTALS ACROSS A LARGER PORTION OF THE
FORECAST AREA /A LOT OF 3-4" TOTALS/. THE GEM/GFS/ECMWF ARE A
LITTLE MORE DIFFUSE WITH THE BOUNDARY AND HAVE THE HIGHER TOTALS
/2-3"/ ACROSS MAINLY SOUTH CENTRAL MN. THE LAST 3 RUNS OF THE SREF
HAVE MAINTAINED AROUND 1" FOR MSP...THE NAM HAS SHOWN
1-3.5"...OVER THE LAST FEW RUNS...AND THE GFS HAS BEEN THE
STEADIEST WITH RIGHT AROUND 2". THE QPF ISN`T OVERLY IMPRESSIVE
/NOT SURPRISING GIVEN THIS IS A NORTHWEST FLOW EVENT/ BUT THE SNOW
RATIOS SHOULD EXCEED 12:1 GIVEN THE COLD PROFILE. HOWEVER...THE
COMBINATION OF STRONG SURFACE WINDS AND UNCERTAINTY IN OVERLAP OF
BEST OMEGA AND THE DENDRITE GROWTH ZONE SUGGESTS RATIOS SHOULD NOT
BE AS THEY COULD BE...PERHAPS 13-15:1. WE HAVE TRACE AMOUNTS IN
THE NORTHERN FORECAST AREA OF CENTRAL MN TO AROUND 3" IN OUR
SOUTH. AT THIS POINT...THE EVENT LOOKS JUST SHY OF NEEDING A
WINTER WEATHER ADVISORY...ESPECIALLY SINCE MOST OF THE ACTIVITY
WILL FALL BETWEEN THE EVENING AND MORNING COMMUTES.
NONETHELESS...THURSDAY NIGHT WILL FEEL MORE LIKE DECEMBER OR
JANUARY WITH FALLING TEMPS...BRISK NORTHERLY WINDS...AND BANDS OF
SNOW.
THE THURSDAY SYSTEM IS THE FIRST OF TWO ARCTIC BOUNDARIES EXPECTED
OVER THE NEXT 7 DAYS. THE WIND AND COLD TEMPS BEHIND THE THURSDAY
SYSTEM WILL DROP WIND CHILLS NEAR OR BELOW ZERO FOR MUCH OF THE
FORECAST AREA...FOR MOST OF THE WEEKEND. ANOTHER...POTENTIALLY
MORE POTENT /IN TERMS OF COLD/ ARCTIC BOUNDARY IS EXPECTED TO
ARRIVE ON TUESDAY. THIS WOULD BE THE COLDEST AIR OF THE SEASON IF
THE GFS/ECMWF PAN OUT. AS A RESULT...MINUS A BRIEF WARM UP ON
MONDAY...MN/WI WILL SEE HIGHS IN THE TEENS AND 20S AND LOWS IN THE
SINGLE DIGITS ABOVE OR BELOW ZERO FROM SATURDAY-WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 555 AM CST WED NOV 20 2013
SOUTHERLY WINDS WILL CONTINUE AHEAD OF AN APPROACHING COLD FRONT
THAT WILL MOVE THROUGH THE REGION LATER TONIGHT. BEHIND THE FRONT
EXPECT MVFR/IFR CIGS AND NORTHWEST WINDS OF GUSTING IN EXCESS OF
25KTS AT TIMES. MEANWHILE TODAY MOISTURE WILL SURGE UP FROM THE
SOUTH AND BRING SOME MVFR/IFR CONDITIONS ACROSS WESTERN MN...WHICH
WILL LINGER OVERNIGHT AT KEAU AND KRNH.
KMSP...
LATEST HIRES MODELS HAVE THE LOW CIGS JUST TO THE SOUTH AND EAST
OF THE METRO AREA THIS EVENING/OVERNIGHT...SO HAVE TRENDED IN THAT
DIRECTION. CONFIDENCE IS HIGHER IN MVFR CIGS THURSDAY MORNING AS
THE COLD FRONT MOVES IN FROM THE NORTHWEST.
/OUTLOOK FOR KMSP/
THU...VFR WITH MVFR/IFR AND -SN LATE. WINDS NNW AT 15G20KTS.
FRI...MVFR/IFR AND -SN ENDING. THEN VFR. WINDS NNW AT 10KTS.
SAT...VFR/MVFR. WINDS NW AT 15G25KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
UPDATE...99
SHORT TERM...JRB
LONG TERM...CLF
AVIATION...JRB
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1128 AM CST WED NOV 20 2013
.UPDATE...
ISSUED AT 1124 AM CST WED NOV 20 2013
LOW AMPLITUDE FAST-MOVING S/W TROF LOCATED OVER IOWA AS OF LATE
THIS MORNING WILL RAPIDLY EJECT NORTHEASTWARD TO THE UPPER
PENINSULA OF MICHIGAN BY LATE THIS EVENING WHILE DEAMPLIFYING.
THIS WAVE IS MOSTLY A MID-LEVEL FEATURE..AND CROSS SECTIONS REVEAL
A FAIR AMOUNT OF INSTABILITY AVAILABLE FOR FORCING TO ACT ON IN
THE 700-500 MB LAYER. THIS SEEMS TO BE SUPPORTED BY THE
DEVELOPMENT OF CONVECTIVE RADAR ECHOES AND SEVERAL LIGHTNING
STRIKES OVER NCENT IOWA OVER THE PAST 90 MINUTES OR SO. WHILE PEAK
PERIOD OF STRONGEST ASCENT IS ONLY EXPECTED TO BE 2 TO 4
HOURS..MAGNITUDE OF VERTICAL MOTIONS AND PRECIP RATES MAY BE
SUFFICIENT TO ELICIT A CHANGE OVER TO WET SNOW FOR A SHORT TIME
ACROSS OUR FAR SOUTHEAST CWA LATE THIS AFTERNOON/EARLY EVENING.
STILL..A PRECISE CALL ON PTYPE IS QUITE DIFFICULT AS NEAR SURFACE
TEMPS HAVE RISEN INTO THE LOWER 40S..BUT YET AIRMASS IS STILL QUITE
FAR FROM SATURATION AS WELL. THUS..IT WILL BE A BATTLE BETWEEN
DIABATIC/EVAPORATIONAL/SUBLIMATION COOLING EFFECTS AND NEAR SURFACE
WARM AIR..WITH THE ULTIMATE DETERMINING FACTOR LIKELY BEING PRECIP
RATE IN MANY LOCALES.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY AFTERNOON)
ISSUED AT 345 AM CST WED NOV 20 2013
MAIN CONCERNS IN THE SHORT TERM ARE FOCUSED AROUND THE RAIN/SNOW MIX
EXPECTED TO DEVELOP LATE THIS MORNING AND CONTINUE THROUGH THE
AFTERNOON AND EVENING MAINLY ACROSS NW WI EVENTUALLY SPREADING
WWD INTO EXTREME E-CENTRAL/NE MN...AND THE COLD FRONT CURRENTLY
OVER ERN ND EXPECTED TO PUSH EWD THROUGH THE NORTHLAND TONIGHT AND
EARLY THURSDAY WITH SCATTERED SNOW SHOWERS AND GUSTY N/NW WINDS
AND FALLING TEMPERATURES THROUGH THUR AFTERNOON. THE OTHER AREA OF
CONCERN WILL BE THE LAKE EFFECT SNOW POTENTIAL ALONG THE SOUTH
SHORE THUR AFTERNOON. FAVORABLE CONDITIONS WILL ALLOW FOR
ACCUMULATING LES TO INITIATE AND CONTINUE THROUGH THE NIGHT.
WEAK UPPER TROUGH CURRENTLY SITUATED OVER THE WRN US WITH A LOW
AMPLITUDE RIDGE ACROSS THE ERN GREAT LAKES/NERN US. AT THE
SFC...HIGH PRESSURE IS DOMINATING THE CNTRL GRT LKS AND AN AREA OF
LOW PRESSURE IS DEVELOPING OVER THE FRONT RANGE OF THE ROCKIES.
THIS SET UP IS PRODUCING A TIGHT PRESSURE GRADIENT ACROSS THE
UPPER MIDWEST AND FAVORABLE CONDITIONS FOR STRONG SLY FLOW AND
GUSTY WINDS. THIS WARM FLOW HAS ALLOW TEMPERATURES TO REMAIN MILD
THIS MORNING...WITH TEMPS FROM THE MID 30S TO LOWER 40S.
A WEAK S/W WILL EJECT NEWD OUT OF THE SRN ROCKIES/PLAINS THIS
MORNING AND WILL TRACK FROM OKLA TO THE MICH U.P. TODAY AND TONIGHT.
THIS SYSTEM WILL INTERACT WITH THE RELATIVELY WARM AND MOIST AIR
MASS IN PLACE TO PRODUCE MAINLY A RAIN/SNOW MIX OVER THE ERN HALF OF
THE NORTHLAND. TEMP PROFILES IN THE MID LEVELS WILL HOVER AROUND OR
JUST BELOW FREEZING...WITH SFC TEMPS A FEW DEG ABOVE 32F. THIS
SET UP SHOULD BE CONDUCIVE FOR A RA/SN MIX. A FEW OF THESE SHOWERS
COULD BECOME ENHANCED AS THE THERMAL GRADIENT TIGHTENS THIS
AFTERNOON/EVENING WITH THE APPROACH OF A STRONG COLD FRONT FROM THE
WEST. THE STRONG MOISTURE CONTENT AND POTENTIALLY INTENSIFYING
SHOWERS MIGHT ALLOW THE PRECIP TO CHANGE OVER TO ALL SNOW IN SOME
LOCATIONS. HOWEVER...WILL BE DIFFICULT TO NAIL DOWN THESE SMALL
SCALE DETAILS.
TONIGHT AND MAINLY TOMORROW THE MAIN AREA OF CONCERN SHIFTS TO THE
APPROACHING COLD FRONT. THE FRONT IS EXPECTED TO TRACK FAIRLY SLOWLY
EWD THROUGH NRN MN LATE TONIGHT AND THROUGH THUR MORNING AS THE S/W
TO THE EAST LIFTS INTO THE GRT LKS. THE COLD FRONT WILL HAVE AN
ARCTIC AIR MASS BEHIND IT AND USHER IN SNOW SHOWERS OVER MUCH OF THE
NORTHLAND. THE SNOW WILL BE FAIRLY WIDESPREAD DURING THE DAY
THURSDAY...BUT ONLY LIGHT AMTS ARE EXPECTED WITH DRY AIR MOVING
IN BEHIND THE FRONT. HIGH PRESSURE WILL BUILD IN OVER THE
DAKOTAS...NW MN...AND WRN ONTARIO THUR AFTERNOON AND ALLOW WINDS
TO SHIFT TO THE NORTH AND BECOME QUITE GUSTY. THE COLD TEMPS AND
STRONG WINDS WILL MAKE CONDITIONS FEEL VERY COLD. HIGHS WILL LEVEL
OUT IN THE TEENS TO THE NORTH AND LOW 30S TO THE SOUTH...WITH
STEADY OR FALLING TEMPS FROM WEST TO EAST THROUGH THE DAY.
THE COLD AIR MASS MOVING IN AND VEERING NORTH WINDS OVER WRN LAKE
SUPERIOR WILL PRODUCE FAVORABLE CONDITIONS FOR LAKE EFFECT SNOW
ALONG THE SOUTH SHORE BEGINNING THUR AFTERNOON. BL MOISTURE PROFILES
WILL BE HIGH ENOUGH DURING THE AFTERNOON TO ALLOW THE LES TO
INITIATE BEFORE THE DRIER AIR MOVES IN. STEEP LOW LVL LAPSE RATES
AND WEAK INSTABILITY WITH A LONG FETCH OVER LS WILL ALL AID IN THE
DEVELOPMENT OF SNOW SHOWERS OVER BAYFIELD ASHLAND AND IRON
COUNTIES. COULD SEE AN INCH OR SO OF ACCUMULATION BEFORE 6 PM
THURSDAY...AFTER WHICH ADDITIONAL SNOW IS LIKELY.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 345 AM CST WED NOV 20 2013
THE EXTENDED PERIOD WILL FEATURE SOME VERY COLD AIR MOVING OVER THE
NORTHLAND FRIDAY INTO FRIDAY NIGHT AND PERIODS OF LAKE EFFECT SNOW.
A COLD FRONT WILL MOVE THROUGH THE REGION THURSDAY. THURSDAY
NIGHT...A MID LEVEL FRONT AND FGEN WILL BRING A CHANCE FOR SNOW TO
ABOUT THE SOUTHERN HALF OF THE NORTHLAND...WITH CHANCES HIGHEST OVER
NORTHWEST WISCONSIN. SOME LIGHT SNOWFALL...UP TO 2 INCHES IN
SPOTS...WILL BE POSSIBLE. THE EXCEPTION WILL BE THE SNOWBELT OF
ASHLAND AND IRON COUNTIES WHICH SHOULD SEE HIGHER SNOWFALL DUE TO
NORTHERLY WINDS DEVELOPING AND THE STABILITY BEING LOW ENOUGH FOR
LAKE EFFECT SNOW.
ANOTHER SHORTWAVE AND STRONGER COLD FRONT WILL SWEEP THROUGH THE
AREA FRIDAY INTO FRIDAY NIGHT. THE FRONT WILL BRING A CHANCE FOR
LIGHT SNOW...WITH LIMITED SNOW ACCUMULATIONS EXPECTED. AT THIS
TIME...WE THINK A NARROW BAND OF STRONGER FAST MOVING SNOW SHOWERS
WILL BE POSSIBLE WITH THE FRONT. 850MB TEMPS ARE FORECAST TO DROP TO
-23C FAR NORTH TO -19C IN OUR SOUTHERN ZONES BY 12Z SAT. WE ARE
EXPECTING LOWS SATURDAY MORNING TO BE AROUND ZERO NORTH TO 10 TO 15
ACROSS NORTHERN WISCONSIN. TEMPS COULD BE EVEN COLDER IF WINDS CAN
DROP OFF MORE THAN IS EXPECTED ATTM. HIGHS SATURDAY WILL ONLY REACH
AROUND 10 ABOVE ACROSS FAR NORTHERN MINNESOTA...TO THE TEENS SOUTH.
THE LAKE WILL BECOME ACTIVE AGAIN FRIDAY NIGHT INTO SATURDAY
NIGHT...WITH SOME SIGNIFICANT SNOWFALL LIKELY ACROSS THE SNOWBELT OF
ASHLAND AND IRON COUNTIES WITH THE VERY COLD TEMPS CROSSING THE LAKE
WITH A FAVORABLE FETCH.
WAA WILL DEVELOP SATURDAY NIGHT INTO SUNDAY...WITH SOME LIGHT SNOW
POSSIBLE ACROSS THE REGION. ANOTHER STRONG COLD FRONT WILL THEN
SWEEP THROUGH THE REGION MONDAY INTO MONDAY NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 550 AM CST WED NOV 20 2013
VFR CONDITIONS COVERED THE NORTHLAND EARLY THIS MORNING. A LLJ
REMAINED OVER MUCH OF THE NORTHLAND CREATING SOME LLWS THAT WILL
CONTINUE EARLY THIS MORNING.
A COLD FRONT IN NORTHWEST MINNESOTA WILL CONTINUE TO SLOWLY MOVE
SOUTHEAST TODAY. MVFR CEILINGS WILL MOVE IN FROM THE
NORTHWEST...AND WERE SEEN IN OBSERVATIONS/SATELLITE OVER PORTIONS
OF MB/OT. THE RAP WAS HANDLING THESE CLOUDS FAIRLY WELL. MORE MVFR
OR LOW END VFR CLOUDS ARE EXPECTED TO DEVELOP AND MOVE NORTH
TOWARD NORTHERN WISCONSIN THIS AFTERNOON. MVFR OR IFR CEILINGS ARE
EXPECTED OVER ALL AREAS TONIGHT. SOME LIGHT PRECIPITATION WILL
DEVELOP AS WELL TODAY...BOTH BEHIND THE COLD FRONT...AND WELL
AHEAD OVER NORTHERN WISCONSIN/FAR EASTERN MINNESOTA LATER THIS
AFTERNOON. THE PRECIPITATION MAY START OUT AS RAIN...OR A
MIX...BUT WILL TRANSITION TO MAINLY SNOW TONIGHT. SOUNDINGS ALSO
SUGGEST SOME DRYING ALOFT LATER TONIGHT WHICH COULD LEAD TO
DRIZZLE AS WE LOSE ICE IN THE CLOUDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 43 26 27 14 / 30 30 30 30
INL 40 16 19 5 / 40 60 30 10
BRD 46 22 25 13 / 10 20 20 20
HYR 41 30 30 19 / 40 50 40 60
ASX 44 32 32 20 / 40 50 60 50
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR LSZ121-
142-143-146>148.
SMALL CRAFT ADVISORY UNTIL 10 PM CST THIS EVENING FOR LSZ140-141.
&&
$$
UPDATE...MILLER
SHORT TERM...BJT
LONG TERM...MELDE
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
603 AM CST WED NOV 20 2013
.UPDATED FOR 12Z AVIATION DISCUSSION...
ISSUED AT 555 AM CST WED NOV 20 2013
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST WED NOV 20 2013
EARLY MORNING WATER VAPOR IMAGERY TOGETHER WITH GFS20.00 500MB
HEIGHTS AND WINDS SHOWS SPLIT FLOW ACROSS NORTH AMERICA...WITH THE
NORTHERN STREAM SET UP ACROSS SOUTHERN CANADA...WHILE THE ZONAL
SOUTHERN STREAM WAS POSITIONED FROM SOUTHERN CALIFORNIA TO GEORGIA.
A LOW AMPLITUDE SOUTHERN STREAM SHORTWAVE CURRENTLY LOCATED ACROSS
EASTERN COLORADO WILL TRACK NORTHEASTWARD TODAY...AND THIS WILL
PROVIDE THE LARGE SCALE FORCING FOR A FEW LIGHT RAIN/SNOW SHOWERS IN
WESTERN WISCONSIN AND FAR EASTERN MINNESOTA. RAP FORECAST SOUNDINGS
FOR EAU CLAIRE SHOW AROUND 15UB/S OF LIFT CENTERED AROUND THE 600MB
LAYER..WITH AN ISOTHERMAL LAYER IN THE LOWEST 4000FT HOVERING AROUND
0C. THE WARM NEAR SURFACE TEMPERATURES SHOULD MELT THE PRECIP DURING
THE AFTERNOON...BUT EXPECT A TRANSITION TO A RAIN/SNOW MIX DURING
THE EVENING AND OVERNIGHT HOURS. ANY SNOW ACCUMULATIONS SHOULD BE
CONFINED TO GRASSY SURFACES...AND RANGE FROM A TRACE TO A HALF INCH.
MEANWHILE A STRONGER NORTHERN STREAM SHORTWAVE WILL MOVE ACROSS
SOUTHERN CANADA AND DRIVE A COLD FRONT THROUGH THE DAKOTAS INTO
NORTHWEST MN. A BAND OF POST FRONTAL SNOW WILL GIVE A QUICK 2-3
INCHES OF SNOW UP THERE...BUT THIS WILL WEAKEN AS IT APPROACHES WEST
CENTRAL MN. THEREFORE JUST HAVE CHANCE POPS IN...WITH LITTLE IF ANY
ACCUMULATION. THE MOST NOTICEABLE CHANGE IN THE WEATHER WILL BE
STRONG OVERNIGHT NORTHWEST WINDS OF 25MPH...WITH GUSTS NEAR 35MPH
ASSOCIATED WITH THE COLD AIR ADVECTION BEHIND THE SURFACE FRONT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 340 AM CST WED NOV 20 2013
THE BIG WEATHER STORY OVER THE COMING DAYS IS THE SNOW EVENT
EXPECTED THURSDAY AFTERNOON - THURSDAY NIGHT. THE FEATURE EXPECTED
TO BRING MN/WI SNOW THIS WEEK IS CURRENTLY LOCATED IN THE PACIFIC
NORTHWEST AND NORTHERN ROCKIES THIS MORNING...BUT REALLY DOESN`T
SHOW MUCH AMPLIFICATION THIS MORNING. HOWEVER...THERE IS A WELL
DEFINED ARCTIC BOUNDARY NEAR THE US/CANADIAN BORDER IN
MT/ND...WITH COLD AIR ALREADY SPILLING ACROSS THE BORDER. THIS
WAVE WILL DROP SOUTHEAST OVER THE NEXT COUPLE DAYS...BECOME A
LITTLE SHARPER/WELL-DEFINED AND PASS THROUGH THE FORECAST AREA
BETWEEN 21Z THURSDAY AND 12Z FRIDAY. A SW/NE ORIENTATED BAND OF
600-700MB FGEN WILL SWING THROUGH THE FORECAST THIS AREA DURING
THIS TIME...YIELDING A 3-6 HR WINDOW WITH LIGHT TO MODERATE SNOW.
THE 20.00-06Z NAM HAVE A SHARPER WAVE AND STRONGER FGEN. AS A
RESULT...THE NAM HAS HIGHER TOTALS ACROSS A LARGER PORTION OF THE
FORECAST AREA /A LOT OF 3-4" TOTALS/. THE GEM/GFS/ECMWF ARE A
LITTLE MORE DIFFUSE WITH THE BOUNDARY AND HAVE THE HIGHER TOTALS
/2-3"/ ACROSS MAINLY SOUTH CENTRAL MN. THE LAST 3 RUNS OF THE SREF
HAVE MAINTAINED AROUND 1" FOR MSP...THE NAM HAS SHOWN
1-3.5"...OVER THE LAST FEW RUNS...AND THE GFS HAS BEEN THE
STEADIEST WITH RIGHT AROUND 2". THE QPF ISN`T OVERLY IMPRESSIVE
/NOT SURPRISING GIVEN THIS IS A NORTHWEST FLOW EVENT/ BUT THE SNOW
RATIOS SHOULD EXCEED 12:1 GIVEN THE COLD PROFILE. HOWEVER...THE
COMBINATION OF STRONG SURFACE WINDS AND UNCERTAINTY IN OVERLAP OF
BEST OMEGA AND THE DENDRITE GROWTH ZONE SUGGESTS RATIOS SHOULD NOT
BE AS THEY COULD BE...PERHAPS 13-15:1. WE HAVE TRACE AMOUNTS IN
THE NORTHERN FORECAST AREA OF CENTRAL MN TO AROUND 3" IN OUR
SOUTH. AT THIS POINT...THE EVENT LOOKS JUST SHY OF NEEDING A
WINTER WEATHER ADVISORY...ESPECIALLY SINCE MOST OF THE ACTIVITY
WILL FALL BETWEEN THE EVENING AND MORNING COMMUTES.
NONETHELESS...THURSDAY NIGHT WILL FEEL MORE LIKE DECEMBER OR
JANUARY WITH FALLING TEMPS...BRISK NORTHERLY WINDS...AND BANDS OF
SNOW.
THE THURSDAY SYSTEM IS THE FIRST OF TWO ARCTIC BOUNDARIES EXPECTED
OVER THE NEXT 7 DAYS. THE WIND AND COLD TEMPS BEHIND THE THURSDAY
SYSTEM WILL DROP WIND CHILLS NEAR OR BELOW ZERO FOR MUCH OF THE
FORECAST AREA...FOR MOST OF THE WEEKEND. ANOTHER...POTENTIALLY
MORE POTENT /IN TERMS OF COLD/ ARCTIC BOUNDARY IS EXPECTED TO
ARRIVE ON TUESDAY. THIS WOULD BE THE COLDEST AIR OF THE SEASON IF
THE GFS/ECMWF PAN OUT. AS A RESULT...MINUS A BRIEF WARM UP ON
MONDAY...MN/WI WILL SEE HIGHS IN THE TEENS AND 20S AND LOWS IN THE
SINGLE DIGITS ABOVE OR BELOW ZERO FROM SATURDAY-WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 555 AM CST WED NOV 20 2013
SOUTHERLY WINDS WILL CONTINUE AHEAD OF AN APPROACHING COLD FRONT
THAT WILL MOVE THROUGH THE REGION LATER TONIGHT. BEHIND THE FRONT
EXPECT MVFR/IFR CIGS AND NORTHWEST WINDS OF GUSTING IN EXCESS OF
25KTS AT TIMES. MEANWHILE TODAY MOISTURE WILL SURGE UP FROM THE
SOUTH AND BRING SOME MVFR/IFR CONDITIONS ACROSS WESTERN MN...WHICH
WILL LINGER OVERNIGHT AT KEAU AND KRNH.
KMSP...
LATEST HIRES MODELS HAVE THE LOW CIGS JUST TO THE SOUTH AND EAST
OF THE METRO AREA THIS EVENING/OVERNIGHT...SO HAVE TRENDED IN THAT
DIRECTION. CONFIDENCE IS HIGHER IN MVFR CIGS THURSDAY MORNING AS
THE COLD FRONT MOVES IN FROM THE NORTHWEST.
/OUTLOOK FOR KMSP/
THU...VFR WITH MVFR/IFR AND -SN LATE. WINDS NNW AT 15G20KTS.
FRI...MVFR/IFR AND -SN ENDING. THEN VFR. WINDS NNW AT 10KTS.
SAT...VFR/MVFR. WINDS NW AT 15G25KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...CLF
AVIATION...JRB
AREA FORECAST DISCUSSION
NWS DULUTH MN
550 AM CST WED NOV 20 2013
.SHORT TERM...(TODAY THROUGH THURSDAY AFTERNOON)
ISSUED AT 345 AM CST WED NOV 20 2013
MAIN CONCERNS IN THE SHORT TERM ARE FOCUSED AROUND THE RAIN/SNOW MIX
EXPECTED TO DEVELOP LATE THIS MORNING AND CONTINUE THROUGH THE
AFTERNOON AND EVENING MAINLY ACROSS NW WI EVENTUALLY SPREADING
WWD INTO EXTREME E-CENTRAL/NE MN...AND THE COLD FRONT CURRENTLY
OVER ERN ND EXPECTED TO PUSH EWD THROUGH THE NORTHLAND TONIGHT AND
EARLY THURSDAY WITH SCATTERED SNOW SHOWERS AND GUSTY N/NW WINDS
AND FALLING TEMPERATURES THROUGH THUR AFTERNOON. THE OTHER AREA OF
CONCERN WILL BE THE LAKE EFFECT SNOW POTENTIAL ALONG THE SOUTH
SHORE THUR AFTERNOON. FAVORABLE CONDITIONS WILL ALLOW FOR
ACCUMULATING LES TO INITIATE AND CONTINUE THROUGH THE NIGHT.
WEAK UPPER TROUGH CURRENTLY SITUATED OVER THE WRN US WITH A LOW
AMPLITUDE RIDGE ACROSS THE ERN GREAT LAKES/NERN US. AT THE
SFC...HIGH PRESSURE IS DOMINATING THE CNTRL GRT LKS AND AN AREA OF
LOW PRESSURE IS DEVELOPING OVER THE FRONT RANGE OF THE ROCKIES.
THIS SET UP IS PRODUCING A TIGHT PRESSURE GRADIENT ACROSS THE
UPPER MIDWEST AND FAVORABLE CONDITIONS FOR STRONG SLY FLOW AND
GUSTY WINDS. THIS WARM FLOW HAS ALLOW TEMPERATURES TO REMAIN MILD
THIS MORNING...WITH TEMPS FROM THE MID 30S TO LOWER 40S.
A WEAK S/W WILL EJECT NEWD OUT OF THE SRN ROCKIES/PLAINS THIS
MORNING AND WILL TRACK FROM OKLA TO THE MICH U.P. TODAY AND TONIGHT.
THIS SYSTEM WILL INTERACT WITH THE RELATIVELY WARM AND MOIST AIR
MASS IN PLACE TO PRODUCE MAINLY A RAIN/SNOW MIX OVER THE ERN HALF OF
THE NORTHLAND. TEMP PROFILES IN THE MID LEVELS WILL HOVER AROUND OR
JUST BELOW FREEZING...WITH SFC TEMPS A FEW DEG ABOVE 32F. THIS
SET UP SHOULD BE CONDUCIVE FOR A RA/SN MIX. A FEW OF THESE SHOWERS
COULD BECOME ENHANCED AS THE THERMAL GRADIENT TIGHTENS THIS
AFTERNOON/EVENING WITH THE APPROACH OF A STRONG COLD FRONT FROM THE
WEST. THE STRONG MOISTURE CONTENT AND POTENTIALLY INTENSIFYING
SHOWERS MIGHT ALLOW THE PRECIP TO CHANGE OVER TO ALL SNOW IN SOME
LOCATIONS. HOWEVER...WILL BE DIFFICULT TO NAIL DOWN THESE SMALL
SCALE DETAILS.
TONIGHT AND MAINLY TOMORROW THE MAIN AREA OF CONCERN SHIFTS TO THE
APPROACHING COLD FRONT. THE FRONT IS EXPECTED TO TRACK FAIRLY SLOWLY
EWD THROUGH NRN MN LATE TONIGHT AND THROUGH THUR MORNING AS THE S/W
TO THE EAST LIFTS INTO THE GRT LKS. THE COLD FRONT WILL HAVE AN
ARCTIC AIR MASS BEHIND IT AND USHER IN SNOW SHOWERS OVER MUCH OF THE
NORTHLAND. THE SNOW WILL BE FAIRLY WIDESPREAD DURING THE DAY
THURSDAY...BUT ONLY LIGHT AMTS ARE EXPECTED WITH DRY AIR MOVING
IN BEHIND THE FRONT. HIGH PRESSURE WILL BUILD IN OVER THE
DAKOTAS...NW MN...AND WRN ONTARIO THUR AFTERNOON AND ALLOW WINDS
TO SHIFT TO THE NORTH AND BECOME QUITE GUSTY. THE COLD TEMPS AND
STRONG WINDS WILL MAKE CONDITIONS FEEL VERY COLD. HIGHS WILL LEVEL
OUT IN THE TEENS TO THE NORTH AND LOW 30S TO THE SOUTH...WITH
STEADY OR FALLING TEMPS FROM WEST TO EAST THROUGH THE DAY.
THE COLD AIR MASS MOVING IN AND VEERING NORTH WINDS OVER WRN LAKE
SUPERIOR WILL PRODUCE FAVORABLE CONDITIONS FOR LAKE EFFECT SNOW
ALONG THE SOUTH SHORE BEGINNING THUR AFTERNOON. BL MOISTURE PROFILES
WILL BE HIGH ENOUGH DURING THE AFTERNOON TO ALLOW THE LES TO
INITIATE BEFORE THE DRIER AIR MOVES IN. STEEP LOW LVL LAPSE RATES
AND WEAK INSTABILITY WITH A LONG FETCH OVER LS WILL ALL AID IN THE
DEVELOPMENT OF SNOW SHOWERS OVER BAYFIELD ASHLAND AND IRON
COUNTIES. COULD SEE AN INCH OR SO OF ACCUMULATION BEFORE 6 PM
THURSDAY...AFTER WHICH ADDITIONAL SNOW IS LIKELY.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 345 AM CST WED NOV 20 2013
THE EXTENDED PERIOD WILL FEATURE SOME VERY COLD AIR MOVING OVER THE
NORTHLAND FRIDAY INTO FRIDAY NIGHT AND PERIODS OF LAKE EFFECT SNOW.
A COLD FRONT WILL MOVE THROUGH THE REGION THURSDAY. THURSDAY
NIGHT...A MID LEVEL FRONT AND FGEN WILL BRING A CHANCE FOR SNOW TO
ABOUT THE SOUTHERN HALF OF THE NORTHLAND...WITH CHANCES HIGHEST OVER
NORTHWEST WISCONSIN. SOME LIGHT SNOWFALL...UP TO 2 INCHES IN
SPOTS...WILL BE POSSIBLE. THE EXCEPTION WILL BE THE SNOWBELT OF
ASHLAND AND IRON COUNTIES WHICH SHOULD SEE HIGHER SNOWFALL DUE TO
NORTHERLY WINDS DEVELOPING AND THE STABILITY BEING LOW ENOUGH FOR
LAKE EFFECT SNOW.
ANOTHER SHORTWAVE AND STRONGER COLD FRONT WILL SWEEP THROUGH THE
AREA FRIDAY INTO FRIDAY NIGHT. THE FRONT WILL BRING A CHANCE FOR
LIGHT SNOW...WITH LIMITED SNOW ACCUMULATIONS EXPECTED. AT THIS
TIME...WE THINK A NARROW BAND OF STRONGER FAST MOVING SNOW SHOWERS
WILL BE POSSIBLE WITH THE FRONT. 850MB TEMPS ARE FORECAST TO DROP TO
-23C FAR NORTH TO -19C IN OUR SOUTHERN ZONES BY 12Z SAT. WE ARE
EXPECTING LOWS SATURDAY MORNING TO BE AROUND ZERO NORTH TO 10 TO 15
ACROSS NORTHERN WISCONSIN. TEMPS COULD BE EVEN COLDER IF WINDS CAN
DROP OFF MORE THAN IS EXPECTED ATTM. HIGHS SATURDAY WILL ONLY REACH
AROUND 10 ABOVE ACROSS FAR NORTHERN MINNESOTA...TO THE TEENS SOUTH.
THE LAKE WILL BECOME ACTIVE AGAIN FRIDAY NIGHT INTO SATURDAY
NIGHT...WITH SOME SIGNIFICANT SNOWFALL LIKELY ACROSS THE SNOWBELT OF
ASHLAND AND IRON COUNTIES WITH THE VERY COLD TEMPS CROSSING THE LAKE
WITH A FAVORABLE FETCH.
WAA WILL DEVELOP SATURDAY NIGHT INTO SUNDAY...WITH SOME LIGHT SNOW
POSSIBLE ACROSS THE REGION. ANOTHER STRONG COLD FRONT WILL THEN
SWEEP THROUGH THE REGION MONDAY INTO MONDAY NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 550 AM CST WED NOV 20 2013
VFR CONDITIONS COVERED THE NORTHLAND EARLY THIS MORNING. A LLJ
REMAINED OVER MUCH OF THE NORTHLAND CREATING SOME LLWS THAT WILL
CONTINUE EARLY THIS MORNING.
A COLD FRONT IN NORTHWEST MINNESOTA WILL CONTINUE TO SLOWLY MOVE
SOUTHEAST TODAY. MVFR CEILINGS WILL MOVE IN FROM THE
NORTHWEST...AND WERE SEEN IN OBSERVATIONS/SATELLITE OVER PORTIONS
OF MB/OT. THE RAP WAS HANDLING THESE CLOUDS FAIRLY WELL. MORE MVFR
OR LOW END VFR CLOUDS ARE EXPECTED TO DEVELOP AND MOVE NORTH
TOWARD NORTHERN WISCONSIN THIS AFTERNOON. MVFR OR IFR CEILINGS ARE
EXPECTED OVER ALL AREAS TONIGHT. SOME LIGHT PRECIPITATION WILL
DEVELOP AS WELL TODAY...BOTH BEHIND THE COLD FRONT...AND WELL
AHEAD OVER NORTHERN WISCONSIN/FAR EASTERN MINNESOTA LATER THIS
AFTERNOON. THE PRECIPITATION MAY START OUT AS RAIN...OR A
MIX...BUT WILL TRANSITION TO MAINLY SNOW TONIGHT. SOUNDINGS ALSO
SUGGEST SOME DRYING ALOFT LATER TONIGHT WHICH COULD LEAD TO
DRIZZLE AS WE LOSE ICE IN THE CLOUDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 42 26 27 14 / 30 30 30 30
INL 38 16 19 5 / 20 60 30 10
BRD 45 22 25 13 / 10 20 20 20
HYR 41 30 30 19 / 40 50 40 60
ASX 43 32 32 20 / 30 50 60 50
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR LSZ121-
142-143-146>148.
SMALL CRAFT ADVISORY UNTIL 10 AM CST THIS MORNING FOR LSZ144-145.
SMALL CRAFT ADVISORY UNTIL 10 PM CST THIS EVENING FOR LSZ140-141.
&&
$$
SHORT TERM...BJT
LONG TERM...MELDE
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
425 AM CST WED NOV 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST WED NOV 20 2013
EARLY MORNING WATER VAPOR IMAGERY TOGETHER WITH GFS20.00 500MB
HEIGHTS AND WINDS SHOWS SPLIT FLOW ACROSS NORTH AMERICA...WITH THE
NORTHERN STREAM SET UP ACROSS SOUTHERN CANADA...WHILE THE ZONAL
SOUTHERN STREAM WAS POSITIONED FROM SOUTHERN CALIFORNIA TO GEORGIA.
A LOW AMPLITUDE SOUTHERN STREAM SHORTWAVE CURRENTLY LOCATED ACROSS
EASTERN COLORADO WILL TRACK NORTHEASTWARD TODAY...AND THIS WILL
PROVIDE THE LARGE SCALE FORCING FOR A FEW LIGHT RAIN/SNOW SHOWERS IN
WESTERN WISCONSIN AND FAR EASTERN MINNESOTA. RAP FORECAST SOUNDINGS
FOR EAU CLAIRE SHOW AROUND 15UB/S OF LIFT CENTERED AROUND THE 600MB
LAYER..WITH AN ISOTHERMAL LAYER IN THE LOWEST 4000FT HOVERING AROUND
0C. THE WARM NEAR SURFACE TEMPERATURES SHOULD MELT THE PRECIP DURING
THE AFTERNOON...BUT EXPECT A TRANSITION TO A RAIN/SNOW MIX DURING
THE EVENING AND OVERNIGHT HOURS. ANY SNOW ACCUMULATIONS SHOULD BE
CONFINED TO GRASSY SURFACES...AND RANGE FROM A TRACE TO A HALF INCH.
MEANWHILE A STRONGER NORTHERN STREAM SHORTWAVE WILL MOVE ACROSS
SOUTHERN CANADA AND DRIVE A COLD FRONT THROUGH THE DAKOTAS INTO
NORTHWEST MN. A BAND OF POST FRONTAL SNOW WILL GIVE A QUICK 2-3
INCHES OF SNOW UP THERE...BUT THIS WILL WEAKEN AS IT APPROACHES WEST
CENTRAL MN. THEREFORE JUST HAVE CHANCE POPS IN...WITH LITTLE IF ANY
ACCUMULATION. THE MOST NOTICEABLE CHANGE IN THE WEATHER WILL BE
STRONG OVERNIGHT NORTHWEST WINDS OF 25MPH...WITH GUSTS NEAR 35MPH
ASSOCIATED WITH THE COLD AIR ADVECTION BEHIND THE SURFACE FRONT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 340 AM CST WED NOV 20 2013
THE BIG WEATHER STORY OVER THE COMING DAYS IS THE SNOW EVENT
EXPECTED THURSDAY AFTERNOON - THURSDAY NIGHT. THE FEATURE EXPECTED
TO BRING MN/WI SNOW THIS WEEK IS CURRENTLY LOCATED IN THE PACIFIC
NORTHWEST AND NORTHERN ROCKIES THIS MORNING...BUT REALLY DOESN`T
SHOW MUCH AMPLIFICATION THIS MORNING. HOWEVER...THERE IS A WELL
DEFINED ARCTIC BOUNDARY NEAR THE US/CANADIAN BORDER IN
MT/ND...WITH COLD AIR ALREADY SPILLING ACROSS THE BORDER. THIS
WAVE WILL DROP SOUTHEAST OVER THE NEXT COUPLE DAYS...BECOME A
LITTLE SHARPER/WELL-DEFINED AND PASS THROUGH THE FORECAST AREA
BETWEEN 21Z THURSDAY AND 12Z FRIDAY. A SW/NE ORIENTATED BAND OF
600-700MB FGEN WILL SWING THROUGH THE FORECAST THIS AREA DURING
THIS TIME...YIELDING A 3-6 HR WINDOW WITH LIGHT TO MODERATE SNOW.
THE 20.00-06Z NAM HAVE A SHARPER WAVE AND STRONGER FGEN. AS A
RESULT...THE NAM HAS HIGHER TOTALS ACROSS A LARGER PORTION OF THE
FORECAST AREA /A LOT OF 3-4" TOTALS/. THE GEM/GFS/ECMWF ARE A
LITTLE MORE DIFFUSE WITH THE BOUNDARY AND HAVE THE HIGHER TOTALS
/2-3"/ ACROSS MAINLY SOUTH CENTRAL MN. THE LAST 3 RUNS OF THE SREF
HAVE MAINTAINED AROUND 1" FOR MSP...THE NAM HAS SHOWN
1-3.5"...OVER THE LAST FEW RUNS...AND THE GFS HAS BEEN THE
STEADIEST WITH RIGHT AROUND 2". THE QPF ISN`T OVERLY IMPRESSIVE
/NOT SURPRISING GIVEN THIS IS A NORTHWEST FLOW EVENT/ BUT THE SNOW
RATIOS SHOULD EXCEED 12:1 GIVEN THE COLD PROFILE. HOWEVER...THE
COMBINATION OF STRONG SURFACE WINDS AND UNCERTAINTY IN OVERLAP OF
BEST OMEGA AND THE DENDRITE GROWTH ZONE SUGGESTS RATIOS SHOULD NOT
BE AS THEY COULD BE...PERHAPS 13-15:1. WE HAVE TRACE AMOUNTS IN
THE NORTHERN FORECAST AREA OF CENTRAL MN TO AROUND 3" IN OUR
SOUTH. AT THIS POINT...THE EVENT LOOKS JUST SHY OF NEEDING A
WINTER WEATHER ADVISORY...ESPECIALLY SINCE MOST OF THE ACTIVITY
WILL FALL BETWEEN THE EVENING AND MORNING COMMUTES.
NONETHELESS...THURSDAY NIGHT WILL FEEL MORE LIKE DECEMBER OR
JANUARY WITH FALLING TEMPS...BRISK NORTHERLY WINDS...AND BANDS OF
SNOW.
THE THURSDAY SYSTEM IS THE FIRST OF TWO ARCTIC BOUNDARIES EXPECTED
OVER THE NEXT 7 DAYS. THE WIND AND COLD TEMPS BEHIND THE THURSDAY
SYSTEM WILL DROP WIND CHILLS NEAR OR BELOW ZERO FOR MUCH OF THE
FORECAST AREA...FOR MOST OF THE WEEKEND. ANOTHER...POTENTIALLY
MORE POTENT /IN TERMS OF COLD/ ARCTIC BOUNDARY IS EXPECTED TO
ARRIVE ON TUESDAY. THIS WOULD BE THE COLDEST AIR OF THE SEASON IF
THE GFS/ECMWF PAN OUT. AS A RESULT...MINUS A BRIEF WARM UP ON
MONDAY...MN/WI WILL SEE HIGHS IN THE TEENS AND 20S AND LOWS IN THE
SINGLE DIGITS ABOVE OR BELOW ZERO FROM SATURDAY-WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1133 PM CST TUE NOV 19 2013
THE BIGGEST UNCERTAINTY FOR THE TAF PERIOD WILL BE THE ARRIVAL OF
LOWER CIGS LATER WEDNESDAY. A SLUG OF MOISTURE WILL DEVELOP OVER
THE MID MISSOURI VALLEY AND TRACK NORTHEAST INTO WISCONSIN
WEDNESDAY AFTERNOON. A FEW SHOWERS MAY IMPACT EAU DURING THIS TIME
ALONG WITH SOME MVFR CIGS. THE COLD FRONT WILL SLOW A BIT DURING
THE DAY AS THIS DISTURBANCE RIDES NORTHEAST IN ADVANCE OF IT.
BEHIND THE FRONT...THERE IS HIGH CONFIDENCE OF MVFR...POSSIBLY IFR
CIGS PERSISTING INTO WEDNESDAY NIGHT. WHERE THE UNCERTAINTY
RESIDES IS BETWEEN THESE TWO FEATURES - THE FRONT AND THE
DISTURBANCE. MODELS ARE CURRENTLY ALL OVER THE PLACE WITH LOW
LEVEL MOISTURE CONTENT AND THUS TIMING OF LOWER CIGS MAY CHANGE IN
FUTURE FORECASTS. IN THE MEANTIME...VFR CONDITIONS EXPECTED WITH
WIND SHEAR DIMINISHING OVERNIGHT.
KMSP...VFR CONDITIONS EXPECTED INTO EARLY WEDNESDAY AFTERNOON.
THEREAFTER...UNCERTAINTY IS RELATIVELY HIGH WITH REGARDS TO TIMING
OF LOWER CIGS AS OUTLINED ABOVE. THINK PRECIPITATION WILL REMAIN
WELL EAST OF MSP WEDNESDAY AFTERNOON.
/OUTLOOK FOR KMSP/
THU...VFR. N WIND 12-15 KTS.
THU NGT...MVFR/SN LIKELY. NE WIND 10 KTS.
FRI...VFR. MVFR POSSIBLE FRIDAY NIGHT. N TO NW WIND 5-10 KTS.
SAT...MVFR POSSIBLE. NW WIND 15G25KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...CLF
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1234 PM CST Wed Nov 20 2013
.UPDATE...
Issued at 1216 PM CST WED NOV 20 2013
We have trimmed PoPs back into the 20-30 percent range from mid to
late afternoon as isentropic upglide along a weakening low level
jet shifts east of the region. We also did some adjusting to
expected high temperatures out east as cloud cover and
precipitation have held down temperatures all morning.
On the other hand, partial clearing has resulted in a jump to
temperatures across southeastern Kansas and western Missouri this
morning. We have made adjustments to sky grids into this afternoon
along with bumping up expected highs a degree or two around Joplin.
We did also do an unscheduled fire weather update as mixing in the
partial clearing area has resulted in dew points dropping into the
lower and middle 20s. This will result in elevated fire weather
conditions for the remainder of this afternoon south of Interstate
44 and west of Highway 65.
&&
.SHORT TERM...(Today and Tonight)
Issued at 304 AM CST WED NOV 20 2013
Currently...as expected, isentropic upglide is underway in the
300-310K layer with a solid pressure advection signal. Regional
radar has seen a gradual increase in showers and even a few
lightning strikes. MUCAPE according to the short range models is
in the 100-200 J/kg range (slightly higher to the west over KS/OK)
and supports at least a slight chance mention for thunder for the
remainder of this morning.
Could see varying precip types this morning given the very dry low
levels. The 00z soundings from KSGF/KLZK/KSHV all show a very
stout low level dry layer. RUC initializations from 07z still
indicating dewpoint depressions around 900mb in the 30-50 C range!
With a southeast downsloping wind, dewpoints are struggling at the
surface, dropping into the teens in many locations, especially
northwest of the plateau and ahead of the incoming radar echoes.
Precip falling from these echoes is likely falling as (mainly)
rain, but cannot rule out some poor man`s sleet mixing in given a
6000 foot layer of wet bulb temperatures aloft at or just below 0C.
With a little bit of elevated instability, cannot argue with very
small hail with any storms.
The short wave responsible for instigating this activity will move
from the central Plains and toward the Great Lakes region through
the day. The area will remain in the left exit region of an upper
jet most of the morning, so there will be broad scale lift
support. In the mid to lower levels, isentropic upglide/pressure
advection will continue in the 300-310K layer this morning,
shunting to the northeast into northern Missouri during the
afternoon hours. Will maintain scattered to numerous shower
wording this morning with a mention of sleet possibly mixing in
from time to time through the mid morning hours. During the
afternoon, have lowered PoPs a bit and changed to chance wording
as most of the shower activity should be exiting into central and
northern Missouri.
There will likely be a brief lull in the rainfall from late this
afternoon into the early evening. However, the next shortwave will
be ready to move into the region during the overnight hours. Have
ramped up PoPs during the overnight hours as showers and a few
embedded thunderstorms should envelope the area from southwest to
northeast.
Temperatures will be a challenge today given wet bulbing,
scattered showers and cloud cover. Have held close to a consensus
of the MOS and raw models, which keep readings mainly in the 50-55
degree range (slightly warmer across far southwestern MO).
.LONG TERM...(Thursday through Tuesday)
Issued at 304 AM CST WED NOV 20 2013
Periods of rain are expected on Thursday across the entire outlook
area. NAM/GFS continue to suffer from convective feedback, though
it is indicative of locally heavy rainfall potential. This heavier
rainfall will likely occur in a narrow, mesoscale band, almost
impossible to pin point. Yet another shortwave will move into the
region later Thursday night into early Friday resulting in yet
more periods of rainfall. By Thursday night, model consensus
indicates that a cold front and shallow low level cold airmass
will begin moving into the region, spreading across the entire
area Friday morning. At this point, thermal profiles from all
models support a wet forecast, rather than wintry. We will have
to keep a very sharp eye on this airmass intrusion, especially
across the northwest third of the CWA.
Some good news is that the global models continue to indicate a
progressive invasion of colder and drier air for Friday night.
Have lowered PoPs a bit more and if present trends continue,
Friday night may only feature a few lingering light rain showers
or flurries. Storm total rainfall accumulation for this event
continues to suggest a widespread 0.50" to 2.00" with a mesoscale
band of locally higher amounts possible.
The weekend will be cold and mostly dry as a 1050mb surface high
pressure settles down from southern Canada into the Midwest
region. The center of the high will be near the Missouri Ozarks
area Saturday night into Sunday morning. This will be the coldest
night with clear skies and light winds...temperatures will be
likely in the middle to upper teens. High temperatures this
weekend will be only in the 30s despite sunshine.
The next big question will be what does the cut off low over the
southwest U.S. do for the early part of next week and how much
cold air will be around when this system moves out into the
southern Plains region.
The latest runs of the GFS..ECMWF...GEM...indicate this system
will affect the area by Monday morning. There is still some
disagreement on track and timing but the consensus is that precip
may begin to develop late Sunday night into Monday morning and
spread into the area. It does appear at this time that light
wintry weather mainly in the form of light snow will be possible.
The ECMWF and GEM are the most bullish with the QPF. With
temperatures not climbing much on Monday...there will be a
rain/snow mix possible and lingering through Monday night. Will
need to monitor future trends with model data but the Monday
morning commute could be tricky with light snow in the area but
amounts appear light at this time up to an inch possible. Below
average temperatures will continue through middle of next week
with another surge of cold air moving in.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1216 PM CST WED NOV 20 2013
As of early this afternoon, rain showers have vacated the
southern Missouri TAF sites. We may still see a scattered shower
or two this afternoon...otherwise broken mid-level clouds and VFR
conditions will prevail. Shower coverage will then increase
tonight...especially after midnight. Steadier rain and even a few
thunderstorms are then expected Thursday morning as a frontal
boundary sets up over the region. High confidence exists in low-
end MVFR flight conditions. There is also a decent signal there
for IFR, but IFR coverage will depend on the exact location of
this frontal boundary and heavier precipitation. We have elected
to go with a TEMPO IFR group to cover this for now. One other
final impact to note will be low level wind shear conditions from
this evening into Thursday morning.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
UPDATE...Schaumann
SHORT TERM...Gagan
LONG TERM...Gagan/Griffin
AVIATION...Schaumann
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
524 AM CST Wed Nov 20 2013
...Aviation Forecast Update...
.SHORT TERM...(Today and Tonight)
Issued at 304 AM CST WED NOV 20 2013
Currently...as expected, isentropic upglide is underway in the
300-310K layer with a solid pressure advection signal. Regional
radar has seen a gradual increase in showers and even a few
lightning strikes. MUCAPE according to the short range models is
in the 100-200 J/kg range (slightly higher to the west over KS/OK)
and supports at least a slight chance mention for thunder for the
remainder of this morning.
Could see varying precip types this morning given the very dry low
levels. The 00z soundings from KSGF/KLZK/KSHV all show a very
stout low level dry layer. RUC initializations from 07z still
indicating dewpoint depressions around 900mb in the 30-50 C range!
With a southeast downsloping wind, dewpoints are struggling at the
surface, dropping into the teens in many locations, especially
northwest of the plateau and ahead of the incoming radar echoes.
Precip falling from these echoes is likely falling as (mainly)
rain, but cannot rule out some poor man`s sleet mixing in given a
6000 foot layer of wet bulb temperatures aloft at or just below 0C.
With a little bit of elevated instability, cannot argue with very
small hail with any storms.
The short wave responsible for instigating this activity will move
from the central Plains and toward the Great Lakes region through
the day. The area will remain in the left exit region of an upper
jet most of the morning, so there will be broad scale lift
support. In the mid to lower levels, isentropic upglide/pressure
advection will continue in the 300-310K layer this morning,
shunting to the northeast into northern Missouri during the
afternoon hours. Will maintain scattered to numerous shower
wording this morning with a mention of sleet possibly mixing in
from time to time through the mid morning hours. During the
afternoon, have lowered PoPs a bit and changed to chance wording
as most of the shower activity should be exiting into central and
northern Missouri.
There will likely be a brief lull in the rainfall from late this
afternoon into the early evening. However, the next shortwave will
be ready to move into the region during the overnight hours. Have
ramped up PoPs during the overnight hours as showers and a few
embedded thunderstorms should envelope the area from southwest to
northeast.
Temperatures will be a challenge today given wet bulbing,
scattered showers and cloud cover. Have held close to a consensus
of the MOS and raw models, which keep readings mainly in the 50-55
degree range (slightly warmer across far southwestern MO).
.LONG TERM...(Thursday through Tuesday)
Issued at 304 AM CST WED NOV 20 2013
Periods of rain are expected on Thursday across the entire outlook
area. NAM/GFS continue to suffer from convective feedback, though
it is indicative of locally heavy rainfall potential. This heavier
rainfall will likely occur in a narrow, mesoscale band, almost
impossible to pin point. Yet another shortwave will move into the
region later Thursday night into early Friday resulting in yet
more periods of rainfall. By Thursday night, model consensus
indicates that a cold front and shallow low level cold airmass
will begin moving into the region, spreading across the entire
area Friday morning. At this point, thermal profiles from all
models support a wet forecast, rather than wintry. We will have
to keep a very sharp eye on this airmass intrusion, especially
across the northwest third of the CWA.
Some good news is that the global models continue to indicate a
progressive invasion of colder and drier air for Friday night.
Have lowered PoPs a bit more and if present trends continue,
Friday night may only feature a few lingering light rain showers
or flurries. Storm total rainfall accumulation for this event
continues to suggest a widespread 0.50" to 2.00" with a mesoscale
band of locally higher amounts possible.
The weekend will be cold and mostly dry as a 1050mb surface high
pressure settles down from southern Canada into the Midwest
region. The center of the high will be near the Missouri Ozarks
area Saturday night into Sunday morning. This will be the coldest
night with clear skies and light winds...temperatures will be
likely in the middle to upper teens. High temperatures this
weekend will be only in the 30s despite sunshine.
The next big question will be what does the cut off low over the
southwest U.S. do for the early part of next week and how much
cold air will be around when this system moves out into the
southern Plains region.
The latest runs of the GFS..ECMWF...GEM...indicate this system
will affect the area by Monday morning. There is still some
disagreement on track and timing but the consensus is that precip
may begin to develop late Sunday night into Monday morning and
spread into the area. It does appear at this time that light
wintry weather mainly in the form of light snow will be possible.
The ECMWF and GEM are the most bullish with the QPF. With
temperatures not climbing much on Monday...there will be a
rain/snow mix possible and lingering through Monday night. Will
need to monitor future trends with model data but the Monday
morning commute could be tricky with light snow in the area but
amounts appear light at this time up to an inch possible. Below
average temperatures will continue through middle of next week
with another surge of cold air moving in.
&&
.AVIATION...(For the 12Z TAFS through 12Z Thursday Morning)
Issued at 509 AM CST WED NOV 20 2013
Scattered showers will be around through mid morning but mainly
VFR conditions will prevail. Winds will remain gusty out of the
southeast especially for SGF up to 25 knots. A broken to overcast deck
will remain through the afternoon around 10k feet. The next round
of showers will be developing after 00z tonight with showers
likely at all terminals by 06z. Have included low level wind shear
through 16z this morning at all terminals and again after 00z
tonight.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Gagan
LONG TERM...Gagan/Griffin
AVIATION...Griffin
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
304 AM CST Wed Nov 20 2013
.SHORT TERM...(Today and Tonight)
Issued at 304 AM CST WED NOV 20 2013
Currently...as expected, isentropic upglide is underway in the
300-310K layer with a solid pressure advection signal. Regional
radar has seen a gradual increase in showers and even a few
lightning strikes. MUCAPE according to the short range models is
in the 100-200 J/kg range (slightly higher to the west over KS/OK)
and supports at least a slight chance mention for thunder for the
remainder of this morning.
Could see varying precip types this morning given the very dry low
levels. The 00z soundings from KSGF/KLZK/KSHV all show a very
stout low level dry layer. RUC initializations from 07z still
indicating dewpoint depressions around 900mb in the 30-50 C range!
With a southeast downsloping wind, dewpoints are struggling at the
surface, dropping into the teens in many locations, especially
northwest of the plateau and ahead of the incoming radar echoes.
Precip falling from these echoes is likely falling as (mainly)
rain, but cannot rule out some poor man`s sleet mixing in given a
6000 foot layer of wet bulb temperatures aloft at or just below 0C.
With a little bit of elevated instability, cannot argue with very
small hail with any storms.
The short wave responsible for instigating this activity will move
from the central Plains and toward the Great Lakes region through
the day. The area will remain in the left exit region of an upper
jet most of the morning, so there will be broad scale lift
support. In the mid to lower levels, isentropic upglide/pressure
advection will continue in the 300-310K layer this morning,
shunting to the northeast into northern Missouri during the
afternoon hours. Will maintain scattered to numerous shower
wording this morning with a mention of sleet possibly mixing in
from time to time through the mid morning hours. During the
afternoon, have lowered PoPs a bit and changed to chance wording
as most of the shower activity should be exiting into central and
northern Missouri.
There will likely be a brief lull in the rainfall from late this
afternoon into the early evening. However, the next shortwave will
be ready to move into the region during the overnight hours. Have
ramped up PoPs during the overnight hours as showers and a few
embedded thunderstorms should envelope the area from southwest to
northeast.
Temperatures will be a challenge today given wet bulbing,
scattered showers and cloud cover. Have held close to a consensus
of the MOS and raw models, which keep readings mainly in the 50-55
degree range (slightly warmer across far southwestern MO).
.LONG TERM...(Thursday through Tuesday)
Issued at 304 AM CST WED NOV 20 2013
Periods of rain are expected on Thursday across the entire outlook
area. NAM/GFS continue to suffer from convective feedback, though
it is indicative of locally heavy rainfall potential. This heavier
rainfall will likely occur in a narrow, mesoscale band, almost
impossible to pin point. Yet another shortwave will move into the
region later Thursday night into early Friday resulting in yet
more periods of rainfall. By Thursday night, model consensus
indicates that a cold front and shallow low level cold airmass
will begin moving into the region, spreading across the entire
area Friday morning. At this point, thermal profiles from all
models support a wet forecast, rather than wintry. We will have
to keep a very sharp eye on this airmass intrusion, especially
across the northwest third of the CWA.
Some good news is that the global models continue to indicate a
progressive invasion of colder and drier air for Friday night.
Have lowered PoPs a bit more and if present trends continue,
Friday night may only feature a few lingering light rain showers
or flurries. Storm total rainfall accumulation for this event
continues to suggest a widespread 0.50" to 2.00" with a mesoscale
band of locally higher amounts possible.
The weekend will be cold and mostly dry as a 1050mb surface high
pressure settles down from southern Canada into the Midwest
region. The center of the high will be near the Missouri Ozarks
area Saturday night into Sunday morning. This will be the coldest
night with clear skies and light winds...temperatures will be
likely in the middle to upper teens. High temperatures this
weekend will be only in the 30s despite sunshine.
The next big question will be what does the cut off low over the
southwest U.S. do for the early part of next week and how much
cold air will be around when this system moves out into the
southern Plains region.
The latest runs of the GFS..ECMWF...GEM...indicate this system
will affect the area by Monday morning. There is still some
disagreement on track and timing but the consensus is that precip
may begin to develop late Sunday night into Monday morning and
spread into the area. It does appear at this time that light
wintry weather mainly in the form of light snow will be possible.
The ECMWF and GEM are the most bullish with the QPF. With
temperatures not climbing much on Monday...there will be a
rain/snow mix possible and lingering through Monday night. Will
need to monitor future trends with model data but the Monday
morning commute could be tricky with light snow in the area but
amounts appear light at this time up to an inch possible. Below
average temperatures will continue through middle of next week
with another surge of cold air moving in.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
Issued at 1129 PM CST TUE NOV 19 2013
Pilots can expect VFR ceilings to blanket the region tonight and
Wednesday while gusty southerly winds continue.
Scattered showers will develop overnight and continue into
Wednesday morning but the visibility will be predominately VFR.
Surface winds will gusts to over 20 kts at the Joplin and
Springfield terminals through Wednesday. Low level wind shear will
impact the terminal sites through Wednesday morning and will
return Wednesday night.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Gagan
LONG TERM...Gagan/Griffin
AVIATION...Foster
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
919 AM MST WED NOV 20 2013
.UPDATE...
ARCTIC FRONT PUSHED THROUGH THE FORECAST AREA EARLY THIS MORNING.
TEMPERATURES HAVE FALLEN INTO THE UPPER TEENS TO LOWER 20S ACROSS
THE AREA. RADAR SHOWING LIGHT TO MODERATE SNOW ACROSS
WHEATLAND...GOLDEN VALLEY AND MUSSELSHELL COUNTIES MOVING EAST BUT
THE BAND ITSELF IS SLOWING SINKING SOUTH AND HAS ENTERED NORTHWEST
YELLOWSTONE COUNTY. GFS AND RAP PAINT A GOOD SWATH OF QPF ACROSS
WHEATLAND COUNTY TO MUSSELSHELL COUNTY SO HAVE ADDED THESE AREAS
TO THE SNOW ADVISORY FOR THE DAY. ONLY OTHER CHANGES WAS SOME
WORDING WITH THE ADVISORY. SINCE THE ARCTIC FRONT MOVED IN EARLIER
THAN ANTICIPATED AND ROAD SURFACES ARE WELL BELOW FREEZING THERE
MAY NOT BE THE INITIAL SNOWMELT ON ROADS FOLLOWED BY A QUICK
FREEZE. HOWEVER...TRAFFIC MAY STILL ALLOW FOR SOME MELTING
INITIALLY. IN ANY CASE...STILL LOOKING AT DIFFICULT TRAVEL
CONDITIONS SPREADING FROM NORTH TO SOUTH ACROSS THE ENTIRE AREA
TODAY. UPDATED FORECAST AND ADVISORIES HAVE BEEN ISSUED. HOOLEY
&&
.SHORT TERM...VALID FOR TDY AND THU...
ARCTIC COLD FRONT PUSHED THROUGH THE BILLINGS AREA AROUND
MIDNIGHT LAST NIGHT AND IS CONTINUING ITS SOUTHWARD TREK THROUGH
THE FORECAST AREA. ON THE AVERAGE...TEMPERATURES FELL ABOUT 20
DEGREES WITH THE FRONTAL PASSAGE.
TODAY...HIGH TEMPERATURES OCCURRED AROUND MIDNIGHT AND A STEADY
FALL OF TEMPERATURES CAN BE EXPECTED THROUGHOUT THE DAY AS STRONG
COLD ADVECTION CONTINUES. FOR HIGHS TODAY...HAVE GONE WITH
EXPECTED HIGHS AT 6 AM AS NO RECOVERY IS EXPECTED. IN
FACT...TEMPERATURES WILL FALL INTO THE LOW TEENS BY AFTERNOON.
SHORT WAVE ENERGY MOVING OVER NORTHWEST MONTANA THIS MORNING AND
WILL BEGIN TO IMPACT OUR AREA AROUND 12Z. FAIRLY GOOD LIFT ACROSS
THE REGION TODAY WITH FRONTOGENESIS INCREASING AS THE COLD AIR
DEEPENS. WINDS ALOFT WILL CONTINUE BACKING TO THE NORTH AND THIS
WILL BRING INCREASING UPSLOPE FLOW...ESPECIALLY TO THE FOOTHILLS.
MODELS ALSO SHOWING A BRIEF PERIOD OF ISENTROPIC LIFT MOVING IN BY
LATE MORNING. CROSS SECTIONS INDICATING DEEP MOISTURE FIELD MOVING
ACROSS THE AREA ALONG WITH A LOWERING DENDRITIC LAYER. THIS
FORCING WILL BRING PERIODS OF MODERATE SNOWFALL TODAY AND 2 TO 4
INCHES OVER THE PLAINS LOOKS ON TRACK AS DOES 3 TO 6 INCHES ALONG
THE FOOTHILLS. EXPECT 4 TO 8 INCHES IN THE MOUNTAINS BUT SNOW
AMOUNTS WILL REMAIN BELOW WARNING CRITERIA.
BIGGEST IMPACT TODAY WILL BE ICY ROADWAYS. WARM SURFACE
TEMPERATURES WILL MELT WITH INITIAL SNOWFALL THIS MORNING. AS
COLDER AIR CONTINUES TO ADVECT INTO THE AREA...ROADS WILL FREEZE
OVER AND THIS WILL CREATE DANGEROUS TRAVELING CONDITIONS. CURRENT
WINTER WEATHER ADVISORIES ON TRACK AND WILL KEEP IT GOING TODAY.
UPPER LEVEL FORCING AND COLD AIR WILL MOVE INTO NORTHERN WYOMING
THIS AFTERNOON. 2 TO 4 INCHES IS EXPECTED IN THE SHERIDAN AREA
ALONG WITH ICY ROAD CONDITIONS.
TONIGHT...SNOW WILL BE ENDING FROM NORTH TO SOUTH. CLOUDS WILL BE
DECREASING AND VERY COLD TEMPERATURES ARE EXPECTED. MOST AREAS
WILL SEE SINGLE DIGITS FOR OVERNIGHT LOWS WITH A FEW AREAS OVER
SOUTHEAST MONTANA POSSIBLY SLIPPING INTO THE SINGLE DIGITS BELOW
ZERO.
THURSDAY AND THURSDAY NIGHT...DRY BUT COLD CONDITIONS WILL
CONTINUE ACROSS THE AREA. TEMPERATURES WILL WARM SLIGHTLY AS
HEIGHTS ALOFT BEGIN TO INCREASE BUT WE ARE ONLY EXPECT HIGHS TO
REACH INTO THE LOW TO MID 20S. OVERNIGHT LOWS WILL BE IN THE
TEENS. RICHMOND
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
ONLY RELATIVELY MINOR CHANGES TO THE EXTENDED PERIOD AGAIN THIS
MORNING...MAINLY FOR COORDINATION PURPOSED. OVERALL THE STORY
REMAINS THE SAME WITH MAINLY DRY CONDITIONS PREVAILING ACROSS THE
REGION THROUGHOUT THE EXTENDED PERIOD. THERE WILL EB A GENERAL
WARMING TREND THROUGH ABOUT MONDAY...WHEN ANOTHER BATCH OF COOLER
AIR MOVES ACROSS THE REGION.
CURRENTLY THE ONLY CHANCE FOR PRECIP APPEARS TO BE FOR
FRIDAY...AS A REINFORCING PUSH OF COLD AIR PUSH EASTWARD OUT OF
THE REGION. ONCE PROGGED AS A DISCRETE PUSH OF COLD AIR ON
FRIDAY...THIS COLD PUSH APPEARS TO HAVE COMBINED WITH THE EXIT OF
THE COLD AIR FROM THE SHORT TERM PERIOD. THIS REINFORCING COLD
PUSH NOW PROGGED TO SLIP FURTHER TO THE EAST...WITH THE EXIT OF
THE PREVIOUS SYSTEM. HAVE COOLED EXTREME EAST SLIGHTLY...BUT KEPT
WEST WARMER...WITH DOWNSLOPE FLOW. PARED POPS BACK TO SLIGHT
CHANCE FOR FRIDAY AFTERNOON...BUT MAY BE TOO DRY WITHOUT A BREAK
IN COLD FOR SOME MELTING AND EVAPORATION TO OCCUR. WARMING TREND
PERSISTS THROUGH SUNDAY...WITH TEMPS BACK INTO THE 40S AND 50S.
ANOTHER SHORTWAVE WILL SWING THROUGH THE AREA SUNDAY NIGHT/MONDAY
AS AN UPPER LEVEL TROF SLIDES ACROSS SOUTHERN CANADA TOWARD THE
HUDSON BAY AREA. AT THIS TIME IT APPEARS TO BE A GLANCING
BLOW...WITH ONLY A SLIGHT COOL OFF AND LITTLE IN THE WAY OF ENERGY
FOR PRECIP PRODUCTION. HAVE CONTINUED WITH DRY FORECAST THROUGH
WEDNESDAY...WITH SLIGHTLY COOLER TEMPS FOR THE BEGINNING OF THE
WORK WEEK. AAG
&&
.AVIATION...
SNOW WILL CONTINUE TO OVERSPREAD THE REGION FROM THE NORTH AND
WEST. LOW CLOUDS AND SNOW WILL RESULT IN WIDESPREAD MVFR TO LIFR
FLIGHT CONDITIONS INTO THIS EVENING. SURFACE WINDS WILL REMAIN
NORTH TO NORTHEASTERLY AT ALL TERMINALS TODAY. STC
&&
.PRELIMINARY POINT TEMP/POPS...
TDY THU FRI SAT SUN MON TUE
-------------------------------------------------------
BIL 023 006/024 018/034 012/041 024/052 027/047 025/044
9/S 20/B 02/J 10/U 00/N 00/B 00/B
LVM 034 004/026 016/035 016/043 028/049 026/047 020/043
8/S 20/B 01/B 10/U 00/N 00/B 00/B
HDN 026 006/025 011/033 008/040 018/049 022/046 021/042
9/S 30/B 03/J 10/U 00/U 00/B 00/B
MLS 019 001/023 006/026 004/034 018/043 023/043 019/038
9/S 20/B 03/J 10/U 00/U 00/U 00/B
4BQ 028 003/022 005/028 002/036 019/045 022/044 020/039
8/S 52/J 03/J 10/U 00/U 00/U 00/B
BHK 022 002/021 006/024 004/029 017/042 020/042 016/035
9/S 40/B 03/J 10/B 00/U 00/U 00/B
SHR 033 007/024 004/036 010/042 022/048 023/047 022/043
7/S 72/J 02/J 10/U 00/U 00/B 00/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 PM MST THIS EVENING
FOR ZONES 28>42-56>58-63>66.
WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 AM MST THURSDAY FOR
ZONE 99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1022 PM MST Tue Nov 19 2013
update aviation section
.DISCUSSION...
Update forthcoming. Strong cold front continues to push south across
the area this evening. The front has moved to the Little Belt
mountains and has moved through Lewistown. Radar returns indicate
snow continuing to develop over the western mountains and push east
across the plains. The winter weather highlight for the Northern
Rocky Mountain Front will continue. Winds behind the front have gone
northerly and the upslope flow will help generate areas of light
snow. The latest RUC analysis shows the snow becoming more
widespread after midnight and sagging south. The snow will increase
over the mountains of Beaverhead, Madison, and Gallatin counties and
the winter weather highlight for this area will continue. Snow
amounts over the plains continue to look on the light side with
generally 1 to 2 inches expected. Have adjusted the hourly
temperatures to better align with reality. Emanuel
&&
.AVIATION...
UPDATED 0522Z.
A cold front continues to push through the forecast area from the
north. While it has made it through north central Montana...it is
presently hung up over the Little Belts. Over the nighttime...the
cold airmass will deepen...eventually making its way to the Helena
valley around 1200Z. Lower clouds behind the front will cause
MVFR/IFR conditions along with some snow. As the front continues
through the CWA, expect low clouds and light snow most areas tonight
and gradually diminishing from the northwest during the morning
daylight hours on Wednesday. db
&&
.PREV DISCUSSION...Issued 303 PM MST Tue Nov 19 2013
Cold Canadian airmass continues to slowly expand south into north
central MT, with leading edge as far south as Heart Butte,
Choteau, Power and Ft Benton to the Bears Paw Mtns. Expect the
front the continue south through the remainder of north central MT
through the remainder of this afternoon and evening, bringing an
abrupt drop in temperatures to the Great Falls area by 5pm and
Lewistown by 9pm. In the upper levels a broad trough will push
east into northern Rockies tonight and across MT tomorrow while an
upper level jet maximum moves east along the Canadian border.
Gusty winds will continue across most of the forecast area tonight
with some potential for strong winds along the continental
divide and Rocky Mtn Front from MacDonald Pass north through
Augusta until the front passes this evening. expect light snow
showers to develop over much of north central MT tonight as cold
air deepens and northerly upslope winds spread south into central
MT. Snow accumulations look to be around an inch or less on the
plains with slightly higher amounts near the little Belts. As the
frontal boundary sags south into SW MT late tonight and the upper
level trough and jet maximum move over the region, snow will
increase over the mtns of Gallatin/Madison and Beaverhead county
with 4 to 6 inches of accumulation likely at elevations above 6000
ft, manly south of I90. temperatures will cool into the single
digits and low teens over north central MT tonight with the cold
airmass deepening over the entire forecast area on Wednesday with
temperatures about 15-25 degrees below seasonal averages. coldest
temperatures of the period look to occur Wednesday night as cold
airmass remains in place with clearing skies and light winds
allowing temperatures to fall into the single digits or colder at
many locations. An upper level ridge moves into the region
Thursday for dry conditions and moderating temperatures. Hoenisch
Thursday Night through Tuesday...Mainly dry, northwest flow will
persist through the period with little precipitation chances. A weak
surface cold front will reinforce the cold, Canadian airmass as it
backs into eastern portions of the forecast area. Despite the
limited moisture, weak convergence and upslope should support a few
snow showers so have kept a slight chance of precipitation across
north-central Montana for Friday. As a ridge of high pressure builds
over the West Coast this weekend, northwest flow aloft will persist
with little chance of precipitation through early next week.
Temperatures will moderate to seasonal averages by Saturday and then
above seasonal averages through early next week. Southwest surface
winds will be breezy at times throughout the forecast period, but
periods of high winds are not anticipated. Long-range models beyond
the forecast period are hinting at a possible weather system for the
middle to end of next week, which is during the Thanksgiving holiday
travel period. Forecast confidence is very low due to uncertainty in
the models, but continue to monitor the forecast for updates
throughout the week. MLV
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 8 17 3 28 / 60 40 0 0
CTB -2 13 0 30 / 60 30 0 0
HLN 24 28 8 29 / 40 50 0 0
BZN 28 35 6 28 / 40 70 10 0
WEY 25 32 3 18 / 80 80 30 10
DLN 29 38 11 30 / 30 50 10 0
HVR 5 15 -1 25 / 60 40 0 0
LWT 12 16 1 28 / 60 60 0 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 11 PM this evening to 5 PM MST
Wednesday FOR ELEVATIONS ABOVE 6000 FEET FOR Beaverhead...
Gallatin...Madison.
WINTER WEATHER ADVISORY until 5 AM MST Wednesday FOR ELEVATIONS
ABOVE 5000 FEET FOR Northern Rocky Mountain Front.
&&
$$
weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/US.NationalWeatherService.GreatFalls.gov
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
900 PM MST Tue Nov 19 2013
.DISCUSSION...
Update forthcoming. Strong cold front continues to push south across
the area this evening. The front has moved to the Little Belt
mountains and has moved through Lewistown. Radar returns indicate
snow continuing to develop over the western mountains and push east
across the plains. The winter weather highlight for the Northern
Rocky Mountain Front will continue. Winds behind the front have gone
northerly and the upslope flow will help generate areas of light
snow. The latest RUC analysis shows the snow becoming more
widespread after midnight and sagging south. The snow will increase
over the mountains of Beaverhead, Madison, and Gallatin counties and
the winter weather highlight for this area will continue. Snow
amounts over the plains continue to look on the light side with
generally 1 to 2 inches expected. Have adjusted the hourly
temperatures to better align with reality. Emanuel
&&
.AVIATION...
UPDATED 2330Z.
A cold front pushing through the forecast area from north to south
had made it to Great Falls by 2330Z. Lower clouds behind the front
will cause MVFR/IFR conditions along with some snow. As the front
continues through the CWA, expect low clouds and light snow most
areas tonight and gradually diminishing from the northwest during
the morning daylight hours on Wednesday. db
&&
.PREV DISCUSSION...Issued 303 PM MST Tue Nov 19 2013
Cold Canadian airmass continues to slowly expand south into north
central MT, with leading edge as far south as Heart Butte,
Choteau, Power and Ft Benton to the Bears Paw Mtns. Expect the
front the continue south through the remainder of north central MT
through the remainder of this afternoon and evening, bringing an
abrupt drop in temperatures to the Great Falls area by 5pm and
Lewistown by 9pm. In the upper levels a broad trough will push
east into northern Rockies tonight and across MT tomorrow while an
upper level jet maximum moves east along the Canadian border.
Gusty winds will continue across most of the forecast area tonight
with some potential for strong winds along the continental
divide and Rocky Mtn Front from MacDonald Pass north through
Augusta until the front passes this evening. expect light snow
showers to develop over much of north central MT tonight as cold
air deepens and northerly upslope winds spread south into central
MT. Snow accumulations look to be around an inch or less on the
plains with slightly higher amounts near the little Belts. As the
frontal boundary sags south into SW MT late tonight and the upper
level trough and jet maximum move over the region, snow will
increase over the mtns of Gallatin/Madison and Beaverhead county
with 4 to 6 inches of accumulation likely at elevations above 6000
ft, manly south of I90. temperatures will cool into the single
digits and low teens over north central MT tonight with the cold
airmass deepening over the entire forecast area on Wednesday with
temperatures about 15-25 degrees below seasonal averages. coldest
temperatures of the period look to occur Wednesday night as cold
airmass remains in place with clearing skies and light winds
allowing temperatures to fall into the single digits or colder at
many locations. An upper level ridge moves into the region
Thursday for dry conditions and moderating temperatures. Hoenisch
Thursday Night through Tuesday...Mainly dry, northwest flow will
persist through the period with little precipitation chances. A weak
surface cold front will reinforce the cold, Canadian airmass as it
backs into eastern portions of the forecast area. Despite the
limited moisture, weak convergence and upslope should support a few
snow showers so have kept a slight chance of precipitation across
north-central Montana for Friday. As a ridge of high pressure builds
over the West Coast this weekend, northwest flow aloft will persist
with little chance of precipitation through early next week.
Temperatures will moderate to seasonal averages by Saturday and then
above seasonal averages through early next week. Southwest surface
winds will be breezy at times throughout the forecast period, but
periods of high winds are not anticipated. Long-range models beyond
the forecast period are hinting at a possible weather system for the
middle to end of next week, which is during the Thanksgiving holiday
travel period. Forecast confidence is very low due to uncertainty in
the models, but continue to monitor the forecast for updates
throughout the week. MLV
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 8 17 3 28 / 60 40 0 0
CTB -2 13 0 30 / 60 30 0 0
HLN 24 28 8 29 / 40 50 0 0
BZN 28 35 6 28 / 40 70 10 0
WEY 25 32 3 18 / 80 80 30 10
DLN 29 38 11 30 / 30 50 10 0
HVR 5 15 -1 25 / 60 40 0 0
LWT 12 16 1 28 / 60 60 0 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 11 PM this evening to 5 PM MST
Wednesday FOR ELEVATIONS ABOVE 6000 FEET FOR Beaverhead...
Gallatin...Madison.
WINTER WEATHER ADVISORY until 5 AM MST Wednesday FOR ELEVATIONS
ABOVE 5000 FEET FOR Northern Rocky Mountain Front.
&&
$$
weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/US.NationalWeatherService.GreatFalls.gov
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1002 PM CST THU NOV 21 2013
.UPDATE...
ISSUED AT 1002 PM CST THU NOV 21 2013
PREVIOUS FORECAST HAD POPS THROUGH TOMORROW MORNING...WITH
MORNING POPS MAINLY ACROSS OUR KANSAS COUNTIES. SOUNDINGS ARE
INDICATING A DRIER ATMOSPHERE THAN PREVIOUSLY FORECAST. RADAR
TRENDS ARE ALSO INDICATING DECREASING COVERAGE ACROSS THE AREA.
00Z NAM SHOWS DRY CONDITIONS. FURTHERMORE...THE HRRR IS PAINTING
DRY CONDITIONS ACROSS THE FORECAST AREA. CONSEQUENTLY...DECREASED
POPS ACROSS THE OUTLOOK AREA FOR THE REST OF THIS EVENING AND INTO
TOMORROW MORNING. BASICALLY A DRY FORECAST THROUGH TOMORROW.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 549 PM CST THU NOV 21 2013
TONIGHT AND FRIDAY. MAIN CONCERNS CONTINUE TO BE THE CURRENT
WINTER WEATHER SYSTEM AND WHEN SNOW WILL COME TO AN END.
LATEST RADAR TRENDS HAVE THE HEAVIER PRECIPITATION RETURNS ACROSS
THE FAR SOUTHEAST PART OF THE FORECAST AREA...AND EVEN THESE ARE
DIMINISHING SOME EARLY THIS AFTERNOON. THESE ARE PRIMARILY LIGHT
FREEZING RAIN OR SLEET. IN THE WEST THERE ARE SOME LIGHTER RETURNS
AND OBSERVATIONS AND WEB CAMS INDICATE THAT THIS IS SOME LIGHT SNOW.
MODELS CONTINUE TO BRING IN ANOTHER WEAK UPPER LEVEL DURING THE
EVENING AND THE SNOW ACROSS WESTERN NEBRASKA WILL CONTINUE TO MOVE
TO THE EAST AND INTO THE FORECAST AREA DURING THE LATE AFTERNOON AND
EVENING. HAVE MAINTAINED THE HIGH POPS ACROSS THE AREA THROUGH THE
AFTERNOON AND THEN SLOWLY DIMINISHED THE CHANCES DURING THE EVENING
AND ESPECIALLY OVERNIGHT. THE MAIN QUESTION IS WHAT TYPE OF
PRECIPITATION WILL HAPPEN IN THE SOUTHEAST. THE LATEST MODEL
GUIDANCE HAS A WARM LAYER THAT FINALLY COOLS ENOUGH TO PRODUCE A
SLEET/SNOW MIXTURE BY MID AFTERNOON AND SHOULD BE ALL SNOW BY
EVENING. WILL CONTINUE THE ADVISORY.
THE SNOW WILL GRADUALLY COME TO AN END FROM WEST TO EAST LATE
TONIGHT. THE ONLY EXCEPTION TO THIS WILL BE ACROSS KANSAS. THERE IS
A WEAK UPPER LEVEL WAVE THAT WILL MOVE INTO THE AREA FRIDAY MORNING.
THERE IS A BAND OF SNOW THAT IS EXPECTED TO DEVELOP IN THE VICINITY
OF INTERSTATE 70. THE MODELS INDICATE THAT MOST OF THE SNOW SHOULD
BE TO THE SOUTH OF THE FORECAST AREA SO HAVE KEPT SOME LOW POPS
MAINLY ACROSS THE FAR SOUTH.
CLOUDS SHOULD DIMINISH SLOWLY ACROSS THE AREA ON FRIDAY...ALTHOUGH
PARTLY TO MOSTLY CLOUDY SKIES ARE EXPECTED IN THE SOUTHERN PART OF
THE AREA.
COLD AIR WILL CONTINUE TO PUSH INTO THE AREA TONIGHT WITH LOWS IN
THE TEENS. THE COLD AIR WILL CONTINUE ACROSS THE AREA ON FRIDAY WITH
HIGHS IN THE LOWER 30S.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 549 PM CST THU NOV 21 2013
THE OVERALL TREND FOR THE SATURDAY THROUGH THANKSGIVING DAY
TIME FRAME IS COOLER THAN NORMAL TEMPERATURES...AND GENERALLY DRY
CONDITIONS. WE WILL BREAK IT DOWN INTO TWO TIME FRAMES.
SATURDAY-MONDAY...SATURDAY IS FLAT OUT COLD. SECONDARY PUSH OF COLD AIR
OVERNIGHT FRIDAY NIGHT WILL INCREASE WINDS FOR THE FIRST HALF OF THE
DAY SATURDAY AND WILL PUSH WIND CHILLS AT OR BELOW ZERO THROUGH
MIDDAY SATURDAY. BOTH THE NAM/GFS HINT AT SOME BROKEN LOW STRATUS
BEHIND THE FRONT OVER/NEAR THE NORTHERN PART OF THE AREA. WINDS WILL
DROP OFF QUICKLY DROP THANKFULLY BY LATE AFTERNOON...BUT TEMPERATURES
WILL BE 15-20 DEGREES BELOW NORMAL. ON SUNDAY...A RETURN SOUTHERLY
FLOW WILL PUSH TEMPERATURES UP BACK INTO THE 30S...BUT THOSE SOUTH
WINDS WILL BE CHILLING A LOT LIKELY SATURDAY. ANOTHER COLD ONE. THERE
ARE MODEL HINTS/IDEAS OF A CUT OFF SOUTHWEST U.S. LOW PRESSURE TRYING
TO MEANDER INTO THE SOUTHERN PLAINS SUNDAY/MONDAY TIME FRAME. THERE
ARE DIFFERENCES IN LOCATION/TIMING. BELIEVE WE WILL SEE CLOUDS
INCREASE SUNDAY...BUT MODELS TEND TO BRING PRECIPITATION TOO FAR
NORTH INTO COLD AIR MASSES SUCH AS THIS. COMFORTABLE WITH NO CHANCE
OF MEASURABLE PRECIPITATION AT THIS POINT...WITH UPCOMING FORECAST
CREWS NEEDING TO KEEP AN EYE ON THE SYSTEM AND ITS MOVEMENT CLOSELY.
TUESDAY-THANKSGIVING DAY...OVERALL THE CENTRAL PLAINS WILL BE COOLER
THAN NORMAL...THANKS SHARING IN CHILLY...CYCLONIC FLOW AROUND HUDSON
BAY VORTEX. THERE IS NO INDICATION AT THIS JUNCTURE OF ANY MAJOR
WEATHER SYSTEM IMPACTING THANKSGIVING DAY...THE WEDNESDAY BEFORE OR
BLACK FRIDAY REALLY. LOOK FOR LOTS OF HIGHS IN THE 30S AN AND
OCCASIONAL LOWER 40 DEGREE DAY NEXT WEEK. THIS COOLISH WEATHER
PATTERN WILL TAKE US RIGHT INTO DECEMBER...AS THE REGION GENERALLY
REMAINS INFLUENCED BY A COLDER WEST/NORTHWEST FLOW AND OCCASIONAL
COLD AIR INTRUSIONS FROM THE CANADIAN PROVINCES.
&&
.AVIATION...(FOR THE 00Z KGRI TAF THROUGH 00Z FRIDAY EVENING)
ISSUED AT 549 PM CST THU NOV 21 2013
MVFR CIGS AND VSBYS WILL CONTINUE AT THE TERMINAL IN AREAS OF -SN
FOR THE NEXT COUPLE OF HOURS AS A MID LEVEL DISTURBANCE PUSHES
EAST ACROSS THE STATE OF NEBRASKA. EXPECT CONDITIONS TO BEGIN TO
IMPROVE AROUND 22/03Z...WITH CIGS THEN SLOWLY LIFTING AND WINDS
DECREASING THEREAFTER. EXPECT BROKEN HIGH LEVEL CLOUDS AT THE
TERMINAL THROUGH THE DAYTIME HOURS FRIDAY WITH WINDS CONTINUING TO
RELAX AS THEY SHIFT AND BECOME MORE WESTERLY THROUGH THE DAY AS AN
AREA OF SURFACE HIGH PRESSURE TRACKS ACROSS KANSAS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...GUERRERO
SHORT TERM...JCB
LONG TERM...MORITZ
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
904 PM EST THU NOV 21 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTH THROUGH THE AREA TONIGHT AND EARLY
FRIDAY AND BRING RAIN SHOWERS WITH IT. A COLD FRONT WILL SWEEP
THROUGH THE AREA LATER FRIDAY CHANGING ANY RAIN SHOWERS OVER TO
LIGHT SNOW SHOWERS OR FLURRIES FRIDAY NIGHT. A STRONGER COLDER FRONT
WILL SURGE ACROSS THE REGION SATURDAY NIGHT BRINGING ADDITIONAL
SNOW SHOWERS AND FLURRIES WITH UNSEASONABLY COLD AIR TO THE REGION
FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
900 PM UPDATE...UPDATED TO SPEED UP THE ARRIVAL OF THE SHRA ACRS
SRN NY AND NE PA. LATEST HRRR MODEL REFLECTIVITY WAS A TRACK AND
UPDATED HOURLY POPS USING MODEL-RADAR SMART TOOL THRU 9Z. THE HRRR
SHOWS A WIDESPREAD AREA OF LIGHT SHRA SPREADING W-E INTO THE
OVERNIGHT. TEMPERATURES ACRS THE ENTIRE FORECAST AREA WERE ABV
FREEZING. UPPER MOHAWK VALLEY WILL NOT SEE ANY SIGNIFICANT MIXED
PRECIP AS PER LATEST RAP...NAM AND GFS MODEL SOUNDINGS AND ALSO BNDRY
LAYER TEMPS WHICH WERE ARND 40F. LATEST LAPS WET BULB TEMPS WERE
IN THE MID TO UPPER 30S IN ONEIDA CO SO THIS COMBINED WITH LOW-
LEVEL WAA SHUD PRECLUDE ANY CHANCE FOR FZRA AS PRECIP CONTS TO
WORK INTO THESE AREAS. SMALL CHC FOR A LITTLE IP BUT IT WON/T BE
SIGNIFICANT ENUF TO WARRANT MENTION IN GRIDS OR ANY PRODUCTS.
TWEAKED REST OF SHORT TERM GRIDS JUST A LITTLE.
PREVIOUS DSCN IS BELOW FROM 700 PM UPDATE..
700 PM UPDATE...AREA RADARS SHOWG SHRA SPREADING INTO WRN AND
CNTRL NY AND NW PA/NC PA AT THIS TIME. THESE SHRA WERE ASSCTD WITH
AN ACCELERATING SWRLY LOW-LEVEL JET ARND 850 MB WHICH WAS RISING
ISENTROPICALLY INTO NY AND NRN PA THIS EVE. THIS LL JET WAS TIED
TO AN UPPER LEVEL JET STREAK AND ASSCTD UPR WAVE WHICH WAS
PROPAGATING INTO THE GREAT LAKES AND UPR OH VLLY. THIS SHOT OF
ISEN LIFT/WAA WILL SHOOT THRU THE REGION BETWEEN 00Z AND 12Z FRI.
FOLLOWED LATEST HRRR FOR TIMING OF HOURLY POPS IN GRIDS TONIGHT AS
THIS MODEL SEEMS TO HAVE THE BEST HANDLE ON THE PRESENTLY EVOLVING
SHRA.
AFTER THIS FIRST UPR LVL WAVE AND ASSCTD LLJ PASSES E AND
WEAKENS BY 12Z...THERE WILL BE A LULL IN THE PRECIP FOR MUCH OF
FRI. I CAN SEE ISLD TO SCT SHRA ACVTY AT BEST AS WE WAIT FOR THE
NEXT LARGER SCALE UPR LVL WAVE TO MAKE A PUSH TO THE E INTO THE UPR
LAKES AND ONT BY 21Z FRI TO 00Z SAT. THIS WILL BE THE IMPETUS TO
PUSH THE SFC CD FRNT INTO WRN AND CNTRL NY LATE FRIDAY PM. HAVE
TRENDED POPS DOWNWARD FRI AM AND BRING THEM BACK UP BY LATE FRI AS
RESULT TO ACCOUNT FOR THIS LULL IN ACTY. I MAY FURTHER REFINE THIS
WITH NEXT UPDATE AS WELL.
AS FOR PRECIP TYPE...I SEE ALL RAIN TONIGHT THRU FRI. MODEL
SOUNDING DATA IS QUITE WARM EVEN IN OUR COLDEST LOCATIONS IN THE
UPPER MOHAWK VALLEY AND CATSKILLS WHERE LL TEMPS ARE WELL ABV
FREEZING AT THE ONSET OF THIS EVE/S PRECIP. THE COLDER AIR DOES NOT
ARRIVE UNTIL FRI NGT TO TURN PRECIP TO SNOW BEFORE IT ENDS. SO
JUST PLAIN RAIN ALL DAY FRI.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
330 PM EST UPDATE...
THE CHANCE FOR RAIN SHOWERS WILL INCREASE EARLY FRIDAY MORNING
FROM WEST TO EAST AS THE ATMOSPHERIC COLUMN BECOMES SATURATED AND
STRONG ISENTROPIC LIFT REMAINS OVER NY/PA. THE BEST CHANCE FOR
RAIN SHOWERS FRIDAY MORNING WILL BE OVER THE WESTERN PORTIONS OF
THE CWA WHERE THE GREATEST UPPER LEVEL SUPPORT IS LOCATED. FRIDAY
AFTERNOON THERE WILL BE A BRIEF DECREASE IN ACTIVITY AHEAD OF AN
ADVANCING STRONG COLD FRONT/SFC TROUGH. THE COLD FRONT IS
EXPECTED TO PUSH INTO THE CWA BETWEEN 18 AND 00Z ON SATURDAY.
GUSTY WINDS AND COLDER AIR WILL FOLLOW THE FRONT.THE CHANCE FOR
RAIN SHOWERS WILL INCREASE OVER THE WESTERN PORTIONS OF THE CWA
WITH THE FROPA. VERY DRY AIR WILL QUICKLY FUNNEL INTO THE REGION
BEHIND THE FRONT... THUS THE CHANCE FOR SHOWERS WILL GREATLY
DIMINISH AFTER 03Z. RAIN IS EXPECTED FIRST AND AS THE COLDER AIR
MOVES IN... RAIN MAY TRANSITION OVER TO SNOW. BEHIND THE FROPA
THERE IS A BRIEF WINDOW FOR FREEZING DRIZZLE. THIS WINDOW IS
BETWEEN 06 AND 09Z SATURDAY AS VERY DRY AIR PUSHES IN. CONFIDENCE
IS NOT HIGH ON THIS SCENARIO... AND CLOSE ATTENTION WILL BE PAID
TO FUTURE MODEL RUNS TO DETERMINE IF THIS SITUATION IS
PLAUSIBLE... SO DECIDED TO LEAVE OUT OF CURRENT FORECAST FOR THE
TIME BEING.
EVEN THOUGH 850MB TEMPS WILL FALL TO -8 DEGREES CELSIUS MAKING
SATURDAY QUITE A CHILLY START... THE REAL COLD AIR WILL SURGE
INTO THE REGION LATE SATURDAY AFTERNOON/EARLY EVENING WITH A
SECONDARY COLD FRONT. 850MB TEMPS SUNDAY AFTERNOON WILL BE -19
DEGREES CELSIUS! THIS WILL BE A FIRST REAL TASTE OF COLD AIR OF
THE SEASON WITH TEMPERATURES REACHING THE UPPER TEENS TO LOW 20S
ACROSS THE CWA WITH WINDS SUSTAINED AROUND 15-20 MPH. WIND CHILL
VALUES WILL BE NEAR ZERO.
LE SNOW SHOWERS WILL BE LIKELY WITH RAPID COOLING ACROSS NY.
INITIAL FLOW BEHIND THE FROPA INDICATES A SINGLE BAND DEVELOPING
EAST OF LAKE ONTARIO THEN THE FLOW VEERING AND BECOMING MULTIBAND
ACROSS CENTRAL NY. MADE MINOR ADJUSTMENTS TO PREVIOUS FORECAST...
AND ADVISORY AND POTENTIALLY WARNING AMOUNT SNOWFALLS LOOK TO BE A
POSSIBILITY BY THE LATTER STAGE OF THE WEEKEND AND WILL CONTINUE
TO KEEP A CLOSE EYE ON THIS LE EVENT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
EXTENDED PERIOD WILL FEATURE AN UPPER LEVEL TROF ACROSS THE
NORTHEAST WHICH WILL RESULT IN A CONTINUATION OF MUCH COOLER THAN
NORMAL TEMPERATURES. SUNDAY NIGHT THE ONGOING LAKE EFFECT SNOW
SHOWERS WILL GRADUALLY DIMINISH AS IT LIFTS NORTH ACROSS THE
NORTHERN CWA. MONDAY LOOKS PRIMARILY DRY AS SFC LOW PRES MOVES INTO
EASTERN CANADA AND THE ASSOCIATED WARM FRONT BRINGS JUST A SLIGHT
CHC OF SNOW SHOWERS TO THE NRN CWA. MONDAY NIGHT THROUGH WEDNESDAY
CONTINUED WITH CHC POPS FOR SNOW SHOWERS AS A NORTHERN STREAM SYSTEM
CONTINUES TRACKING THROUGH EASTERN CANADA AND DRAGS A TRAILING COLD
FRONT THROUGH THE REGION TUE NIGHT. BEHIND THIS FEATURE MORE COLD
AIR AND NORTHWEST FLOW IS EXPECTED WITH SCATTERED SNOW SHOWERS
ESPECIALLY SOUTHEAST OF LAKE ONTARIO.
LATEST ECMWF NOW SHOWS MORE PHASING WITH NRN/SRN STREAM TUE NIGHT
AND WED WITH A COASTAL SYSTEM BRUSHING THE REGION. ITS ALSO WARMER
INDICATING THE POTENTIAL FOR RAIN OVER THE E/SE PTN OF THE FA. THE
GFS CONTINUES TO SHOW SYSTEM PASSING WELL SOUTH OF THE AREA AND NOT
AFFECTING CENTRAL NY/NE PA. FOLLOWED WPC GUIDANCE WHICH KEEPS SYSTEM
SOUTHEAST OF FA AND POPS ONLY IN THE CHC CATEGORY.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
00Z FRI UPDATE... MAINLY VFR CONDS ARE EXPECTED THIS EVE ACRS
CNY/NE PA...WITH THE PSBL EXCEPTION OF BRIEF MVFR CIGS AT KAVP.
LTR TNT...AN AREA OF LWR CIGS/-SHRA SHOULD MOVE INTO THE
RGN...WITH MVFR RESTRICTIONS BCMG WIDESPREAD BY 06-09Z. THERE IS
SOME PSBLTY OF IFR CIGS TWDS DAYBREAK...BUT ATTM...THERE IS ENUF
UNCERTAINTY SO AS TO PRECLUDE THIS MENTION IN THE TERMINALS.
DURG MOST OF FRI...MVFR CIGS AND A FEW -SHRA ARE ANTICIPATED...AS
A MOIST ATMOSPHERE REMAINS IN PLACE. A COLD FRNT IS SLATED TO
CROSS THE RGN LTR IN THE DAY OR BY EARLY EVE (GENERALLY 21-00Z
SAT). AS THE FRNT MOVES IN...CIG BASES MAY LWR A BIT...WITH MORE
WIDESPREAD -SHRA...BUT AGN...NOT CONFIDENT ENUF JUST YET TO
INSERT ANY IFR RESTRICTIONS.
LGT SRLY WINDS OVERNIGHT...WILL BECOME SW 5-10 KT FRI...SHIFTING
TO W OR NW LATE IN THE AFTN...AS THE COLD FRNT PUSHES ACRS THE AREA.
OUTLOOK...
SAT...PRIMARILY VFR.
SAT NGT AND SUN...RESTRICTIONS LIKELY FROM LAKE EFFECT
SHSN...ESPECIALLY CENTRAL NY TERMINALS.
SUN NIGHT AND MON...MOSTLY VFR.
MON NIGHT/TUE...SOME RESTRICTIONS PSBL IN SCTD -SHSN.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...KAH
LONG TERM...PVN/RRM
AVIATION...MLJ/RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
720 PM EST THU NOV 21 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTH THROUGH THE AREA TONIGHT AND EARLY
FRIDAY AND BRING RAIN SHOWERS WITH IT. A COLD FRONT WILL SWEEP
THROUGH THE AREA LATER FRIDAY CHANGING ANY RAIN SHOWERS OVER TO
LIGHT SNOW SHOWERS OR FLURRIES FRIDAY NIGHT. A STRONGER COLDER FRONT
WILL SURGE ACROSS THE REGION SATURDAY NIGHT BRINGING ADDITIONAL
SNOW SHOWERS AND FLURRIES WITH UNSEASONABLY COLD AIR TO THE REGION
FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
AREA RADARS SHOWG SHRA SPREADING INTO WRN AND CNTRL NY AND NW
PA/NC PA AT THIS TIME. THESE SHRA WERE ASSCTD WITH AN ACCELERATING
SWRLY LOW-LEVEL JET ARND 850 MB WHICH WAS RISING ISENTROPICALLY
INTO NY AND NRN PA THIS EVE. THIS LL JET WAS TIED TO AN UPPER LEVEL
JET STREAK AND ASSCTD UPR WAVE WHICH WAS PROPAGATING INTO THE
GREAT LAKES AND UPR OH VLLY. THIS SHOT OF ISEN LIFT/WAA WILL SHOOT
THRU THE REGION BETWEEN 00Z AND 12Z FRI. FOLLOWED LATEST HRRR FOR
TIMING OF HOURLY POPS IN GRIDS TONIGHT AS THIS MODEL SEEMS TO
HAVE THE BEST HANDLE ON THE PRESENTLY EVOLVING SHRA.
AFTER THIS FIRST UPR LVL WAVE AND ASSCTD LLJ PASSES E AND
WEAKENS BY 12Z...THERE WILL BE A LULL IN THE PRECIP FOR MUCH OF
FRI. I CAN SEE ISLD TO SCT SHRA ACVTY AT BEST AS WE WAIT FOR THE
NEXT LARGER SCALE UPR LVL WAVE TO MAKE A PUSH TO THE E INTO THE UPR
LAKES AND ONT BY 21Z FRI TO 00Z SAT. THIS WILL BE THE IMPETUS TO
PUSH THE SFC CD FRNT INTO WRN AND CNTRL NY LATE FRIDAY PM. HAVE
TRENDED POPS DOWNWARD FRI AM AND BRING THEM BACK UP BY LATE FRI AS
RESULT TO ACCOUNT FOR THIS LULL IN ACTY. I MAY FURTHER REFINE THIS
WITH NEXT UPDATE AS WELL.
AS FOR PRECIP TYPE...I SEE ALL RAIN TONIGHT THRU FRI. MODEL
SOUNDING DATA IS QUITE WARM EVEN IN OUR COLDEST LOCATIONS IN THE
UPPER MOHAWK VALLEY AND CATSKILLS WHERE LL TEMPS ARE WELL ABV
FREEZING AT THE ONSET OF THIS EVE/S PRECIP. THE COLDER AIR DOES NOT
ARRIVE UNTIL FRI NGT TO TURN PRECIP TO SNOW BEFORE IT ENDS. SO
JUST PLAIN RAIN ALL DAY FRI.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
330 PM EST UPDATE...
THE CHANCE FOR RAIN SHOWERS WILL INCREASE EARLY FRIDAY MORNING
FROM WEST TO EAST AS THE ATMOSPHERIC COLUMN BECOMES SATURATED AND
STRONG ISENTROPIC LIFT REMAINS OVER NY/PA. THE BEST CHANCE FOR
RAIN SHOWERS FRIDAY MORNING WILL BE OVER THE WESTERN PORTIONS OF
THE CWA WHERE THE GREATEST UPPER LEVEL SUPPORT IS LOCATED. FRIDAY
AFTERNOON THERE WILL BE A BRIEF DECREASE IN ACTIVITY AHEAD OF AN
ADVANCING STRONG COLD FRONT/SFC TROUGH. THE COLD FRONT IS
EXPECTED TO PUSH INTO THE CWA BETWEEN 18 AND 00Z ON SATURDAY.
GUSTY WINDS AND COLDER AIR WILL FOLLOW THE FRONT.THE CHANCE FOR
RAIN SHOWERS WILL INCREASE OVER THE WESTERN PORTIONS OF THE CWA
WITH THE FROPA. VERY DRY AIR WILL QUICKLY FUNNEL INTO THE REGION
BEHIND THE FRONT... THUS THE CHANCE FOR SHOWERS WILL GREATLY
DIMINISH AFTER 03Z. RAIN IS EXPECTED FIRST AND AS THE COLDER AIR
MOVES IN... RAIN MAY TRANSITION OVER TO SNOW. BEHIND THE FROPA
THERE IS A BRIEF WINDOW FOR FREEZING DRIZZLE. THIS WINDOW IS
BETWEEN 06 AND 09Z SATURDAY AS VERY DRY AIR PUSHES IN. CONFIDENCE
IS NOT HIGH ON THIS SCENARIO... AND CLOSE ATTENTION WILL BE PAID
TO FUTURE MODEL RUNS TO DETERMINE IF THIS SITUATION IS
PLAUSIBLE... SO DECIDED TO LEAVE OUT OF CURRENT FORECAST FOR THE
TIME BEING.
EVEN THOUGH 850MB TEMPS WILL FALL TO -8 DEGREES CELSIUS MAKING
SATURDAY QUITE A CHILLY START... THE REAL COLD AIR WILL SURGE
INTO THE REGION LATE SATURDAY AFTERNOON/EARLY EVENING WITH A
SECONDARY COLD FRONT. 850MB TEMPS SUNDAY AFTERNOON WILL BE -19
DEGREES CELSIUS! THIS WILL BE A FIRST REAL TASTE OF COLD AIR OF
THE SEASON WITH TEMPERATURES REACHING THE UPPER TEENS TO LOW 20S
ACROSS THE CWA WITH WINDS SUSTAINED AROUND 15-20 MPH. WIND CHILL
VALUES WILL BE NEAR ZERO.
LE SNOW SHOWERS WILL BE LIKELY WITH RAPID COOLING ACROSS NY.
INITIAL FLOW BEHIND THE FROPA INDICATES A SINGLE BAND DEVELOPING
EAST OF LAKE ONTARIO THEN THE FLOW VEERING AND BECOMING MULTIBAND
ACROSS CENTRAL NY. MADE MINOR ADJUSTMENTS TO PREVIOUS FORECAST...
AND ADVISORY AND POTENTIALLY WARNING AMOUNT SNOWFALLS LOOK TO BE A
POSSIBILITY BY THE LATTER STAGE OF THE WEEKEND AND WILL CONTINUE
TO KEEP A CLOSE EYE ON THIS LE EVENT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
EXTENDED PERIOD WILL FEATURE AN UPPER LEVEL TROF ACROSS THE
NORTHEAST WHICH WILL RESULT IN A CONTINUATION OF MUCH COOLER THAN
NORMAL TEMPERATURES. SUNDAY NIGHT THE ONGOING LAKE EFFECT SNOW
SHOWERS WILL GRADUALLY DIMINISH AS IT LIFTS NORTH ACROSS THE
NORTHERN CWA. MONDAY LOOKS PRIMARILY DRY AS SFC LOW PRES MOVES INTO
EASTERN CANADA AND THE ASSOCIATED WARM FRONT BRINGS JUST A SLIGHT
CHC OF SNOW SHOWERS TO THE NRN CWA. MONDAY NIGHT THROUGH WEDNESDAY
CONTINUED WITH CHC POPS FOR SNOW SHOWERS AS A NORTHERN STREAM SYSTEM
CONTINUES TRACKING THROUGH EASTERN CANADA AND DRAGS A TRAILING COLD
FRONT THROUGH THE REGION TUE NIGHT. BEHIND THIS FEATURE MORE COLD
AIR AND NORTHWEST FLOW IS EXPECTED WITH SCATTERED SNOW SHOWERS
ESPECIALLY SOUTHEAST OF LAKE ONTARIO.
LATEST ECMWF NOW SHOWS MORE PHASING WITH NRN/SRN STREAM TUE NIGHT
AND WED WITH A COASTAL SYSTEM BRUSHING THE REGION. ITS ALSO WARMER
INDICATING THE POTENTIAL FOR RAIN OVER THE E/SE PTN OF THE FA. THE
GFS CONTINUES TO SHOW SYSTEM PASSING WELL SOUTH OF THE AREA AND NOT
AFFECTING CENTRAL NY/NE PA. FOLLOWED WPC GUIDANCE WHICH KEEPS SYSTEM
SOUTHEAST OF FA AND POPS ONLY IN THE CHC CATEGORY.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
00Z FRI UPDATE... MAINLY VFR CONDS ARE EXPECTED THIS EVE ACRS
CNY/NE PA...WITH THE PSBL EXCEPTION OF BRIEF MVFR CIGS AT KAVP.
LTR TNT...AN AREA OF LWR CIGS/-SHRA SHOULD MOVE INTO THE
RGN...WITH MVFR RESTRICTIONS BCMG WIDESPREAD BY 06-09Z. THERE IS
SOME PSBLTY OF IFR CIGS TWDS DAYBREAK...BUT ATTM...THERE IS ENUF
UNCERTAINTY SO AS TO PRECLUDE THIS MENTION IN THE TERMINALS.
DURG MOST OF FRI...MVFR CIGS AND A FEW -SHRA ARE ANTICIPATED...AS
A MOIST ATMOSPHERE REMAINS IN PLACE. A COLD FRNT IS SLATED TO
CROSS THE RGN LTR IN THE DAY OR BY EARLY EVE (GENERALLY 21-00Z
SAT). AS THE FRNT MOVES IN...CIG BASES MAY LWR A BIT...WITH MORE
WIDESPREAD -SHRA...BUT AGN...NOT CONFIDENT ENUF JUST YET TO
INSERT ANY IFR RESTRICTIONS.
LGT SRLY WINDS OVERNIGHT...WILL BECOME SW 5-10 KT FRI...SHIFTING
TO W OR NW LATE IN THE AFTN...AS THE COLD FRNT PUSHES ACRS THE AREA.
OUTLOOK...
SAT...PRIMARILY VFR.
SAT NGT AND SUN...RESTRICTIONS LIKELY FROM LAKE EFFECT
SHSN...ESPECIALLY CENTRAL NY TERMINALS.
SUN NIGHT AND MON...MOSTLY VFR.
MON NIGHT/TUE...SOME RESTRICTIONS PSBL IN SCTD -SHSN.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...KAH
LONG TERM...PVN/RRM
AVIATION...MLJ/RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
305 PM EST WED NOV 20 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE NORTHEAST UNITED STATES WILL MOVE OFF THE
COAST TONIGHT AND LEAD TO A SOUTHERLY FLOW OF MILDER AIR FOR
THURSDAY. A WARM FRONT WILL MOVE THROUGH THE REGION THURSDAY NIGHT
AND FRIDAY BRINGING SOME RAIN SHOWERS WITH IT. A STRONG COLD
FRONT WILL MOVE THROUGH THE REGION SATURDAY WHICH WILL USHER IN
MUCH COLDER AIR FOR SUNDAY AND EARLY NEXT WEEK. THIS COLD AIR
COULD GENERATE SIGNIFICANT LAKE EFFECT SNOWS IN THE LAKE EFFECT
SNOW BELTS OF NORTH CENTRAL NEW YORK.
&&
.NEAR TERM /THROUGH THURSDAY/...
HIGH PRESSURE WILL DOMINATE THE NORTHEAST U.S INTO THIS EVENING AS
THE UPPER LEVEL RDG AXIS SLOWLY MOVES E. EXPECT ONLY SOME PATCHY
CIRRUS AT TIMES WORKG OVER THE UPR LVL RDG AXIS WHICH WILL BE MOVG
OHVD THIS EVE. OTHERWISE FAIR WX THIS EVENING.
FOR OVERNIGHT...THE SFC HI WORKS E OVER ERN NEW ENGLAND WITH THE
UPPER LEVEL RDG AXIS OVHD. CIRRUS WILL CONT TO SPILL OVER THE RDG
ALOFT. THE NAM12..12Z CMC AND RUC13 AS WELL AS THE LATEST 12Z GFS
ALL SUGGEST A MARINE LAYER OF LOW CLOUDS FORMING AGAIN IN THE
MIDDLE ATLANTIC STATES TONIGHT. THE GFS/NAM HAS THIS LAYER WORKING
NORTHWARD REACHING FAR NRN PA BY 12Z THU. THE RAP AT 9Z HAS THIS
LAYER FARTHER S THAN THE GFS AND NAM. FOR NOW WILL HAVE SOME CLDS
REACHING NRN PA BY 12Z AS PER PREVIOUS FORECAST AND LATEST NAM/GFS
AND CMC.
ON THURSDAY THERE WILL BE A SOUTHERLY RETURN FLOW SETTING UP AS
THE SFC HIGH IS OFFSHORE. THE 925 MB TO 850 MB WINDS WILL BE FROM
THE SOUTH AND BASED ON THE LATEST NAM...GFS AND CMC MODELS LL
MOISTURE WILL BE ON THE INCREASE THURSDAY AS CIRRUS AND MID CLDS
POUR IN FROM THE WEST AS HI LEVEL THERMAL ADVECTIONS BEGIN IN
ADVANCE OF THE NEXT SYSTEM. THEREFORE WILL HAVE INCREASING AMNTS
OF CLDS DURING THE DAY THURSDAY. LOOKS LIKE ANY PRECIP WILL HOLD
OFF B4 00Z FRI.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
FOR THURSDAY NIGHT...AN UPPER LEVEL JET STREAK WITH THE NEXT
SYSTEM WILL PUSH INTO THE LOWER LAKES/UPPR OH VLLY AND SUPPORT A
SWRLY LLJ AT ARND 850 MB WHICH WILL LEAD TO A SHOT OF WAA AND
MOISTURE ADVTN INTO NY AND NRN PA. THIS WAA WILL LEAD TO A BATCH
OF LIGHT RAIN SPREADING ACRS MOST OF THE CWA BETWEEN 6Z AND
12Z FRI...WITH SOME LIGHTER PRECIP POTENTIALLY ARRIVING A TAD EARLIER
IN WRN NY. MODEL SOUNDING DATA SUGGESTS ALL RAIN SPREADING EWRD AS
THERE WILL BE NON-DIURNAL TEMP TRENDS WITH THE MIN/S OCCURRING IN
THU EVENING AND RISING TEMPS OVERNIGHT INTO FRI AM WHEN THE BULK OF
THE PRECIP ARRIVES.
AFTER THIS FIRST SHOT OF WAA RAIN SHRA PASSES...THERE WILL BE A
LULL IN THE RAINFALL FRI AM IN ADVANCE OF THE CD FRNT WHICH
REACHES WRN NY BY 18Z AND THEN CROSSES THE REST OF C NY/NE PA BY
FRI EVE. THERE WILL BE SHRA WITH THIS FRONT AND A LITTLE BEHIND IT. THEN
THERE WILL BE ANOTHER LULL IN THE PRECIP UNTIL THE NEXT WAVE
APPROACHES SAT PM WHICH WILL BE ASSCTD WITH A SFC LO AND THE TRUE
ARCTIC FRNT WHICH REACHES INTO THE ERN LAKES SAT PM. FOR SAT...IT
LOOKS LIKE BY AFTERNOON MOST OF THE CWA WILL SEE SN SHWRS AND
FLURRIES AS 850 MB TEMPS DROP TO -10C OR BLO. AGAIN THERE WILL BE
A NON-DIURNAL TEMP TREND SAT PM WITH STRG CAA. MAXES SHUD OCCUR
LATE MORNING SAT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
EXTENDED FORECAST BEGINS WITH A VERY COLD AIRMASS ACROSS THE
NORTHEAST AS A DEEP UPPER LEVEL TROF SWINGS THROUGH THE AREA. BOTH
THE GFS/ECMWF CONTINUE TO ADVERTISE T85 AROUND -16C/-18C FOR 18Z
SUN. THEY BOTH HAVE BEEN CONSISTENT WITH THIS COLD AIRMASS FOR
SEVERAL RUNS NOW INDICATING A HIGH LIKELY HOOD OF OCCURRENCE.
INITIALLY THE LOW LEVEL FLOW SATURDAY NIGHT LOOKS AROUND 290
DEGREES THEN SHIFTS MORE NORTHWEST AFTER 06Z AS A SECONDARY TROF
PASSES. ON SUNDAY, THE LOW LEVEL FLOW WILL BACK AS H85 RIDGE MOVES
THROUGH THE AREA. FOR SATURDAY NIGHT THROUGH SUNDAY WILL CONTINUE
TO ADVERTISE LIKELY POPS FOR LES PRIMARILY SOUTHEAST OF LAKE
ONTARIO. SNOW ACCUMS THROUGH THE PERIOD WILL LIKELY REACH SEVERAL
INCHES WITH A LAKE SNOW ADVISORY MOST LIKELY NEEDED SATURDAY NIGHT
INTO SUNDAY AS THE EVENT APPROACHES. A SHORT FETCH AND LIMITED
SYNOPTIC MOISTURE MAY LIMIT ACCUMS BUT THE AIRMASS IS VERY COLD FOR
THIS TIME OF THE YEAR.
MONDAY NIGHT INTO WEDNESDAY, A NORTHERN STREAM SYSTEM WILL MOVE
THROUGH THE UPPER GREAT LAKES AND ACROSS EASTERN CANADA. WILL
MENTION CHC/SLIGHT CHC POPS FOR SNOW SHOWERS. THE MEDIUM RANGE
MODELS HAVE HINTED AT A NORTHERN/SOUTHERN STREAM PHASING TUE INTO
WED WITH THE DEVELOPMENT OF A STRONG COAST LOW WHICH COULD IMPACT
THE FORECAST AREA. THE LATEST OPERATIONAL RUNS OF THE GFS/ECMWF
NOW SHOW THE SYSTEM REMAINING PRIMARILY EAST/SOUTH OF THE AREA. IT`S
STILL EARLY, SOMETHING TO WATCH.
TEMPS THROUGH THE PERIOD WILL BE AROUND 10-15 DEGREES BELOW NORMAL.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
HIGH PRESSURE IN THE VCNTY WILL MOVE TO THE EAST COAST AT THE END
OF THIS TAF PERIOD WHILE A COLD FRONT DROPS INTO THE UPPER GREAT
LAKES. IN GENERAL VFR CONDITIONS ARE EXPECTED TO CONTINUE. THROUGH
MID MORNING THURSDAY, JUST CI ACROSS THE TERMINALS WITH A MID
DECK DEVELOPING OVER THE AREA LATE IN THE TAF PERIOD.
MODELS ARE INDICATING THE POTENTIAL FOR A MARINE LAYER TOWARD
DAYBREAK ACROSS THE KAVP/KBGM TERMINALS. SINCE THE MODEL SOUNDINGS
DON`T INDICATE THIS POTENTIAL UNTIL ALMOST 12Z AND THE LAYER IS
VERY SHALLOW HAVE DECIDED TO INCLUDE JUST A SCATTERED MVFR LAYER
AT KBGM/KAVP BEGINNING AT 12Z.
LIGHT AND VARIABLE WINDS BECOMING SOUTHEAST AROUND 5 KNOTS
OVERNIGHT THEN SOUTHERLY AROUND 10 KNOTS ON THURSDAY.
OUTLOOK...
THURSDAY NIGHT INTO FRIDAY...RESTRICTIONS LIKELY FROM RAIN SHOWERS.
FRI NIGHT INTO SAT...RESTRICTIONS POSSIBLE FROM SHRA...AS A COLD
FRONT PASSES THROUGH THE AREA.
SAT NGT AND SUN...RESTRICTIONS LIKELY FROM LAKE EFFECT SHSN...ESPECIALLY
CENTRAL NY TERMINALS.
SUNDAY NIGHT...VFR.
MONDAY...RESTRICTIONS POSSIBLE IN SNOW SHOWERS PRIMARILY NYS TERMINALS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...DJN
LONG TERM...RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
142 PM EST WED NOV 20 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE NORTHEAST UNITED STATES WILL MOVE OFF THE
COAST TONIGHT AND LEAD TO A SOUTHERLY FLOW OF MILDER AIR FOR
THURSDAY. A WARM FRONT WILL MOVE THROUGH THE REGION THURSDAY NIGHT
AND FRIDAY BRINGING SOME RAIN SHOWERS WITH IT. A STRONG COLD
FRONT WILL MOVE THROUGH THE REGION SATURDAY WHICH WILL USHER IN
MUCH COLDER AIR FOR SUNDAY AND EARLY NEXT WEEK. THIS COLD AIR
COULD GENERATE SIGNIFICANT LAKE EFFECT SNOWS IN THE LAKE EFFECT
SNOW BELTS OF NORTH CENTRAL NEW YORK.
&&
.NEAR TERM /THROUGH THURSDAY/...
HIGH PRESSURE WILL DOMINATE THE NORTHEAST U.S INTO THIS EVENING AS
THE UPPER LEVEL RDG AXIS SLOWLY MOVES E. EXPECT ONLY SOME PATCHY
CIRRUS AT TIMES WORKG OVER THE UPR LVL RDG AXIS WHICH WILL BE MOVG
OHVD THIS EVE. OTHERWISE FAIR WX THIS EVENING.
FOR OVERNIGHT...THE SFC HI WORKS E OVER ERN NEW ENGLAND WITH THE
UPPER LEVEL RDG AXIS OVHD. CIRRUS WILL CONT TO SPILL OVER THE RDG
ALOFT. THE NAM12..12Z CMC AND RUC13 AS WELL AS THE LATEST 12Z GFS
ALL SUGGEST A MARINE LAYER OF LOW CLOUDS FORMING AGAIN IN THE
MIDDLE ATLANTIC STATES TONIGHT. THE GFS/NAM HAS THIS LAYER WORKING
NORTHWARD REACHING FAR NRN PA BY 12Z THU. THE RAP AT 9Z HAS THIS
LAYER FARTHER S THAN THE GFS AND NAM. FOR NOW WILL HAVE SOME CLDS
REACHING NRN PA BY 12Z AS PER PREVIOUS FORECAST AND LATEST NAM/GFS
AND CMC.
ON THURSDAY THERE WILL BE A SOUTHERLY RETURN FLOW SETTING UP AS
THE SFC HIGH IS OFFSHORE. THE 925 MB TO 850 MB WINDS WILL BE FROM
THE SOUTH AND BASED ON THE LATEST NAM...GFS AND CMC MODELS LL
MOISTURE WILL BE ON THE INCREASE THURSDAY AS CIRRUS AND MID CLDS
POUR IN FROM THE WEST AS HI LEVEL THERMAL ADVECTIONS BEGIN IN
ADVANCE OF THE NEXT SYSTEM. THEREFORE WILL HAVE INCREASING AMNTS
OF CLDS DURING THE DAY THURSDAY. LOOKS LIKE ANY PRECIP WILL HOLD
OFF B4 00Z FRI.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
FOR THURSDAY NIGHT...AN UPPER LEVEL JET STREAK WITH THE NEXT
SYSTEM WILL PUSH INTO THE LOWER LAKES/UPPR OH VLLY AND SUPPORT A
SWRLY LLJ AT ARND 850 MB WHICH WILL LEAD TO A SHOT OF WAA AND
MOISTURE ADVTN INTO NY AND NRN PA. THIS WAA WILL LEAD TO A BATCH
OF LIGHT RAIN SPREADING ACRS MOST OF THE CWA BETWEEN 6Z AND
12Z FRI...WITH SOME LIGHTER PRECIP POTENTIALLY ARRIVING A TAD EARLIER
IN WRN NY. MODEL SOUNDING DATA SUGGESTS ALL RAIN SPREADING EWRD AS
THERE WILL BE NON-DIURNAL TEMP TRENDS WITH THE MIN/S OCCURRING IN
THU EVENING AND RISING TEMPS OVERNIGHT INTO FRI AM WHEN THE BULK OF
THE PRECIP ARRIVES.
AFTER THIS FIRST SHOT OF WAA RAIN SHRA PASSES...THERE WILL BE A
LULL IN THE RAINFALL FRI AM IN ADVANCE OF THE CD FRNT WHICH
REACHES WRN NY BY 18Z AND THEN CROSSES THE REST OF C NY/NE PA BY
FRI EVE. THERE WILL BE SHRA WITH THIS FRONT AND A LITTLE BEHIND IT. THEN
THERE WILL BE ANOTHER LULL IN THE PRECIP UNTIL THE NEXT WAVE
APPROACHES SAT PM WHICH WILL BE ASSCTD WITH A SFC LO AND THE TRUE
ARCTIC FRNT WHICH REACHES INTO THE ERN LAKES SAT PM. FOR SAT...IT
LOOKS LIKE BY AFTERNOON MOST OF THE CWA WILL SEE SN SHWRS AND
FLURRIES AS 850 MB TEMPS DROP TO -10C OR BLO. AGAIN THERE WILL BE
A NON-DIURNAL TEMP TREND SAT PM WITH STRG CAA. MAXES SHUD OCCUR
LATE MORNING SAT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
115 PM TUE UPDATE...
GENERALLY USED WPC GUIDANCE EXCEPT FOR LOCALIZED ENHANCEMENTS TO
POP AND SKY GRIDS FOR WHEN LAKE EFFECT SNOW WILL BE FAVORABLE.
INTERESTING PATTERN TAKING SHAPE WITH INCREASING CONFIDENCE FOR
SOLID SHOT OF ARCTIC AIR /COLDEST OF SEASON SO FAR/ DURING SECOND
HALF OF WEEKEND...AND FOR LAKE EFFECT SNOW. DETAILS OF THAT SNOW
OF COURSE WILL BE RESOLVED IN COMING DAYS...BUT IN THE BIG PICTURE
IT LOOKS FAVORABLE WITHIN OUR GENERAL AREA AND FORECAST HAS BEEN
ADJUSTED ACCORDINGLY WITH BEST CHANCES SUNDAY IN CENTRAL NEW YORK.
BEFORE THEN HOWEVER...TIMING OF INITIAL COLD FRONT LOOKS LIKELY
FOR SOMETIME FRIDAY NIGHT/EARLY SATURDAY. FRONTAL PRECIPITATION
WILL PROBABLY BE MAINLY RAIN. COLD AIR ADVECTION OCCURS DURING THE
DAY...ALLOWING LINGERING RAIN SHOWERS TO MIX WITH SNOW...THOUGH
AMOUNTS PROBABLY LIMITED BY THEN DUE TO DRY SLOTTING /LOSS OF
DEEPER MOISTURE/. ARCTIC FRONT WILL THEN BLAST THROUGH SOMETIME
SATURDAY NIGHT...PLUMMETING 850MB TEMPERATURES INTO AT LEAST THE
MID TEENS BELOW ZERO ON SUNDAY. WITH THE ARCTIC AIR MASS APPEARING
TO ADVECT IN FROM WNW INSTEAD OF THE NORTHERLY DIRECTION...AND
WITH THE DENDRITIC GROWTH LAYER BECOMING COMFORTABLY CONTAINED IN
THE LOWEST 8 KFT AGL...IT IS A FAVORABLE SET UP FOR ACCUMULATING
LAKE EFFECT SNOW INCLUDING UPSTREAM LAKE-TO-LAKE CONNECTIONS
SUNDAY INTO PERHAPS SUNDAY NIGHT.
IT HAS BEEN COMMON SO FAR THIS SEASON FOR AN INITIALLY VERY COLD
AIR MASS IN THE MODELS...TO MODERATE AS THE EVENT GETS CLOSER TO
THE POINT THAT IT IS NOT QUITE AS COLD AS ORIGINALLY ANTICIPATED
ONCE IT ARRIVES. HOWEVER...IN THIS CASE...THE MODELS HAVE
INDICATED THE ARCTIC AIR FOR AT LEAST A FEW RUNS AND ARE
MAINTAINING ITS MAGNITUDE IF NOT TRENDING EVEN SLIGHTLY COLDER.
BOTH 12Z GFS AND 00Z ECMWF DIVE 1000-500MB THICKNESSES BELOW 510
DECAMETER RANGE. GFS GUIDANCE TEMPERATURES HAVE NOW TRENDED
TOWARDS THE VERY COLD ECMWF GUIDANCE VALUES. WE NOW EXPECT MOST
LOCATIONS NOT TO GET OUT OF THE 20S FOR HIGHS SUNDAY.
DRY SURFACE RIDGE MONDAY WITH WARM AIR ADVECTION ALOFT...BUT
LIKELY MUCH MORE MUTED AT THE SURFACE AS WOULD BE TYPICAL ON BACK
SIDE OF ARCTIC AIR MASS. SO AFTER MAINLY TEENS FOR LOWS SUNDAY
NIGHT...ONLY UPPER 20S TO MID 30S ANTICIPATED FOR HIGHS MONDAY.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
HIGH PRESSURE IN THE VCNTY WILL MOVE TO THE EAST COAST AT THE END
OF THIS TAF PERIOD WHILE A COLD FRONT DROPS INTO THE UPPER GREAT
LAKES. IN GENERAL VFR CONDITIONS ARE EXPECTED TO CONTINUE. THROUGH
MID MORNING THURSDAY, JUST CI ACROSS THE TERMINALS WITH A MID
DECK DEVELOPING OVER THE AREA LATE IN THE TAF PERIOD.
MODELS ARE INDICATING THE POTENTIAL FOR A MARINE LAYER TOWARD
DAYBREAK ACROSS THE KAVP/KBGM TERMINALS. SINCE THE MODEL SOUNDINGS
DON`T INDICATE THIS POTENTIAL UNTIL ALMOST 12Z AND THE LAYER IS
VERY SHALLOW HAVE DECIDED TO INCLUDE JUST A SCATTERED MVFR LAYER
AT KBGM/KAVP BEGINNING AT 12Z.
LIGHT AND VARIABLE WINDS BECOMING SOUTHEAST AROUND 5 KNOTS
OVERNIGHT THEN SOUTHERLY AROUND 10 KNOTS ON THURSDAY.
OUTLOOK...
THURSDAY NIGHT INTO FRIDAY...RESTRICTIONS LIKELY FROM RAIN SHOWERS.
FRI NIGHT INTO SAT...RESTRICTIONS POSSIBLE FROM SHRA...AS A COLD
FRONT PASSES THROUGH THE AREA.
SAT NGT AND SUN...RESTRICTIONS LIKELY FROM LAKE EFFECT SHSN...ESPECIALLY
CENTRAL NY TERMINALS.
SUNDAY NIGHT...VFR.
MONDAY...RESTRICTIONS POSSIBLE IN SNOW SHOWERS PRIMARILY NYS TERMINALS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...DJN
LONG TERM...MDP
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
105 PM EST WED NOV 20 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE REGION WILL RESULT IN FAIR WEATHER AND
NEAR SEASONAL TEMPERATURES FOR THIS AFTERNOON. THIS HIGH WILL
SHIFT OFF THE NORTHEAST COAST TONIGHT AND ALLOW FOR A SOUTHERLY
FLOW OF AIR TO ONCE AGAIN RETURN TO THE AREA. THIS WILL LEAD TO
SLIGHTLY WARMER TEMPERATURES FOR THURSDAY. THE NEXT CHANCE FOR
ORGANIZED RAINFALL WILL ARRIVE THURSDAY NIGHT AS A WARM FRONT
LIFTS NORTH ACROSS THE REGION...WITH RAIN CHANCES FURTHER
INCREASING BOTH FRIDAY AND FRIDAY NIGHT AS A STRONG COLD FRONT
APPROACHES FROM THE WEST. MUCH COLDER AIR WILL THEN SETTLE INTO
THE REGION FOR THE UPCOMING WEEKEND WITH DEVELOPING LAKE EFFECT
SNOW SHOWERS EXPECTED DOWNWIND OF LAKE ONTARIO.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE WILL DOMINATE THE NORTHEAST U.S THIS AFTERNOON AND
EVENING AS THE UPPER LEVEL RDG AXIS SLOWLY MOVES E IN TANDEM WITH
THE LARGE SFC HIGH OVHD. SOME CIRRUS WILL ADVECT OVER THE UPR RDG
AXIS LATER THIS AFTERNOON. IN ADDTN...THERE WAS AN UPPER LEVEL
WAVE MOVING OFF THE MID ATLANTIC COAST THAT HAD SPREAD SOME CIRRUS
TO OUR AREA THIS MORNING. THIS CIRRUS WILL TRACK E OF THE REGION
THIS PM. THE LL/S ARE EXTREMELY DRY AND WE DON/T EXPECT ANY CU OR
SC FORMATION WITH INSOLATION.
FOR TONIGHT...THE SFC HI WORKS E OVER ERN NEW ENGLAND WITH THE
UPPER LEVEL RDG AXIS OVHD. CIRRUS WILL CONT TO SPILL OVER THE RDG
ALOFT. THE NAM12 AND RUC13 AS WELL AS THE LATEST 12Z GFS ALL
SUGGEST A MARINE LAYER OF LOW CLOUDS FORMING AGAIN IN THE MIDDLE
ATLANTIC STATES TONIGHT. THE GFS/NAM HAS THIS LAYER WORKING NORTHWARD
REACHING FAR NRN PA BY 12Z THU. THE RAP AT 9Z HAS THIS LAYER FARTHER
S THAN THE GFS AND NAM. FOR NOW WILL HAVE SOME CLDS REACHING NRN
PA BY 12Z AS PER PREVIOUS FORECAST AND LATEST NAM AND GFS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL REMAIN ANCHORED OVER THE EASTERN SEABOARD ON
THURSDAY WITH SOUTHEAST LOW-LEVEL FLOW PREVAILING OVER MUCH OF
OUR REGION. CLOUDS WILL BE ON THE INCREASE THROUGH THE AFTERNOON
AS FLOW ACROSS THE OHIO VALLEY AND UPPER MIDWEST BEGINS TO
INCREASE AS A STRONG COLD FRONT /BLUE NORTHER/ DROPS ACROSS THE
CENTRAL AND SOUTHERN PLAINS. THIS WILL ULTIMATELY MEAN TEMPS ON
THURSDAY WILL BE A FEW DEGREES WARMER THAN TODAY...WITH LWR TO
MIDDLE 40S EXPECTED REGION-WIDE.
FCST BECOMES A BIT MORE INTERESTING THURSDAY NIGHT AS A WEAK AREA
OF LOW PRESSURE BEGINS MOVING NORTHEAST ALONG A FRONTAL BOUNDARY
DROPPING SOUTH THROUGH THE UPPER MIDWEST/WESTERN GREAT LAKES. AS
THIS FEATURE PASSES TO OUR NORTH AND WEST...A CORRESPONDING WARM
FRONT WILL BEGIN LIFTING NORTH TOWARDS OUR REGION. STRENGTHENING
SOUTHWESTERLY 850 FLOW WILL CREATE MODEST ISENTROPIC ASCENT ALONG
THE 295-300K THETA SURFACES WHICH WILL UNDOUBTEDLY INCREASE CLOUD
COVERAGE WHILE ALSO PROVIDING THE NEXT OPPORTUNITY FOR ORGANIZED
RAINFALL. FOR THURSDAY NIGHT...BEST ISENTROPIC ASCENT WILL BE
CONFINED TO AREAS WEST OF THE INTERSTATE 81 CORRIDOR WHERE HIGH
CHC TO LOW LIKELY POPS HAVE BEEN OFFERED. FURTHER SOUTH AND
EAST...MUCH DRIER AIR WILL BE IN PLACE THANKS TO ANCHORED HIGH
PRESSURE AND ASSOCIATED RIDGE AXIS EXTENDING DOWN THE IMMEDIATE
EASTERN SEABOARD.
WARM FRONT TO CONTINUE LIFTING THROUGH THE REGION EARLY FRIDAY
MORNING BEFORE CLEARING AND PLACING MUCH OF OUR AREA IN THE WARM
SECTOR TEMPORARILY. BEST CHANCES FOR RAIN WILL BE DURING THE AM
HRS AS FEATURE LIFTS NORTH...WITH DECREASING CHANCES EXPECTED BY
AFTERNOON.
FORECAST UNCERTAINLY BEGINS TO REAR ITS UGLY HEAD BY FRI EVENING
AS MAIN COLD FRONT WILL BEGIN PASSING THROUGH THE REGION. DESPITE
OVERALL MODEL AGREEMENT THAT A FRONT WILL PASS...THE GFS AND NAM
REMAIN UP TO 6+ HRS OFF ON TIMING...WITH THE FORMER TRENDING THE
SLOWEST AND HOLDING OFF PASSAGE UNTIL AFTER 00Z. THE NAM ON THE
OTHER HAND WOULD SUGGEST A PASSAGE FRI AFTERNOON. QUICK LOOK AT A
POOR-MAN`S ENSEMBLE WOULD SUGGEST THE NAM MODEL IS THE OUTLIER AS
THE ECMWF/CMC/AND UKMET ALL AGREE FRONT WILL PASS A LITTLE LATER
THAN WHAT THE NAM IS OFFERING. THAT SAID...HAVE INCREASED POPS
INTO SAT MORNING WITH LIKELY POPS OFFERED REGION-WIDE. AS COLD
AIR USHERS INTO THE REGION...RAIN MAY MIX WITH SNOW BEFORE ALL
ACTIVITY PASSES OFF TO THE SOUTH AND EAST AFTER 12Z.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
115 PM TUE UPDATE...
GENERALLY USED WPC GUIDANCE EXCEPT FOR LOCALIZED ENHANCEMENTS TO
POP AND SKY GRIDS FOR WHEN LAKE EFFECT SNOW WILL BE FAVORABLE.
INTERESTING PATTERN TAKING SHAPE WITH INCREASING CONFIDENCE FOR
SOLID SHOT OF ARCTIC AIR /COLDEST OF SEASON SO FAR/ DURING SECOND
HALF OF WEEKEND...AND FOR LAKE EFFECT SNOW. DETAILS OF THAT SNOW
OF COURSE WILL BE RESOLVED IN COMING DAYS...BUT IN THE BIG PICTURE
IT LOOKS FAVORABLE WITHIN OUR GENERAL AREA AND FORECAST HAS BEEN
ADJUSTED ACCORDINGLY WITH BEST CHANCES SUNDAY IN CENTRAL NEW YORK.
BEFORE THEN HOWEVER...TIMING OF INITIAL COLD FRONT LOOKS LIKELY
FOR SOMETIME FRIDAY NIGHT/EARLY SATURDAY. FRONTAL PRECIPITATION
WILL PROBABLY BE MAINLY RAIN. COLD AIR ADVECTION OCCURS DURING THE
DAY...ALLOWING LINGERING RAIN SHOWERS TO MIX WITH SNOW...THOUGH
AMOUNTS PROBABLY LIMITED BY THEN DUE TO DRY SLOTTING /LOSS OF
DEEPER MOISTURE/. ARCTIC FRONT WILL THEN BLAST THROUGH SOMETIME
SATURDAY NIGHT...PLUMMETING 850MB TEMPERATURES INTO AT LEAST THE
MID TEENS BELOW ZERO ON SUNDAY. WITH THE ARCTIC AIR MASS APPEARING
TO ADVECT IN FROM WNW INSTEAD OF THE NORTHERLY DIRECTION...AND
WITH THE DENDRITIC GROWTH LAYER BECOMING COMFORTABLY CONTAINED IN
THE LOWEST 8 KFT AGL...IT IS A FAVORABLE SET UP FOR ACCUMULATING
LAKE EFFECT SNOW INCLUDING UPSTREAM LAKE-TO-LAKE CONNECTIONS
SUNDAY INTO PERHAPS SUNDAY NIGHT.
IT HAS BEEN COMMON SO FAR THIS SEASON FOR AN INITIALLY VERY COLD
AIR MASS IN THE MODELS...TO MODERATE AS THE EVENT GETS CLOSER TO
THE POINT THAT IT IS NOT QUITE AS COLD AS ORIGINALLY ANTICIPATED
ONCE IT ARRIVES. HOWEVER...IN THIS CASE...THE MODELS HAVE
INDICATED THE ARCTIC AIR FOR AT LEAST A FEW RUNS AND ARE
MAINTAINING ITS MAGNITUDE IF NOT TRENDING EVEN SLIGHTLY COLDER.
BOTH 12Z GFS AND 00Z ECMWF DIVE 1000-500MB THICKNESSES BELOW 510
DECAMETER RANGE. GFS GUIDANCE TEMPERATURES HAVE NOW TRENDED
TOWARDS THE VERY COLD ECMWF GUIDANCE VALUES. WE NOW EXPECT MOST
LOCATIONS NOT TO GET OUT OF THE 20S FOR HIGHS SUNDAY.
DRY SURFACE RIDGE MONDAY WITH WARM AIR ADVECTION ALOFT...BUT
LIKELY MUCH MORE MUTED AT THE SURFACE AS WOULD BE TYPICAL ON BACK
SIDE OF ARCTIC AIR MASS. SO AFTER MAINLY TEENS FOR LOWS SUNDAY
NIGHT...ONLY UPPER 20S TO MID 30S ANTICIPATED FOR HIGHS MONDAY.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
HIGH PRESSURE IN THE VCNTY WILL MOVE TO THE EAST COAST AT THE END
OF THIS TAF PERIOD WHILE A COLD FRONT DROPS INTO THE UPPER GREAT
LAKES. IN GENERAL VFR CONDITIONS ARE EXPECTED TO CONTINUE. THROUGH
MID MORNING THURSDAY, JUST CI ACROSS THE TERMINALS WITH A MID
DECK DEVELOPING OVER THE AREA LATE IN THE TAF PERIOD.
MODELS ARE INDICATING THE POTENTIAL FOR A MARINE LAYER TOWARD
DAYBREAK ACROSS THE KAVP/KBGM TERMINALS. SINCE THE MODEL SOUNDINGS
DON`T INDICATE THIS POTENTIAL UNTIL ALMOST 12Z AND THE LAYER IS
VERY SHALLOW HAVE DECIDED TO INCLUDE JUST A SCATTERED MVFR LAYER
AT KBGM/KAVP BEGINNING AT 12Z.
LIGHT AND VARIABLE WINDS BECOMING SOUTHEAST AROUND 5 KNOTS
OVERNIGHT THEN SOUTHERLY AROUND 10 KNOTS ON THURSDAY.
OUTLOOK...
THURSDAY NIGHT INTO FRIDAY...RESTRICTIONS LIKELY FROM RAIN SHOWERS.
FRI NIGHT INTO SAT...RESTRICTIONS POSSIBLE FROM SHRA...AS A COLD
FRONT PASSES THROUGH THE AREA.
SAT NGT AND SUN...RESTRICTIONS LIKELY FROM LAKE EFFECT SHSN...ESPECIALLY
CENTRAL NY TERMINALS.
SUNDAY NIGHT...VFR.
MONDAY...RESTRICTIONS POSSIBLE IN SNOW SHOWERS PRIMARILY NYS TERMINALS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...CMG
LONG TERM...MDP
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1210 PM EST WED NOV 20 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE REGION WILL RESULT IN FAIR WEATHER AND
NEAR SEASONAL TEMPERATURES FOR THIS AFTERNOON. THIS HIGH WILL
SHIFT OFF THE NORTHEAST COAST TONIGHT AND ALLOW FOR A SOUTHERLY
FLOW OF AIR TO ONCE AGAIN RETURN TO THE AREA. THIS WILL LEAD TO
SLIGHTLY WARMER TEMPERATURES FOR THURSDAY. THE NEXT CHANCE FOR
ORGANIZED RAINFALL WILL ARRIVE THURSDAY NIGHT AS A WARM FRONT
LIFTS NORTH ACROSS THE REGION...WITH RAIN CHANCES FURTHER
INCREASING BOTH FRIDAY AND FRIDAY NIGHT AS A STRONG COLD FRONT
APPROACHES FROM THE WEST. MUCH COLDER AIR WILL THEN SETTLE INTO
THE REGION FOR THE UPCOMING WEEKEND WITH DEVELOPING LAKE EFFECT
SNOW SHOWERS EXPECTED DOWNWIND OF LAKE ONTARIO.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE WILL DOMINATE THE NORTHEAST U.S THIS AFTERNOON AND
EVENING AS THE UPPER LEVEL RDG AXIS SLOWLY MOVES E IN TANDEM WITH
THE LARGE SFC HIGH OVHD. SOME CIRRUS WILL ADVECT OVER THE UPR RDG
AXIS LATER THIS AFTERNOON. IN ADDTN...THERE WAS AN UPPER LEVEL
WAVE MOVING OFF THE MID ATLANTIC COAST THAT HAD SPREAD SOME CIRRUS
TO OUR AREA THIS MORNING. THIS CIRRUS WILL TRACK E OF THE REGION
THIS PM. THE LL/S ARE EXTREMELY DRY AND WE DON/T EXPECT ANY CU OR
SC FORMATION WITH INSOLATION.
FOR TONIGHT...THE SFC HI WORKS E OVER ERN NEW ENGLAND WITH THE
UPPER LEVEL RDG AXIS OVHD. CIRRUS WILL CONT TO SPILL OVER THE RDG
ALOFT. THE NAM12 AND RUC13 AS WELL AS THE LATEST 12Z GFS ALL
SUGGEST A MARINE LAYER OF LOW CLOUDS FORMING AGAIN IN THE MIDDLE
ATLANTIC STATES TONIGHT. THE GFS/NAM HAS THIS LAYER WORKING NORTHWARD
REACHING FAR NRN PA BY 12Z THU. THE RAP AT 9Z HAS THIS LAYER FARTHER
S THAN THE GFS AND NAM. FOR NOW WILL HAVE SOME CLDS REACHING NRN
PA BY 12Z AS PER PREVIOUS FORECAST AND LATEST NAM AND GFS.
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL REMAIN ANCHORED OVER THE EASTERN SEABOARD ON
THURSDAY WITH SOUTHEAST LOW-LEVEL FLOW PREVAILING OVER MUCH OF
OUR REGION. CLOUDS WILL BE ON THE INCREASE THROUGH THE AFTERNOON
AS FLOW ACROSS THE OHIO VALLEY AND UPPER MIDWEST BEGINS TO
INCREASE AS A STRONG COLD FRONT /BLUE NORTHER/ DROPS ACROSS THE
CENTRAL AND SOUTHERN PLAINS. THIS WILL ULTIMATELY MEAN TEMPS ON
THURSDAY WILL BE A FEW DEGREES WARMER THAN TODAY...WITH LWR TO
MIDDLE 40S EXPECTED REGION-WIDE.
FCST BECOMES A BIT MORE INTERESTING THURSDAY NIGHT AS A WEAK AREA
OF LOW PRESSURE BEGINS MOVING NORTHEAST ALONG A FRONTAL BOUNDARY
DROPPING SOUTH THROUGH THE UPPER MIDWEST/WESTERN GREAT LAKES. AS
THIS FEATURE PASSES TO OUR NORTH AND WEST...A CORRESPONDING WARM
FRONT WILL BEGIN LIFTING NORTH TOWARDS OUR REGION. STRENGTHENING
SOUTHWESTERLY 850 FLOW WILL CREATE MODEST ISENTROPIC ASCENT ALONG
THE 295-300K THETA SURFACES WHICH WILL UNDOUBTEDLY INCREASE CLOUD
COVERAGE WHILE ALSO PROVIDING THE NEXT OPPORTUNITY FOR ORGANIZED
RAINFALL. FOR THURSDAY NIGHT...BEST ISENTROPIC ASCENT WILL BE
CONFINED TO AREAS WEST OF THE INTERSTATE 81 CORRIDOR WHERE HIGH
CHC TO LOW LIKELY POPS HAVE BEEN OFFERED. FURTHER SOUTH AND
EAST...MUCH DRIER AIR WILL BE IN PLACE THANKS TO ANCHORED HIGH
PRESSURE AND ASSOCIATED RIDGE AXIS EXTENDING DOWN THE IMMEDIATE
EASTERN SEABOARD.
WARM FRONT TO CONTINUE LIFTING THROUGH THE REGION EARLY FRIDAY
MORNING BEFORE CLEARING AND PLACING MUCH OF OUR AREA IN THE WARM
SECTOR TEMPORARILY. BEST CHANCES FOR RAIN WILL BE DURING THE AM
HRS AS FEATURE LIFTS NORTH...WITH DECREASING CHANCES EXPECTED BY
AFTERNOON.
FORECAST UNCERTAINLY BEGINS TO REAR ITS UGLY HEAD BY FRI EVENING
AS MAIN COLD FRONT WILL BEGIN PASSING THROUGH THE REGION. DESPITE
OVERALL MODEL AGREEMENT THAT A FRONT WILL PASS...THE GFS AND NAM
REMAIN UP TO 6+ HRS OFF ON TIMING...WITH THE FORMER TRENDING THE
SLOWEST AND HOLDING OFF PASSAGE UNTIL AFTER 00Z. THE NAM ON THE
OTHER HAND WOULD SUGGEST A PASSAGE FRI AFTERNOON. QUICK LOOK AT A
POOR-MAN`S ENSEMBLE WOULD SUGGEST THE NAM MODEL IS THE OUTLIER AS
THE ECMWF/CMC/AND UKMET ALL AGREE FRONT WILL PASS A LITTLE LATER
THAN WHAT THE NAM IS OFFERING. THAT SAID...HAVE INCREASED POPS
INTO SAT MORNING WITH LIKELY POPS OFFERED REGION-WIDE. AS COLD
AIR USHERS INTO THE REGION...RAIN MAY MIX WITH SNOW BEFORE ALL
ACTIVITY PASSES OFF TO THE SOUTH AND EAST AFTER 12Z.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
115 PM TUE UPDATE...
GENERALLY USED WPC GUIDANCE EXCEPT FOR LOCALIZED ENHANCEMENTS TO
POP AND SKY GRIDS FOR WHEN LAKE EFFECT SNOW WILL BE FAVORABLE.
INTERESTING PATTERN TAKING SHAPE WITH INCREASING CONFIDENCE FOR
SOLID SHOT OF ARCTIC AIR /COLDEST OF SEASON SO FAR/ DURING SECOND
HALF OF WEEKEND...AND FOR LAKE EFFECT SNOW. DETAILS OF THAT SNOW
OF COURSE WILL BE RESOLVED IN COMING DAYS...BUT IN THE BIG PICTURE
IT LOOKS FAVORABLE WITHIN OUR GENERAL AREA AND FORECAST HAS BEEN
ADJUSTED ACCORDINGLY WITH BEST CHANCES SUNDAY IN CENTRAL NEW YORK.
BEFORE THEN HOWEVER...TIMING OF INITIAL COLD FRONT LOOKS LIKELY
FOR SOMETIME FRIDAY NIGHT/EARLY SATURDAY. FRONTAL PRECIPITATION
WILL PROBABLY BE MAINLY RAIN. COLD AIR ADVECTION OCCURS DURING THE
DAY...ALLOWING LINGERING RAIN SHOWERS TO MIX WITH SNOW...THOUGH
AMOUNTS PROBABLY LIMITED BY THEN DUE TO DRY SLOTTING /LOSS OF
DEEPER MOISTURE/. ARCTIC FRONT WILL THEN BLAST THROUGH SOMETIME
SATURDAY NIGHT...PLUMMETING 850MB TEMPERATURES INTO AT LEAST THE
MID TEENS BELOW ZERO ON SUNDAY. WITH THE ARCTIC AIR MASS APPEARING
TO ADVECT IN FROM WNW INSTEAD OF THE NORTHERLY DIRECTION...AND
WITH THE DENDRITIC GROWTH LAYER BECOMING COMFORTABLY CONTAINED IN
THE LOWEST 8 KFT AGL...IT IS A FAVORABLE SET UP FOR ACCUMULATING
LAKE EFFECT SNOW INCLUDING UPSTREAM LAKE-TO-LAKE CONNECTIONS
SUNDAY INTO PERHAPS SUNDAY NIGHT.
IT HAS BEEN COMMON SO FAR THIS SEASON FOR AN INITIALLY VERY COLD
AIR MASS IN THE MODELS...TO MODERATE AS THE EVENT GETS CLOSER TO
THE POINT THAT IT IS NOT QUITE AS COLD AS ORIGINALLY ANTICIPATED
ONCE IT ARRIVES. HOWEVER...IN THIS CASE...THE MODELS HAVE
INDICATED THE ARCTIC AIR FOR AT LEAST A FEW RUNS AND ARE
MAINTAINING ITS MAGNITUDE IF NOT TRENDING EVEN SLIGHTLY COLDER.
BOTH 12Z GFS AND 00Z ECMWF DIVE 1000-500MB THICKNESSES BELOW 510
DECAMETER RANGE. GFS GUIDANCE TEMPERATURES HAVE NOW TRENDED
TOWARDS THE VERY COLD ECMWF GUIDANCE VALUES. WE NOW EXPECT MOST
LOCATIONS NOT TO GET OUT OF THE 20S FOR HIGHS SUNDAY.
DRY SURFACE RIDGE MONDAY WITH WARM AIR ADVECTION ALOFT...BUT
LIKELY MUCH MORE MUTED AT THE SURFACE AS WOULD BE TYPICAL ON BACK
SIDE OF ARCTIC AIR MASS. SO AFTER MAINLY TEENS FOR LOWS SUNDAY
NIGHT...ONLY UPPER 20S TO MID 30S ANTICIPATED FOR HIGHS MONDAY.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
HIPRES OVRHD CNTRL NY AND NEPA WILL BRING MAINLY CLR SKIES AND DRY
AIR THRU THE TAF PD. WINDS WILL BE VRBL THIS MRNG...THAN LESS THAN
10 MPH FROM THE EAST THRU THE DAY INTO THE EVENING.
OUTLOOK...
THU...VFR.
FRI INTO SAT...RESTRICTIONS POSSIBLE FROM SHRA...AS A COLD FRONT
PASSES THROUGH THE AREA.
SAT NGT AND SUN...RESTRICTIONS LIKELY FROM LAKE EFFECT SHSN...ESPECIALLY
CENTRAL NY TERMINALS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...CMG
LONG TERM...MDP
AVIATION...DGM
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1100 PM EST THU NOV 21 2013
.SYNOPSIS...
A COASTAL TROUGH WILL BRING PERIODS OF ATLANTIC CLOUD COVER ONSHORE
THROUGH FRIDAY. A COLD FRONT WILL CROSS THE AREA SATURDAY FOLLOWED
BY A BRIEF PERIOD OF VERY COLD AIR. A SIGNIFICANT RAIN EVENT IS
BECOMING MORE LIKELY TOWARD THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 1045 PM THURSDAY...LATEST HRRR AND SREF PROBABILITY FOR
MEASURABLE PRECIP...KEEP THE BEST CHANCES...ALBEIT SMALL...OVER
THE ADJACENT ATL WATERS MAINLY JUST OFFSHORE AND ALONG A WEAK
INVERTED SFC TROF. LOOKING AT VARIOUS MODEL TIME HEIGHT DISPLAYS
ACROSS THE FA...YIELDS AN ABUNDANCE OF LOW LEVEL MOISTURE THAT
WILL BE CONDUCIVE FOR STRATOCU AND STRATUS BELOW 1K FT.
THEREFORE...SKY CONDITIONS WILL REMAIN MOSTLY OR VARIABLY
CLOUDY FOR THE REMAINDER OF THE OVERNIGHT. THIS WILL PLACE THE FOG
POTENTIAL ON THE LOWER/LESSER SIDE OF OCCURRENCE BUT NEVERTHELESS
ENOUGH TO CONTINUE WITH PATCHY AND/OR AREAS OF FOG. LATEST NAM AND
GFS MODEL MOS GUIDANCE ARE QUITE SIMILAR WITH THEIR LOWS FOR
TONIGHT AND SEE NO REASON TO DETOUR FROM THEIR OVERALL NUMBERS.
THE ONLY CHANGE WILL ALONG THE IMMEDIATE BEACHES WHERE SFC
DEWPOINTS ARE RUNNING HIER THAN GUIDANCE WHICH WILL KEEP THE MINS
A FEW DEGREES HIER OVERNIGHT.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
AS OF 230 PM THURSDAY...HIGH PRESSURE REMAINS ACROSS THE AREA ON
FRIDAY WITH A WEAK TROUGHINESS EVIDENT JUST OFF THE COAST. THE
FORMER WILL SPONSOR UNSEASONABLY WARM TEMPERATURES WHILE THE LATTER
MAKES IT TOUGH TO RULE OUT THE OCCASIONAL SPRINKLE. HAVE NOT LIMITED
THE VERY LOW POPS TO JUST THE COAST HOWEVER AS SOME GUIDANCE SHOWING
VERY GOOD SIGNAL FOR SHALLOW CONVECTION FURTHER INLAND ALONG A LATE
SEASON SEA BREEZE. COLD FRONT WILL BE APPROACHING FROM THE NORTHWEST
AND THIS WILL HELP TO KEEP TEMPS QUITE MILD FRIDAY NIGHT WITH LOWS
ONLY DIPPING INTO THE MID OR UPPER 50S. THE CHANCE FOR MAINLY
NON-MEASURABLE PRECIP WILL CONTINUE. ARCTIC FRONT NOW A LITTLE
FASTER AND LOOKS TO BLAST THROUGH FAR NW ZONES BY MORNING AND AROUND
MIDDAY FURTHER SOUTH AND EAST. THIS HAS CAST SOME SERIOUS DOUBTS ON
SATURDAY`S HIGH TEMPERATURE FORECAST. ALTHOUGH THE MORNING HOURS
SHOULD FEATURE A RAPID JUMP OFF OF NIGHTTIME LOWS THE PASSAGE OF THE
FRONT WILL OBVIOUSLY SHARPLY REVERSE THAT TREND. HOW SOON THIS
HAPPENS WILL HAVE A GREAT IMPACT ON WHAT TEMPS ARE ACHIEVED...BEFORE
THEY START TO TUMBLE EARLIER THAN NORMAL BEHIND THE BOUNDARY. HAVE
TRIMMED HIGHS SOME FOR THIS REASON. A LOT OF TIMES THE STRONG CAA
LAGS A BIT BEHIND THE BOUNDARY HERE IN THE EASTERN CAROLINAS AS THE
PASSAGE ACROSS THE MOUNTAINS FRACTURES THE BOUNDARY IN THE VERTICAL.
THIS WILL ALSO PROBABLY YIELD QUITE A SPREAD IN THE ACTUAL HIGHS
ACHIEVED FROM NW TO SE AND HAVE ADJUSTED FCST ACCORDINGLY.
PREFRONTAL MOISTURE ADVECTION IS LACKLUSTER AND DYNAMICS ALOFT STAY
WELL REMOVED TO OUR NORTH. RAINFALL CHANCES APPEAR TO ONLY WARRANT
CHANCE AND QPF SHOULD BE QUITE MINIMAL.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 230 PM THURSDAY...PERIOD BEGINS QUIET AND COLD WITH HIGH
PRESSURE BUILDING IN FROM THE NORTHWEST. STRONG COLD ADVECTION SUN
WILL HELP KEEP HIGHS FROM REACHING 50 IN MOST PLACES. PROXIMITY TO
SURFACE RIDGE AXIS SUN NIGHT WILL ALLOW SOME RADIATIONAL EFFECT. HOW
STRONG REMAINS IN QUESTION BUT LOWS WILL FALL INTO THE MID 20S.
SURFACE RIDGE AXIS SLOWLY SHIFTS OFFSHORE MON BUT RETURN FLOW NEVER
REALLY DEVELOPS WITH WEAK WEDGE SETTING UP. MON AND MON NIGHT WILL
AGAIN BE COOL AND DRY WITH TEMPERATURES REMAINING BELOW CLIMO. LATE
MON INTO MON NIGHT INCREASING MOISTURE ALOFT AHEAD OF GULF COAST
SYSTEM LEADS TO INCREASING AND SLOWLY LOWERING CLOUD DECK.
SOUTHERN STREAM SYSTEM EMERGING FROM THE SOUTHWEST EARLY NEXT WEEK
WILL BE PROVIDE THE NEXT BATCH OF SIGNIFICANT WEATHER FOR THE
SOUTHEAST DURING THE MIDDLE OF NEXT WEEK. AS THE UPPER LOW EMERGES
OVER THE NORTHERN GULF OF MEXICO IT WILL START TO OPEN UP. THE
LOCATION AND TIMING OF THIS FEATURE REMAINS IN QUESTION AND IS THE
SOURCE OF CONSIDERABLE FORECAST UNCERTAINTY. AT THE SAME TIME A WEAK
COASTAL TROUGH STARTS TO DEVELOP OFF THE CAROLINA COAST. INCREASING
MOISTURE AHEAD OF THE 5H LOW AND ISENTROPIC LIFT ARE LIKELY TO LEAD
TO LIGHT RAIN INCREASING OVER THE AREA TUE AND TUE NIGHT. HAVE
INCREASED POP TO LIKELY. ALSO HAVE QUESTIONS ABOUT HOW THE MID LEVEL
AND SURFACE PATTERN EVOLVE TUE INTO WED. CANNOT RULE OUT A COASTAL
LOW DEVELOPING ALONG THE TROUGH...SOMETHING THE GFS HAS BEEN
SHOWING. THE ECMWF ON THE OTHER HAND MOVES THE TROUGH INLAND WITH
THE SURFACE LOW TRACKING WEST OF THE AREA INSTEAD OF JUMPING OFF THE
COAST. WHILE EITHER SOLUTION IS LIKELY TO RESULT IN PRECIP FALLING
IN THE AREA THE DIFFERENCE LIES IN THE TIMING AND TEMPERATURE
POTENTIAL. GIVEN THE UNCERTAINTY WILL NOT MAKE A LOT OF CHANGES TO
THE EXTENDED. HAVE MAINTAINED POP INTO WED NIGHT WITH HIGHS BELOW
CLIMO AND LOWS NEAR CLIMO.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
AS OF 00Z...VFR THROUGH TONIGHT WITH CONDITIONS DETERIORATING TO
MVFR/POSSIBLE IFR DUE TO LOW CIGS AND FOG. VFR RETURNS BY MID
MORNING ON FRIDAY AND PREVAILS THROUGH THE END OF THE TAF PERIOD.
LATEST RADAR IMAGERY IS QUIET AS ANY LINGERING SHOWERS STAY WELL
OFFSHORE. AS FOR CLOUD COVER...11.9U-3.9U SATELLITE IMAGERY DEPICTS
PATCHES OF BKN/OVC HIGH LEVEL CLOUDS WHILE OTHER LOCATIONS ARE
OBSERVING CLEAR SKIES. ANTICIPATE VFR TO PREVAIL INTO THE EARLY
OVERNIGHT HOURS...WHERE CONDITIONS WILL THEN DETERIORATE TO
MVFR...POSSIBLY IFR/LIFR. AS WINDS BECOME LIGHT AND LOW LEVEL
MOISTURE ALONG WITH AN INVERSION SET UP ACROSS THE AREA...AM
ANTICIPATING FOG AND STRATUS TO AFFECT ALL TAF SITES.
HOWEVER...LATEST GUIDANCE STILL HIGHLIGHTS A SCT/BKN MID CLOUD LAYER
DEVELOPING...POSSIBLY INHIBITING MUCH LOWER VISIBILITIES AS
SUGGESTED IN LATEST TIME-HEIGHT/FCST SOUNDING ANALYSIS. THUS HAVE
OPTED TO ONLY TEMPO IFR ATTM. BY MID MORNING ON FRIDAY...CONDITIONS
IMPROVE TO VFR ACROSS THE AREA. EXPECT SOUTH-SOUTHWEST WINDS 5 TO 10
KTS THROUGHOUT THE DAY.
EXTENDED OUTLOOK...CHANCE OF SHOWERS/MVFR CIGS ON SATURDAY WITH A
COLD FRONT. VFR SUNDAY AND MONDAY. EXPECT GUSTY NORTH WINDS ON
SUNDAY BEHIND THE FRONT. INCREASING CHANCE FOR SHOWERS ON TUESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM THURSDAY...THE BORDERLINE SCA FOR THE NC COASTAL
WATERS CONTINUES THROUGH 3 AM...MAINLY DUE TO SIGNIFICANT SEAS
STAYING RIGHT AT SCA THRESHOLDS ACROSS THE OUTER WATERS OFF CAPE
FEAR. THE BASIC TREND FOR THE OVERNIGHT PERIOD WILL LIE WITH THE
BROAD CENTER OF HIGH PRESSURE DROPPING SOUTH AND EVENTUALLY
PARKING ITSELF ACROSS THE CAROLINAS AND ADJACENT ATL WATERS BY
DAYTIME FRIDAY. THE WEAK INVERTED SFC TROF THIS EVENING WILL AID
THE ENE-E WIND DIRECTION. DEPENDING ON HOW THE BROAD CENTER OF
HIGH PRESSURE ORIENTS ITSELF ACROSS THE FORECAST AREA...ONSHORE
WINDS SHOULD PREVAIL WITH DIMINISHED SPEEDS IE. 10-15 KT OVERNIGHT
DUE TO A RELAXING SFC PG. SIGNIFICANT SEAS WILL HOLD IN THE 3 TO
6 FOOT RANGE OVERNIGHT...WITH THE 6 FOOTERS PRIMARILY OCCURRING
ACROSS THE OUTER WATERS OFF CAPE FEAR INTO THE PRE-DAWN HOURS.
DOMINANT PERIODS WILL RANGE BETWEEN 8 AND 10 SECONDS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 PM THURSDAY...THE PERIOD STARTS OFF RATHER QUIET WITH HIGH
PRESSURE CENTERED OVER GA AND WEAKENING. MEANWHILE A WEAK
TROUGHINESS WILL BE FOUND ALONG THE COAST. WINDS SHOULD BE CAPPED AT
JUST 10 KT OUT OF THE SOUTH. SOME VEERING ON FRIDAY NIGHT IS IN
RESPONSE TO BOTH THE FURTHER WEAKENING OF THE HIGH AS WELL AS THE
APPROACH OF A STRONG COLD FRONT. THIS BOUNDARY WILL PUSH ACROSS THE
WATERS SATURDAY EVENING LEADING TO A VERY SHARP VEER. THE INCREASE
IN WIND SPEEDS HOWEVER WILL BE MORE GRADUAL. ANY HEADLINE OR
ADVISORY CONDITIONS...IF THEY OCCUR...APPEAR SLATED FOR THE LONG
TERM.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 230 PM THURSDAY...STRONG COLD ADVECTION AND PINCHED GRADIENT
ON SUN WILL RESULT IN NORTH TO NORTHWEST FLOW APPROACHING 25 KT AT
TIMES SUN INTO SUN NIGHT. HEADLINES WILL LIKELY BE REQUIRED THOUGH
SEAS MAY END UP REMAINING UNDER 6 FT GIVEN THE OFFSHORE TRAJECTORY.
COLD ADVECTION WEAKENS LATE SUN NIGHT AND GRADIENT RELAXES WITH
WINDS VEERING TO NORTHEAST AND DECREASING AS RIDGE AXIS MOVES CLOSER
TO THE COAST. LIGHT NORTHEAST FLOW WILL CONTINUE MON INTO TUE WITH
SURFACE HIGH RIDGING DOWN THE COAST. SPEEDS WILL DROP UNDER 10 KT BY
AFTERNOON WITH SEAS DROPPING TO 2 TO 3 FT. WEAK COASTAL TROUGH
DEVELOPS EARLY TUE WITH WINDS BECOMING VARIABLE ALONG THE TROUGH
AXIS. SOUTHEAST FLOW DEVELOPS OVER THE WATERS LATER TUE AND STARTS
TO INCREASE AS THE TROUGH MOVES CLOSER TO THE COAST. INCREASE IN
WINDS COMBINED WITH ONSHORE TRAJECTORY PUSHES SEAS TO 3 TO 4 FT BY
THE END OF THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 3 AM EST FRIDAY FOR AMZ250-252.
&&
$$
SYNOPSIS...MBB
NEAR TERM...DCH
SHORT TERM...MBB
LONG TERM...III
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
733 PM EST THU NOV 21 2013
.SYNOPSIS...
A COASTAL TROUGH WILL BRING PERIODS OF ATLANTIC CLOUD COVER ONSHORE
THROUGH FRIDAY. A COLD FRONT WILL CROSS THE AREA SATURDAY FOLLOWED
BY A BRIEF PERIOD OF VERY COLD AIR. A SIGNIFICANT RAIN EVENT IS
BECOMING MORE LIKELY TOWARD THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 645 PM THURSDAY...LATEST HRRR AND SREF PROBABILITIES FOR
MEASURABLE RAIN...KEEP THE BEST CHANCES FOR RAIN...ALBEIT SMALL...
OVER THE ADJACENT ATL WATERS MAINLY JUST OFFSHORE AND ALONG A WEAK
INVERTED SFC TROF. LOOKING AT VARIOUS MODEL TIME HEIGHT DISPLAYS
ACROSS THE FA YIELDS MOISTURE THAT IS AVAILABLE FOR THE
CONTINUATION OF A STRATOCU AND/OR ALTO-CU CLOUD DECKS THROUGH THE
OVERNIGHT. THIS WILL KEEP THE FOG POTENTIAL ON THE LOWER SIDE BUT
NEVERTHELESS ENOUGH TO CONTINUE WITH PATCHY AND/OR AREAS OF FOG.
LATEST NAM AND GFS MODEL MOS GUIDANCE ARE QUITE SIMILAR WITH THEIR
LOWS FOR TONIGHT AND SEE NO REASON TO DETOUR FROM THEIR THINKING.
PREVIOUS DISCUSSION...............................................
AS OF 1 PM THURSDAY...WEDGE IS SLOWLY LOSING ITS GRIP ACROSS THE
INLAND CAROLINAS AS THE PRESSURE GRADUALLY LOWERS. MEANWHILE...A
WEAK SURFACE TROUGH CONTINUES TO PROMOTE WIDELY SCATTERED SHOWERS
OFFSHORE. ISOLATED SHOWERS ARE ALSO NOTED ACROSS NEW HANOVER COUNTY
ASSOCIATED WITH THE NORTHEAST RESULTANT BOUNDARY. THE COASTAL TROUGH
WILL WEAKEN AS IT DRIFTS WEST OVERNIGHT...BUT CAN/T COMPLETELY RULE
OUT AN ISOLATED SHOWER OR TWO THIS AFTERNOON OR TONIGHT FOR THE
COASTAL ZONES. WIDESPREAD VARIABILITY IN THE SKY CONDITIONS THIS
AFTERNOON...FROM FULL SUN FROM E-TOWN TO WHITEVILLE WHILE BROKEN
CONDITIONS EXIST ACROSS THE PEE DEE AND COASTAL CAPE FEAR AREAS.
OVERALL...EXPECT MORE CLOUDS DURING THE OVERNIGHT. IN REGARDS TO
STRATUS/FOG POTENTIAL TONIGHT THERE ARE SOME SIGNALS IN PLACE THAT
AREAS OF STRATUS/FOG COULD DEVELOP FOR A PORTION OF THE FORECAST
AREA. IN PARTICULAR...CROSS OVER TEMPERATURES MAY BE REACHED ACROSS
THE EAST-CENTRAL AND COASTAL ZONES AS DEWPOINTS HAVE INCREASED INTO
THE LOWER AND MID 50S. CURRENTLY PLAN ON MENTIONING AREAS OF FOG FOR
A PORTION OF THE FORECAST AND PATCHY ELSEWHERE. MAV/MET NUMBERS ARE
FINALLY IN GOOD AGREEMENT WITH LOWS AROUND 50 INLAND TO THE LOWER
AND MID 50S AT THE COAST.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
AS OF 230 PM THURSDAY...HIGH PRESSURE REMAINS ACROSS THE AREA ON
FRIDAY WITH A WEAK TROUGHINESS EVIDENT JUST OFF THE COAST. THE
FORMER WILL SPONSOR UNSEASONABLY WARM TEMPERATURES WHILE THE LATTER
MAKES IT TOUGH TO RULE OUT THE OCCASIONAL SPRINKLE. HAVE NOT LIMITED
THE VERY LOW POPS TO JUST THE COAST HOWEVER AS SOME GUIDANCE SHOWING
VERY GOOD SIGNAL FOR SHALLOW CONVECTION FURTHER INLAND ALONG A LATE
SEASON SEA BREEZE. COLD FRONT WILL BE APPROACHING FROM THE NORTHWEST
AND THIS WILL HELP TO KEEP TEMPS QUITE MILD FRIDAY NIGHT WITH LOWS
ONLY DIPPING INTO THE MID OR UPPER 50S. THE CHANCE FOR MAINLY
NON-MEASURABLE PRECIP WILL CONTINUE. ARCTIC FRONT NOW A LITTLE
FASTER AND LOOKS TO BLAST THROUGH FAR NW ZONES BY MORNING AND AROUND
MIDDAY FURTHER SOUTH AND EAST. THIS HAS CAST SOME SERIOUS DOUBTS ON
SATURDAY`S HIGH TEMPERATURE FORECAST. ALTHOUGH THE MORNING HOURS
SHOULD FEATURE A RAPID JUMP OFF OF NIGHTTIME LOWS THE PASSAGE OF THE
FRONT WILL OBVIOUSLY SHARPLY REVERSE THAT TREND. HOW SOON THIS
HAPPENS WILL HAVE A GREAT IMPACT ON WHAT TEMPS ARE ACHIEVED...BEFORE
THEY START TO TUMBLE EARLIER THAN NORMAL BEHIND THE BOUNDARY. HAVE
TRIMMED HIGHS SOME FOR THIS REASON. A LOT OF TIMES THE STRONG CAA
LAGS A BIT BEHIND THE BOUNDARY HERE IN THE EASTERN CAROLINAS AS THE
PASSAGE ACROSS THE MOUNTAINS FRACTURES THE BOUNDARY IN THE VERTICAL.
THIS WILL ALSO PROBABLY YIELD QUITE A SPREAD IN THE ACTUAL HIGHS
ACHIEVED FROM NW TO SE AND HAVE ADJUSTED FCST ACCORDINGLY.
PREFRONTAL MOISTURE ADVECTION IS LACKLUSTER AND DYNAMICS ALOFT STAY
WELL REMOVED TO OUR NORTH. RAINFALL CHANCES APPEAR TO ONLY WARRANT
CHANCE AND QPF SHOULD BE QUITE MINIMAL.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 230 PM THURSDAY...PERIOD BEGINS QUIET AND COLD WITH HIGH
PRESSURE BUILDING IN FROM THE NORTHWEST. STRONG COLD ADVECTION SUN
WILL HELP KEEP HIGHS FROM REACHING 50 IN MOST PLACES. PROXIMITY TO
SURFACE RIDGE AXIS SUN NIGHT WILL ALLOW SOME RADIATIONAL EFFECT. HOW
STRONG REMAINS IN QUESTION BUT LOWS WILL FALL INTO THE MID 20S.
SURFACE RIDGE AXIS SLOWLY SHIFTS OFFSHORE MON BUT RETURN FLOW NEVER
REALLY DEVELOPS WITH WEAK WEDGE SETTING UP. MON AND MON NIGHT WILL
AGAIN BE COOL AND DRY WITH TEMPERATURES REMAINING BELOW CLIMO. LATE
MON INTO MON NIGHT INCREASING MOISTURE ALOFT AHEAD OF GULF COAST
SYSTEM LEADS TO INCREASING AND SLOWLY LOWERING CLOUD DECK.
SOUTHERN STREAM SYSTEM EMERGING FROM THE SOUTHWEST EARLY NEXT WEEK
WILL BE PROVIDE THE NEXT BATCH OF SIGNIFICANT WEATHER FOR THE
SOUTHEAST DURING THE MIDDLE OF NEXT WEEK. AS THE UPPER LOW EMERGES
OVER THE NORTHERN GULF OF MEXICO IT WILL START TO OPEN UP. THE
LOCATION AND TIMING OF THIS FEATURE REMAINS IN QUESTION AND IS THE
SOURCE OF CONSIDERABLE FORECAST UNCERTAINTY. AT THE SAME TIME A WEAK
COASTAL TROUGH STARTS TO DEVELOP OFF THE CAROLINA COAST. INCREASING
MOISTURE AHEAD OF THE 5H LOW AND ISENTROPIC LIFT ARE LIKELY TO LEAD
TO LIGHT RAIN INCREASING OVER THE AREA TUE AND TUE NIGHT. HAVE
INCREASED POP TO LIKELY. ALSO HAVE QUESTIONS ABOUT HOW THE MID LEVEL
AND SURFACE PATTERN EVOLVE TUE INTO WED. CANNOT RULE OUT A COASTAL
LOW DEVELOPING ALONG THE TROUGH...SOMETHING THE GFS HAS BEEN
SHOWING. THE ECMWF ON THE OTHER HAND MOVES THE TROUGH INLAND WITH
THE SURFACE LOW TRACKING WEST OF THE AREA INSTEAD OF JUMPING OFF THE
COAST. WHILE EITHER SOLUTION IS LIKELY TO RESULT IN PRECIP FALLING
IN THE AREA THE DIFFERENCE LIES IN THE TIMING AND TEMPERATURE
POTENTIAL. GIVEN THE UNCERTAINTY WILL NOT MAKE A LOT OF CHANGES TO
THE EXTENDED. HAVE MAINTAINED POP INTO WED NIGHT WITH HIGHS BELOW
CLIMO AND LOWS NEAR CLIMO.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 00Z...VFR THROUGH TONIGHT WITH CONDITIONS DETERIORATING TO
MVFR/POSSIBLE IFR DUE TO LOW CIGS AND FOG. VFR RETURNS BY MID
MORNING ON FRIDAY AND PREVAILS THROUGH THE END OF THE TAF PERIOD.
LATEST RADAR IMAGERY IS QUIET AS ANY LINGERING SHOWERS STAY WELL
OFFSHORE. AS FOR CLOUD COVER...11.9U-3.9U SATELLITE IMAGERY DEPICTS
PATCHES OF BKN/OVC HIGH LEVEL CLOUDS WHILE OTHER LOCATIONS ARE
OBSERVING CLEAR SKIES. ANTICIPATE VFR TO PREVAIL INTO THE EARLY
OVERNIGHT HOURS...WHERE CONDITIONS WILL THEN DETERIORATE TO
MVFR...POSSIBLY IFR/LIFR. AS WINDS BECOME LIGHT AND LOW LEVEL
MOISTURE ALONG WITH AN INVERSION SET UP ACROSS THE AREA...AM
ANTICIPATING FOG AND STRATUS TO AFFECT ALL TAF SITES.
HOWEVER...LATEST GUIDANCE STILL HIGHLIGHTS A SCT/BKN MID CLOUD LAYER
DEVELOPING...POSSIBLY INHIBITING MUCH LOWER VISIBILITIES AS
SUGGESTED IN LATEST TIME-HEIGHT/FCST SOUNDING ANALYSIS. THUS HAVE
OPTED TO ONLY TEMPO IFR ATTM. BY MID MORNING ON FRIDAY...CONDITIONS
IMPROVE TO VFR ACROSS THE AREA. EXPECT SOUTH-SOUTHWEST WINDS 5 TO 10
KTS THROUGHOUT THE DAY.
EXTENDED OUTLOOK...CHANCE OF SHOWERS/MVFR CIGS ON SATURDAY WITH A
COLD FRONT. VFR SUNDAY AND MONDAY. EXPECT GUSTY NORTH WINDS ON
SUNDAY BEHIND THE FRONT. INCREASING CHANCE FOR SHOWERS ON TUESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 645 PM THURSDAY...HAVE EXTENDED THE SCA FOR THE NC COASTAL
WATERS ZONES THROUGH 3 AM...DUE TO SIGNIFICANT SEAS STAYING AT SCA
THRESHOLDS ACROSS THE OUTER WATERS OFF CAPE FEAR. THE BASIC TREND
FOR THE OVERNIGHT PERIOD WILL BE THE BROAD CENTER OF HIGH
PRESSURE DROPPING SOUTH AND EVENTUALLY PARKING ITSELF ACROSS THE
CAROLINAS AND ADJACENT ATL WATERS BY FRIDAY. THE WEAK INVERTED SFC
TROF THIS EVENING WILL AID THE NE-E WINDS AT 10-15 KT WITH FEW
GUSTS UP TO 20 KT DURING THE EVENING. DEPENDING ON HOW THE BROAD
CENTER OF HIGH PRESSURE ORIENTS ITSELF ACROSS THE FORECAST AREA
...ONSHORE WINDS SHOULD PREVAIL WITH DIMINISHED SPEEDS DUE TO THE
SFC PG HAVING RELAXED. SIGNIFICANT SEAS WILL HOLD IN THE 3 TO 6
FOOT RANGE OVERNIGHT...WITH THE 6 FOOTERS PRIMARILY OCCURRING
ACROSS THE OUTER WATERS OFF CAPE FEAR INTO THE PRE-DAWN HOURS.
DOMINANT PERIODS WILL RANGE BETWEEN 8 AND 10 SECONDS.
PREVIOUS DISCUSSION..................................................
AS OF 1 PM THURSDAY...SMALL CRAFT CONDITIONS CONTINUE ACROSS THE
OUTER COASTAL WATERS...EXCEPT FROM LITTLE RIVER INLET TO MURRELLS
INLET. WIND SPEEDS RANGE FROM 10-15 KNOTS MOST MARINE AREAS AND THEY
WILL DIMINISH TO AROUND 10 KNOTS AND VEER OVERNIGHT AS THE COASTAL
TROUGH PUSHES FARTHER WEST. SEAS WILL SUBSIDE TO 3-5 FT
OVERNIGHT...WITH A LARGE CONTRIBUTION OF THE SIGNIFICANT SEAS FROM A
SE 11 SECOND COMPONENT. WIDELY SCATTERED SHOWERS WILL ALSO PERSIST
THROUGH THE OVERNIGHT.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 PM THURSDAY...THE PERIOD STARTS OFF RATHER QUIET WITH HIGH
PRESSURE CENTERED OVER GA AND WEAKENING. MEANWHILE A WEAK
TROUGHINESS WILL BE FOUND ALONG THE COAST. WINDS SHOULD BE CAPPED AT
JUST 10 KT OUT OF THE SOUTH. SOME VEERING ON FRIDAY NIGHT IS IN
RESPONSE TO BOTH THE FURTHER WEAKENING OF THE HIGH AS WELL AS THE
APPROACH OF A STRONG COLD FRONT. THIS BOUNDARY WILL PUSH ACROSS THE
WATERS SATURDAY EVENING LEADING TO A VERY SHARP VEER. THE INCREASE
IN WIND SPEEDS HOWEVER WILL BE MORE GRADUAL. ANY HEADLINE OR
ADVISORY CONDITIONS...IF THEY OCCUR...APPEAR SLATED FOR THE LONG
TERM.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 230 PM THURSDAY...STRONG COLD ADVECTION AND PINCHED GRADIENT
ON SUN WILL RESULT IN NORTH TO NORTHWEST FLOW APPROACHING 25 KT AT
TIMES SUN INTO SUN NIGHT. HEADLINES WILL LIKELY BE REQUIRED THOUGH
SEAS MAY END UP REMAINING UNDER 6 FT GIVEN THE OFFSHORE TRAJECTORY.
COLD ADVECTION WEAKENS LATE SUN NIGHT AND GRADIENT RELAXES WITH
WINDS VEERING TO NORTHEAST AND DECREASING AS RIDGE AXIS MOVES CLOSER
TO THE COAST. LIGHT NORTHEAST FLOW WILL CONTINUE MON INTO TUE WITH
SURFACE HIGH RIDGING DOWN THE COAST. SPEEDS WILL DROP UNDER 10 KT BY
AFTERNOON WITH SEAS DROPPING TO 2 TO 3 FT. WEAK COASTAL TROUGH
DEVELOPS EARLY TUE WITH WINDS BECOMING VARIABLE ALONG THE TROUGH
AXIS. SOUTHEAST FLOW DEVELOPS OVER THE WATERS LATER TUE AND STARTS
TO INCREASE AS THE TROUGH MOVES CLOSER TO THE COAST. INCREASE IN
WINDS COMBINED WITH ONSHORE TRAJECTORY PUSHES SEAS TO 3 TO 4 FT BY
THE END OF THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 3 AM EST FRIDAY FOR AMZ250-252.
&&
$$
SYNOPSIS...MBB
NEAR TERM...DCH/SRP
SHORT TERM...MBB
LONG TERM...III
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
704 PM CST THU NOV 21 2013
.UPDATE...
ISSUED AT 704 PM CST THU NOV 21 2013
TEMPERATURES ARE THE FIRST CONCERN. FOR THE MOST PART...THE
PREVIOUS FORECAST IS UNFOLDING AS EXPECTED. SOME CURRENT VALUES
WITHIN THE DEEPER SNOWPACK ARE A BIT COLDER THAN THE MIN TEMP
FORECAST...BUT WITH WINDS TURNING SOUTHWEST AND WARM AIR
ADVECTION...ADDITIONAL DROP SHOULD BE MINIMAL. USED THE CURRENT
VALUES ALONG WITH THE HRRR FOR TEMPERATURE GUIDANCE OVERNIGHT.
THE NEXT CONCERN WILL BE THE MINOR SNOW EVENT ON FRIDAY. THERE
WILL BE MODERATE 850MB-700MB FRONTOGENETICAL FORCING ALONG AND
BEHIND THE COLD FRONT. SYNOPTIC FORCING IS THEN EXPECTED TO RIDE
THROUGH THE REGION ASSOCIATED WITH A MID-LEVEL SHORTWAVE ON THE
TAIL END OF THE MESOSCALE FORCING. CONSIDERING THIS FORCING...HI-
RESOLUTION MODELS LIKELY HAVE A BETTER HANDLE ON QPF THAN THE
LOWER RESOLUTION MODELS. THE MAIN QUESTION AT THIS POINT IS
EXACTLY WHERE THE HEAVIEST BAND OF QPF MIGHT OCCUR. 18Z MODELS
HAVE SHIFTED THIS BAND SOUTH...MAINLY ACROSS THE DEVILS LAKE BASIN
AND INTO THE CENTRAL RED RIVER VALLEY. FOR THIS UPDATE...WILL
INCREASE POPS TO 50% ACROSS THIS AREA. PWATS WILL ONLY BE AROUND
0.20 INCHES...AND HI-RES MODELS ONLY INDICATE UP TO 0.10 INCHES.
HOWEVER...THE ROEBBER AND CARIBOU SNOW RATIO METHODS BOTH INDICATE
20:1 OR HIGHER. THIS MEANS 1-2 INCHES COULD OCCUR TOMORROW. IF THE
00Z MODELS AGREE WITH THE ABOVE THINKING...WILL CONSIDER
INCREASING POPS FOR THE NEXT UPDATE.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 325 AM CST THU NOV 21 2013
TEMPS ARE THE MAIN ISSUE. EXPECT A ROLLER COASTER NEXT FEW DAYS
AND JUST NOT SURE HOW COLD OR HOW WARM TEMPS WILL GO THRU THE
SHORT RANGE PERIOD.
FOR TONIGHT...HIGH PRESSURE RIDGE CAVALIER TO DEVILS LAKE TO
BISMARCK AT 21Z AND THIS WILL MOVE SOUTH THIS EVE. SKY COVER
REMAINS PARTLY TO MOSTLY CLOUDY IN SE ND/WCNTRL MN WITH MOSTLY MID
OR HIGH LEVEL MOISTURE. NORTH OF THIS IN ZONE DVL-GFK-TVF SKIES
MOSTLY CLEAR (SOME THINNER HIGH CLDS) AND WILL SEE LIGHT WINDS
THIS EVE SO EXPECT A QUICK DROP IN TEMPS TO PERHAPS A BIT BLO ZERO
IN SPOTS...CONSIDERING WE ARE STARTING OUT 3 IN DVL AND 10 AT GFK-
TVF. FOR LANGDON AREA WINDS WILL TURN SOUTHWEST SOON AND THEY MAY
DROP QUICKLY BUT SHOULD RECOVER FASTER AS A BIT WARMER AIR
UPSTREAM IN SASK DROPS IN AHD OF NEXT COLD FRONT. SE ND/WCNTRL MN
SHOULD SEE A MORE TYPICAL CURVE WITH A SLOWER DROP DUE TO NO
SNOWCOVER AND MORE CLOUDS AT LEAST THIS EVE.
SHORT WAVE AT 500 MB RACING ESE THRU ALBERTA INTO CNTRL SASK WILL
MOVE INTO FAR SRN MB/LOW REGION FRIDAY MORNING. COLD FRONT WILL
DROP SOUTH THRU THE AREA IN THE 12Z-15Z PERIOD IN THE NORTH AND IN
THE EARLY-MID AFTN IN THE SOUTH. GOOD DEAL OF PACIFIC MOISTURE
STREAMING ESE FROM SE ALASKA THRU CNTRL ALBERTA INTO SASK ATTM
WITH BAND OF SNOW...AND WHILE IT WILL WEAKEN...DO EXPECT A LEAST
SOME PERIOD OF -SN WITH FRONT AS IT DROPS SOUTH. ACCUMS LOOK LIKE
HALF INCH OR LESS. TEMPS SHOULD DROP BEHIND IT IN NRN ND IN THE
AFTN.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 325 AM CST THU NOV 21 2013
HIGH PRESSURE WILL DROP IN FAST BEHIND IT AND BE OVER ERN ND 12Z
SAT. PRETTY DRY COLD AIR MOVING SHOULD HELP CLEAR OUT MOST CLOUD
COVER...BUT COULD BE PATCHES AROUND AS SOME EVIDENCE OF 850 MB
MOISTURE STILL PRESENT. WITH ANY CLEAR SKY AND COLD ADVECTION
SFC-850 MB LOWS SHOULD DROP INTO THE TEENS BELOW ZERO IN DVL BASIN
AND FAR NRN RRV TO SINGLE DIGITS ABOVE IN WCNTRL MN. NOT A HUGE
RECOVER SATURDAY WITH LIGHT MIXING BUT RETURN FLOW WILL GET GOING
SAT NIGHT AND ESP INTO SUNDAY SOUTH OF LOW PRESSURE WHICH WILL
MOVE SOUTHEAST THRU CNTRL CANADA TOWARD LAKE SUPERIOR. HOW FAST
THE WARM UP WILL BE ALWAYS IN QUESTION..BUT WENT WITH IDEA OF
RISING TEMPS IN ERN ND SAT NIGHT WITH HIGH TEMPS SUNDAY 20S TO
LOWER 30S.
FOR SUNDAY NIGHT THROUGH THURSDAY...LONG TERM MODELS IN GENERAL
AGREEMENT FOR A NORTHWEST FLOW PATTERN ALOFT DOMINATING THE LONG
TERM. IN GENERAL...MAJORITY OF CWA WILL BE DRY BUT THERE ARE A FEW
BRIEF PERIODS OF LOW POPS ACROSS NORTHERN MN AS THE STORM TRACK
SHOULD BE ACROSS CENTRAL SASK/MB INTO SOUTHWESTERN ONT. THIS WILL
ALSO KEEP TEMPS WELL BELOW SEASONAL NORMS...BUT DRY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 704 PM CST THU NOV 21 2013
VFR CIGS EXPECTED THROUGH THE OVERNIGHT HOURS. WINDS WILL BE
LIGHT...SHIFTING FROM NORTHWEST TO SOUTHWEST. ON FRIDAY...A COLD
FRONT WILL SWEEP THROUGH THE REGION. THERE WILL BE A BAND OF
SNOW...BUT IT IS EXPECTED TO BE RELATIVELY NARROW AND UNSURE
WHEN/IF IT WOULD AFFECT ANY TAF SITES. WILL TRY AND OBTAIN MORE
CONFIDENCE BEFORE INSERTING -SN AND/OR LOWER CIGS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...RIDDLE
LONG TERM...RIDDLE/SPEICHER
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
447 PM CST WED NOV 20 2013
.UPDATE...
ISSUED AT 447 PM CST WED NOV 20 2013
QUICK UPDATE TO EXPAND THE WINTER WEATHER ADVISORY INTO
RENVILLE...TOWNER...BOTTINEAU...PIERCE AND ROLETTE COUNTIES.
HEAVY BANDED SNOW IS EXPECTED TO RESULT IN 3 TO 5 INCHES OF SNOW
FOR THESE AREAS WITH VISIBILITIES NEAR ONE QUARTER OF A MILE.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 312 PM CST WED NOV 20 2013
LATEST RADAR AND WEATHER CAMERAS INDICATE SNOW FROM WEST CENTRAL
INTO NORTH CENTRAL NORTH DAKOTA. SNOW HAS BEEN HEAVY AT TIMES WITH
VISIBILITY DOWN TO A QUARTER. LATEST REPORTS AND ESTIMATES INDICATE
1-2 INCHES HAS FALLEN FROM WILLISTON TO DICKINSON. LIKELY SOME
HIGHER AMOUNTS IN A PERSISTENT BAND ACROSS MAINLY MCKENZIE COUNTY.
THIS BAND HAS BECOMING MORE ENHANCED ACROSS MOUNTRAIL INTO WARD
COUNTY IN THE PAST HOUR.
EXPECT ANOTHER 2 TO 4 HOURS OF LIGHT TO MODERATE SNOW IN THE
ADVISORY AREA...BEFORE SHIFTING FARTHER SOUTH AND EAST. 12 UTC
MODEL GUIDANCE AND THE LATEST MESOSCALE RAP AND HRRR SHOW
PRECIPITATION ENDING QUICKLY AROUND 00 UTC IN WESTERN NORTH DAKOTA
AS BEST FRONTOGENETICAL FORCING SHIFTS INTO CENTRAL NORTH DAKOTA.
THIS SHOULD PUT AN END TO ACCUMULATING SNOW OVER THE ADVISORY AREA
BY MID EVENING. CURRENT HAZARD GOES UNTIL 10 PM AND EVENING SHIFT
CAN CANCEL EARLY IF NEEDED.
BEST SNOW CHANCES ARE OVER CENTRAL NORTH DAKOTA THIS EVENING. AND
ACCUMULATIONS OF AROUND AN INCH ARE POSSIBLE OVER THE SOUTH
CENTRAL AND FAR SOUTHWEST...FROM BOWMAN AND HETTINGER TO BISMARCK
AND JAMESTOWN. LESSER AMOUNTS...UNDER AN INCH ARE EXPECTED FROM
SELFRIDGE TO LAMOURE AND OAKES. MODEL SOUNDINGS INDICATE WARM
TEMPERATURES ALOFT IN THE FAR SOUTH CENTRAL...THUS HAVE INCLUDED A
MENTION OF MIXED PRECIPITATION SOUTH OF BISMARCK TO THE SOUTHERN
JAMES RIVER VALLEY.
PRECIPITATION ENDS QUICKLY IN THE CENTRAL AS THE UPPER TROUGH
TRANSLATES INTO THE AREA LATE TONIGHT. THEN WE ARE LOOKING AT VERY
COLD TEMPERATURES AND WIND CHILLS LATE TONIGHT AND THURSDAY. WIND
CHILLS FROM 10 BELOW SOUTH TO 20 BELOW NORTHWEST CAN BE EXPECTED
EARLY THURSDAY MORNING.
THURSDAY IS EXPECTED TO BE DRY BUT COLD WITH HIGHS OF 10 TO 20 ABOVE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 312 PM CST WED NOV 20 2013
THE HIGHLIGHT OF THE EXTENDED FORECAST IS THE COLDEST AIR OF THE
SEASON THUS FAR FOR FRIDAY NIGHT INTO SATURDAY MORNING.
THE 12 UTC DETERMINISTIC SUITE IS IN GOOD AGREEMENT ON A WEAK
CLIPPER SYSTEM PROPAGATING NEAR THE INTERNATIONAL BORDER THURSDAY
NIGHT INTO FRIDAY MORNING. THIS IS FOLLOWED BY A 1050 MB HIGH
BUILDING ACROSS NORTH DAKOTA THROUGH THE REMAINDER OF THE DAY ON
FRIDAY. WHEN COMBINED WITH THE SNOW COVER THAT WILL BE ACROSS THE
NORTH...THE COLDEST NIGHT OF THE SEASON THUS FAR IS EXPECTED WITH
LOWS NEAR -15 NORTH...WITH THE SINGLE DIGITS BELOW ZERO ACROSS THE
SOUTH. DID UNDERCUT ALL GUIDANCE BY AT LEAST FIVE DEGREES ACROSS
THE SNOWPACK FOR LOWS FRIDAY NIGHT. WIND CHILLS MAY APPROACH
ADVISORY CRITERIA OF -25 TO -30 EARLY SATURDAY MORNING ACROSS THE
NORTH. HIGHS WARM BACK INTO THE 30S ON SUNDAY IN THE WARM SECTOR
OF A SOUTHERN CANADA CLIPPER. HOWEVER...THIS WARM UP IS BRIEF AS
ANOTHER COOL CANADIAN AIRMASS PROPAGATES SOUTH EARLY NEXT WEEK
UNDER NORTHWEST FLOW ALOFT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 447 PM CST WED NOV 20 2013
A BAND OF MODERATE TO HEAVY SNOW WILL CONTINUE TO MOVE ACROSS
SOUTHWEST AND CENTRAL NORTH DAKOTA LATE THIS AFTERNOON AND EARLY
THIS EVENING. LIFR CONDITIONS ARE EXPECTED AT KMOT...WITH
CONDITIONS FALLING TO IFR AT KDIK...KBIS AND KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 PM CST THIS EVENING FOR
NDZ003>005-009>013-017-018-021.
&&
$$
UPDATE...AYD
SHORT TERM...TWH
LONG TERM...AYD
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
313 PM CST WED NOV 20 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 312 PM CST WED NOV 20 2013
LATEST RADAR AND WEATHER CAMERAS INDICATE SNOW FROM WEST CENTRAL
INTO NORTH CENTRAL NORTH DAKOTA. SNOW HAS BEEN HEAVY AT TIMES WITH
VISIBILITY DOWN TO A QUARTER. LATEST REPORTS AND ESTIMATES INDICATE
1-2 INCHES HAS FALLEN FROM WILLISTON TO DICKINSON. LIKELY SOME
HIGHER AMOUNTS IN A PERSISTENT BAND ACROSS MAINLY MCKENZIE COUNTY.
THIS BAND HAS BECOMING MORE ENHANCED ACROSS MOUNTRAIL INTO WARD
COUNTY IN THE PAST HOUR.
EXPECT ANOTHER 2 TO 4 HOURS OF LIGHT TO MODERATE SNOW IN THE
ADVISORY AREA...BEFORE SHIFTING FARTHER SOUTH AND EAST. 12 UTC
MODEL GUIDANCE AND THE LATEST MESOSCALE RAP AND HRRR SHOW
PRECIPITATION ENDING QUICKLY AROUND 00 UTC IN WESTERN NORTH DAKOTA
AS BEST FRONTOGENETICAL FORCING SHIFTS INTO CENTRAL NORTH DAKOTA.
THIS SHOULD PUT AN END TO ACCUMULATING SNOW OVER THE ADVISORY AREA
BY MID EVENING. CURRENT HAZARD GOES UNTIL 10 PM AND EVENING SHIFT
CAN CANCEL EARLY IF NEEDED.
BEST SNOW CHANCES ARE OVER CENTRAL NORTH DAKOTA THIS EVENING. AND
ACCUMULATIONS OF AROUND AN INCH ARE POSSIBLE OVER THE SOUTH
CENTRAL AND FAR SOUTHWEST...FROM BOWMAN AND HETTINGER TO BISMARCK
AND JAMESTOWN. LESSER AMOUNTS...UNDER AN INCH ARE EXPECTED FROM
SELFRIDGE TO LAMOURE AND OAKES. MODEL SOUNDINGS INDICATE WARM
TEMPERATURES ALOFT IN THE FAR SOUTH CENTRAL...THUS HAVE INCLUDED A
MENTION OF MIXED PRECIPITATION SOUTH OF BISMARCK TO THE SOUTHERN
JAMES RIVER VALLEY.
PRECIPITATION ENDS QUICKLY IN THE CENTRAL AS THE UPPER TROUGH
TRANSLATES INTO THE AREA LATE TONIGHT. THEN WE ARE LOOKING AT VERY
COLD TEMPERATURES AND WIND CHILLS LATE TONIGHT AND THURSDAY. WIND
CHILLS FROM 10 BELOW SOUTH TO 20 BELOW NORTHWEST CAN BE EXPECTED
EARLY THURSDAY MORNING.
THURSDAY IS EXPECTED TO BE DRY BUT COLD WITH HIGHS OF 10 TO 20 ABOVE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 312 PM CST WED NOV 20 2013
THE HIGHLIGHT OF THE EXTENDED FORECAST IS THE COLDEST AIR OF THE
SEASON THUS FAR FOR FRIDAY NIGHT INTO SATURDAY MORNING.
THE 12 UTC DETERMINISTIC SUITE IS IN GOOD AGREEMENT ON A WEAK
CLIPPER SYSTEM PROPAGATING NEAR THE INTERNATIONAL BORDER THURSDAY
NIGHT INTO FRIDAY MORNING. THIS IS FOLLOWED BY A 1050 MB HIGH
BUILDING ACROSS NORTH DAKOTA THROUGH THE REMAINDER OF THE DAY ON
FRIDAY. WHEN COMBINED WITH THE SNOW COVER THAT WILL BE ACROSS THE
NORTH...THE COLDEST NIGHT OF THE SEASON THUS FAR IS EXPECTED WITH
LOWS NEAR -15 NORTH...WITH THE SINGLE DIGITS BELOW ZERO ACROSS THE
SOUTH. DID UNDERCUT ALL GUIDANCE BY AT LEAST FIVE DEGREES ACROSS
THE SNOWPACK FOR LOWS FRIDAY NIGHT. WIND CHILLS MAY APPROACH
ADVISORY CRITERIA OF -25 TO -30 EARLY SATURDAY MORNING ACROSS THE
NORTH. HIGHS WARM BACK INTO THE 30S ON SUNDAY IN THE WARM SECTOR
OF A SOUTHERN CANADA CLIPPER. HOWEVER...THIS WARM UP IS BRIEF AS
ANOTHER COOL CANADIAN AIRMASS PROPAGATES SOUTH EARLY NEXT WEEK
UNDER NORTHWEST FLOW ALOFT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 312 PM CST WED NOV 20 2013
SNOW WILL MOVE EASTWARD THROUGH NORTH DAKOTA THROUGHOUT THE DAY
AND TAPPER OFF THROUGH THE OVERNIGHT HOURS. MVFR TO IFR CEILINGS
AND REDUCED VISIBILITIES CAN BE EXPECTED THROUGH MUCH OF THE DAY.
THEN IMPROVING FROM WEST TO EAST TONIGHT. WINDS WILL REMAIN
NORTHERLY NEAR 15 MPH THROUGH THE TAF PERIOD...BECOMING WEST TO
SOUTHWESTERLY FROM 12Z TO 18Z THURSDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 PM CST THIS EVENING FOR
NDZ009>011-017-018-021.
&&
$$
SHORT TERM...TWH
LONG TERM...AYD
AVIATION...TWH
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1130 PM CST TUE NOV 19 2013
.UPDATE...
SEE UPDATED AVIATION DISCUSSION BELOW.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT
QUITE A CHANGE COMING IN THE SHORT TERM FROM THIS AFTERNOON
THROUGH THURSDAY NIGHT. FOR TONIGHT...EXPECT RR QUAD JET INDUCED
HIGH CLOUDS TO MOVE ON THIS EVENING WHILE MORE HIGH CLOUDS SPREAD
IN FROM THE WEST. BREEZY SOUTH WINDS WILL DECREASE THIS EVENING
WITH WINDS BECOMING NORTHWEST THROUGH NORTH BY MORNING AS A WEAK
SURFACE LOW PRESSURE TROUGH MOVES THROUGH. TEMPERATURES WILL NOT
FALL OFF MUCH TONIGHT WITH THE MILD AIR MASS REMAINING. LOWS ARE
EXPECTED TO RANGE FROM AROUND 30 DEGREES NORTH CENTRAL TO THE MID
TO UPPER 30S IN THE WATERTOWN/ORTONVILLE AREA. OTHERWISE...HIGHS
ON WEDNESDAY WILL LIKELY BE IN THE MORNING AS AN ARCTIC BOUNDARY
PUSHES IN DURING THE AFTERNOON WITH NORTH WINDS PICKING UP AND
TEMPERATURES FALLING ACROSS THE NORTH. EXPECT WINDS TO BECOME
BLUSTERY AT 15 TO 30 MPH WITH HIGHER GUSTS. THE OTHER ISSUE WILL
BE THE LIGHT SNOW DEVELOPING ALONG AND BEHIND THE SURFACE COLD
FRONT. MID LEVEL FRONTOGENESIS ALONG WITH SOME JET STREAK HELP
WILL BRING LIGHT SNOW TO NORTH CENTRAL SOUTH DAKOTA BY LATE
AFTERNOON. THE MODELS INDICATE LESSER AMOUNTS OF LIFT AND QPF AS
THIS REGION DESCENDS SOUTH ACROSS OUR CWA THROUGH WEDNESDAY NIGHT.
THUS...HAVE LIKELY CHANCES EARLY DIMINISHING THROUGH THE NIGHT.
SNOWFALL AMOUNTS SHOULD BE GENERALLY BELOW AN INCH BY THURSDAY
MORNING. ARCTIC AIR ENCOMPASSES THE ENTIRE CWA ON THURSDAY WITH
LESS WIND. MUCH BELOW NORMAL TEMPERATURES ARE EXPECTED ON
THURSDAY WITH HIGHS IN THE 20 TO 25 DEGREE RANGE ACROSS THE CWA.
THE MODELS THEN SHOW AN UPPER LEVEL LOW PRESSURE TROUGH AND THE
ASSOCIATED LIFT SWINGING OVER THE REGION THURSDAY AND THURSDAY
EVENING. WITH MUCH OF THE NORTHERN CWA UNDER LOW LEVEL DRY
AIR...EXPECT THE BEST CHANCES OF LIGHT SNOW WITH THIS SYSTEM TO
BE FROM PIR TO HURON TO ATY. EXPECT MORE CLOUD COVER AND LIGHT
SNOW TO SPREAD QUICKLY WEST TO EAST ON THURSDAY ACROSS MAINLY THE
SOUTHERN CWA. COULD HAVE SOME MORE SNOWFALL ACCUMULATIONS OF AN INCH
OR TWO. THE LIGHT SNOW WILL END QUICKLY THURSDAY NIGHT WITH
CLEARING SKIES IN BEHIND AND SINGLE DIGIT LOWS.
.LONG TERM...FRIDAY THROUGH TUESDAY
NORTHWEST FLOW ALOFT WILL DOMINATE THE LONG TERM PORTION OF THE
FORECAST. A SURFACE LOW PRESSURE SYSTEM PASSING ACROSS THE GREAT
LAKES REGION ON FRIDAY WILL ALLOW FOR BITTER ARCTIC COLD
TEMPERATURES TO FILTER INTO THE AREA BY FRIDAY NIGHT. BY 12Z
SATURDAY TEMPERATURES AT H85 RANGE IN THE MID TO UPPER TEENS BELOW
ZERO...WHICH IS APPROACHING TWO STANDARD DEVIATIONS BELOW NORMAL. LOW
TEMPERATURES SHOULD EASILY DROP TO THE SINGLE DIGITS ON EITHER
SIDE OF ZERO BY SATURDAY MORNING. THE SURFACE HIGH PRESSURE WILL
EXIT THE REGION ON SATURDAY NIGHT ALLOWING FOR WAA TO SPREAD INTO
THE CWA. TEMPERATURES THROUGH THE REST OF THE PERIOD WILL BE
AROUND NORMAL...DUE TO EXPECTED SNOW COVER. NO SIGNIFICANT
PRECIPITATION CHANCES ARE EXPECTED FOR THE PERIOD.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS ARE EXPECTED THROUGH WEDNESDAY AFTERNOON. KATY
WILL REMAIN BREEZY OVERNIGHT. A LOW WILL BEGIN TO IMPACT
THE REGION LATE WED AFTERNOON. CIGS WILL BEGIN TO LOWER NEAR
KPIR/KMBG WED EVENING WITH LIGHT SNOW MOVING INTO THE WESTERN CWA
BY THE END OF THE TAF PERIOD. WINDS WILL SHIFT TO THE NORTH AND
NORTHWEST BEGINNING LATE WEDNESDAY MORNING AND BECOME GUSTY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...WISE
SHORT TERM...MOHR
LONG TERM...SD
AVIATION...WISE
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
923 PM CST THU NOV 21 2013
.DISCUSSION...ARCTIC COLD FRONT...JUST SOUTH OF A LINE FROM
DALLAS TO SAN ANGELO AT 03Z...CONTINUES TO SURGE SOUTH AT AROUND
25 MPH. LATEST MSAS ANALYSIS SHOWS 3 HOURLY PRESSURE RISES OF
6 TO 8 MBS OVER THE BIG COUNTRY AND CROSS TIMBERS REGIONS IN
NORTHWEST TEXAS. BELIEVE 00Z RUC/RAPID REFRESH MODEL ALONG WITH
THE LATEST SREF AND 3KM TEXAS TECH MODEL HAVE A BETTER HANDLE
ON THE PROGRESSION OF THIS STRONG SHALLOW ARCTIC AIR MASS. WENT
WITH 00Z RUC WITH BRINGING IN THE FRONT SHORTLY AFTER 12Z INTO
THE NORTHERN COUNTIES AND FRONTAL PASSAGE THROUGH THE SOUTHERN
COASTAL BEND BY 18Z FRIDAY AND THROUGH THE COASTAL WATERS BY 21Z.
STRONG COLD AIR ADVECTION BEHIND THE FRONT WILL BRING DOWN THE
TEMPERATURES INTO THE 40S ACROSS THE INLAND AREAS BY AFTERNOON
AND LOWER 50S ALONG THE COAST. LOWERED THE MINIMUM TEMPS JUST
SLIGHTLY FOR FRIDAY NIGHT. NO ADJUSTMENTS WERE MADE TO THE
CURRENT WEATHER/POPS CONFIGURATION FOR FRIDAY.
&&
.PREV DISCUSSION... /ISSUED 534 PM CST THU NOV 21 2013/
DISCUSSION...PLEASE SEE THE AVIATION DISCUSSION BELOW FOR MORE
DETAILS.
AVIATION...MVFR STRATUS WL QUICKLY DEVELOP OVER THE NEXT FEW
HOURS AS A VERY MOIST BOUNDARY LAYER ALONG WITH SUBTLE COOLING WL
PROMOTE RAPID STRATUS DEVELOPMENT. A FEW ISOLATED STREAMER SHRAS
WL BE POSSIBLE TNT...MAINLY THE VCT AREA. PATCHY IFR CONDITIONS WL
ALSO BE POSSIBLE MAINLY THE VCT AREA AFTER 04Z. THE MAIN STORY WL
BE THE SLIGHTLY FASTER TIMING OF THE STRONG COLD FRONT WHICH IS
CURRENTLY MOVING RAPIDLY THROUGH NORTH TEXAS. THE 18Z MODELS HAVE
PICKED UP ON THIS FASTER MOVEMENT AND WL THUS LEAN TWDS THIS
QUICKER FROPA TIMING. AS A RESULT...WL SHOW FROPA AROUND 13Z FOR
VCT AND AROUND 16Z ELSEWHERE. SUFFICIENT MOISTURE AND LIFTING
ALONG AND BEHIND THE FRONT WL PRODUCE SCATTERED TO NUMEROUS
SHOWERS WITH EMBEDDED THUNDERSTORMS ACROSS MOST OF SOUTH TX ON
FRIDAY. THE PCPN WL TEND TO TAPER OFF FROM NORTH TO SOUTH BY THE
AFTN.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 74 75 41 49 46 / 30 70 60 70 40
VICTORIA 65 69 40 51 44 / 40 70 60 60 40
LAREDO 73 73 41 48 43 / 20 70 60 40 40
ALICE 74 75 41 48 44 / 30 70 60 60 40
ROCKPORT 72 72 46 51 47 / 30 70 60 70 40
COTULLA 65 66 40 45 42 / 50 70 60 40 30
KINGSVILLE 74 77 41 48 45 / 20 70 60 60 40
NAVY CORPUS 73 73 46 51 48 / 20 70 60 70 40
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
TMT/89...SHORT TERM
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
856 PM CST THU NOV 21 2013
.UPDATE...
ARCTIC FRONT ALONG A PECOS TO SAN ANGELO TO STEPHENVILLE LINE WAS
SURGING SOUTH AHEAD OF SCHEDULE. NOW EXPECT FRONT WILL ENTER THE
NORTHERN HILL COUNTRY AROUND MIDNIGHT...MOVE ACROSS THE AUSTIN AND
SAN ANTONIO AREAS BETWEEN 2 AND 4 AM AND EXIT SOUTH CENTRAL TEXAS
BY SUNRISE. AS A RESULT...HAVE LOWERED TEMPERATURES AND DEW POINTS
FOR OVERNIGHT INTO FRIDAY ALONG WITH AN EARLIER ONSET OF MODERATE
GUSTY NORTHERLY WINDS. ALSO...HAVE REMOVED MENTION OF THUNDER FOR
FRIDAY AS INSTABILITY IS GONE AND CHANGED SHOWERS TO LIGHT RAIN.
REMAINDER OF SOUTH CENTRAL TEXAS FORECAST IS ON TRACK. 18Z MODEL
SUITE AND NEW 00Z NAM CONTINUE TO SUGGEST A MIX OF LIGHT SLEET AND
RAIN DURING THE OVERNIGHT INTO EARLY MORNING HOURS FRIDAY NIGHT
THROUGH MONDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 535 PM CST THU NOV 21 2013/
DISCUSSION...
SEE AVIATION FOR THE 00Z TAF DISCUSSION.
AVIATION...
AT 23Z THE COLD FRONT WAS MOVING SOUTHWARD ACROSS NORTH TEXAS. THE
FRONT WILL MOVE INTO THE HILL COUNTRY AFTER MIDNIGHT...REACHING
THE TEXAS COAST BY EARLY AFTERNOON ON FRIDAY. THE TIMING OF THE
FROPA AND ASSOCIATED WIND SHIFT AT THE TERMINALS WILL BE BASED ON
A BLEND OF THE LATEST RUC AND LAMP GUIDANCE. NUMEROUS SHOWERS AND
ISOLATED THUNDERSTORMS WILL OCCUR IN THE VICINITY OF THE FRONTAL
BOUNDARY AS IT INTERACTS WITH THE MOISTURE LADEN GULF AIRMASS.
POST-FRONTAL PCPN WILL BE MAINLY ELEVATED SHOWERS.
I-35 TERMINALS...VFR CONDITIONS WILL LOWER TO MVFR BETWEEN 02Z AND
04Z...LOWERING TO IFR BY 15Z. THE BEST CHANCE FOR CONVECTION TO
IMPACT THE TAFS SITES WILL BE A FEW HOURS BEFORE AND DURING THE
FROPA. WINDS WILL SHIFT TO THE NORTH AT 12 TO 15 KTS WITH GUSTS OF
25 KTS. FROPA AT KAUS...08Z...KSAT AND KSSF AROUND 10Z.
THE KDRT TERMINAL...VFR CONDITIONS WILL LOWER TO MVFR BY 01Z...IFR
BY 08Z...IMPROVING TO MVFR BY 22Z. ORGANIZED CONVECTION IS EXPECTED
TO STAY EAST OF THE TERMINAL. WINDS WILL SHIFT TO THE NORTH AT 15
TO 20 KTS WITH GUSTS OF 25 KTS FOLLOWING THE FROPA. FROPA IS EXPECTED
AROUND 08Z.
PREV DISCUSSION... /ISSUED 318 PM CST THU NOV 21 2013/
SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...
THE STRONG COLD FRONT HAS REACHED THE PANHANDLE. THE COLD AIR
ADVECTION IN THE WAKE OF THE FRONT IS CLEARLY EVIDENT...SFC OBS
INDICATE TEMPERATURES PLUMMETING BY 20 DEGREES OR MORE IN THE WAKE
OF THE FROPA. THE FRONT WILL CONTINUE TO PUSH SOUTHWARD ACROSS THE
STATE TONIGHT AND WILL REACH THE HILL COUNTRY BEFORE SUNRISE. THE
FRONT WILL CONTINUE TO QUICKLY MOVE THROUGH THE AREA...AND IS
EXPECTED TO REACH OUR SOUTHERN COUNTIES BEFORE NOON. DUE TO THE
TIMING OF THE FROPA...CALENDAR DAY "HIGH" TEMPERATURES FOR FRIDAY
WILL OCCUR DURING THE OVERNIGHT HOURS TONIGHT. TEMPERATURES DURING
THE DAY ON FRIDAY WILL FALL BEHIND THE FRONT...WITH AFTERNOON
TEMPERATURES REMAINING IN THE 40S (UPPER 30S HILL COUNTRY). STRONG
NORTHERLY WINDS OF 15 TO 25 MPH WILL LEAD TO WIND CHILLS IN THE
LOW TO MID 30S ACROSS MUCH OF THE AREA...AND INTO THE MID/UPPER
20S ACROSS THE HILL COUNTRY.
CHANCES FOR RAIN WILL INCREASE TONIGHT AND PERSIST THROUGH THE
WEEKEND. ISOLATED THUNDERSTORMS ARE POSSIBLE THIS EVENING THROUGH
FRIDAY. TEMPERATURES FRIDAY NIGHT WILL FALL INTO THE MID-30S ACROSS
THE HILL COUNTRY...BRINGING THE POTENTIAL FOR ISOLATED LIGHT SLEET
TO MIX-IN WITH THE COLD RAIN. NO SLEET ACCUMULATIONS ARE EXPECTED.
THE LINGERING MOISTURE/CHANCES FOR RAIN/CLOUD COVER WILL OTHERWISE
KEEP LOW TEMPERATURES IN THE UPPER 30S TO LOW 40S FRIDAY NIGHT.
LONG TERM (SATURDAY THROUGH THURSDAY)...
A DEEP UPPER LOW PARKED OVER THE SOUTHWESTERN U.S. WILL KEEP CLOUDY
SKIES AND GOOD CHANCES FOR RAIN OVER THE WEEKEND AND INTO EARLY
NEXT WEEK. HIGH TEMPERATURES WILL REMAIN UNSEASONABLY COLD. THERE
IS A RENEWED CHANCE FOR ISOLATED LIGHT SLEET TO MIX-IN WITH THE
RAIN ACROSS THE HILL COUNTRY SATURDAY NIGHT/SUNDAY MORNING AND
AGAIN SUNDAY NIGHT/MONDAY MORNING. SURFACE TEMPERATURES ARE
EXPECTED TO REMAIN ABOVE FREEZING AND THEREFORE SLEET
ACCUMULATIONS ARE AGAIN NOT EXPECTED.
THE UPPER LOW WILL EJECT EASTWARD ON MONDAY. CHANCES FOR RAIN WILL
BEGIN TO DECREASE MONDAY NIGHT AND WILL END LATE TUESDAY AS THE
UPPER LOW MOVES TO OUR EAST. SKIES WILL BEGIN TO CLEAR FROM THE
WEST LATE TUESDAY...WITH SUNSHINE FINALLY RETURNING ON WEDNESDAY.
HIGH TEMPERATURES WILL BEGIN TO WARM...BUT MOSTLY CLEAR SKIES
DURING THE OVERNIGHT HOURS WILL ALLOW LOW TEMPERATURES TO FALL
INTO THE 30S ACROSS MUCH OF THE CWA. SPOTTY FREEZING TEMPERATURES
ARE POSSIBLE THANKSGIVING MORNING.
CLIMATE...
RECORD COLD HIGH TEMPERATURES FOR NOV 23 THROUGH 24:
23RD 24TH
AUSTIN CAMP MABRY...40/1937...42/1982
AUSTIN BERGSTROM....43/1957...44/1972
SAN ANTONIO.........41/1932...44/1982
DEL RIO.............40/1957...42/1918
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 43 45 39 43 38 / 90 70 70 60 60
AUSTIN BERGSTROM INTL AIRPORT 45 47 38 45 40 / 80 70 70 60 60
NEW BRAUNFELS MUNI AIRPORT 47 52 37 44 38 / 80 70 70 60 60
BURNET MUNI AIRPORT 39 40 34 41 34 / 90 70 70 60 60
DEL RIO INTL AIRPORT 46 52 38 42 36 / 50 60 60 50 50
GEORGETOWN MUNI AIRPORT 40 41 34 42 34 / 90 70 70 60 60
HONDO MUNI AIRPORT 49 56 40 46 39 / 70 70 70 60 60
SAN MARCOS MUNI AIRPORT 46 49 38 43 38 / 80 70 70 60 60
LA GRANGE - FAYETTE REGIONAL 51 57 43 48 43 / 70 70 70 60 60
SAN ANTONIO INTL AIRPORT 48 55 40 45 39 / 70 70 70 60 60
STINSON MUNI AIRPORT 52 63 42 48 42 / 70 70 70 60 60
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...13
SYNOPTIC/GRIDS...04
PUBLIC SERVICE/DATA COLLECTION...32
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
535 PM CST THU NOV 21 2013
.DISCUSSION...
SEE AVIATION FOR THE 00Z TAF DISCUSSION.
&&
.AVIATION...
AT 23Z THE COLD FRONT WAS MOVING SOUTHWARD ACROSS NORTH TEXAS. THE
FRONT WILL MOVE INTO THE HILL COUNTRY AFTER MIDNIGHT...REACHING
THE TEXAS COAST BY EARLY AFTERNOON ON FRIDAY. THE TIMING OF THE
FROPA AND ASSOCIATED WIND SHIFT AT THE TERMINALS WILL BE BASED ON
A BLEND OF THE LATEST RUC AND LAMP GUIDANCE. NUMEROUS SHOWERS AND
ISOLATED THUNDERSTORMS WILL OCCUR IN THE VICINITY OF THE FRONTAL
BOUNDARY AS IT INTERACTS WITH THE MOISTURE LADEN GULF AIRMASS.
POST-FRONTAL PCPN WILL BE MAINLY ELEVATED SHOWERS.
I-35 TERMINALS...VFR CONDITIONS WILL LOWER TO MVFR BETWEEN 02Z AND
04Z...LOWERING TO IFR BY 15Z. THE BEST CHANCE FOR CONVECTION TO
IMPACT THE TAFS SITES WILL BE A FEW HOURS BEFORE AND DURING THE
FROPA. WINDS WILL SHIFT TO THE NORTH AT 12 TO 15 KTS WITH GUSTS OF
25 KTS. FROPA AT KAUS...08Z...KSAT AND KSSF AROUND 10Z.
THE KDRT TERMINAL...VFR CONDITIONS WILL LOWER TO MVFR BY 01Z...IFR
BY 08Z...IMPROVING TO MVFR BY 22Z. ORGANIZED CONVECTION IS EXPECTED
TO STAY EAST OF THE TERMINAL. WINDS WILL SHIFT TO THE NORTH AT 15
TO 20 KTS WITH GUSTS OF 25 KTS FOLLOWING THE FROPA. FROPA IS EXPECTED
AROUND 08Z.
&&
.PREV DISCUSSION... /ISSUED 318 PM CST THU NOV 21 2013/
SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...
THE STRONG COLD FRONT HAS REACHED THE PANHANDLE. THE COLD AIR
ADVECTION IN THE WAKE OF THE FRONT IS CLEARLY EVIDENT...SFC OBS
INDICATE TEMPERATURES PLUMMETING BY 20 DEGREES OR MORE IN THE WAKE
OF THE FROPA. THE FRONT WILL CONTINUE TO PUSH SOUTHWARD ACROSS THE
STATE TONIGHT AND WILL REACH THE HILL COUNTRY BEFORE SUNRISE. THE
FRONT WILL CONTINUE TO QUICKLY MOVE THROUGH THE AREA...AND IS
EXPECTED TO REACH OUR SOUTHERN COUNTIES BEFORE NOON. DUE TO THE
TIMING OF THE FROPA...CALENDAR DAY "HIGH" TEMPERATURES FOR FRIDAY
WILL OCCUR DURING THE OVERNIGHT HOURS TONIGHT. TEMPERATURES DURING
THE DAY ON FRIDAY WILL FALL BEHIND THE FRONT...WITH AFTERNOON
TEMPERATURES REMAINING IN THE 40S (UPPER 30S HILL COUNTRY). STRONG
NORTHERLY WINDS OF 15 TO 25 MPH WILL LEAD TO WIND CHILLS IN THE
LOW TO MID 30S ACROSS MUCH OF THE AREA...AND INTO THE MID/UPPER
20S ACROSS THE HILL COUNTRY.
CHANCES FOR RAIN WILL INCREASE TONIGHT AND PERSIST THROUGH THE
WEEKEND. ISOLATED THUNDERSTORMS ARE POSSIBLE THIS EVENING THROUGH
FRIDAY. TEMPERATURES FRIDAY NIGHT WILL FALL INTO THE MID-30S ACROSS
THE HILL COUNTRY...BRINGING THE POTENTIAL FOR ISOLATED LIGHT SLEET
TO MIX-IN WITH THE COLD RAIN. NO SLEET ACCUMULATIONS ARE EXPECTED.
THE LINGERING MOISTURE/CHANCES FOR RAIN/CLOUD COVER WILL OTHERWISE
KEEP LOW TEMPERATURES IN THE UPPER 30S TO LOW 40S FRIDAY NIGHT.
LONG TERM (SATURDAY THROUGH THURSDAY)...
A DEEP UPPER LOW PARKED OVER THE SOUTHWESTERN U.S. WILL KEEP CLOUDY
SKIES AND GOOD CHANCES FOR RAIN OVER THE WEEKEND AND INTO EARLY
NEXT WEEK. HIGH TEMPERATURES WILL REMAIN UNSEASONABLY COLD. THERE
IS A RENEWED CHANCE FOR ISOLATED LIGHT SLEET TO MIX-IN WITH THE
RAIN ACROSS THE HILL COUNTRY SATURDAY NIGHT/SUNDAY MORNING AND
AGAIN SUNDAY NIGHT/MONDAY MORNING. SURFACE TEMPERATURES ARE
EXPECTED TO REMAIN ABOVE FREEZING AND THEREFORE SLEET
ACCUMULATIONS ARE AGAIN NOT EXPECTED.
THE UPPER LOW WILL EJECT EASTWARD ON MONDAY. CHANCES FOR RAIN WILL
BEGIN TO DECREASE MONDAY NIGHT AND WILL END LATE TUESDAY AS THE
UPPER LOW MOVES TO OUR EAST. SKIES WILL BEGIN TO CLEAR FROM THE
WEST LATE TUESDAY...WITH SUNSHINE FINALLY RETURNING ON WEDNESDAY.
HIGH TEMPERATURES WILL BEGIN TO WARM...BUT MOSTLY CLEAR SKIES
DURING THE OVERNIGHT HOURS WILL ALLOW LOW TEMPERATURES TO FALL
INTO THE 30S ACROSS MUCH OF THE CWA. SPOTTY FREEZING TEMPERATURES
ARE POSSIBLE THANKSGIVING MORNING.
CLIMATE...
RECORD COLD HIGH TEMPERATURES FOR NOV 23 THROUGH 24:
23RD 24TH
AUSTIN CAMP MABRY...40/1937...42/1982
AUSTIN BERGSTROM....43/1957...44/1972
SAN ANTONIO.........41/1932...44/1982
DEL RIO.............40/1957...42/1918
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 52 54 39 43 38 / 90 100 70 60 60
AUSTIN BERGSTROM INTL AIRPORT 53 55 38 45 40 / 80 100 70 60 60
NEW BRAUNFELS MUNI AIRPORT 59 62 37 44 38 / 80 100 70 60 60
BURNET MUNI AIRPORT 47 49 34 41 34 / 90 80 70 60 60
DEL RIO INTL AIRPORT 61 65 38 42 36 / 50 60 60 50 50
GEORGETOWN MUNI AIRPORT 48 51 34 42 34 / 90 100 70 60 60
HONDO MUNI AIRPORT 64 68 40 46 39 / 70 100 70 60 60
SAN MARCOS MUNI AIRPORT 55 58 38 43 38 / 80 100 70 60 60
LA GRANGE - FAYETTE REGIONAL 61 64 44 48 43 / 70 100 70 60 60
SAN ANTONIO INTL AIRPORT 62 67 41 45 39 / 70 100 70 60 60
STINSON MUNI AIRPORT 65 69 42 48 42 / 70 100 70 60 60
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...13
SYNOPTIC/GRIDS...04
PUBLIC SERVICE/DATA COLLECTION...32
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
913 PM CST THU NOV 21 2013
.UPDATE...
THE LIGHT PRECIP EXPECTED TONIGHT HAS BEEN DELAYED. DRIER AIR AND
A LACK OF ANY GOOD FORCING THIS EVENING HAS KEPT THINGS DRY
ACROSS THE AREA SO FAR. HOWEVER...A STRONG MID LEVEL SHORT WAVE
PUSHING IN AFTER MIDNIGHT AND A RAPIDLY STRENGTHENING UPPER LEVEL
JET /GOING FROM 70KTS TO 140KTS IN 18HRS/ SHOULD HELP TO BRING
SOME LIGHT PRECIP LATER. IT WON/T LAST LONG AS DRY AIR IS PUNCHING
IN SHORTLY AFTER SUNRISE ON FRIDAY. SO...THE BEST CHANCE FOR ANY
PRECIP TONIGHT WILL RUN FROM ABOUT MIDNIGHT THROUGH ABOUT 7-8 AM
FRIDAY MORNING. STARTING EARLIER WEST OF MADISON...LATER TO THE
EAST. GIVEN THE DELAY...THE PRECIP SHOULD START AS A RAIN/SNOW MIX
THEN CHANGE TO ALL LIGHT SNOW. ANY ACCUMULATIONS WILL BE LESS THAN
1/2 INCH AND MOSTLY ON GRASSY AREAS. THEN SUNSHINE BEGINS ARRIVING
FRIDAY MORNING...BUT TEMPERATURES WILL BE COLD WITH A BRISK
NORTHERLY WIND.
&&
.AVIATION/06Z TAFS/...
EXPECT A MIX OF MVFR/IFR CIGS/VSBYS ACROSS THE AREA OVERNIGHT AS
COLDER AIR FLOWS SOUTH INTO THE REGION IN THE WAKE OF A COLD FRONT
THAT PASSED THROUGH EARLIER. A MID LEVEL SHORT WAVE ARRIVING AFTER
MIDNIGHT WILL HELP SPREAD A WINTRY MIX OF LIGHT PRECIPITATION
ACROSS THE AREA TONIGHT. IT SHOULD START IN MADISON BY AROUND 06Z
AND KMKE BY 08Z. INITIALLY...A LIGHT RAIN/SNOW MIX IS EXPECTED BUT
IT SHOULD CHANGE TO ALL LIGHT SNOW WITHIN A FEW HOURS AS
TEMPERATURES CONTINUE TO FALL. ANY ACCUMULATIONS WILL BE 1/2 INCH
OR LESS. THIS IS A FAST MOVING SYSTEM AND WILL BE CLEARING OUT OF
MADISON BY AROUND 12Z FRI MORNING AND MILWAUKEE BY 8 AM. THEN LOOK
FOR CLEARING SKIES.
&&
.PREV DISCUSSION... /ISSUED 327 PM CST THU NOV 21 2013/
SHORT TERM...
TONIGHT AND FRIDAY...FORECAST CONFIDENCE IS MEDIUM.
LATEST RUNS OF HRRR AND 4 KM WRF/NMM MODELS ARE INDICATING THAT THE
MOISTURE WILL BE DELAYED UNTIL LATER THIS EVENING FOR THE ARRIVAL OF
THE EXPECTED AREA OF PRECIPITATION. CURRENT AREA OF PRECIPITATION
OVER SOUTH CENTRAL IOWA MAY STRUGGLE TO MAKE IT HERE...AS THIS WILL
FIGHT DRY LOW LEVELS OVER THE AREA. FOR NOW...WILL PUSH BACK ARRIVAL
OF PRECIPITATION A BIT THIS EVENING...AS WELL AS THE CHANGEOVER TO
LIGHT SNOW LATER TONIGHT.
SYNOPTIC AND MESOSCALE MODELS ARE SLOWING THE SATURATION OF THE AIR
COLUMN UNTIL MID TO LATE EVENING FROM SOUTHWEST TO NORTHEAST. AREA
OF GOOD 850MB TO 700MB FRONTOGENESIS RESPONSE WILL PUSH EAST
SOUTHEAST THROUGH THE AREA BETWEEN 06Z AND 15Z FRIDAY...DRIVING THE
MAIN AREA OF PRECIPITATION. BEST UPWARD VERTICAL MOTION WILL BE OVER
THE NORTHWEST HALF OF THE AREA LATER TONIGHT...WITH AREAS TO THE
SOUTHEAST SEEING LESS.
AIR COLUMN WILL COOL FROM THE TOP DOWN AS COLD AIR ADVECTION KICKS
IN TONIGHT...SO WILL CONTINUE THE TRANSITION FROM RAIN OR RAIN/SNOW
MIX TO ALL LIGHT SNOW FROM NORTHWEST TO SOUTHEAST. EXPECTING AROUND
0.5 INCHES ON GRASSY AREAS FROM DARLINGTON TO MADISON TO SHEBOYGAN
AND NORTHWESTWARD...WITH LOWER AMOUNTS TO THE SOUTHEAST.
MILWAUKEE...RACINE AND KENOSHA MAY ONLY SEE A DUSTING AT BEST.
CLOUDS WILL GRADUALLY MIX OUT LATER ON FRIDAY...WITH COLD AIR
ADVECTION CONTINUING. WINDS WILL GRADUALLY WEAKEN AS THE DAY GOES
ON...BUT TEMPERATURES WILL STRUGGLE TO RISE MUCH OUT OF THE LOWER
TO MID 30S.
FRIDAY NIGHT THROUGH SUNDAY...FORECAST CONFIDENCE HIGH
LOW PRESSURE MOVING EAST ACROSS THE NORTHERN GREAT LAKES AND NEW
ENGLAND WILL SWEEP AN ARCTIC COLD FRONT ACROSS THE REGION FRI NT
INTO SAT. 850 MB TEMPS TO DROP TO -17C ON SAT AND SCT-BKN
STRATOCUMULUS CLOUDS ARE EXPECTED. HIGH TEMPS ONLY IN THE 20S
ARE FORECAST AND BRISK WINDS WILL MAKE FOR WIND CHILLS IN THE
SINGLE DIGITS AND TEENS ALL WEEKEND. ARCTIC HIGH PRESSURE TO THEN
MOVE FROM THE NRN PLAINS TO THE UPPER MS RIVER VALLEY BY 12Z SUN.
LIGHTER WIND AND RADIATIONAL COOLING WILL SUPPORT VERY COLD TEMPS
IN THE SINGLE DIGITS OVER SOUTH CENTRAL WI AND TEENS IN ERN WI.
THE HIGH WILL MOVE EAST FOR SUN AFTERNOON WITH SWLY WINDS AND WARM
ADVECTION BEGINNING. HIGH TEMPS ONCE AGAIN STUCK IN THE 20S.
LONG TERM...
SUNDAY NIGHT THROUGH THURSDAY...FORECAST CONFIDENCE MEDIUM
SWLY WINDS AND WARM ADVECTION WILL CONTINUE SUN NT INTO MON AS LOW
PRESSURE ONCE AGAIN TRACKS EAST ACROSS SRN CANADA. THERE ARE SMALL
CHANCES OF LGT SNOW WITH THE WARM ADVECTION DURING THIS TIME. A
COLD FRONT...WEAKER THAN PREVIOUS FRONTS...WILL MOVE ACROSS THE
REGION MON NT AND WILL BE ABLE TO MAINTAIN BELOW NORMAL TEMPS.
NWLY WINDS WILL THEN PREVAIL TUE-WED WITH A POLAR HIGH FINALLY
ARRIVING OVER WI FOR THANKSGIVING DAY. MAINLY DRY AND COLD
CONDITIONS ARE EXPECTED.
AVIATION/00Z TAFS/...
MVFR CEILINGS ARE EXPECTED TO SPREAD EAST ACROSS THE EASTERN SITES
BY EARLY THIS EVENING. MADISON WILL SEE MVFR CEILINGS AS WELL. WINDS
WILL BECOME NORTH NORTHWESTERLY THIS EVENING...GRADUALLY BECOMING
STRONGER AS THE NIGHT GOES ON.
EXPECTING LIGHT RAIN WITH MVFR VISIBILITIES AND IFR CEILINGS TO MOVE
INTO MADISON AROUND 03Z FRIDAY...AND AROUND 05Z FRIDAY AT THE
EASTERN SITES. THE LIGHT RAIN SHOULD MIX WITH LIGHT SNOW FOR A FEW
HOURS STARTING BETWEEN 06Z TO 08Z FRIDAY...BEFORE BECOMING ALL LIGHT
SNOW BETWEEN 08Z AND 10Z FRIDAY.
ANY LINGERING LIGHT SNOW SHOULD END BETWEEN 13Z TO 15Z FRIDAY WEST
TO EAST. GUSTY NORTH NORTHWEST WINDS SHOULD OCCUR BY 10Z
FRIDAY...LINGERING THROUGH FRIDAY.
SNOW ACCUMULATIONS ON GRASSY AREAS SHOULD BE AROUND 0.5 INCHES AT
MADISON...WITH A DUSTING AT BEST AT THE EASTERN SITES. RUNWAYS
SHOULD REMAIN JUST WET DURING THIS TIME...AS GROUND TEMPERATURES
REMAIN AROUND OR JUST ABOVE FREEZING DURING THE LIGHT SNOW. MVFR
CLOUDS SHOULD GRADUALLY MIX OUT IN THE AFTERNOON...WITH
NORTH NORTHWEST WINDS GRADUALLY WEAKENING BY LATE AFTERNOON.
MARINE...
SMALL CRAFT ADVISORY REMAINS IN EFFECT FROM LATE TONIGHT INTO LATE
FRIDAY NIGHT ACROSS THE NEARSHORE WATERS. A TIGHT PRESSURE GRADIENT
WILL DEVELOP WITH THE COLD AIRMASS MOVING INTO THE REGION DURING
THIS TIME...GENERATING GUSTY NORTH NORTHWEST WINDS. THESE WINDS WILL
GENERATE HIGH WAVES UP TO 4 TO 7 FEET FRIDAY.
THE SMALL CRAFT ADVISORY WILL LIKELY NEED TO BE EXTENDED THROUGH
SATURDAY NIGHT...AS ANOTHER SHOT OF COLD AIR SURGES INTO THE AREA.
NORTHWEST WIND GUSTS MAY REACH 35 KNOTS AT TIMES...SO A GALE WATCH
WOULD NEED TO BE CONSIDERED AS WELL. HIGH WAVES WOULD REMAIN TOWARD
AND OVER THE OPEN WATERS.
WINDS WILL BE NEAR SMALL CRAFT ADVISORY LEVELS AT TIMES INTO EARLY
NEXT WEEK...AS THE PRESSURE GRADIENT REMAINS TIGHT ACROSS THE AREA.
HIGH WAVES MAY OCCUR TOWARD THE OPEN WATERS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 4 AM FRIDAY TO 6 PM CST SATURDAY FOR
LMZ643>646.
&&
$$
UPDATE...DAVIS
TONIGHT/FRIDAY AND AVIATION/MARINE...WOOD
FRIDAY NIGHT THROUGH THURSDAY...GEHRING
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1205 PM CST WED NOV 20 2013
.UPDATE...
AREA OF PRECIPITATION OVER EASTERN IOWA AND SOUTHWARD WILL
CONTINUE TO SHIFT NORTHEAST INTO THE AREA THIS AFTERNOON...MOVING
ACROSS THIS EVENING. THIS IS BEING DRIVEN BY FOCUSED WARM AIR
ADVECTION...ALONG WITH PASSING 500 MB SHORTWAVE TROUGH. DRY AIR IN
THE LOW LEVELS WILL LIMIT THE PUSH OF LIGHT RAIN INTO WESTERN
PORTIONS OF THE AREA...BEFORE BECOMING MORE WIDESPREAD WEST TO
EAST AROUND 00Z THURSDAY PER HRRR AND 4 KM WRF/NMM MODELS.
FORECAST SOUNDINGS ACROSS THE WESTERN PORTIONS OF THE AREA ARE
TRYING TO SHOW SOME LIGHT SNOW MIXING IN WITH THE LIGHT RAIN EARLY
THIS EVENING...BUT PUSH OF WARM AIR ADVECTION SHOULD KEEP WET BULB
PROFILES WARM ENOUGH FOR LIGHT RAIN. TEMPERATURES MAY BE A BIT TOO
WARM...SO WILL ADJUST AS NEEDED FOR CURRENT TRENDS.
&&
.AVIATION/12Z TAFS/...
LIGHT RAIN SHOULD SPREAD EASTWARD ACROSS TAF SITES...FROM BETWEEN
22Z WEDNESDAY AT MADISON...TO AROUND 00Z THURSDAY AT THE EASTERN
SITES. THE LIGHT RAIN WILL END BETWEEN 05Z AT MADISON...AND 08Z AT
THE EASTERN TAF SITES. MVFR CEILINGS AND VISIBILITIES ARE EXPECTED
ONCE THE RAIN MOVES IN...AND CONTINUING THROUGH THE REST OF
TONIGHT. THE MVFR CEILINGS WILL LINGER ON THURSDAY.
GUSTY SOUTH SOUTHEAST WINDS THIS AFTERNOON WILL GRADUALLY SUBSIDE
BY EVENING ACROSS TAF SITES...WITH SOUTHEAST WINDS CONTINUING TO
WEAKEN TONIGHT. LIGHT AND VARIABLE WINDS ARE THEN EXPECTED LATER
TONIGHT INTO THURSDAY...BEFORE BECOMING LIGHT NORTH TO NORTHEAST
LATE THURSDAY AFTERNOON.
&&
.MARINE...
SMALL CRAFT ADVISORY CONTINUES ACROSS THE NEARSHORE WATERS OF LAKE
MICHIGAN UNTIL 10Z THURSDAY. MARINE OBSERVATIONS ALONG THE SHORE
HAVE SHOWN SOME SOUTH SOUTHEAST GUSTS IN THE 30 TO 35 KNOT
RANGE...BUT SHOULD GRADUALLY DIMINISH THIS AFTERNOON INTO THIS
EVENING.
WINDS WILL BECOME LIGHT LATER TONIGHT INTO THURSDAY...BEFORE
BECOMING NORTH TO NORTHEAST LATER THURSDAY AFTERNOON. HIGH WAVES
OF 5 TO 8 FEET WILL GRADUALLY SUBSIDE WITH THE WEAKENING WINDS BY
LATER TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 400 AM CST WED NOV 20 2013/
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH.
MODELS DIFFER A BIT IN TIMING WITH ISENTROPICALLY-DRIVEN PCPN...SO
USED A BLENDED SOLUTION FOR POPS. INITIAL PCPN BANDS ON AREA RADARS
ONLY PRODUCING ISOLATED TRACE AMOUNTS WITH CLOUD BASES BETWEEN 7K
AND 9K FT...REFLECTING DIFFICULTY OF GETTING MEASURABLE PCPN UNTIL
LOWER LAYERS SATURATE. COULD SEE A FEW SPRINKLES THIS MORNING
WITH THESE INITIAL BANDS...BUT WILL SEE BETTER CHANCES OF LIGHT
RAIN MOVE IN LATE MORNING/EARLY AFTERNOON IN THE WEST AND LATE
AFTERNOON/EVENING IN THE EAST WITH SECOND SURGE OF ISENTROPIC LIFT
AND LOWER CONDENSATION PRESSURE DEFICITS...AS WELL AS ADDITIONAL
FORCING FROM DCVA AHEAD OF SHORT WAVE. AMOUNTS WILL BE LIGHT...BUT
UPPED POPS TO CATEGORICAL WEST AND HIGH LIKELY EAST.
BLENDED SOLUTION TAKES PRECIPITATION OUT OF CWA WITH WAVE BETWEEN
06Z AND 09Z. RIGHT NOW THE FORECAST SOUNDINGS INDICATE PCPN ALL
LIQUID...BUT MAY HAVE TO WATCH FOR SOME SNOW FLAKES MIXING IN THE
NORTH AS PCPN ENDS.
WARM AIR ADVECTION REMAINS STRONGER ALOFT...WITH CLOUDS AND PCPN
FURTHER LIMITING TEMPS...BUT SHOULD STILL SEE HIGHS IN THE LOW 40S.
NOT MUCH OF A DROP OFF TONIGHT WITH LOWS ABOUT 7-8F LOWER THAN
DAYTIME HIGHS AS COOLER AIR STAYS TO THE NW OF SURFACE TROUGH
THAT IS JUST SAGGING INTO NW PORTION OF CWA AT 12Z THURSDAY.
THURSDAY AND FRIDAY - CONFIDENCE...MEDIUM
BRIEF RIDGING ALOFT AFTER THE PASSAGE OF THE WEDNESDAY NIGHT
WAVE. THE NEXT 500 MILLIBAR SHORTWAVE ARRIVES FOR THURSDAY
AFTERNOON BRINGING ANOTHER ROUND OF LIGHT PRECIPITATION. WEAK
700-300 MILLIBAR Q-VECTOR CONVERGENCE. BEST 850-700 MILLIBAR
Q-VECTOR CONVERGENCE TO THE SOUTHEAST. UPPER JET COMES INTO PLAY
THOUGH MODEL DIVERGENT SIGNALS ARE WEAK. LOW LEVEL THERMAL
PROFILES SUPPORT RAIN DURING THURSDAY THEN 925/850 MILLIBAR COLD
AIR PUSH STARTS TO SLIDE INTO THE CWA THURSDAY NIGHT...SO WILL
SHOW A GRADUAL TRANSITION TO A MIX AND EVENTUALLY ALL LIGHT SNOW
IN THE NW CWA. HIGHS WILL OCCUR EARLY FRIDAY AS COLDER AIRMASS
CONTINUES TO PUSH IN WITH 850/925 COLD AIR ADVECTION. MODELS SHOW
PRETTY DECENT DRY PUSH WORKING IN AS THE DAY GOES ON...NAM IS
ESPECIALLY AGGRESSIVE IN SCOURING OUT THE CLOUD COVER.
SATURDAY - CONFIDENCE...MEDIUM
COLD AIRMASS CONTINUES TO POUR INTO THE AREA WITH 850 TEMPS
DROPPING TO -18 TO -20C. UPPER FLOW IS STILL STRONGLY CYCLONIC
THOUGH AIRMASS PROGGD TO BE VERY DRY. WILL LEAVE DRY FCST INTACT.
HIGHS FOR MOST AREAS WILL REMAIN IN THE 20S.
SUNDAY - CONFIDENCE...MEDIUM DECENT 850 WAA PATTERN SETS UP. AT
925...THERMAL TROUGH LINGERS THROUGH THE MORNING WITH SOME
MODIFICATION INTO THE AFTERNOON. GFS SOUNDINGS SHOW POTENTIAL TO
MIX TO 925 WHICH SHOWS RECOVERY TO THE MID 20S.
MONDAY AND TUESDAY - CONFIDENCE...MEDIUM
COLD AIRMASS GETS REINFORCED WITH ANOTHER FRONT MONDAY NIGHT. 850
TEMPS BACK INTO THE TEENS BELOW ZERO CELSIUS. CURRENT ALLBLEND
GIVING HIGHS IN THE LOW/MID 30S THOUGH WITH 925 TEMPS PROGGD
ANYWHERE FROM -7 TO -10C MAY BE ANOTHER TOUGH DAY GETTING OUT OF
THE 20S. BASED ON COLLAB WITH SURROUNDING OFFICES TWEAKED TEMPS
DOWN A SMIDGE FOR STARTERS.
AVIATION/12Z TAFS/...EXPECT VFR CLOUD DECK TO LOWER WITH
CONTINUING WARM AIR/MOISTURE ADVECTION. COULD SEE A FEW SPRINKLES
BUT BETTER CHANCES FOR STEADY LIGHT RAIN WITH MVFR VSBYS COME
INTO KMSN LATE MORNING/EARLY AFTERNOON AND INTO EASTERN TAF SITE
BY EARLY EVENING. SOME CONCERN WITH NAM SHOWING LOWER CIGS
SETTLING IN AS PCPN MOVES OUT.
MARINE...NO CHANGE TO GOING SMALL CRAFT ADVISORY HEADLINE.
FORECAST WIND GUSTS WILL APPROACH GALE FORCE FOR A TIME
TODAY...WITH WINDS SLOWLY EASING STARTING LATE THIS AFTERNOON
INTO THE EVENING. END TIME OF ADVISORY WILL ALLOW TIME FOR WAVES
TO SUBSIDE...THOUGH THEY WILL STAY IN THE 3 TO 4 FOOT RANGE INTO
THURSDAY MORNING IN THE NORTHERN ZONES.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM CST THURSDAY FOR LMZ643>646.
&&
$$
UPDATE...WOOD
TODAY/TONIGHT AND AVIATION/MARINE...REM
THURSDAY THROUGH TUESDAY...COLLAR
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1040 PM MST THU NOV 21 2013
.UPDATE...
ISSUED AT 947 PM MST THU NOV 21 2013
LATEST 00Z RUNS HAVE GENERALLY SHIFTED THE HEAVIER ACCUMS FARTHER
TO THE SOUTH AND WEST. AREA OF ISENTROPIC UPGLIDE/FRONTOGENESIS
WILL SHIFT NORTHWARD ACROSS THE AREA TONIGHT...THOUGH UPGLIDE
WEAKENS AS IT SHIFTS INTO NORTHERN PORTIONS OF THE FORECAST AREA
ON FRIDAY. THEREFORE...HEAVIEST HIT AREAS STILL APPEAR TO BE
ACROSS THE SOUTHERN MOUNTAINS WITH THE EASTERN SAN JUANS BEING THE
BIG WINNERS WITH OVER A FOOT TO 16 INCHES POSSIBLE BY FRIDAY
EVENING. H7 WINDS SHIFT AROUND FROM THE EAST TOMORROW...SO THINK
THAT THE EASTERN SLOPES OF THE WETS AND SANGRES COULD PICK UP
AROUND A FOOT IN SOME PLACES MEETING THE 24 HOUR WARNING CRITERIA
AMOUNTS WITH THE AIDE OF SOME UPSLOPE FLOW. BOTH GFS AND NAM12
SUGGEST A GOOD 6 INCHES ACROSS MOST OF THE SAN LUIS
VALLEY...THOUGH WESTERN VALLEY EDGES COULD PICK UP SUBSTANTIALLY
MORE...SO WINTER STORM WARNING THERE STILL LOOKS GOOD. WARNING
CRITERIA AMOUNTS MAY HIT ON THE LOW SIDE ACROSS THE RATON MESA
REGION...BUT NAM12 IS STILL HITTING THIS AREA WITH AROUND 8
INCHES...AS OPPOSED TO GFS`S MORE CONSERVATIVE 3 TO 5. HUNG ON TO
THE LOWER SIDE OF THESE AMOUNTS FOR NOW AS ISENTROPIC UPGLIDE
LOOKS STRONGEST FARTHER SOUTH ACROSS NM AND TEXAS. REMAINDER OF
HEADLINES STILL LOOK GOOD. WE MAY COME UP ON THE SHORT SIDE OF
ADVISORY NUMBERS FOR CROWLEY COUNTY...BUT THEN AGAIN...GFS IS MORE
GUNG HO UP THAT WAY SATURDAY AFTERNOON AS THE BAND LIFTS
NORTHWARD...SO WILL HOLD THE COURSE.
FRIDAY EVENING...MODELS SPREAD A DRY SLOT NORTHWARD ACROSS THE
AREA WHICH CUTS BACK ON THE HEAVIER PRECIPITATION FAIRLY QUICKLY.
NAM12 STILL KEEPS SOME MODERATE 2-4 INCH ACCUMULATIONS ACROSS
NORTHWEST PORTIONS OF THE ADVISORY/WARNING AREAS...BUT GFS IS MUCH
LIGHTER. WILL LEAVE THE END TIME OF THE HIGHLIGHTS AT 6 PM FRI FOR
NOW AND LET SOME OF THE HIGHER RES MODELS RESOLVE THIS TIMING A
LITTLE BETTER. -KT
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 248 PM MST THU NOV 21 2013
...SNOW BAND TO BRING LOCALLY HEAVY SNOW AMOUNTS TO PART OF SOUTHERN
COLORADO...
CURRENTLY...
ARCTIC AIRMASS HAS MOVED ACROSS THE PLAINS...WITH TEMPS IN THE 20S
PLAINS AND OVC SKIES. COLD AIR HAS NOT MADE IT OVER THE MTNS YET AND
THE SLV STILL HAD TEMPS AOA 50F.
A WELL DEFINED JET STREAK WAS NOTED RAGING ACROSS S CALIF INTO THE 4
CORNERS.
REST OF TODAY THROUGH TOMORROW...
SIMULATIONS CONTINUE TO INDICATE A SNOW BAND CAPABLE OF LOCALLY
HEAVY SNOW WILL SET UP OVER SOUTHERN COLORADO LATER THIS EVENING
INTO TOMORROW. THE GUIDANCE HAS BEEN VERY CONSISTENT WITH THIS BAND
OVER THE LAST SEVERAL DAYS. LATEST 18Z NAM CONTINUES TO SHOW THIS
PATTERN AND THE HRRR SUPPORTS THE DEVELOPMENT OF THIS BAND. THIS
BAND IS ASSOCIATED WITH A BAROCLINIC ZONE IN THE 600-7000MB LAYER
THAT IS PROGGED NOT TOO MOVE TOO MUCH. IT APPEARS AT THIS TIME THE
BEST CHANCE OF HEAVIER SNOW WILL FALL GENERALLY ALONG AND SOUTH OF
US HIGHWAY 50.
SNOWFALL AMOUNTS WITH THIS BAND FOR TONIGHT THROUGH TOMORROW
ACCORDING TO GUIDANCE ARE RATHER IMPRESSIVE..AND HAVE CUT BACK FROM
GUIDANCE...STILL 4-7" AMOUNTS WILL BE POSSIBLE OVER NEARLY ALL OF
THE SAN LUIS VALLEY AND MOST OF THE PLAINS GENERALLY SOUTH OF
HIGHWAY 50 AND WEST OF SPRINGFIELD.
THE SANGRES...WETS AND SAN JUANS SHOULD DO VERY WELL WITH THIS
EVENT...WITH 12-18" OVER THE SAN JUANS AND NEAR A FOOT OVER THE
SANGRES AND WETS.
FARTHER NORTH LESS SNOW IS LIKELY AND HAVE CUT BACK ON AMOUNTS IN
THE CENTRAL MOUNTAINS. HAVE ALSO DOWNGRADED WARNINGS TO ADVISORIES
FOR PARTS OF THE CENTRAL MOUNTAIN REGION.
THE PIKES PEAK REGION WILL SEE ON AND OF SNOW SHOWERS WITH 1-3"
POSSIBLE THROUGH THE PERIOD. THE BEST CHANCE OF SNOW MAY OCCUR LATER
TOMORROW AS THE BAND LIFTS A BIT TO THE NORTH. HOWEVER THE SNOW IS
EXPECTED TO BE DECREASING AS THE FRONTOGENETICAL FORCING LESSENS
WITH TIME.
TOMORROW WILL BE ANOTHER COLD DAY WITH HIGHS ON THE 20S ALL AREAS.
WE MAY SEE SOME BREAKS IN THE CLOUDS LATE IN THE DAY OVER THE
NORTHERN PARTS OF THE CWA. /HODANISH
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 248 PM MST THU NOV 21 2013
...SNOW AND COLD CONTINUES...
FRIDAY NIGHT-SATURDAY...SNOW ACROSS THE EASTERN PLAINS WILL SLOWLY
WIND DOWN BETWEEN 06Z-09Z EARLY SATURDAY MORNING ACROSS THE EASTERN
PLAINS AS THE BEST LIFT MOVES AWAY FROM THE AREA.
ATTENTION THEN TURNS TO THE CUT OFF LOW SPINNING OVER SOUTHERN
CALIFORNIA. THE GFS AND THE NAM ARE IN SOMEWHAT BETTER AGREEMENT
WITH THE EC MODELS HANDLING OF THE LOW AND AM NOW MORE CONFIDENT THE
LOW WILL TAKE A MORE NORTHERLY TRACK THEN PREVIOUS GFS FORECASTS
HAVE SHOWN. IN COORDINATION WITH DDC/GLD/GJT I HAVE INCREASED POPS
ACROSS ALL OF THE MOUNTAIN AREAS SATURDAY AND SUNDAY...AND ACROSS
THE PLAINS ON SUNDAY. IF CURRENT MODEL TRENDS CONTINUE...I AM FAIRLY
CERTAIN THE WINTER STORM WARNING FOR THE SAN JUANS WILL NEED TO BE
EXTENDED THROUGH AT LEAST SATURDAY EVENING. THE 18Z NAM12 SHOWS 30
INCHES OF SNOWFALL BETWEEN 00Z SATURDAY AND 12Z SUNDAY ACROSS THE
SAN JUANS. THE 12Z GFS PAINTS 20 INCHES DURING THE SAME TIME FRAME.
TOO EARLY TO EXTEND THE WARNING AT THIS TIME.
SUNDAY...AS SNOW CHANCES REMAIN HIGH ALONG THE CONTINENTAL
DIVIDE...MODELS DIFFER ON HOW MUCH SNOW WILL FALL ACROSS THE EASTERN
MOUNTAINS AND THE PLAINS ON SUNDAY. THE GFS/NAM12 SHOW A
VORT MAX ROTATING AROUND THE CUTOFF LOW BETWEEN 09Z-12Z SUNDAY
MORNING...AND PUSHING IT THROUGH THE EASTERN PLAINS. THE GFS IS MUCH
WEAKER WITH THIS FEATURE AND SHOWS NO MORE THEN A DUSTING OF SNOW
ACROSS THE PLAINS...3 TO 6 INCHES IN THE WET MOUNTAINS AND THE
SANGRES THROUGH 00Z MONDAY. THE NAM SHOWS ALMOST A FOOT OF SNOW
ACROSS THE SAME MOUNTAIN ZONES AND UP TO 3 INCHES ALONG THE HIGHWAY
50 CORRIDOR EAST OF PUB (LAA/LHX). I HAVE TAKEN THE MORE
CONSERVATIVE GFS ROUTE AT THIS TIME...INCREASING POPS AND SNOW
AMOUNTS SLIGHTLY. HIGHLIGHT CRITERIA MAY BE REACHED IN THE
SANGRES/WETS IF THE NAM SOLUTION VERIFIES.
MONDAY-THURSDAY...MODELS DRY OUT THE FORECAST AREA RATHER QUICKLY
MONDAY...WITH ONLY A FEW REMAINING SNOW SHOWERS MONDAY MORNING. WEST
AND NORTHWEST FLOW WILL KEEP THE AREA DRY THROUGHOUT THE PERIOD.
500MB AND 700MB WINDS TURN MORE WEST AND SOUTHWEST LATE WEDNESDAY
THROUGH THURSDAY AHEAD OF ANOTHER PACIFIC STORM SYSTEM. TEMPERATURES
WILL REBOUND BACK TO AVERAGE LEVELS AS WELL. -PJC
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1031 PM MST THU NOV 21 2013
VFR CIGS/VIS WILL DROP INTO THE IFR CATEGORY OVERNIGHT AS UPPER
LIFT FROM AN APPROACHING SYSTEM SPREADS SNOW INTO THE REGION. A
ROUND OF SCATTERED SHOWERS HAS BEEN SPREADING EASTWARD ACROSS THE
AREA LATE THIS EVENING AN ALL TERMINALS SHOULD START TO SEE SOME
-SHSN BY 08Z. SNOW WILL BECOME HEAVY AT TIMES AFTER 10Z FOR KALS
WITH LIFR CONDITIONS. IFR CONDITIONS WILL SPREAD INTO THE KPUB
THEN KCOS TAF SITES BY 12Z AS A BAND OF SNOW DEVELOPS ACROSS
SOUTHERN CO. THIS BAND WILL SHIFT NORTHWARD THROUGH THE MORNING ON
FRIDAY WITH IMPROVING CONDITIONS EXPECTED FROM SOUTH TO NORTH
FRIDAY AFTERNOON. ACCUMULATIONS AT THE TERMINALS WILL RANGE FROM
AROUND 6 INCHES FOR KALS...TO AROUND 2 TO 3 FOR KCOS AND KPUB BY
EARLY FRIDAY EVENING. HEAVIER SNOWFALL AMOUNTS OF A FOOT OR MORE
WILL BE POSSIBLE ACROSS THE SOUTHERN MOUNTAINS...WITH AROUND 3 TO
6 INCHES POSSIBLE MAINLY TO THE SOUTH OF HIGHWAY 50 ACROSS THE
PLAINS. WIDESPREAD MTN OBSCURATIONS WILL CONTINUE THROUGH FRIDAY
WITH LIFR CONDITIONS DUE TO PERIODS OF SNOW. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM MST FRIDAY FOR COZ062-063-
076>078-083-086-089-093-097>099.
WINTER WEATHER ADVISORY UNTIL 6 PM MST FRIDAY FOR COZ058-059-061-
064.
WINTER STORM WARNING UNTIL 6 PM MST FRIDAY FOR COZ069>075-079-
080-087-088-094.
WINTER STORM WARNING UNTIL 6 PM MST FRIDAY FOR COZ060-065>068.
&&
$$
UPDATE...KT
SHORT TERM...HODANISH
LONG TERM...PJC
AVIATION...KT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1006 PM MST THU NOV 21 2013
.UPDATE...
ISSUED AT 947 PM MST THU NOV 21 2013
LATEST 00Z RUNS HAVE GENERALLY SHIFTED THE HEAVIER ACCUMS FARTHER
TO THE SOUTH AND WEST. AREA OF ISENTROPIC UPGLIDE/FRONTOGENESIS
WILL SHIFT NORTHWARD ACROSS THE AREA TONIGHT...THOUGH UPGLIDE
WEAKENS AS IT SHIFTS INTO NORTHERN PORTIONS OF THE FORECAST AREA
ON FRIDAY. THEREFORE...HEAVIEST HIT AREAS STILL APPEAR TO BE
ACROSS THE SOUTHERN MOUNTAINS WITH THE EASTERN SAN JUANS BEING THE
BIG WINNERS WITH OVER A FOOT TO 16 INCHES POSSIBLE BY FRIDAY
EVENING. H7 WINDS SHIFT AROUND FROM THE EAST TOMORROW...SO THINK
THAT THE EASTERN SLOPES OF THE WETS AND SANGRES COULD PICK UP
AROUND A FOOT IN SOME PLACES MEETING THE 24 HOUR WARNING CRITERIA
AMOUNTS WITH THE AIDE OF SOME UPSLOPE FLOW. BOTH GFS AND NAM12
SUGGEST A GOOD 6 INCHES ACROSS MOST OF THE SAN LUIS
VALLEY...THOUGH WESTERN VALLEY EDGES COULD PICK UP SUBSTANTIALLY
MORE...SO WINTER STORM WARNING THERE STILL LOOKS GOOD. WARNING
CRITERIA AMOUNTS MAY HIT ON THE LOW SIDE ACROSS THE RATON MESA
REGION...BUT NAM12 IS STILL HITTING THIS AREA WITH AROUND 8
INCHES...AS OPPOSED TO GFS`S MORE CONSERVATIVE 3 TO 5. HUNG ON TO
THE LOWER SIDE OF THESE AMOUNTS FOR NOW AS ISENTROPIC UPGLIDE
LOOKS STRONGEST FARTHER SOUTH ACROSS NM AND TEXAS. REMAINDER OF
HEADLINES STILL LOOK GOOD. WE MAY COME UP ON THE SHORT SIDE OF
ADVISORY NUMBERS FOR CROWLEY COUNTY...BUT THEN AGAIN...GFS IS MORE
GUNG HO UP THAT WAY SATURDAY AFTERNOON AS THE BAND LIFTS
NORTHWARD...SO WILL HOLD THE COURSE.
FRIDAY EVENING...MODELS SPREAD A DRY SLOT NORTHWARD ACROSS THE
AREA WHICH CUTS BACK ON THE HEAVIER PRECIPITATION FAIRLY QUICKLY.
NAM12 STILL KEEPS SOME MODERATE 2-4 INCH ACCUMULATIONS ACROSS
NORTHWEST PORTIONS OF THE ADVISORY/WARNING AREAS...BUT GFS IS MUCH
LIGHTER. WILL LEAVE THE END TIME OF THE HIGHLIGHTS AT 6 PM FRI FOR
NOW AND LET SOME OF THE HIGHER RES MODELS RESOLVE THIS TIMING A
LITTLE BETTER. -KT
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 248 PM MST THU NOV 21 2013
...SNOW BAND TO BRING LOCALLY HEAVY SNOW AMOUNTS TO PART OF SOUTHERN
COLORADO...
CURRENTLY...
ARCTIC AIRMASS HAS MOVED ACROSS THE PLAINS...WITH TEMPS IN THE 20S
PLAINS AND OVC SKIES. COLD AIR HAS NOT MADE IT OVER THE MTNS YET AND
THE SLV STILL HAD TEMPS AOA 50F.
A WELL DEFINED JET STREAK WAS NOTED RAGING ACROSS S CALIF INTO THE 4
CORNERS.
REST OF TODAY THROUGH TOMORROW...
SIMULATIONS CONTINUE TO INDICATE A SNOW BAND CAPABLE OF LOCALLY
HEAVY SNOW WILL SET UP OVER SOUTHERN COLORADO LATER THIS EVENING
INTO TOMORROW. THE GUIDANCE HAS BEEN VERY CONSISTENT WITH THIS BAND
OVER THE LAST SEVERAL DAYS. LATEST 18Z NAM CONTINUES TO SHOW THIS
PATTERN AND THE HRRR SUPPORTS THE DEVELOPMENT OF THIS BAND. THIS
BAND IS ASSOCIATED WITH A BAROCLINIC ZONE IN THE 600-7000MB LAYER
THAT IS PROGGED NOT TOO MOVE TOO MUCH. IT APPEARS AT THIS TIME THE
BEST CHANCE OF HEAVIER SNOW WILL FALL GENERALLY ALONG AND SOUTH OF
US HIGHWAY 50.
SNOWFALL AMOUNTS WITH THIS BAND FOR TONIGHT THROUGH TOMORROW
ACCORDING TO GUIDANCE ARE RATHER IMPRESSIVE..AND HAVE CUT BACK FROM
GUIDANCE...STILL 4-7" AMOUNTS WILL BE POSSIBLE OVER NEARLY ALL OF
THE SAN LUIS VALLEY AND MOST OF THE PLAINS GENERALLY SOUTH OF
HIGHWAY 50 AND WEST OF SPRINGFIELD.
THE SANGRES...WETS AND SAN JUANS SHOULD DO VERY WELL WITH THIS
EVENT...WITH 12-18" OVER THE SAN JUANS AND NEAR A FOOT OVER THE
SANGRES AND WETS.
FARTHER NORTH LESS SNOW IS LIKELY AND HAVE CUT BACK ON AMOUNTS IN
THE CENTRAL MOUNTAINS. HAVE ALSO DOWNGRADED WARNINGS TO ADVISORIES
FOR PARTS OF THE CENTRAL MOUNTAIN REGION.
THE PIKES PEAK REGION WILL SEE ON AND OF SNOW SHOWERS WITH 1-3"
POSSIBLE THROUGH THE PERIOD. THE BEST CHANCE OF SNOW MAY OCCUR LATER
TOMORROW AS THE BAND LIFTS A BIT TO THE NORTH. HOWEVER THE SNOW IS
EXPECTED TO BE DECREASING AS THE FRONTOGENETICAL FORCING LESSENS
WITH TIME.
TOMORROW WILL BE ANOTHER COLD DAY WITH HIGHS ON THE 20S ALL AREAS.
WE MAY SEE SOME BREAKS IN THE CLOUDS LATE IN THE DAY OVER THE
NORTHERN PARTS OF THE CWA. /HODANISH
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 248 PM MST THU NOV 21 2013
...SNOW AND COLD CONTINUES...
FRIDAY NIGHT-SATURDAY...SNOW ACROSS THE EASTERN PLAINS WILL SLOWLY
WIND DOWN BETWEEN 06Z-09Z EARLY SATURDAY MORNING ACROSS THE EASTERN
PLAINS AS THE BEST LIFT MOVES AWAY FROM THE AREA.
ATTENTION THEN TURNS TO THE CUT OFF LOW SPINNING OVER SOUTHERN
CALIFORNIA. THE GFS AND THE NAM ARE IN SOMEWHAT BETTER AGREEMENT
WITH THE EC MODELS HANDLING OF THE LOW AND AM NOW MORE CONFIDENT THE
LOW WILL TAKE A MORE NORTHERLY TRACK THEN PREVIOUS GFS FORECASTS
HAVE SHOWN. IN COORDINATION WITH DDC/GLD/GJT I HAVE INCREASED POPS
ACROSS ALL OF THE MOUNTAIN AREAS SATURDAY AND SUNDAY...AND ACROSS
THE PLAINS ON SUNDAY. IF CURRENT MODEL TRENDS CONTINUE...I AM FAIRLY
CERTAIN THE WINTER STORM WARNING FOR THE SAN JUANS WILL NEED TO BE
EXTENDED THROUGH AT LEAST SATURDAY EVENING. THE 18Z NAM12 SHOWS 30
INCHES OF SNOWFALL BETWEEN 00Z SATURDAY AND 12Z SUNDAY ACROSS THE
SAN JUANS. THE 12Z GFS PAINTS 20 INCHES DURING THE SAME TIME FRAME.
TOO EARLY TO EXTEND THE WARNING AT THIS TIME.
SUNDAY...AS SNOW CHANCES REMAIN HIGH ALONG THE CONTINENTAL
DIVIDE...MODELS DIFFER ON HOW MUCH SNOW WILL FALL ACROSS THE EASTERN
MOUNTAINS AND THE PLAINS ON SUNDAY. THE GFS/NAM12 SHOW A
VORT MAX ROTATING AROUND THE CUTOFF LOW BETWEEN 09Z-12Z SUNDAY
MORNING...AND PUSHING IT THROUGH THE EASTERN PLAINS. THE GFS IS MUCH
WEAKER WITH THIS FEATURE AND SHOWS NO MORE THEN A DUSTING OF SNOW
ACROSS THE PLAINS...3 TO 6 INCHES IN THE WET MOUNTAINS AND THE
SANGRES THROUGH 00Z MONDAY. THE NAM SHOWS ALMOST A FOOT OF SNOW
ACROSS THE SAME MOUNTAIN ZONES AND UP TO 3 INCHES ALONG THE HIGHWAY
50 CORRIDOR EAST OF PUB (LAA/LHX). I HAVE TAKEN THE MORE
CONSERVATIVE GFS ROUTE AT THIS TIME...INCREASING POPS AND SNOW
AMOUNTS SLIGHTLY. HIGHLIGHT CRITERIA MAY BE REACHED IN THE
SANGRES/WETS IF THE NAM SOLUTION VERIFIES.
MONDAY-THURSDAY...MODELS DRY OUT THE FORECAST AREA RATHER QUICKLY
MONDAY...WITH ONLY A FEW REMAINING SNOW SHOWERS MONDAY MORNING. WEST
AND NORTHWEST FLOW WILL KEEP THE AREA DRY THROUGHOUT THE PERIOD.
500MB AND 700MB WINDS TURN MORE WEST AND SOUTHWEST LATE WEDNESDAY
THROUGH THURSDAY AHEAD OF ANOTHER PACIFIC STORM SYSTEM. TEMPERATURES
WILL REBOUND BACK TO AVERAGE LEVELS AS WELL. -PJC
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 248 PM MST THU NOV 21 2013
A SNOW BAND WILL DEVELOP OVER SOUTHERN COLORADO LATER THIS AFTERNOON
AND LAST INTO TOMORROW. THE HEAVIEST SNOW WILL FALL GENERALLY ALONG
AND SOUTH OF HIGHWAY 50. KALS WILL BE IMPACTED WITH SIGNIFICANT
ACCUMULATING SNOW LIKELY...WITH UP TO 6" POSSIBLE. SNOW WILL BEGIN
AT KALS THIS EVENING...~03Z...AND LAST INTO TOMORROW.
KPUB WILL BE ON THE NORTHERN GRADIENT BUT STILL EXPECT 1-3" OF
ACCUMULATING SNOW TONIGHT INTO TOMORROW.
KCOS WILL SEE MUCH SNOW...BUT LOW CIGS WILL LIKELY LAST THROUGH
TOMORROW. THE BEST CHANCE FORM SOME ACCUMULATING SNOW MAY ACTUALLY
BE TOMORROW AFTERNOON AS THE BAND LIFTS A BIT TO THE NORTH.
GIVEN THE CURRENT GUIDANCE...ALL AIRPORTS...KCOS...KALS AND KPUB
WILL SEE IFR CONDITIONS FORM MOST IF NOT ALL OF THE NEXT 24H.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM MST FRIDAY FOR COZ062-063-
076>078-083-086-089-093-097>099.
WINTER WEATHER ADVISORY UNTIL 6 PM MST FRIDAY FOR COZ058-059-061-
064.
WINTER STORM WARNING UNTIL 6 PM MST FRIDAY FOR COZ069>075-079-
080-087-088-094.
WINTER STORM WARNING UNTIL 6 PM MST FRIDAY FOR COZ060-065>068.
&&
$$
UPDATE...KT
SHORT TERM...HODANISH
LONG TERM...PJC
AVIATION...HODANISH
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
420 AM EST FRI NOV 22 2013
.DISCUSSION...
...HIGH RISK OF RIP CURRENTS AT THE ATLANTIC BEACHES TODAY...
...STRONG FRONT WILL BRING HAZARDOUS MARINE CONDITIONS AND ROUGH AND
POUNDING SURF SUNDAY AND MONDAY...
TODAY AND TONIGHT...LOW LEVEL CONVERGENCE IN COMBINATION WITH STOUT
EASTERLY FLOW CONTINUES TO PRODUCE BANDS OF SHOWERS ACROSS THE
ATLANTIC. AMPLE MOISTURE...ESPECIALLY IN THE LOWER LEVELS...WILL
PROMOTE SCATTERED RAIN COVERAGE MAINLY ALONG THE TREASURE COAST
THROUGH THIS MORNING.
WHILE THURSDAY EVENING`S SOUNDINGS STILL INDICATE A RATHER MOIST LOW
LEVEL ENVIRONMENT ACROSS THE STATE (PWATS ~1.6" TO 1.9")...WE ARE
EXPECTING THAT TO CHANGE OVER THE NEXT 12 HOURS. LATEST RUC ANALYSIS
ALONG WITH TONIGHT`S MODEL RUNS INDICATE A POCKET OF RELATIVELY DRY
AIR WORKING ITS WAY CLOSER TO THE PENINSULA. DRYING IN THE
1000-700MB LAYER COMBINED WITH WEAK RIDGING ALOFT SHOULD ALLOW FOR A
MARKED DECREASE IN SHOWER ACTIVITY TODAY COMPARED TO YESTERDAY. THE
DRY AIR WILL WORK ITS WAY INTO THE AREA FROM NORTH TO SOUTH...SO
HIGHER RAIN CHANCES (30-40 PERCENT) EXIST ACROSS THE TREASURE COAST
AND OKEECHOBEE COUNTY.
ONSHORE FLOW SHOULD KEEP TEMPERATURES IN THE UPPER 70S/NEAR 80
CLOSER TO THE COAST...BUT WITH LESS CLOUD COVER THAN TODAY...AM
EXPECTING IT TO FEEL WARMER. ADVERTISING LOW 80S ACROSS THE INTERIOR
FOR THIS AFTERNOON.
SATURDAY...THE SFC RIDGE WILL SETTLE SOUTH AND EXTEND OFFSHORE FROM
NE FL ON SAT. THIS WILL ALLOW FOR WEAKENING ONSHORE FLOW AND A
RATHER DRY AIRMASS SOUTH OF THE LOW LVL RIDGE AXIS ACROSS E CENTRAL
FL. PWAT VALUES ARE FORECAST AROUND 1.2 INCHES WITH AFTERNOON HIGHS
EXPECTED IN THE LOWER 80S. AREA SHOULD REMAIN DRY WITH THE ONLY
HAZARD EXPECTED TO BE AN ENHANCED RIP CURRENT RISK AT THE BEACHES.
SATURDAY NIGHT...A SPRAWLING HIGH PRESSURE CENTER MOVING SE THROUGH
THE MIDWEST WILL ALLOW ANOTHER COLD FRONT TO MOVE SOUTH INTO CENTRAL
FLORIDA SAT NIGHT. BREEZY TO WINDY CONDITIONS ARE EXPECTED TO
DEVELOP ALONG THE VOLUSIA AND BREVARD COUNTY COASTS WITH
STRENGTHENING N/NNE LOW LVL FLOW AFTER MIDNIGHT. A FRONTAL CLOUD
BAND WILL BRING MOSTLY CLOUDY SKIES TO NRN SECTIONS AND A SLGT CHC
FOR SHOWERS ALONG THE COAST. LOWS WILL RANGE FROM 60 ACROSS LAKE
COUNTY TO THE UPPER 60S ALONG THE TREASURE COAST.
SUNDAY...THE FRONT WILL SWEEP TWD S FL WITH WINDY NE WINDS EXPECTED
AS THE SFC HIGH PRESSURE AREA BUILDS TOWARD THE OHIO VALLEY AND SE
STATES. BAND OF FRONTAL CLOUD COVER START ACROSS THE NRN AREAS AND
MOVE SOUTH THROUGH THE DAY. EXPECT ISOLATED TO SCATTERED ATLANTIC
SHOWERS TO MOVE ONSHORE IN THE VERY STRONG LOW LVL NE FLOW AND PUSH
INTO THE INTERIOR INTO THE AFTERNOON. WINDY CONDITIONS WILL LIKELY
REQUIRE A LAKE WIND OR WIND ADVISORY ACROSS THE AREA. NE WINDS OF 20
TO 25 MPH WITH GUSTS TO 30 TO 35 MPH. HIGHS WILL BE MUCH COOLER THAN
SATURDAY IN THE MID TO UPPER 60S NRN ZONES TO THE MID 70S ACROSS
OKEECHOBEE COUNTY AND THE TREASURE COAST. HAZARDOUS SURF IS EXPECTED
TO DEVELOP AT THE BEACHES INTO THE AFTERNOON HOURS WITH LARGE
BREAKING WAVES DEVELOPING.
MONDAY...THE HIGH CENTER WILL SHIFT TOWARD THE MID ATLC ON MONDAY
KEEPING BREEZY TO WINDY EASTERLY FLOW ACROSS THE AREA. THERE WILL BE
SOME MID LVL DRYING BUT PROBABLY ENOUGH LOW LVL MOISTURE FOR SOME
ISOLATED ATLC SHOWERS TO CONTINUE TO MOVE ONSHORE. HIGHS WILL RANGE
FROM AROUND 70 NORTH TO THE MID 70S SRN AREAS. ROUGH SURF AND THE
RISK FOR RIP CURRENTS IS EXPECTED AT THE BEACHES.
TUESDAY-WEDNESDAY NIGHT...A PROGRESSIVE MID LVL S/W TROUGH EJECTING
FROM THE SRN PLAINS ACROSS THE SE STATES AND THEN TWD THE MID ATLC
WILL INDUCE A SFC LOW TO DEVELOP AND MOVE FROM SE LA TO THE FL
PANHANDLE AND NE ALONG THE SE ATLC COAST. THIS SYSTEM WILL VEER THE
LOW LVL FLOW FROM ESE TO SOUTHERLY ON TUESDAY AND BEGIN TO DRAW
DEEPER MOISTURE ACROSS THE FLORIDA PENINSULA BY TUE AFTERNOON. E
CENTRAL FL WILL BE IN THE WARM SECTOR BY THE AFTERNOON HOURS ON
TUESDAY WITH A FRONT APPROACHING THE AREA LATE TUE NIGHT OR EARLY
WEDNESDAY. SCATTERED SHOWERS SHOULD DEVELOP TUE AFTN INTO TUE NIGHT
WITH THE CHANCE FOR LIGHTNING STORMS TUE AFTN AND ALSO TUE NIGHT
AHEAD OF THE ADVANCING FRONT. 00Z GFS/ECMWF SWEEP THE FRONT ACROSS
THE AREA BY WED MORNING WITH BREEZY WNW/NW FLOW AND DEEP LAYER
DRYING TAKING HOLD WED AFTERNOON WITH FALLING TEMPERATURES AFTER THE
FRONTAL PASSAGE LATE IN THE DAY. AFTER A WARM DAY WITH HIGHS AROUND
80 TUESDAY AND LOWS IN THE 60S TUE NIGHT EXPECT COOLER TEMPS BY WED
NIGHT IN THE 50S BEHIND THE FRONT.
THANKSGIVING DAY INTO FRIDAY...HIGH PRESSURE WILL BUILD TOWARD THE
MID ATLC THROUGH LATE WEEK WITH BREEZY NE LOW LVL FLOW ON
THANKSGIVING DAY BEHIND THE FRONT ALLOWING FOR ISOLATED SHOWERS TO
MOVE ONSHORE ALONG THE COAST. HIGHS WILL COOL TO AROUND 70 AND THE
MID 70S SOUTH. FOR FRIDAY...HIGH PRESSURE NEAR THE MID ATLC WILL
ALLOW FOR BREEZY EASTERLY FLOW AND ISOLATED SHOWERS MOVING ONSHORE
FROM THE ATLANTIC AND MOVING INTO THE INTERIOR. HIGHS IN THE LOWER
70S NORTH TO MID-UPPER 70S SOUTH.
&&
.AVIATION...
EXPECTING LESS IN THE WAY OF SHOWER COVERAGE TODAY COMPARED TO
YESTERDAY AS DRIER AIR FILTERS DOWN THE PENINSULA. CIGS BETWEEN
FL050-080 LIKELY THIS MORNING. EASTERLY FLOW WILL KEEP THE CHANCE OF
BRIEF MVFR CIGS IN SHOWERS ALONG COASTAL SITES (MAINLY
KMLB-KVRB-KFPR-KSUA).
&&
.MARINE...
TODAY AND TONIGHT...BUOY 41009 STILL SHOWING 15-20KTS SUSTAINED AND
SEAS OF 7-8 FEET. EAST WINDS 15-20KTS ANTICIPATED THROUGH
TONIGHT...KEEPING SEAS ELEVATED (5-7FT NEARSHORE...7-9FT OFFSHORE).
SMALL CRAFT ADVISORY REMAINS IN EFFECT THROUGH 21Z.
WINDS SHOULD BEGIN TO LESSEN THIS EVENING AS OUR LOCAL PRESSURE
GRADIENT SLACKENS. SEAS WILL BE SLOWER TO RESPOND. WILL GO WITH AN
ADVISORY FOR SEAS THROUGH LATE TONIGHT (03Z SATURDAY) ACROSS OUR
OFFSHORE ZONES AND NEARSHORE WATERS SOUTH OF SEBASTIAN INLET.
SATURDAY...WINDS WILL DECREASE FROM THE ENE TO 5-10 KNOTS WITH A
RESIDUAL SWELL OF 4-6 FT. A STRONG FRONT WILL SWEEP ACROSS THE
WATERS LATE EARLY SUNDAY...INCREASING NNE WINDS TO AROUND 25 KNOTS
WITH GUSTS TO 35 KNOTS. SEAS WILL BUILD RAPIDLY AND REACH OVER 10
FEET IN THE GULF STREAM BY SUNDAY AFTERNOON AND SUNDAY NIGHT. THIS
WILL MAKE CONDITIONS VERY HAZARDOUS FOR SMALL CRAFT. CONDITIONS MAY
APPROACH GALE CRITERIA ON SUNDAY AFTERNOON-SUNDAY NIGHT. SOLID
ADVISORY CONDITIONS TO CONTINUE INTO EARLY NEXT WEEK AS FLOW VEERS
WITH WINDS TO 20-25 KNOTS MONDAY AND TUESDAY. NEXT COLD FRONT EARLY
WEDNESDAY WILL BRING A WIND SHIFT TO THE NORTHWEST BY WED AFTERNOON.
ALL IN ALL...SATURDAY LOOKS TO BE THE LAST SOMEWHAT FAVORABLE
BOATING DAY WITH STRONG WIND AND HAZARDOUS SEAS EXPECTED SUNDAY INTO
INTO THE MIDDLE OF NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 81 62 81 61 / 10 10 10 20
MCO 83 62 83 62 / 10 10 10 10
MLB 81 68 82 68 / 20 10 10 20
VRB 82 67 82 67 / 30 10 10 20
LEE 82 61 82 60 / 10 10 10 10
SFB 83 62 83 62 / 10 10 10 10
ORL 82 63 83 63 / 10 10 10 10
FPR 81 66 82 65 / 30 10 10 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE
OUT 20 NM-COASTAL WATERS FROM SEBASTIAN INLET TO JUPITER
INLET OUT 20 NM-COASTAL WATERS FROM VOLUSIA BREVARD COUNTY
LINE TO SEBASTIAN INLET OUT 20 NM-WATERS FROM FLAGLER BEACH
TO VOLUSIA BREVARD COUNTY LINE 20 TO 60 NM OFFSHORE-WATERS
FROM SEBASTIAN INLET TO JUPITER INLET 20 TO 60 NM OFFSHORE-
WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET
20 TO 60 NM OFFSHORE.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 PM THIS AFTERNOON
TO 10 PM EST THIS EVENING FOR COASTAL WATERS FROM SEBASTIAN
INLET TO JUPITER INLET OUT 20 NM-WATERS FROM FLAGLER BEACH
TO VOLUSIA BREVARD COUNTY LINE 20 TO 60 NM OFFSHORE-WATERS
FROM SEBASTIAN INLET TO JUPITER INLET 20 TO 60 NM OFFSHORE-
WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET
20 TO 60 NM OFFSHORE.
&&
$$
SHORT TERM/AVIATION...ULRICH
LONG TERM....VOLKMER
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1135 PM CST Thu Nov 21 2013
.UPDATE...
Issued at 955 PM CST THU NOV 21 2013
The low-level CAA will continue to deepen the drier cold airmass
over the CWA through the morning hours. The patchy freezing
drizzle will end after midnight. The NAM model continues to show a
band of mid-level frontogenetical forcing moving east across
eastern KS tonight. This may cause snow flurries or scattered snow
and sleet showers through the early morning hours. Meanwhile, the
low-levels of the atmosphere will continue to dry through the
night due to the stronger low-level CAA. Any additional patchy
freezing drizzle along with wet road surfaces from the earlier
freezing rain will cause roadways to be very slick through
sunrise as overnight lows drop into the upper teens to mid 20s.
Therefore, the winter weather advisory will continue across
northeast and east central KS through 12Z. The next shift may
expire the winter weather advisory before 400 AM if road
conditions improve.
The 00z run of the NAM shows the next band of stronger
frontogenetical forcing remaining south of the CWA across southern
KS and northern OK, where steady light snow may develop. Therefore, I have
expired the winter weather advisory for our southeast counties for
Friday morning between 600 AM and noon.
&&
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Friday)
Issued at 256 PM CST THU NOV 21 2013
.Synopsis...
Water vapor imagery shows a shortwave trough over the northern
plains propagating east towards the great lakes, while energy
begins to cut off over central CA. At the surface, a strong cold
front has pushed through the entire forecast area with
temperatures continuing to fall in response to strong cold air
advection.
.Short Term... (Tonight)
For tonight the forcing for continued precipitation looks to be
mainly driven by mid level frontogenesis. The NAM and RAP progs
show weakening isentropic upglide early in the evening as the 850
front continues to push south. Then by the late evening and
overnight mid level drying near the better mid level
frontogenetical forcing suggests that precip could come to an end
since there is no lift within the low level cloud from isentropic
features for light freezing drizzle. With this in mind have
trended POPs down for most areas overnight. The latest
HRRR/RAP13/NAM12 continue to show this band of precip currently
from Minneapolis to Hiawatha, associated with some mid level
frontogenesis, to lift northeast into northwest MO. Therefore have
some likely pops for the early evening across far northeast KS.
Otherwise the forecast will only have some chance pops through the
rest of tonight. Did not feel confident enough to lower pops any
further since there will be some mid level frontogenesis through
the night. Also will not make any major changes to the advisory
other than to end it earlier in the day Friday. It is one of those
situations that with the advisory already out it doesn`t make
sense to cancel it early since there remains the potential for
some light frozen precip with reports of slick roads coming in.
Since forcing is weak and moisture will continue to lessen through
the night, additional precipitation is anticipated to be on the
light side with accumulations generally around a tenth of an inch in
water equivalent. The mid level drying will also make it difficult
for snow to occur since the dendritic growth zone is not expected to
be saturated. Because of this there shouldn`t be any ice crystals
for snow. So think freezing rain and sleet will be the primary
precip type through the night if precip does fall. Continued cold
air advection should cause temperatures to fall into the teens and
mid 20s for the forecast area by sunrise Friday.
.LONG TERM...(Friday Night through Thursday)
Issued at 256 PM CST THU NOV 21 2013
Friday...Becomes a race with the incoming drier air as to how much
precipitation can fall on Friday as high pressure continues to surge
into the southern plains through the day. Back to the west an upper
low advances into Baja, lifting a lobe of moisture into southern
Kansas in the mid levels. Frontogenesis gets some further
enhancement from northern trof dropping energy into the area mid to
late day. Isentropic charts indicate downglide in the lower levels,
with 700mb chart showing some broad convergence in the wind field
through the noon hour. With lack of strong lift and incoming drier
air have pulled back on precip chances and amounts but not ready to
remove entirely for the southern counties just yet. Enough
consensus in incoming dry air from north to end the advisory earlier
for generally the I70 counties, but will hang onto it through noon
for those south of I70. Temperature profiles are finally cold enough
for all snow along the northern edge but hold onto a weak warm nose
across the SE and will keep a S/IP mix for these areas. Went colder
on both highs and lows given current reflection in observations with
highs upper 20s to near freezing and dropping overnight into the
upper teens.
Saturday and Sunday... Continue to go on the cool side of guidance
on Saturday with high pressure still on the move to the south. Have
highs near freezing and lows in the lower to middle teens. Incoming
clouds from the southwest on Sunday plus a return to southerly
surface low on the wrn side of the high should bring highs back into
the middle 30s on Sunday.
Monday: An upper level trough forming out of the Four Corners region
will propagate to the east. The 12Z ECMWF/GFS are in reasonable
agreement pertaining to the location of the trough. A jet streak of
up to 100kt winds associated with this trough should eject
additional moisture into Oklahoma and Kansas. Southerly winds in
this region should help support moisture transfer over eastern
Kansas. This additional moisture, along with freezing temperatures,
could support light snow over eastern Kansas.
By Tuesday, the trough should pivot to the south due to a ridging
stream wave over the western CONUS. The trough should stay further
south into Texas and Oklahoma. Winds shift from southerly to
northerly as the trough moves south. The ridging pattern over the
western CONUS will translate towards the east by Wednesday, bringing
quiet weather to the region. Lows will be in the 20s overnight and
highs will be in the upper 30s/lower 40s for the rest of the week.
&&
.AVIATION...(For the 06Z TAFs through 06Z Friday Night)
Issued at 1128 PM CST THU NOV 21 2013
Stratus cloud cover with MVFR ceilings will continue through the
night and morning hours of Friday. There may be some patchy light
freezing drizzle at the KFOE and KTOP terminals through 8Z FRI.
May see occasional flurries through the night. The lower stratus
should scatter out by early afternoon at the TAF sites. North
winds of 12 to 15 KTS with higher gusts this morning will diminish
by mid and late afternoon.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until 6 AM CST Friday FOR KSZ010>012-
022>024-026-036>040-054>056-058-059.
&&
$$
UPDATE...Gargan
SHORT TERM...67/Wolters
LONG TERM...67/JTS
AVIATION...Gargan
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1012 PM CST Thu Nov 21 2013
.UPDATE...
Issued at 955 PM CST THU NOV 21 2013
The low-level CAA will continue to deepen the drier cold airmass
over the CWA through the morning hours. The patchy freezing
drizzle will end after midnight. The NAM model continues to show a
band of mid-level frontogenetical forcing moving east across
eastern KS tonight. This may cause snow flurries or scattered snow
and sleet showers through the early morning hours. Meanwhile, the
low-levels of the atmosphere will continue to dry through the
night due to the stronger low-level CAA. Any additional patchy
freezing drizzle along with wet road surfaces from the earlier
freezing rain will cause roadways to be very slick through
sunrise as overnight lows drop into the upper teens to mid 20s.
Therefore, the winter weather advisory will continue across
northeast and east central KS through 12Z. The next shift may
expire the winter weather advisory before 400 AM if road
conditions improve.
The 00z run of the NAM shows the next band of stronger
frontogenetical forcing remaining south of the CWA across southern
KS and northern OK, where steady light snow may develop. Therefore, I have
expired the winter weather advisory for our southeast counties for
Friday morning between 600 AM and noon.
Gargan
&&
.SHORT TERM...(This Evening through Friday)
Issued at 256 PM CST THU NOV 21 2013
.Synopsis...
Water vapor imagery shows a shortwave trough over the northern
plains propagating east towards the great lakes, while energy
begins to cut off over central CA. At the surface, a strong cold
front has pushed through the entire forecast area with
temperatures continuing to fall in response to strong cold air
advection.
.Short Term... (Tonight)
For tonight the forcing for continued precipitation looks to be
mainly driven by mid level frontogenesis. The NAM and RAP progs
show weakening isentropic upglide early in the evening as the 850
front continues to push south. Then by the late evening and
overnight mid level drying near the better mid level
frontogenetical forcing suggests that precip could come to an end
since there is no lift within the low level cloud from isentropic
features for light freezing drizzle. With this in mind have
trended POPs down for most areas overnight. The latest
HRRR/RAP13/NAM12 continue to show this band of precip currently
from Minneapolis to Hiawatha, associated with some mid level
frontogenesis, to lift northeast into northwest MO. Therefore have
some likely pops for the early evening across far northeast KS.
Otherwise the forecast will only have some chance pops through the
rest of tonight. Did not feel confident enough to lower pops any
further since there will be some mid level frontogenesis through
the night. Also will not make any major changes to the advisory
other than to end it earlier in the day Friday. It is one of those
situations that with the advisory already out it doesn`t make
sense to cancel it early since there remains the potential for
some light frozen precip with reports of slick roads coming in.
Since forcing is weak and moisture will continue to lessen through
the night, additional precipitation is anticipated to be on the
light side with accumulations generally around a tenth of an inch in
water equivalent. The mid level drying will also make it difficult
for snow to occur since the dendritic growth zone is not expected to
be saturated. Because of this there shouldn`t be any ice crystals
for snow. So think freezing rain and sleet will be the primary
precip type through the night if precip does fall. Continued cold
air advection should cause temperatures to fall into the teens and
mid 20s for the forecast area by sunrise Friday.
.LONG TERM...(Friday Night through Thursday)
Issued at 256 PM CST THU NOV 21 2013
Friday...Becomes a race with the incoming drier air as to how much
precipitation can fall on Friday as high pressure continues to surge
into the southern plains through the day. Back to the west an upper
low advances into Baja, lifting a lobe of moisture into southern
Kansas in the mid levels. Frontogenesis gets some further
enhancement from northern trof dropping energy into the area mid to
late day. Isentropic charts indicate downglide in the lower levels,
with 700mb chart showing some broad convergence in the wind field
through the noon hour. With lack of strong lift and incoming drier
air have pulled back on precip chances and amounts but not ready to
remove entirely for the southern counties just yet. Enough
consensus in incoming dry air from north to end the advisory earlier
for generally the I70 counties, but will hang onto it through noon
for those south of I70. Temperature profiles are finally cold enough
for all snow along the northern edge but hold onto a weak warm nose
across the SE and will keep a S/IP mix for these areas. Went colder
on both highs and lows given current reflection in observations with
highs upper 20s to near freezing and dropping overnight into the
upper teens.
Saturday and Sunday... Continue to go on the cool side of guidance
on Saturday with high pressure still on the move to the south. Have
highs near freezing and lows in the lower to middle teens. Incoming
clouds from the southwest on Sunday plus a return to southerly
surface low on the wrn side of the high should bring highs back into
the middle 30s on Sunday.
Monday: An upper level trough forming out of the Four Corners region
will propagate to the east. The 12Z ECMWF/GFS are in reasonable
agreement pertaining to the location of the trough. A jet streak of
up to 100kt winds associated with this trough should eject
additional moisture into Oklahoma and Kansas. Southerly winds in
this region should help support moisture transfer over eastern
Kansas. This additional moisture, along with freezing temperatures,
could support light snow over eastern Kansas.
By Tuesday, the trough should pivot to the south due to a ridging
stream wave over the western CONUS. The trough should stay further
south into Texas and Oklahoma. Winds shift from southerly to
northerly as the trough moves south. The ridging pattern over the
western CONUS will translate towards the east by Wednesday, bringing
quiet weather to the region. Lows will be in the 20s overnight and
highs will be in the upper 30s/lower 40s for the rest of the week.
&&
.AVIATION...(For the 00Z TAFs through 00Z Friday Evening)
Issued at 527 PM CST THU NOV 21 2013
Stronger forcing now coming through the Taf sites with an IFR mixture
of freezing drizzle...sleet and snow. Expect this precip to
gradually diminish through 04z but with mvfr cigs in its wake. As
drier air aloft moves in...still some potential for light freezing
drizzle but confidence remains too low to insert into Tafs at
this point. North winds will gust to 25 kts overnight...but
steadily decrease through the day Friday. MVFR cigs should scatter
to vfr in the 19-21Z time frame.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until 6 AM CST Friday FOR KSZ010>012-
022>024-026-036>040-054>056-058-059.
&&
$$
UPDATE...Gargan
SHORT TERM...67/Wolters
LONG TERM...67/JTS
AVIATION...63
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
504 AM EST FRI NOV 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 444 AM EST FRI NOV 22 2013
BROAD AREA OF LIGHT SNOW ASSOCIATED WITH A COUPLED UPPER
JET...SHORTWAVE ENERGY AND MID-LEVEL Q-VECTOR CONVERGENCE CONTINUES
TO SLIDE EAST EARLY THIS MORNING ACROSS UPPER MICHIGAN AND
WISCONSIN. GENERALLY LIGHT SNOW WITH VISIBILITIES IN MOST LOCATIONS
OF 2 TO 5 MILES. WE SAW FINE FLAKES AT OUR OFFICE MOST OF THE
NIGHT...WHICH HAS BEEN HELPFUL IN REDUCING VISIBILITIES. ONE REPORT
FROM NORTHERN WISCONSIN INDICATED A HALF AN INCH OF SNOW
ACCUMULATION AND OUR OFFICE HAD 0.6 INCH AS OF 1AM. THE SNOW HAS
ALREADY ENDED OVER WESTERN UPPER MICHIGAN (KCMX/KIWD OBS) AND
STARTING TO SEE THE REFLECTIVITIES QUICKLY DIMINISH OVER BARAGA
AND IRON COUNTIES. AS THE UPPER LEVEL FEATURES CONTINUE TO SHIFT
EAST THIS MORNING...EXPECT THE SYNOPTIC SNOWFALL TO QUICKLY
DIMINISH THROUGH MID MORNING.
OVER NORTHERN UPPER MICHIGAN...LOW LEVEL 925-850MB NORTH-NORTHWEST
FLOW (ON KMQT VAD AND RAP ANALYSIS) ACROSS LAKE SUPERIOR...ALONG
WITH 850MB TEMPS OF -7C TO -11C FROM EAST TO WEST HAS LED TO SOME
LAKE ENHANCEMENT EARLY THIS MORNING...WITH THE STRONGEST RETURNS ON
RADAR AND OBS INDICATING THE HEAVIEST SNOW OVER EASTERN
MARQUETTE AND WESTERN ALGER COUNTIES. THIS ENHANCEMENT
WILL ALSO BE DIMINISHING QUICKLY THIS MORNING AS A HIGH PRESSURE
RIDGE FROM NORTHERN MINNESOTA NOSES INTO THE AREA. VERY DRY AIR
ABOVE THE INVERSION AT 920MB ON THE 00Z KINL SOUNDING WILL BE WHAT
IS MOVING INTO THE AREA AND REALLY DIMINISH THE INTENSITY OF THE
LAKE ENHANCEMENT OVER THE NORTH CENTRAL THIS MORNING. THIS WILL ALSO
LEAD TO A DIMINISHING TREND TO THE LAKE EFFECT CLOUDS FROM WEST TO
EAST TODAY AS THE LAKE INDUCED INSTABILITY AND MOISTURE IS PINCHED
BY THAT LOWERING INVERSION FROM THE HIGH PRESSURE RIDGE. EXPECT THE
LAKE CLOUDS TO HANG ON THE LONGEST OVER THE KEWEENAW AND THE EAST
WHERE THE BACKING WINDS WINDS WILL STAY FAVORABLE THE LONGEST. THE
REST OF THE AREA SHOULD SEE SKIES BECOMING PARTLY CLOUDY IF NOT
MOSTLY SUNNY LATE THIS MORNING THROUGH THE AFTERNOON.
FOCUS THEN TURNS TO THE MAIN WEATHER MAKER FOR THE FORECAST
PERIOD...WHICH IS ASSOCIATED WITH A LOW THAT IS CURRENTLY LOCATED
NEAR LAKE WINNIPEG. THIS LOW AND POTENT SHORTWAVE NOTED ON WV
IMAGERY WILL QUICKLY SWEEP SOUTHEAST ACROSS LAKE SUPERIOR LATE THIS
AFTERNOON AND EVENING. STRONG CONVERGENCE ALONG TWO ASSOCIATED
TROUGHS WILL LEAD TO A COUPLE MODERATE TO POTENTIALLY HEAVY PERIODS
OF SNOW BEFORE THE LAKE EFFECT REALLY KICKS IN OVERNIGHT.
THE FIRST TROUGH WILL SHIFT WINDS TO THE NORTHWEST AND MOVE INTO THE
KEWEENAW AND WESTERN UPPER MICHIGAN AROUND DINNER TIME AND THE REST
OF THE CWA DURING THE EVENING HOURS. EXPECT THE STRONGEST SNOW TO
OCCUR OVER THE WEST WITH THE FAVORABLE UPSLOPE WINDS AND LEAD TO A
COUPLE HOUR PERIOD OF STRONG SNOW SHOWERS. THEN THERE MAY BE
A SHORT PERIOD OF LIGHTER SNOW AS THE DEEPER MOISTURE CUTS OUT FOR
A FEW HOURS. THE SECONDARY TROUGH (WITH ANOTHER BURST OF
MODERATE TO HEAVY SNOWFALL) WILL THEN DROP SOUTH ACROSS THE KEWEENAW
AND WESTERN UPPER MICHIGAN AROUND OR SHORTLY AFTER
MIDNIGHT...SHIFTING THE WINDS TO ALMOST NORTHERLY AND THE LAKE
EFFECT SNOW SHOULD REALLY KICK IN. EXPECT A SIMILAR OCCURRENCE
ACROSS THE REST OF NORTHERN UPPER MICHIGAN WITH MORE OF A DELAY ON
THE SECONDARY TROUGH UNTIL THE 08-09Z TIME FRAME. IN ADDITION...WITH
THE FIRST FRONT SHIFTING WINDS TO LESS FAVORABLE NORTHWESTERLY
DOWNSLOPING FLOW FOR THE NORTH CENTRAL...THEY WILL LIKELY NOT SEE
MUCH SNOW ACCUMULATION UNTIL THE SECONDARY TROUGH MOVES THROUGH AND
LAKE EFFECT DEVELOPS.
BEHIND THE TROUGHS...850MB TEMPS WILL FALL FROM AROUND -10C AT 18Z
TODAY TO -20C AT 12Z SATURDAY. THIS WILL PROVIDE SIGNIFICANT OVER
THE LAKE INSTABILITY (DELTA-T VALUES APPROACHING 25) AND LEAD TO
LAKE INDUCED CAPE AND EQL LEVELS OF 800 J/KG AND 13-14K
FT RESPECTIVELY. BEST DEEP MOISTURE WILL BE FOCUSED OVER THE EAST
CLOSER TO THE LOW MOVING THROUGH. THUS...EXPECT REALLY GOOD
CONDITIONS FOR MODERATE TO HEAVY LAKE EFFECT SNOW DURING THE
OVERNIGHT HOURS AND CONTINUING INTO SATURDAY. SNOW RATIOS WILL BE
ON THE INCREASE THROUGH THE FORECAST PERIOD...STARTING AROUND
10-15 TO 1 BEFORE INCREASING TO THE LOW 20S ONCE THE LAKE EFFECT
KICKS IN. WITH THE BEST LAKE INDUCED LIFT RIGHT IN THE DGZ...THERE
IS THE POTENTIAL THAT SNOW RATIOS COULD BE HIGHER IN THE STRONGER
BANDS (ESPECIALLY TOWARDS IRONWOOD WHERE THE WINDS ARE LIGHTER) AND
MAY BE SOMETHING TO MONITOR.
AS FOR SNOW AMOUNTS FOR THE WEST FIRST. WHILE THERE WILL BE SOME
BURSTS LATE THIS AFTERNOON AND EVENING...OVERALL AMOUNTS SHOULD BE
IN THE 1-3 INCH RANGE. THEN AS THE LAKE EFFECT KICKS IN
TONIGHT...HAVE ANOTHER 2-4 INCHES OVER THE HIGHER TERRAIN FROM THE
KEWEENAW THROUGH GOGEBIC COUNTIES. THIS PRODUCES TOTALS BY 12Z
SATURDAY OF 3-7 INCHES...WITH THE HIGHEST FOR GOGEBIC/ONTONAGON
DUE TO THE LONGER FETCH AND WEAKER WINDS INCREASING RESIDENCE
TIME OVER THE LAKE. ALSO...IT APPEARS THE INITIAL TROUGH WILL BECOME
HUNG UP IN THAT AREA THIS EVENING...WHICH WOULD ALLOW THE SNOW TO
PERSIST FOR MUCH OF THE EVENING HOURS. MARQUETTE/BARAGA COUNTY AND
LOCATIONS EASTWARD WILL LIKELY NOT REALLY SEE THE SNOW PICKING UP
UNTIL AFTER MIDNIGHT AND LIKELY AROUND 08-09Z WHEN THE TROUGH
FINALLY SHIFTS THROUGH AND SWITCHES THE WINDS MORE NORTH-NORTHWEST.
THIS BECOMES FAIRLY FAVORABLE FOR NORTH CENTRAL AND EASTERN PARTS OF
MARQUETTE COUNTY AND FOCUSED INTO ALGER COUNTY LATE TONIGHT...SO
EXPECT CONDITIONS TO DETERIORATE VERY QUICKLY THERE. WITH AN INCH
AN HOUR SNOW OVER MARQUETTE COUNTY LATE TONIGHT...EXPECT TOTALS IN
THE 2-5 INCH RANGE FROM THE HURON MOUNTAINS THROUGH
NEGAUNEE/SKANDIA BY 12Z. FARTHER EAST...THE DELAYED ARRIVAL WILL
LIKELY KEEP AMOUNTS IN THE 1-3 INCH RANGE.
ALONG WITH THE SNOW...WINDS WILL ALSO INCREASE BEHIND THE
FRONTS...GUSTING TO 40KT GALES OVER CENTRAL AND EASTERN LAKE
SUPERIOR DURING THE OVERNIGHT HOURS. GUSTS TO 35-40MPH WILL BE
COMMON OVER THE KEWEENAW STARTING LATE THIS EVENING AND LATE
TONIGHT EAST OF MARQUETTE. AS THE SNOW STARTS TO
ACCUMULATE...BLOWING SNOW BECOMES A LARGER ISSUE THROUGH THE NIGHT
AND INTO SATURDAY WITH SNOW BEING ON THE GROUND.
AS FOR HEADLINES...COORDINATION WITH THE LONG TERM SHIFT LED TO
SWITCHING GOGEBIC/ONTONAGON AND ALGER/LUCE...NORTHERN SCHOOLCRAFT
TO LAKE EFFECT SNOW WARNINGS DUE TO THEIR FAVORABLE CONDITIONS AND
EXPECTED SNOW ACCUMULATIONS. THERE WAS ENOUGH UNCERTAINTY ON
SNOWFALL AMOUNTS FOR THE KEWEENAW PENINSULA TO OPT FOR AN ADVISORY
AT THIS POINT...SINCE THE LIMITED FETCH (AND UPSLOPE) WITH THE
WINDS WILL KEEP AMOUNTS LOWER. THOSE WINDS COULD ALSO MAKE FOR
WORSE VISIBILITIES AND COULD ALMOST JUSTIFY A WARNING. MARQUETTE
WAS SIMILAR (AND MAY NEED TO BE UPGRADED WITH THE DAY SHIFT)...SINCE
AMOUNTS IN 12 HOURS ARE JUST UNDER WARNING CRITERIA AND THERE IS
SOME UNCERTAINTY ON THE EXACT LOCATION OF THE STRONGER BANDS OFF
LAKE NIPIGON. FINALLY...THE REST OF THE AREAS IN THE WATCH WERE
SWITCHED TO AN ADVISORY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 503 AM EST FRI NOV 22 2013
THE MAIN FCST CONCERNS ARE THE LES POTENTIAL FROM SAT INTO EARLY
SUNDAY ALONG WITH BLOWING SNOW AND WIND CHILLS IN THE VERY COLD
ARCTIC AIRMASS.
SAT INTO SAT NIGHT...
WITH MODEL FCST 850MB TEMPS FALLING TO -18 TO -21C BY 12Z
SAT...VIGOROUS NW/NNW FLOW ORIENTED LAKE EFFECT SNOW BANDS WILL BE
ONGOING IN THE WAKE OF THE ARCTIC FRONT. MODELS SUGGEST THAT THE
DEEPER MOISTURE TO AROUND 8K TO 10K FEET WILL PERSIST LONGER OVER
THE ERN FCST AREA. THE FAVORABLE MOISTURE PROFILE AND THE DGZ WITHIN
THE CONVECTIVE LAYER WILL SUPPORT SNOWFALL RATES OF AT LEAST 1 TO 2
INCHES PER HOUR IN THE STRONGER BANDS. HOWEVER...SNOWFLAKE
FRACTURING AND COMPACTION WITH TEH STRONG WINDS SHOULD LIMIT
SNOW/WATER RATIOS TO AROUND 20/1.
AS IS OFTEN THE CASE...THE MOST INTENSE DOMINANT BAND SHOULD
ORIGINATE WITH PRECONDITIONING OFF OF LAKE NIPIGON. THERE IS LESS
CONFIDENCE ON WHERE THAT BAND WILL SET UP AND HOW LONG IT WILL LAST
IN ANY ONE LOCATION. THE HIGHER RESOLUTION MODELS SUGGEST THAT THE
BAND MAY START OUT NEAR MARQUETTE AND THEN SHIFT EAST TOWARD SHOT
POINT AND INTO ALGER COUNTY BY LATE SATURDAY MORNING WHERE THE
HEAVIER LES WILL THEN PERSIST FROM SAT AFTERNOON INTO SAT NIGHT. 12
HOUR SNOWFALL AMOUNTS OF AROUND 8 INCHES ARE EXPECTED BOTH SATURDAY
AND SAT NIGHT FOR ALGER AND NRN SCHOOLCRAFT COUNTIES WHERE LES
WARNINGS WERE POSTED. THERE WAS GREATER UNCERTAINTY FOR MARQUETTE
COUNTY WHERE AN ADVISORY WAS POSTED. SNOWFALL TOTALS SHOULD BE
GREATEST IN THE 6Z-18Z/SAT PERIOD WHEN AMOUNTS IN THE 3 TO 7 INCH RANGE
ARE EXPECTED. AN UPGRADE TO A WARNING MAY BE NEEDED IF ANY STRONG
BANDS PERSIST LONGER THAN EXPECTED.
OVER THE WEST...INVERSION HEIGHTS DROPPING TO AROUND 5K-6K FT WILL
LIMIT LES INTENSITY. HOWEVER...WITH STRONG NRLY UPSLOPE FLOW INTO
THE HIGHER TERRAIN WILL SUPPORT ADDITIONAL SNOWFALL AMOUNTS OF 3 TO
5 INCHES SATURDAY WITH ANOTHER 2 TO 4 INCHES SAT NIGHT.
GUSTY WINDS TO 30-40 MPH WILL ALSO PRODUCE CONSIDERABLE BLOWING SNOW
WITH SHARPLY REDUCED VISIBILITY IN THE HEAVIER SNOW BANDS.
THE LES SHOULD MOSTLY END SUNDAY FROM W TO E AS WINDS BACK TO THE SW
AHEAD OF THE NEXT CLIPPER SHORTWAVE TROUGH DIVING SE THROUGH SOUTH
CNTRL CANADA. HOWEVER...A DEVELOPING WAA PATTERN WITH STRONG
285K-295K ISENTROPIC LIFT WILL PROBABLY LEAD TO AN AREA OF -SN
STREAKING SE INTO THE AREA SUN AFTN/NIGHT. HOWEVER...SINCE THE
STRONGER 700-300 MB QVECTOR CONV REMAINS WELL TO THE NORTH WITH THE
TRACK OF THE SHRTWV AND LOWER LEVELS ARE VERY DRY...ONLY CHANCE POPS
WERE INCLUDED FOR SNOWFALL AMOUNTS THAT WOULD AMOUNT TO LESS THAN AN
INCH OVER MOST OF THE CWA.
TUE-THU...THE GFS/GEFS/ECMWF WERE IN REASONABLE AGREEMENT THAT
ANOTHER BATCH OF ARCTIC AIR IS EXPECTED TO MOVE INTO THE NRN GREAT
LAKES IN THE WAKE OF A STRONGER SHORTWAVE MOVING THROUGH NRN ONTARIO
ON TUE. WITH 850 MB TEMPS DROPPING TO AROUND -17C...ANOTHER EXTENDED
PERIOD OF LES WITH AT LEAST MODERATE ACCUMULATIONS IS LIKELY FOR NW
TO N FLOW FAVORED LOCATIONS. THE LES SHOULD DIMINISH BY THU AS THE
SFC HIGH BUILDS INTO THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1229 AM EST FRI NOV 22 2013
A NNW FLOW OF VERY COLD AIR ACROSS LAKE SUP WL RESULT IN LES AND
MVFR TO OCNL IFR CONDITIONS EARLY THIS MRNG. BUT AS DRIER AND MORE
STABLE AIR SHOWN ON THE 00Z INL RAOB ARRIVES AFT 08Z...THE LES WL
DIMINISH EVEN AS THE MVFR CIGS PERSIST. AS THE FLOW BACKS MORE TO
THE W AND THEN THE SW WITH THE APRCH AND PASSAGE OF A HI PRES RDG
AXIS LATER THIS MRNG INTO EARLY AFTN...THESE LO CLDS WL GIVE WAY TO
VFR CONDITIONS. MORE MVFR CONDITIONS ARE LIKELY TO REACH THE TAF
SITES W TO E LATER THIS AFTN/EVNG AS A STRONG COLD FNT PASSES. WITH
A MORE ROBUST UPSLOPE WNW WIND COMPONENT...EXPECT MORE LES/IFR WX TO
DVLP AT CMX AND IWD. THE DOWNSLOPE NATURE OF THIS FLOW WL SLOW THE
ARRIVAL OF THESE MORE AUSTERE CONDITIONS AT SAW UNTIL AFT THIS TAF
PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 444 AM EST FRI NOV 22 2013
A FAIRLY ACTIVE NEXT COUPLE DAYS IS IN STORE FOR LAKE SUPERIOR. A
TROUGH THAT MOVED THROUGH LAKE SUPERIOR THIS PAST EVENING WILL
CONTINUE EAST EARLY THIS MORNING...WHILE A HIGH PRESSURE RIDGE
MOVES ACROSS THE LAKE THROUGH EARLY AFTERNOON. THERE WERE A FEW
GALE FORCE GUSTS TO 35KTS SHORTLY AFTER MIDNIGHT...BUT THEY HAVE
SINCE DIMINISHED AND EXPECT A DIMINISHING TREND TO THE WINDS THIS
MORNING. AS THE HIGH PRESSURE RIDGE SHIFTS EAST THIS AFTERNOON
SOUTHWESTERLY WINDS WILL BE ON THE INCREASE OVER WESTERLY LAKE
SUPERIOR AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. THIS SYSTEM
WILL QUICKLY DIVE SOUTHEAST ACROSS LAKE SUPERIOR LATE THIS AFTERNOON
AND EVENING...QUICKLY SHIFTING WINDS TO THE NORTH-NORTHWEST AND
PRODUCING GALE FORCE WINDS TO 40KTS. THERE COULD EVEN BE SOME GUSTS
TO 45KTS RIGHT AS WINDS SHIFT TO THE NORTH-NORTHWEST AFTER MIDNIGHT
OVER EASTERN LAKE SUPERIOR. THE GALE WARNING THAT IS IN PLACE LOOKS
TO BE IN GOOD SHAPE. A STRONG HIGH DROPPING SOUTH THROUGH THE
NORTHERN PLAINS ON SATURDAY WILL BEGIN TO NOSE A RIDGE OVER WESTERN
LAKE SUPERIOR ON SATURDAY AFTERNOON AND THEN PUSH ACROSS THE ENTIRE
LAKE SATURDAY NIGHT AND SUNDAY. THIS WILL LEAD TO DIMINISHING AND
BACKING WINDS DURING THAT PERIOD. THAT DIMINISHING TREND WILL BE
SHORT LIVED AS WINDS WILL INCREASE ON SUNDAY NIGHT OUT OF THE
SOUTHWEST (TO 30KTS) AHEAD OF LOW MOVING SOUTHEAST THROUGH ONTARIO
LATE SUNDAY NIGHT AND MONDAY. THIS LOW WILL DRAG A COUPLE TROUGHS
ACROSS LAKE SUPERIOR MONDAY AND MONDAY NIGHT...WITH THE SECOND ONE
STALLING OVER SOUTHEAST LAKE SUPERIOR THROUGH WEDNESDAY. AT THIS
POINT...NORTHWEST WINDS UP TO 30KTS ARE EXPECTED BEHIND THE
TROUGHS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 1 AM EST
SUNDAY FOR MIZ004-084.
LAKE EFFECT SNOW WARNING FROM MIDNIGHT TONIGHT TO NOON EST
SUNDAY FOR MIZ006-007-085.
LAKE EFFECT SNOW ADVISORY FROM 5 PM THIS AFTERNOON TO 7 AM EST
SUNDAY FOR MIZ001-003.
LAKE EFFECT SNOW WARNING FROM 6 PM EST /5 PM CST/ THIS EVENING
TO 7 AM EST /6 AM CST/ SUNDAY FOR MIZ002-009.
LAKE EFFECT SNOW ADVISORY FROM 1 AM TO 10 PM EST SATURDAY FOR
MIZ005.
LAKE EFFECT SNOW ADVISORY FROM 1 AM SATURDAY TO 7 AM EST SUNDAY
FOR MIZ014.
LAKE EFFECT SNOW ADVISORY FROM 1 AM SATURDAY TO 5 AM EST SUNDAY
FOR MIZ013.
LAKE SUPERIOR...
GALE WARNING FROM 11 PM THIS EVENING TO 1 AM EST SUNDAY FOR
LSZ266-267.
GALE WARNING FROM 1 AM TO 10 PM EST SATURDAY FOR LSZ248>251-265.
GALE WARNING FROM 10 PM THIS EVENING TO 10 PM EST SATURDAY FOR
LSZ264.
GALE WARNING FROM 10 PM THIS EVENING TO 10 AM EST SATURDAY FOR
LSZ263.
GALE WARNING FROM 10 PM THIS EVENING TO 7 PM EST SATURDAY FOR
LSZ244-245.
GALE WARNING FROM 10 PM THIS EVENING TO 7 AM EST SATURDAY FOR
LSZ242-243.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
445 AM EST FRI NOV 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 444 AM EST FRI NOV 22 2013
BROAD AREA OF LIGHT SNOW ASSOCIATED WITH A COUPLED UPPER
JET...SHORTWAVE ENERGY AND MID-LEVEL Q-VECTOR CONVERGENCE CONTINUES
TO SLIDE EAST EARLY THIS MORNING ACROSS UPPER MICHIGAN AND
WISCONSIN. GENERALLY LIGHT SNOW WITH VISIBILITIES IN MOST LOCATIONS
OF 2 TO 5 MILES. WE SAW FINE FLAKES AT OUR OFFICE MOST OF THE
NIGHT...WHICH HAS BEEN HELPFUL IN REDUCING VISIBILITIES. ONE REPORT
FROM NORTHERN WISCONSIN INDICATED A HALF AN INCH OF SNOW
ACCUMULATION AND OUR OFFICE HAD 0.6 INCH AS OF 1AM. THE SNOW HAS
ALREADY ENDED OVER WESTERN UPPER MICHIGAN (KCMX/KIWD OBS) AND
STARTING TO SEE THE REFLECTIVITIES QUICKLY DIMINISH OVER BARAGA
AND IRON COUNTIES. AS THE UPPER LEVEL FEATURES CONTINUE TO SHIFT
EAST THIS MORNING...EXPECT THE SYNOPTIC SNOWFALL TO QUICKLY
DIMINISH THROUGH MID MORNING.
OVER NORTHERN UPPER MICHIGAN...LOW LEVEL 925-850MB NORTH-NORTHWEST
FLOW (ON KMQT VAD AND RAP ANALYSIS) ACROSS LAKE SUPERIOR...ALONG
WITH 850MB TEMPS OF -7C TO -11C FROM EAST TO WEST HAS LED TO SOME
LAKE ENHANCEMENT EARLY THIS MORNING...WITH THE STRONGEST RETURNS ON
RADAR AND OBS INDICATING THE HEAVIEST SNOW OVER EASTERN
MARQUETTE AND WESTERN ALGER COUNTIES. THIS ENHANCEMENT
WILL ALSO BE DIMINISHING QUICKLY THIS MORNING AS A HIGH PRESSURE
RIDGE FROM NORTHERN MINNESOTA NOSES INTO THE AREA. VERY DRY AIR
ABOVE THE INVERSION AT 920MB ON THE 00Z KINL SOUNDING WILL BE WHAT
IS MOVING INTO THE AREA AND REALLY DIMINISH THE INTENSITY OF THE
LAKE ENHANCEMENT OVER THE NORTH CENTRAL THIS MORNING. THIS WILL ALSO
LEAD TO A DIMINISHING TREND TO THE LAKE EFFECT CLOUDS FROM WEST TO
EAST TODAY AS THE LAKE INDUCED INSTABILITY AND MOISTURE IS PINCHED
BY THAT LOWERING INVERSION FROM THE HIGH PRESSURE RIDGE. EXPECT THE
LAKE CLOUDS TO HANG ON THE LONGEST OVER THE KEWEENAW AND THE EAST
WHERE THE BACKING WINDS WINDS WILL STAY FAVORABLE THE LONGEST. THE
REST OF THE AREA SHOULD SEE SKIES BECOMING PARTLY CLOUDY IF NOT
MOSTLY SUNNY LATE THIS MORNING THROUGH THE AFTERNOON.
FOCUS THEN TURNS TO THE MAIN WEATHER MAKER FOR THE FORECAST
PERIOD...WHICH IS ASSOCIATED WITH A LOW THAT IS CURRENTLY LOCATED
NEAR LAKE WINNIPEG. THIS LOW AND POTENT SHORTWAVE NOTED ON WV
IMAGERY WILL QUICKLY SWEEP SOUTHEAST ACROSS LAKE SUPERIOR LATE THIS
AFTERNOON AND EVENING. STRONG CONVERGENCE ALONG TWO ASSOCIATED
TROUGHS WILL LEAD TO A COUPLE MODERATE TO POTENTIALLY HEAVY PERIODS
OF SNOW BEFORE THE LAKE EFFECT REALLY KICKS IN OVERNIGHT.
THE FIRST TROUGH WILL SHIFT WINDS TO THE NORTHWEST AND MOVE INTO THE
KEWEENAW AND WESTERN UPPER MICHIGAN AROUND DINNER TIME AND THE REST
OF THE CWA DURING THE EVENING HOURS. EXPECT THE STRONGEST SNOW TO
OCCUR OVER THE WEST WITH THE FAVORABLE UPSLOPE WINDS AND LEAD TO A
COUPLE HOUR PERIOD OF STRONG SNOW SHOWERS. THEN THERE MAY BE
A SHORT PERIOD OF LIGHTER SNOW AS THE DEEPER MOISTURE CUTS OUT FOR
A FEW HOURS. THE SECONDARY TROUGH (WITH ANOTHER BURST OF
MODERATE TO HEAVY SNOWFALL) WILL THEN DROP SOUTH ACROSS THE KEWEENAW
AND WESTERN UPPER MICHIGAN AROUND OR SHORTLY AFTER
MIDNIGHT...SHIFTING THE WINDS TO ALMOST NORTHERLY AND THE LAKE
EFFECT SNOW SHOULD REALLY KICK IN. EXPECT A SIMILAR OCCURRENCE
ACROSS THE REST OF NORTHERN UPPER MICHIGAN WITH MORE OF A DELAY ON
THE SECONDARY TROUGH UNTIL THE 08-09Z TIME FRAME. IN ADDITION...WITH
THE FIRST FRONT SHIFTING WINDS TO LESS FAVORABLE NORTHWESTERLY
DOWNSLOPING FLOW FOR THE NORTH CENTRAL...THEY WILL LIKELY NOT SEE
MUCH SNOW ACCUMULATION UNTIL THE SECONDARY TROUGH MOVES THROUGH AND
LAKE EFFECT DEVELOPS.
BEHIND THE TROUGHS...850MB TEMPS WILL FALL FROM AROUND -10C AT 18Z
TODAY TO -20C AT 12Z SATURDAY. THIS WILL PROVIDE SIGNIFICANT OVER
THE LAKE INSTABILITY (DELTA-T VALUES APPROACHING 25) AND LEAD TO
LAKE INDUCED CAPE AND EQL LEVELS OF 800 J/KG AND 13-14K
FT RESPECTIVELY. BEST DEEP MOISTURE WILL BE FOCUSED OVER THE EAST
CLOSER TO THE LOW MOVING THROUGH. THUS...EXPECT REALLY GOOD
CONDITIONS FOR MODERATE TO HEAVY LAKE EFFECT SNOW DURING THE
OVERNIGHT HOURS AND CONTINUING INTO SATURDAY. SNOW RATIOS WILL BE
ON THE INCREASE THROUGH THE FORECAST PERIOD...STARTING AROUND
10-15 TO 1 BEFORE INCREASING TO THE LOW 20S ONCE THE LAKE EFFECT
KICKS IN. WITH THE BEST LAKE INDUCED LIFT RIGHT IN THE DGZ...THERE
IS THE POTENTIAL THAT SNOW RATIOS COULD BE HIGHER IN THE STRONGER
BANDS (ESPECIALLY TOWARDS IRONWOOD WHERE THE WINDS ARE LIGHTER) AND
MAY BE SOMETHING TO MONITOR.
AS FOR SNOW AMOUNTS FOR THE WEST FIRST. WHILE THERE WILL BE SOME
BURSTS LATE THIS AFTERNOON AND EVENING...OVERALL AMOUNTS SHOULD BE
IN THE 1-3 INCH RANGE. THEN AS THE LAKE EFFECT KICKS IN
TONIGHT...HAVE ANOTHER 2-4 INCHES OVER THE HIGHER TERRAIN FROM THE
KEWEENAW THROUGH GOGEBIC COUNTIES. THIS PRODUCES TOTALS BY 12Z
SATURDAY OF 3-7 INCHES...WITH THE HIGHEST FOR GOGEBIC/ONTONAGON
DUE TO THE LONGER FETCH AND WEAKER WINDS INCREASING RESIDENCE
TIME OVER THE LAKE. ALSO...IT APPEARS THE INITIAL TROUGH WILL BECOME
HUNG UP IN THAT AREA THIS EVENING...WHICH WOULD ALLOW THE SNOW TO
PERSIST FOR MUCH OF THE EVENING HOURS. MARQUETTE/BARAGA COUNTY AND
LOCATIONS EASTWARD WILL LIKELY NOT REALLY SEE THE SNOW PICKING UP
UNTIL AFTER MIDNIGHT AND LIKELY AROUND 08-09Z WHEN THE TROUGH
FINALLY SHIFTS THROUGH AND SWITCHES THE WINDS MORE NORTH-NORTHWEST.
THIS BECOMES FAIRLY FAVORABLE FOR NORTH CENTRAL AND EASTERN PARTS OF
MARQUETTE COUNTY AND FOCUSED INTO ALGER COUNTY LATE TONIGHT...SO
EXPECT CONDITIONS TO DETERIORATE VERY QUICKLY THERE. WITH AN INCH
AN HOUR SNOW OVER MARQUETTE COUNTY LATE TONIGHT...EXPECT TOTALS IN
THE 2-5 INCH RANGE FROM THE HURON MOUNTAINS THROUGH
NEGAUNEE/SKANDIA BY 12Z. FARTHER EAST...THE DELAYED ARRIVAL WILL
LIKELY KEEP AMOUNTS IN THE 1-3 INCH RANGE.
ALONG WITH THE SNOW...WINDS WILL ALSO INCREASE BEHIND THE
FRONTS...GUSTING TO 40KT GALES OVER CENTRAL AND EASTERN LAKE
SUPERIOR DURING THE OVERNIGHT HOURS. GUSTS TO 35-40MPH WILL BE
COMMON OVER THE KEWEENAW STARTING LATE THIS EVENING AND LATE
TONIGHT EAST OF MARQUETTE. AS THE SNOW STARTS TO
ACCUMULATE...BLOWING SNOW BECOMES A LARGER ISSUE THROUGH THE NIGHT
AND INTO SATURDAY WITH SNOW BEING ON THE GROUND.
AS FOR HEADLINES...COORDINATION WITH THE LONG TERM SHIFT LED TO
SWITCHING GOGEBIC/ONTONAGON AND ALGER/LUCE...NORTHERN SCHOOLCRAFT
TO LAKE EFFECT SNOW WARNINGS DUE TO THEIR FAVORABLE CONDITIONS AND
EXPECTED SNOW ACCUMULATIONS. THERE WAS ENOUGH UNCERTAINTY ON
SNOWFALL AMOUNTS FOR THE KEWEENAW PENINSULA TO OPT FOR AN ADVISORY
AT THIS POINT...SINCE THE LIMITED FETCH (AND UPSLOPE) WITH THE
WINDS WILL KEEP AMOUNTS LOWER. THOSE WINDS COULD ALSO MAKE FOR
WORSE VISIBILITIES AND COULD ALMOST JUSTIFY A WARNING. MARQUETTE
WAS SIMILAR (AND MAY NEED TO BE UPGRADED WITH THE DAY SHIFT)...SINCE
AMOUNTS IN 12 HOURS ARE JUST UNDER WARNING CRITERIA AND THERE IS
SOME UNCERTAINTY ON THE EXACT LOCATION OF THE STRONGER BANDS OFF
LAKE NIPIGON. FINALLY...THE REST OF THE AREAS IN THE WATCH WERE
SWITCHED TO AN ADVISORY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 405 PM EST THU NOV 21 2013
MAIN FOCUS IN LONG TERM WILL BE THE PASSAGE OF A STRONG ARCTIC COLD
FRONT FRIDAY NIGHT AND POTENTIAL FOR MODERATE TO HEAVY LAKE EFFECT
SNOW ALONG WITH BLOWING SNOW FRI NIGHT THROUGH SAT NIGHT ACROSS THE
NRN AND ERN SECTIONS OF THE CWA. MUCH COLDER TEMPS AND VERY COLD
WIND CHILL VALUES WILL ALSO ACCOMPANY THE FRONTAL PASSAGE.
FRI NIGHT INTO SATURDAY NIGHT...SHORTWAVE ENERGY FROM NW CANADA
DROPS SE LEADING TO UPPER TROF AMPLIFICATION OVER THE GREAT LAKES
THIS WEEKEND. BRIEF PERIOD OF VIGOROUS UPPER FORCING NOTED PER MODEL
DEEP LAYER Q-VECT CONV WILL ENHANCE STRONG OVERWATER INSTABILITY
LEADING TO THE TYPICAL BURST OF MODERATE TO HEAVY LAKE ENHANCED SNOW
OFF LAKE SUPERIOR ALONG THE ASSOCIATED ARCTIC COLD FRONT FRI NIGHT.
THIS BURST OF SNOW COULD ARRIVE AS EARLY AS LATE FRI AFTERNOON OVER
THE KEWEENAW. CONVERGENCE ALONG ARCTIC FRONT SHOULD INCREASE
SUBSTANTIALLY AS THE FRONT CROSSES THE RELATIVELY WARM WATERS OF
LAKE SUPERIOR WITH THE MOST INTENSE BURST OF SNOWFALL ALONG THE
FROPA TO LIKELY IMPACT AREAS EAST OF MARQUETTE. WITH MODEL FCST
850MB TEMPS FALLING TO -17 TO -21C BY 12Z SAT...VIGOROUS NW/NNW FLOW
ORIENTED LAKE EFFECT SNOW BANDS SHOULD QUICKLY ORGANIZE FRI NIGHT
AFTER THE ARCTIC FRONT PASSES. 850MB TEMPS BOTTOM OUT AROUND -21C TO
-22C ACROSS THE AREA SAT. CONSENSUS OF MODEL GUIDANCE IS FOR DEEPER
MOISTURE TO PERSIST LONGER OVER THE ERN FCST AREA WITH BOTH THE GFS
AND NAM SNDGS SHOWING MOISTURE UP TO 700 MB OR AROUND 10KFT THROUGH
12Z SAT. THIS DEEPER MOISTURE COMBINED WITH PRECONDITIONING MOISTURE
OFF LAKE NIPIGON AND A FAVORABLE PLACEMENT OF THE DGZ WITHIN
VIGOROUS UPWARD MOTION ZONE SHOULD LEAD TO A SIGNIFICANT LAKE EFFECT
EVENT FOR ALGER/WRN LUCE/NRN SCHOOLCRAFT. HEAVIEST SNOW FOR THE
EVENT WILL FALL WHERE LES BANDS REALIZE ADDED OVERWATER
FETCH/PRECONDITIONING OFF LAKE NIPIGON. EARLY ON SAT...WINDS ARE
NORTHERLY ENOUGH THAT THE HEAVIEST LES BANDS OR BAND CONNECTED TO
LAKE NIPIGON WILL PROBABLY IMPACT KEWEENAW COUNTY AND MARQUETTE
COUNTY BEFORE WINDS BACK SLIGHTLY FOR THE AFTN. DOMINANT LES BAND
SHOULD THEN SPEND THE REST OF SAT AFTERNOON AND SAT NIGHT IMPACTING
ALGER...SCHOOLCRAFT COUNTIES AND PROBABLY THE NE CORNER OF DELTA
COUNTY.
GUSTY WINDS OF 30-40MPH LATE FRI NIGHT THRU SAT AFTN WILL ALSO LEAD
TO CONSIDERABLE BLOWING AND DRIFTING SNOW AS SNOW ACCUMULATES. OUT
W...SHORTER FETCH...LOWER DGZ AND QUICKER SHALLOWING OF MOISTURE TO
AROUND 6KFT WILL WORK TO LIMIT SNOW ACCUMULATIONS THERE COMPARED TO
THE E. HOWEVER...UPSLOPE TERRAIN ENHANCEMENT AND ENHANCED LOW-LVL
CONVERGENCE COULD STILL LEAD TO SIGNIFICANT TOTAL SNOW ACCUMULATION
OVER PORTIONS OF GOGEBIC/ONTONAGON COUNTIES.
GIVEN SNOW AND BLOWING SNOW POTENTIAL...COMBINED WITH MUCH COLDER
TEMPS AND WIND CHILLS (LOWERING TO -5 TO 5F RANGE) HAVE DECIDED TO
POST WINTER STORM WATCHES ACROSS ALL COUNTIES BORDERING LAKE
SUPERIOR FOR FRI NIGHT INTO SAT NIGHT. WILL ALSO INCLUDE ALL OF
SCHOOLCRAFT COUNTY AS THERE IS A POTENTIAL THAT DOMINANT LES BAND
INITIATING OFF LAKE NIPIGON COULD AFFECT AND EXTEND FAIRLY FAR SOUTH
THROUGH COUNTY GIVEN STRENGTH OF WINDS WITHIN MIXED LAYER. FOR NOW
WILL LEAVE DELTA COUNTY OUT OF WATCH AS THE HEAVIEST SNOW/BLOWING
SNOW WILL AFFECT MAINLY THE NE PORTION OF THE COUNTY...BUT THEY WILL
MOST CERTAINLY NEED AN ADVISORY AT LEAST. TEMPS WILL REMAIN STEADY
OR EVEN FALL SAT AS CORE OF ARCTIC AIR ARRIVES. MOST AREAS WILL STAY
IN THE TEENS SAT.
LES SHOULD MOSTLY END SUNDAY FROM W TO E AS WINDS BACK TO THE SW
AHEAD OF THE NEXT CLIPPER SHORTWAVE DIVING SE THRU SCNTRL CANADA.
HOWEVER...DEVELOPING STRONG WAA PATTERN WILL PROBABLY LEAD TO AN
AREA OF -SN STREAKING SE INTO THE AREA SUN AFTN/NIGHT. IN
FACT...WINDS MAY EVEN BACK ENOUGH FOR LAKE ENHANCED SNOW TO DEVELOP
OFF LAKE MICHIGAN AND IMPACT THE FAR ERN FCST AREA SUN NIGHT. TRACK
OF MAIN SHORTWAVE WILL BE WELL N OF THE FCST AREA SO NOT MUCH OF A
PUSH OF COLD AIR WILL FOLLOW. ANY LES BEHIND THE SYSTEM ON MONDAY
WILL BE MINIMAL.
AS PER PREV FCST...WILL CONTINUE TO LEAN TOWARD THE MORE CONSISTENT
ECMWF FOR TUE/WED...WITH A PAIR OF SHORTWAVES EXPECTED TO REAMPLIFY
THE TROF INTO THE GREAT LAKES. AS WIND SHIFTS TO NW TO N WITH
ASSOCIATED ARCTIC FRONT EXPECT ROUND OF POTENTIALLY SIGNIFICANT LES
OFF LAKE SUPERIOR FOR MON NIGHT INTO WED. LES SHOULD LINGER INTO AT
LEAST THU MORNING AS ECMWF SHOWS CORE OF COLDEST 8H TEMPS (-22C!)
MOVING ACROSS THE REGION BY 12Z THU. RIDGING/SUBSIDENCE FROM WEST
WILL BEGIN TO DIMINISH LES FROM WEST TO EAST THU AFTERNOON.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1229 AM EST FRI NOV 22 2013
A NNW FLOW OF VERY COLD AIR ACROSS LAKE SUP WL RESULT IN LES AND
MVFR TO OCNL IFR CONDITIONS EARLY THIS MRNG. BUT AS DRIER AND MORE
STABLE AIR SHOWN ON THE 00Z INL RAOB ARRIVES AFT 08Z...THE LES WL
DIMINISH EVEN AS THE MVFR CIGS PERSIST. AS THE FLOW BACKS MORE TO
THE W AND THEN THE SW WITH THE APRCH AND PASSAGE OF A HI PRES RDG
AXIS LATER THIS MRNG INTO EARLY AFTN...THESE LO CLDS WL GIVE WAY TO
VFR CONDITIONS. MORE MVFR CONDITIONS ARE LIKELY TO REACH THE TAF
SITES W TO E LATER THIS AFTN/EVNG AS A STRONG COLD FNT PASSES. WITH
A MORE ROBUST UPSLOPE WNW WIND COMPONENT...EXPECT MORE LES/IFR WX TO
DVLP AT CMX AND IWD. THE DOWNSLOPE NATURE OF THIS FLOW WL SLOW THE
ARRIVAL OF THESE MORE AUSTERE CONDITIONS AT SAW UNTIL AFT THIS TAF
PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 444 AM EST FRI NOV 22 2013
A FAIRLY ACTIVE NEXT COUPLE DAYS IS IN STORE FOR LAKE SUPERIOR. A
TROUGH THAT MOVED THROUGH LAKE SUPERIOR THIS PAST EVENING WILL
CONTINUE EAST EARLY THIS MORNING...WHILE A HIGH PRESSURE RIDGE
MOVES ACROSS THE LAKE THROUGH EARLY AFTERNOON. THERE WERE A FEW
GALE FORCE GUSTS TO 35KTS SHORTLY AFTER MIDNIGHT...BUT THEY HAVE
SINCE DIMINISHED AND EXPECT A DIMINISHING TREND TO THE WINDS THIS
MORNING. AS THE HIGH PRESSURE RIDGE SHIFTS EAST THIS AFTERNOON
SOUTHWESTERLY WINDS WILL BE ON THE INCREASE OVER WESTERLY LAKE
SUPERIOR AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. THIS SYSTEM
WILL QUICKLY DIVE SOUTHEAST ACROSS LAKE SUPERIOR LATE THIS AFTERNOON
AND EVENING...QUICKLY SHIFTING WINDS TO THE NORTH-NORTHWEST AND
PRODUCING GALE FORCE WINDS TO 40KTS. THERE COULD EVEN BE SOME GUSTS
TO 45KTS RIGHT AS WINDS SHIFT TO THE NORTH-NORTHWEST AFTER MIDNIGHT
OVER EASTERN LAKE SUPERIOR. THE GALE WARNING THAT IS IN PLACE LOOKS
TO BE IN GOOD SHAPE. A STRONG HIGH DROPPING SOUTH THROUGH THE
NORTHERN PLAINS ON SATURDAY WILL BEGIN TO NOSE A RIDGE OVER WESTERN
LAKE SUPERIOR ON SATURDAY AFTERNOON AND THEN PUSH ACROSS THE ENTIRE
LAKE SATURDAY NIGHT AND SUNDAY. THIS WILL LEAD TO DIMINISHING AND
BACKING WINDS DURING THAT PERIOD. THAT DIMINISHING TREND WILL BE
SHORT LIVED AS WINDS WILL INCREASE ON SUNDAY NIGHT OUT OF THE
SOUTHWEST (TO 30KTS) AHEAD OF LOW MOVING SOUTHEAST THROUGH ONTARIO
LATE SUNDAY NIGHT AND MONDAY. THIS LOW WILL DRAG A COUPLE TROUGHS
ACROSS LAKE SUPERIOR MONDAY AND MONDAY NIGHT...WITH THE SECOND ONE
STALLING OVER SOUTHEAST LAKE SUPERIOR THROUGH WEDNESDAY. AT THIS
POINT...NORTHWEST WINDS UP TO 30KTS ARE EXPECTED BEHIND THE
TROUGHS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 5 PM THIS AFTERNOON TO 7 AM EST
SUNDAY FOR MIZ001-003.
LAKE EFFECT SNOW ADVISORY FROM 1 AM SATURDAY TO 5 AM EST SUNDAY
FOR MIZ013.
LAKE EFFECT SNOW ADVISORY FROM 1 AM SATURDAY TO 7 AM EST SUNDAY
FOR MIZ014.
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 1 AM EST
SUNDAY FOR MIZ004-084.
LAKE EFFECT SNOW WARNING FROM 6 PM EST /5 PM CST/ THIS EVENING
TO 7 AM EST /6 AM CST/ SUNDAY FOR MIZ002-009.
LAKE EFFECT SNOW ADVISORY FROM 1 AM TO 10 PM EST SATURDAY FOR
MIZ005.
LAKE EFFECT SNOW WARNING FROM MIDNIGHT TONIGHT TO NOON EST
SUNDAY FOR MIZ006-007-085.
LAKE SUPERIOR...
GALE WARNING FROM 11 PM THIS EVENING TO 1 AM EST SUNDAY FOR
LSZ266-267.
GALE WARNING FROM 1 AM TO 10 PM EST SATURDAY FOR LSZ265.
GALE WARNING FROM 10 PM THIS EVENING TO 10 PM EST SATURDAY FOR
LSZ264.
GALE WARNING FROM 10 PM THIS EVENING TO 10 AM EST SATURDAY FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...VOSS
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1152 PM CST THU NOV 21 2013
.UPDATE...
ISSUED AT 1002 PM CST THU NOV 21 2013
PREVIOUS FORECAST HAD POPS THROUGH TOMORROW MORNING...WITH
MORNING POPS MAINLY ACROSS OUR KANSAS COUNTIES. SOUNDINGS ARE
INDICATING A DRIER ATMOSPHERE THAN PREVIOUSLY FORECAST. RADAR
TRENDS ARE ALSO INDICATING DECREASING COVERAGE ACROSS THE AREA.
00Z NAM SHOWS DRY CONDITIONS. FURTHERMORE...THE HRRR IS PAINTING
DRY CONDITIONS ACROSS THE FORECAST AREA. CONSEQUENTLY...DECREASED
POPS ACROSS THE OUTLOOK AREA FOR THE REST OF THIS EVENING AND INTO
TOMORROW MORNING. BASICALLY A DRY FORECAST THROUGH TOMORROW.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 549 PM CST THU NOV 21 2013
TONIGHT AND FRIDAY. MAIN CONCERNS CONTINUE TO BE THE CURRENT
WINTER WEATHER SYSTEM AND WHEN SNOW WILL COME TO AN END.
LATEST RADAR TRENDS HAVE THE HEAVIER PRECIPITATION RETURNS ACROSS
THE FAR SOUTHEAST PART OF THE FORECAST AREA...AND EVEN THESE ARE
DIMINISHING SOME EARLY THIS AFTERNOON. THESE ARE PRIMARILY LIGHT
FREEZING RAIN OR SLEET. IN THE WEST THERE ARE SOME LIGHTER RETURNS
AND OBSERVATIONS AND WEB CAMS INDICATE THAT THIS IS SOME LIGHT SNOW.
MODELS CONTINUE TO BRING IN ANOTHER WEAK UPPER LEVEL DURING THE
EVENING AND THE SNOW ACROSS WESTERN NEBRASKA WILL CONTINUE TO MOVE
TO THE EAST AND INTO THE FORECAST AREA DURING THE LATE AFTERNOON AND
EVENING. HAVE MAINTAINED THE HIGH POPS ACROSS THE AREA THROUGH THE
AFTERNOON AND THEN SLOWLY DIMINISHED THE CHANCES DURING THE EVENING
AND ESPECIALLY OVERNIGHT. THE MAIN QUESTION IS WHAT TYPE OF
PRECIPITATION WILL HAPPEN IN THE SOUTHEAST. THE LATEST MODEL
GUIDANCE HAS A WARM LAYER THAT FINALLY COOLS ENOUGH TO PRODUCE A
SLEET/SNOW MIXTURE BY MID AFTERNOON AND SHOULD BE ALL SNOW BY
EVENING. WILL CONTINUE THE ADVISORY.
THE SNOW WILL GRADUALLY COME TO AN END FROM WEST TO EAST LATE
TONIGHT. THE ONLY EXCEPTION TO THIS WILL BE ACROSS KANSAS. THERE IS
A WEAK UPPER LEVEL WAVE THAT WILL MOVE INTO THE AREA FRIDAY MORNING.
THERE IS A BAND OF SNOW THAT IS EXPECTED TO DEVELOP IN THE VICINITY
OF INTERSTATE 70. THE MODELS INDICATE THAT MOST OF THE SNOW SHOULD
BE TO THE SOUTH OF THE FORECAST AREA SO HAVE KEPT SOME LOW POPS
MAINLY ACROSS THE FAR SOUTH.
CLOUDS SHOULD DIMINISH SLOWLY ACROSS THE AREA ON FRIDAY...ALTHOUGH
PARTLY TO MOSTLY CLOUDY SKIES ARE EXPECTED IN THE SOUTHERN PART OF
THE AREA.
COLD AIR WILL CONTINUE TO PUSH INTO THE AREA TONIGHT WITH LOWS IN
THE TEENS. THE COLD AIR WILL CONTINUE ACROSS THE AREA ON FRIDAY WITH
HIGHS IN THE LOWER 30S.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 549 PM CST THU NOV 21 2013
THE OVERALL TREND FOR THE SATURDAY THROUGH THANKSGIVING DAY
TIME FRAME IS COOLER THAN NORMAL TEMPERATURES...AND GENERALLY DRY
CONDITIONS. WE WILL BREAK IT DOWN INTO TWO TIME FRAMES.
SATURDAY-MONDAY...SATURDAY IS FLAT OUT COLD. SECONDARY PUSH OF COLD AIR
OVERNIGHT FRIDAY NIGHT WILL INCREASE WINDS FOR THE FIRST HALF OF THE
DAY SATURDAY AND WILL PUSH WIND CHILLS AT OR BELOW ZERO THROUGH
MIDDAY SATURDAY. BOTH THE NAM/GFS HINT AT SOME BROKEN LOW STRATUS
BEHIND THE FRONT OVER/NEAR THE NORTHERN PART OF THE AREA. WINDS WILL
DROP OFF QUICKLY DROP THANKFULLY BY LATE AFTERNOON...BUT TEMPERATURES
WILL BE 15-20 DEGREES BELOW NORMAL. ON SUNDAY...A RETURN SOUTHERLY
FLOW WILL PUSH TEMPERATURES UP BACK INTO THE 30S...BUT THOSE SOUTH
WINDS WILL BE CHILLING A LOT LIKELY SATURDAY. ANOTHER COLD ONE. THERE
ARE MODEL HINTS/IDEAS OF A CUT OFF SOUTHWEST U.S. LOW PRESSURE TRYING
TO MEANDER INTO THE SOUTHERN PLAINS SUNDAY/MONDAY TIME FRAME. THERE
ARE DIFFERENCES IN LOCATION/TIMING. BELIEVE WE WILL SEE CLOUDS
INCREASE SUNDAY...BUT MODELS TEND TO BRING PRECIPITATION TOO FAR
NORTH INTO COLD AIR MASSES SUCH AS THIS. COMFORTABLE WITH NO CHANCE
OF MEASURABLE PRECIPITATION AT THIS POINT...WITH UPCOMING FORECAST
CREWS NEEDING TO KEEP AN EYE ON THE SYSTEM AND ITS MOVEMENT CLOSELY.
TUESDAY-THANKSGIVING DAY...OVERALL THE CENTRAL PLAINS WILL BE COOLER
THAN NORMAL...THANKS SHARING IN CHILLY...CYCLONIC FLOW AROUND HUDSON
BAY VORTEX. THERE IS NO INDICATION AT THIS JUNCTURE OF ANY MAJOR
WEATHER SYSTEM IMPACTING THANKSGIVING DAY...THE WEDNESDAY BEFORE OR
BLACK FRIDAY REALLY. LOOK FOR LOTS OF HIGHS IN THE 30S AN AND
OCCASIONAL LOWER 40 DEGREE DAY NEXT WEEK. THIS COOLISH WEATHER
PATTERN WILL TAKE US RIGHT INTO DECEMBER...AS THE REGION GENERALLY
REMAINS INFLUENCED BY A COLDER WEST/NORTHWEST FLOW AND OCCASIONAL
COLD AIR INTRUSIONS FROM THE CANADIAN PROVINCES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1138 PM CST THU NOV 21 2013
CONDITIONS WILL CONTINUE TO GRADUALLY IMPROVE OVERNIGHT WITH VFR
CONDITIONS EXPECTED. MID-LEVEL CEILINGS SHOULD LIFT TO HIGHER
LEVELS AS THE WEATHER SYSTEM GIVING US SOME LIGHT SNOW CONTINUES
TO MOVE EAST.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...GUERRERO
SHORT TERM...JCB
LONG TERM...MORITZ
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
232 AM EST FRI NOV 22 2013
.SYNOPSIS...
WIDELY SCATTERED SHOWERS THIS MORNING WILL TAPPER OFF BY EARLY
AFTERNOON IN ADVANCE OF A COLD FRONT THAT WILL MOVE THROUGH THE
AREA LATER THIS EVENING. AS THIS FRONT CROSS THE AREA...EXPECT
SHOWERS TO REDEVELOP WITH RAINFALL THEN COMING TO AN END SHORTLY
AFTER MIDNIGHT. MOSTLY DRY CONDITIONS ON SATURDAY WILL QUICKLY
GIVE WAY TO DEVELOPING SNOW SHOWERS BY AFTERNOON AND EVENING AS A
STRONG ARCTIC COLD FRONT MOVES THROUGH THE AREA. AS THE COLDEST
AIRMASS OF THE SEASON DESCENDS UPON THE REGION...EXPECT DEVELOPING
LAKE EFFECT SNOWS SOUTHEAST OF LAKE ONTARIO. SNOW WILL INCREASE IN
INTENSITY SATURDAY NIGHT WITH HEAVY ACCUMULATIONS POSSIBLE FOR
PORTIONS OF CENTRAL NEW YORK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1 AM UPDATE...
RAIN SHOWERS CONTINUING TO DEVELOP ACROSS THE REGION EARLY THIS
MORNING AS WARM AIR ADVECTION IN ADVANCE OF AN APPROACHING WARM
FRONT COMBINED WITH THE PASSAGE OF A WEAK SHORTWAVE IN WEST
SOUTHWEST FLOW ALOFT. HAVE INCREASED POPS BASED ON LATEST RADAR
TRENDS AND EXPECTATIONS FOR FURTHER MOVEMENT LATER THIS MORNING.
TEMPS/DEWPOINTS LOOK GOOD...NO REAL ADJUSTMENTS NEEDED AT THIS
TIME.
900 PM UPDATE...UPDATED TO SPEED UP THE ARRIVAL OF THE SHRA ACRS
SRN NY AND NE PA. LATEST HRRR MODEL REFLECTIVITY WAS A TRACK AND
UPDATED HOURLY POPS USING MODEL-RADAR SMART TOOL THRU 9Z. THE HRRR
SHOWS A WIDESPREAD AREA OF LIGHT SHRA SPREADING W-E INTO THE
OVERNIGHT. TEMPERATURES ACRS THE ENTIRE FORECAST AREA WERE ABV
FREEZING. UPPER MOHAWK VALLEY WILL NOT SEE ANY SIGNIFICANT MIXED
PRECIP AS PER LATEST RAP...NAM AND GFS MODEL SOUNDINGS AND ALSO
BNDRY LAYER TEMPS WHICH WERE ARND 40F. LATEST LAPS WET BULB TEMPS
WERE IN THE MID TO UPPER 30S IN ONEIDA CO SO THIS COMBINED WITH
LOW- LEVEL WAA SHUD PRECLUDE ANY CHANCE FOR FZRA AS PRECIP CONTS
TO WORK INTO THESE AREAS. SMALL CHC FOR A LITTLE IP BUT IT WON/T
BE SIGNIFICANT ENUF TO WARRANT MENTION IN GRIDS OR ANY PRODUCTS.
TWEAKED REST OF SHORT TERM GRIDS JUST A LITTLE. PREVIOUS DSCN IS
BELOW FROM 700 PM UPDATE..
700 PM UPDATE...AREA RADARS SHOWG SHRA SPREADING INTO WRN AND
CNTRL NY AND NW PA/NC PA AT THIS TIME. THESE SHRA WERE ASSCTD WITH
AN ACCELERATING SWRLY LOW-LEVEL JET ARND 850 MB WHICH WAS RISING
ISENTROPICALLY INTO NY AND NRN PA THIS EVE. THIS LL JET WAS TIED
TO AN UPPER LEVEL JET STREAK AND ASSCTD UPR WAVE WHICH WAS
PROPAGATING INTO THE GREAT LAKES AND UPR OH VLLY. THIS SHOT OF
ISEN LIFT/WAA WILL SHOOT THRU THE REGION BETWEEN 00Z AND 12Z FRI.
FOLLOWED LATEST HRRR FOR TIMING OF HOURLY POPS IN GRIDS TONIGHT AS
THIS MODEL SEEMS TO HAVE THE BEST HANDLE ON THE PRESENTLY EVOLVING
SHRA.
AFTER THIS FIRST UPR LVL WAVE AND ASSCTD LLJ PASSES E AND
WEAKENS BY 12Z...THERE WILL BE A LULL IN THE PRECIP FOR MUCH OF
FRI. I CAN SEE ISLD TO SCT SHRA ACVTY AT BEST AS WE WAIT FOR THE
NEXT LARGER SCALE UPR LVL WAVE TO MAKE A PUSH TO THE E INTO THE UPR
LAKES AND ONT BY 21Z FRI TO 00Z SAT. THIS WILL BE THE IMPETUS TO
PUSH THE SFC CD FRNT INTO WRN AND CNTRL NY LATE FRIDAY PM. HAVE
TRENDED POPS DOWNWARD FRI AM AND BRING THEM BACK UP BY LATE FRI AS
RESULT TO ACCOUNT FOR THIS LULL IN ACVTY. I MAY FURTHER REFINE THIS
WITH NEXT UPDATE AS WELL.
AS FOR PRECIP TYPE...I SEE ALL RAIN TONIGHT THRU FRI. MODEL
SOUNDING DATA IS QUITE WARM EVEN IN OUR COLDEST LOCATIONS IN THE
UPPER MOHAWK VALLEY AND CATSKILLS WHERE LL TEMPS ARE WELL ABV
FREEZING AT THE ONSET OF THIS EVE/S PRECIP. THE COLDER AIR DOES NOT
ARRIVE UNTIL FRI NGT TO TURN PRECIP TO SNOW BEFORE IT ENDS. SO
JUST PLAIN RAIN ALL DAY FRI.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
330 PM EST UPDATE...
THE CHANCE FOR RAIN SHOWERS WILL INCREASE EARLY FRIDAY MORNING
FROM WEST TO EAST AS THE ATMOSPHERIC COLUMN BECOMES SATURATED AND
STRONG ISENTROPIC LIFT REMAINS OVER NY/PA. THE BEST CHANCE FOR
RAIN SHOWERS FRIDAY MORNING WILL BE OVER THE WESTERN PORTIONS OF
THE CWA WHERE THE GREATEST UPPER LEVEL SUPPORT IS LOCATED. FRIDAY
AFTERNOON THERE WILL BE A BRIEF DECREASE IN ACTIVITY AHEAD OF AN
ADVANCING STRONG COLD FRONT/SFC TROUGH. THE COLD FRONT IS
EXPECTED TO PUSH INTO THE CWA BETWEEN 18 AND 00Z ON SATURDAY.
GUSTY WINDS AND COLDER AIR WILL FOLLOW THE FRONT.THE CHANCE FOR
RAIN SHOWERS WILL INCREASE OVER THE WESTERN PORTIONS OF THE CWA
WITH THE FROPA. VERY DRY AIR WILL QUICKLY FUNNEL INTO THE REGION
BEHIND THE FRONT... THUS THE CHANCE FOR SHOWERS WILL GREATLY
DIMINISH AFTER 03Z. RAIN IS EXPECTED FIRST AND AS THE COLDER AIR
MOVES IN... RAIN MAY TRANSITION OVER TO SNOW. BEHIND THE FROPA
THERE IS A BRIEF WINDOW FOR FREEZING DRIZZLE. THIS WINDOW IS
BETWEEN 06 AND 09Z SATURDAY AS VERY DRY AIR PUSHES IN. CONFIDENCE
IS NOT HIGH ON THIS SCENARIO... AND CLOSE ATTENTION WILL BE PAID
TO FUTURE MODEL RUNS TO DETERMINE IF THIS SITUATION IS
PLAUSIBLE... SO DECIDED TO LEAVE OUT OF CURRENT FORECAST FOR THE
TIME BEING.
EVEN THOUGH 850MB TEMPS WILL FALL TO -8 DEGREES CELSIUS MAKING
SATURDAY QUITE A CHILLY START... THE REAL COLD AIR WILL SURGE
INTO THE REGION LATE SATURDAY AFTERNOON/EARLY EVENING WITH A
SECONDARY COLD FRONT. 850MB TEMPS SUNDAY AFTERNOON WILL BE -19
DEGREES CELSIUS! THIS WILL BE A FIRST REAL TASTE OF COLD AIR OF
THE SEASON WITH TEMPERATURES REACHING THE UPPER TEENS TO LOW 20S
ACROSS THE CWA WITH WINDS SUSTAINED AROUND 15-20 MPH. WIND CHILL
VALUES WILL BE NEAR ZERO.
LE SNOW SHOWERS WILL BE LIKELY WITH RAPID COOLING ACROSS NY.
INITIAL FLOW BEHIND THE FROPA INDICATES A SINGLE BAND DEVELOPING
EAST OF LAKE ONTARIO THEN THE FLOW VEERING AND BECOMING MULTIBAND
ACROSS CENTRAL NY. MADE MINOR ADJUSTMENTS TO PREVIOUS FORECAST...
AND ADVISORY AND POTENTIALLY WARNING AMOUNT SNOWFALLS LOOK TO BE A
POSSIBILITY BY THE LATTER STAGE OF THE WEEKEND AND WILL CONTINUE
TO KEEP A CLOSE EYE ON THIS LE EVENT.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
230 AM UPDATE...
LONG TERM STARTS OUT WITH A NRN STREAM SYSTEM JUST SKIRTING OUR NRN
ZONES. UL FLOW BCMS MORE ZONAL DRG THE DAY MONDAY WITH TEMPS RISING
TO NR FRZG BY THE AFTN (STILL SOME 10F DEGREES BLO NORMAL) BUT WRMR
THAN SUNDAY.
DRG THE DAY TUESDAY, MED RANGE MODELS ARE VRY SLOWLY BEGINNING TO
COME TOGETHER ON DVLPMNT OF EVENTUAL COASTAL LOW. 00Z EC HAS COME
MORE INTO LINE WITH 00Z GFS WITH SRN STREAM WV RESULTING IN SFC
LOPRES DVLPNG ACRS NRN GOM BY 12Z TUESDAY. INDICATIONS ARE THAT NOW
PCPN WL OVRSPRD SRN PORTIONS OF CWA BY 12Z WED WITH PHASING OCCURRING
SOMETIME DRG THE DAY WED. 00Z EC HAS COME IN CLDR WITH H8 TEMPS THAN
PRIOR RUN BUT STILL TOO EARLY AT THIS POINT TO DETERMINE WHAT PTYPE
MAY EVENTUALLY BE. THAT IS ASSUMING THE SFC LOW TRACKS CLOSE ENUF TO
THE COAST TO IMPACT CWA. AT THIS TIME 00Z NAM IS RIGHT ON TARGET
WITH 00Z GFS/CMC AND EURO THRU THE LAST FRAME (12Z MON) WITH SRN
STREAM WV. HV MADE NO CHGS TO GRIDS FOR MID-WEEK AS IT IS TOO FAR
OUT AND WAY TOO EARLY TO JUMP ON ANYTHING AT THIS POINT SO AS TO
AVOID FLIP-FLOPPING ON HOLIDAY FCST.
SYSTEM EXITS OFF TO THE NORTHEAST SOMETIME WED AFTN/WED NGT. THIS
PULLS DOWN MUCH CLDR AIR FOR THANKSGIVING WITH THICKNESSES DROPPING
DOWN INTO THE LOW 500S. THUS WL LWR TEMPS SLIGHTLY FOR WED NGT/THUR.
THIS WL LKLY RESULT IN CONTD LES THRU THE END OF THE LONG TERM.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
06Z UPDATE...
LIGHT VFR SHOWERS MOVING ACROSS NY TERMINALS TONIGHT. MVFR CIGS AT
KAVP EARLY ON WITH LITTLE IN THE WAY OF SHOWERS BUT -SHRA SHOULD
MOVE INTO TERMINAL AFTER 10Z WITH MVFR RESTRICTIONS CONTINUING
THROUGH THE DAY.
FURTHER NORTH ACROSS NY TERMINALS, CONDITIONS EXPECTED TO
DETERIORATE TO MVFR AFTER 08Z OR 09Z DUE TO CIGS. MVFR
RESTRICTIONS EXPECTED THROUGH END OF TAF VALID TIME, THOUGH
POSSIBLE THAT CONDITIONS COULD IMPROVE TO VFR IMMEDIATELY
FOLLOWING COLD FRONTAL PASSAGE CLOSE TO 06Z. POTENTIAL WILL BE
POSSIBLE FOR IFR CIGS TOWARD 12Z THIS MORNING BUT CONFIDENCE IS
STILL TOO LOW AT THIS TIME TO INCLUDE MENTION IN TERMINALS.
COLD FRONT PASSAGE LOOKS TO OCCUR IN THE 00Z-03Z TIMEFRAME WITH
SHOWERS/MVFR CIGS EXPECTED ALONG THE FRONT.
LIGHT S-SE WINDS TONIGHT WILL BECOME SOUTHWESTERLY BTWN 5-10KTS
DURING THE AFTERNOON AHEAD OF CDFNT. FOLLOWING FROPA, WINDS QUICKLY
SHIFT AROUND TO THE NW WITH SUSTAINED 10-15KTS WITH GUSTS AROUND
20KTS.
OUTLOOK...
SAT...PRIMARILY VFR.
SAT NGT AND SUN...RESTRICTIONS LIKELY FROM LAKE EFFECT
SHSN...ESPECIALLY CENTRAL NY TERMINALS.
SUN NIGHT AND MON...MOSTLY VFR.
MON NIGHT/TUE...SOME RESTRICTIONS PSBL IN SCTD -SHSN.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...CMG
SHORT TERM...CMG/KAH
LONG TERM...PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
111 AM EST FRI NOV 22 2013
.SYNOPSIS...
WIDELY SCATTERED SHOWERS THIS MORNING WILL TAPPER OFF BY EARLY
AFTERNOON IN ADVANCE OF A COLD FRONT THAT WILL MOVE THROUGH THE
AREA LATER THIS EVENING. AS THIS FRONT CROSS THE AREA...EXPECT
SHOWERS TO REDEVELOP WITH RAINFALL THEN COMING TO AN END SHORTLY
AFTER MIDNIGHT. MOSTLY DRY CONDITIONS ON SATURDAY WILL QUICKLY
GIVE WAY TO DEVELOPING SNOW SHOWERS BY AFTERNOON AND EVENING AS A
STRONG ARCTIC COLD FRONT MOVES THROUGH THE AREA. AS THE COLDEST
AIRMASS OF THE SEASON DESCENDS UPON THE REGION...EXPECT DEVELOPING
LAKE EFFECT SNOWS SOUTHEAST OF LAKE ONTARIO. SNOW WILL INCREASE IN
INTENSITY SATURDAY NIGHT WITH HEAVY ACCUMULATIONS POSSIBLE FOR
PORTIONS OF CENTRAL NEW YORK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1 AM UPDATE...
RAIN SHOWERS CONTINUING TO DEVELOP ACROSS THE REGION EARLY THIS
MORNING AS WARM AIR ADVECTION IN ADVANCE OF AN APPROACHING WARM
FRONT COMBINED WITH THE PASSAGE OF A WEAK SHORTWAVE IN WEST
SOUTHWEST FLOW ALOFT. HAVE INCREASED POPS BASED ON LATEST RADAR
TRENDS AND EXPECTATIONS FOR FURTHER MOVEMENT LATER THIS MORNING.
TEMPS/DEWPOINTS LOOK GOOD...NO REAL ADJUSTMENTS NEEDED AT THIS
TIME.
900 PM UPDATE...UPDATED TO SPEED UP THE ARRIVAL OF THE SHRA ACRS
SRN NY AND NE PA. LATEST HRRR MODEL REFLECTIVITY WAS A TRACK AND
UPDATED HOURLY POPS USING MODEL-RADAR SMART TOOL THRU 9Z. THE HRRR
SHOWS A WIDESPREAD AREA OF LIGHT SHRA SPREADING W-E INTO THE
OVERNIGHT. TEMPERATURES ACRS THE ENTIRE FORECAST AREA WERE ABV
FREEZING. UPPER MOHAWK VALLEY WILL NOT SEE ANY SIGNIFICANT MIXED
PRECIP AS PER LATEST RAP...NAM AND GFS MODEL SOUNDINGS AND ALSO
BNDRY LAYER TEMPS WHICH WERE ARND 40F. LATEST LAPS WET BULB TEMPS
WERE IN THE MID TO UPPER 30S IN ONEIDA CO SO THIS COMBINED WITH
LOW- LEVEL WAA SHUD PRECLUDE ANY CHANCE FOR FZRA AS PRECIP CONTS
TO WORK INTO THESE AREAS. SMALL CHC FOR A LITTLE IP BUT IT WON/T
BE SIGNIFICANT ENUF TO WARRANT MENTION IN GRIDS OR ANY PRODUCTS.
TWEAKED REST OF SHORT TERM GRIDS JUST A LITTLE. PREVIOUS DSCN IS
BELOW FROM 700 PM UPDATE..
700 PM UPDATE...AREA RADARS SHOWG SHRA SPREADING INTO WRN AND
CNTRL NY AND NW PA/NC PA AT THIS TIME. THESE SHRA WERE ASSCTD WITH
AN ACCELERATING SWRLY LOW-LEVEL JET ARND 850 MB WHICH WAS RISING
ISENTROPICALLY INTO NY AND NRN PA THIS EVE. THIS LL JET WAS TIED
TO AN UPPER LEVEL JET STREAK AND ASSCTD UPR WAVE WHICH WAS
PROPAGATING INTO THE GREAT LAKES AND UPR OH VLLY. THIS SHOT OF
ISEN LIFT/WAA WILL SHOOT THRU THE REGION BETWEEN 00Z AND 12Z FRI.
FOLLOWED LATEST HRRR FOR TIMING OF HOURLY POPS IN GRIDS TONIGHT AS
THIS MODEL SEEMS TO HAVE THE BEST HANDLE ON THE PRESENTLY EVOLVING
SHRA.
AFTER THIS FIRST UPR LVL WAVE AND ASSCTD LLJ PASSES E AND
WEAKENS BY 12Z...THERE WILL BE A LULL IN THE PRECIP FOR MUCH OF
FRI. I CAN SEE ISLD TO SCT SHRA ACVTY AT BEST AS WE WAIT FOR THE
NEXT LARGER SCALE UPR LVL WAVE TO MAKE A PUSH TO THE E INTO THE UPR
LAKES AND ONT BY 21Z FRI TO 00Z SAT. THIS WILL BE THE IMPETUS TO
PUSH THE SFC CD FRNT INTO WRN AND CNTRL NY LATE FRIDAY PM. HAVE
TRENDED POPS DOWNWARD FRI AM AND BRING THEM BACK UP BY LATE FRI AS
RESULT TO ACCOUNT FOR THIS LULL IN ACVTY. I MAY FURTHER REFINE THIS
WITH NEXT UPDATE AS WELL.
AS FOR PRECIP TYPE...I SEE ALL RAIN TONIGHT THRU FRI. MODEL
SOUNDING DATA IS QUITE WARM EVEN IN OUR COLDEST LOCATIONS IN THE
UPPER MOHAWK VALLEY AND CATSKILLS WHERE LL TEMPS ARE WELL ABV
FREEZING AT THE ONSET OF THIS EVE/S PRECIP. THE COLDER AIR DOES NOT
ARRIVE UNTIL FRI NGT TO TURN PRECIP TO SNOW BEFORE IT ENDS. SO
JUST PLAIN RAIN ALL DAY FRI.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
330 PM EST UPDATE...
THE CHANCE FOR RAIN SHOWERS WILL INCREASE EARLY FRIDAY MORNING
FROM WEST TO EAST AS THE ATMOSPHERIC COLUMN BECOMES SATURATED AND
STRONG ISENTROPIC LIFT REMAINS OVER NY/PA. THE BEST CHANCE FOR
RAIN SHOWERS FRIDAY MORNING WILL BE OVER THE WESTERN PORTIONS OF
THE CWA WHERE THE GREATEST UPPER LEVEL SUPPORT IS LOCATED. FRIDAY
AFTERNOON THERE WILL BE A BRIEF DECREASE IN ACTIVITY AHEAD OF AN
ADVANCING STRONG COLD FRONT/SFC TROUGH. THE COLD FRONT IS
EXPECTED TO PUSH INTO THE CWA BETWEEN 18 AND 00Z ON SATURDAY.
GUSTY WINDS AND COLDER AIR WILL FOLLOW THE FRONT.THE CHANCE FOR
RAIN SHOWERS WILL INCREASE OVER THE WESTERN PORTIONS OF THE CWA
WITH THE FROPA. VERY DRY AIR WILL QUICKLY FUNNEL INTO THE REGION
BEHIND THE FRONT... THUS THE CHANCE FOR SHOWERS WILL GREATLY
DIMINISH AFTER 03Z. RAIN IS EXPECTED FIRST AND AS THE COLDER AIR
MOVES IN... RAIN MAY TRANSITION OVER TO SNOW. BEHIND THE FROPA
THERE IS A BRIEF WINDOW FOR FREEZING DRIZZLE. THIS WINDOW IS
BETWEEN 06 AND 09Z SATURDAY AS VERY DRY AIR PUSHES IN. CONFIDENCE
IS NOT HIGH ON THIS SCENARIO... AND CLOSE ATTENTION WILL BE PAID
TO FUTURE MODEL RUNS TO DETERMINE IF THIS SITUATION IS
PLAUSIBLE... SO DECIDED TO LEAVE OUT OF CURRENT FORECAST FOR THE
TIME BEING.
EVEN THOUGH 850MB TEMPS WILL FALL TO -8 DEGREES CELSIUS MAKING
SATURDAY QUITE A CHILLY START... THE REAL COLD AIR WILL SURGE
INTO THE REGION LATE SATURDAY AFTERNOON/EARLY EVENING WITH A
SECONDARY COLD FRONT. 850MB TEMPS SUNDAY AFTERNOON WILL BE -19
DEGREES CELSIUS! THIS WILL BE A FIRST REAL TASTE OF COLD AIR OF
THE SEASON WITH TEMPERATURES REACHING THE UPPER TEENS TO LOW 20S
ACROSS THE CWA WITH WINDS SUSTAINED AROUND 15-20 MPH. WIND CHILL
VALUES WILL BE NEAR ZERO.
LE SNOW SHOWERS WILL BE LIKELY WITH RAPID COOLING ACROSS NY.
INITIAL FLOW BEHIND THE FROPA INDICATES A SINGLE BAND DEVELOPING
EAST OF LAKE ONTARIO THEN THE FLOW VEERING AND BECOMING MULTIBAND
ACROSS CENTRAL NY. MADE MINOR ADJUSTMENTS TO PREVIOUS FORECAST...
AND ADVISORY AND POTENTIALLY WARNING AMOUNT SNOWFALLS LOOK TO BE A
POSSIBILITY BY THE LATTER STAGE OF THE WEEKEND AND WILL CONTINUE
TO KEEP A CLOSE EYE ON THIS LE EVENT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
EXTENDED PERIOD WILL FEATURE AN UPPER LEVEL TROF ACROSS THE
NORTHEAST WHICH WILL RESULT IN A CONTINUATION OF MUCH COOLER THAN
NORMAL TEMPERATURES. SUNDAY NIGHT THE ONGOING LAKE EFFECT SNOW
SHOWERS WILL GRADUALLY DIMINISH AS IT LIFTS NORTH ACROSS THE
NORTHERN CWA. MONDAY LOOKS PRIMARILY DRY AS SFC LOW PRES MOVES INTO
EASTERN CANADA AND THE ASSOCIATED WARM FRONT BRINGS JUST A SLIGHT
CHC OF SNOW SHOWERS TO THE NRN CWA. MONDAY NIGHT THROUGH WEDNESDAY
CONTINUED WITH CHC POPS FOR SNOW SHOWERS AS A NORTHERN STREAM SYSTEM
CONTINUES TRACKING THROUGH EASTERN CANADA AND DRAGS A TRAILING COLD
FRONT THROUGH THE REGION TUE NIGHT. BEHIND THIS FEATURE MORE COLD
AIR AND NORTHWEST FLOW IS EXPECTED WITH SCATTERED SNOW SHOWERS
ESPECIALLY SOUTHEAST OF LAKE ONTARIO.
LATEST ECMWF NOW SHOWS MORE PHASING WITH NRN/SRN STREAM TUE NIGHT
AND WED WITH A COASTAL SYSTEM BRUSHING THE REGION. ITS ALSO WARMER
INDICATING THE POTENTIAL FOR RAIN OVER THE E/SE PTN OF THE FA. THE
GFS CONTINUES TO SHOW SYSTEM PASSING WELL SOUTH OF THE AREA AND NOT
AFFECTING CENTRAL NY/NE PA. FOLLOWED WPC GUIDANCE WHICH KEEPS SYSTEM
SOUTHEAST OF FA AND POPS ONLY IN THE CHC CATEGORY.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
06Z UPDATE...
LIGHT VFR SHOWERS MOVING ACROSS NY TERMINALS TONIGHT. MVFR CIGS AT
KAVP EARLY ON WITH LITTLE IN THE WAY OF SHOWERS BUT -SHRA SHOULD
MOVE INTO TERMINAL AFTER 10Z WITH MVFR RESTRICTIONS CONTINUING
THROUGH THE DAY.
FURTHER NORTH ACROSS NY TERMINALS, CONDITIONS EXPECTED TO
DETERIORATE TO MVFR AFTER 08Z OR 09Z DUE TO CIGS. MVFR
RESTRICTIONS EXPECTED THROUGH END OF TAF VALID TIME, THOUGH
POSSIBLE THAT CONDITIONS COULD IMPROVE TO VFR IMMEDIATELY
FOLLOWING COLD FRONTAL PASSAGE CLOSE TO 06Z. POTENTIAL WILL BE
POSSIBLE FOR IFR CIGS TOWARD 12Z THIS MORNING BUT CONFIDENCE IS
STILL TOO LOW AT THIS TIME TO INCLUDE MENTION IN TERMINALS.
COLD FRONT PASSAGE LOOKS TO OCCUR IN THE 00Z-03Z TIMEFRAME WITH
SHOWERS/MVFR CIGS EXPECTED ALONG THE FRONT.
LIGHT S-SE WINDS TONIGHT WILL BECOME SOUTHWESTERLY BTWN 5-10KTS
DURING THE AFTERNOON AHEAD OF CDFNT. FOLLOWING FROPA, WINDS QUICKLY
SHIFT AROUND TO THE NW WITH SUSTAINED 10-15KTS WITH GUSTS AROUND
20KTS.
OUTLOOK...
SAT...PRIMARILY VFR.
SAT NGT AND SUN...RESTRICTIONS LIKELY FROM LAKE EFFECT
SHSN...ESPECIALLY CENTRAL NY TERMINALS.
SUN NIGHT AND MON...MOSTLY VFR.
MON NIGHT/TUE...SOME RESTRICTIONS PSBL IN SCTD -SHSN.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...CMG
SHORT TERM...CMG/KAH
LONG TERM...PVN/RRM
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1248 AM EST FRI NOV 22 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTH THROUGH THE AREA TONIGHT AND EARLY
FRIDAY AND BRING RAIN SHOWERS WITH IT. A COLD FRONT WILL SWEEP
THROUGH THE AREA LATER FRIDAY CHANGING ANY RAIN SHOWERS OVER TO
LIGHT SNOW SHOWERS OR FLURRIES FRIDAY NIGHT. A STRONGER COLDER FRONT
WILL SURGE ACROSS THE REGION SATURDAY NIGHT BRINGING ADDITIONAL
SNOW SHOWERS AND FLURRIES WITH UNSEASONABLY COLD AIR TO THE REGION
FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH TODAY/...
900 PM UPDATE...UPDATED TO SPEED UP THE ARRIVAL OF THE SHRA ACRS
SRN NY AND NE PA. LATEST HRRR MODEL REFLECTIVITY WAS A TRACK AND
UPDATED HOURLY POPS USING MODEL-RADAR SMART TOOL THRU 9Z. THE HRRR
SHOWS A WIDESPREAD AREA OF LIGHT SHRA SPREADING W-E INTO THE
OVERNIGHT. TEMPERATURES ACRS THE ENTIRE FORECAST AREA WERE ABV
FREEZING. UPPER MOHAWK VALLEY WILL NOT SEE ANY SIGNIFICANT MIXED
PRECIP AS PER LATEST RAP...NAM AND GFS MODEL SOUNDINGS AND ALSO BNDRY
LAYER TEMPS WHICH WERE ARND 40F. LATEST LAPS WET BULB TEMPS WERE
IN THE MID TO UPPER 30S IN ONEIDA CO SO THIS COMBINED WITH LOW-
LEVEL WAA SHUD PRECLUDE ANY CHANCE FOR FZRA AS PRECIP CONTS TO
WORK INTO THESE AREAS. SMALL CHC FOR A LITTLE IP BUT IT WON/T BE
SIGNIFICANT ENUF TO WARRANT MENTION IN GRIDS OR ANY PRODUCTS.
TWEAKED REST OF SHORT TERM GRIDS JUST A LITTLE.
PREVIOUS DSCN IS BELOW FROM 700 PM UPDATE..
700 PM UPDATE...AREA RADARS SHOWG SHRA SPREADING INTO WRN AND
CNTRL NY AND NW PA/NC PA AT THIS TIME. THESE SHRA WERE ASSCTD WITH
AN ACCELERATING SWRLY LOW-LEVEL JET ARND 850 MB WHICH WAS RISING
ISENTROPICALLY INTO NY AND NRN PA THIS EVE. THIS LL JET WAS TIED
TO AN UPPER LEVEL JET STREAK AND ASSCTD UPR WAVE WHICH WAS
PROPAGATING INTO THE GREAT LAKES AND UPR OH VLLY. THIS SHOT OF
ISEN LIFT/WAA WILL SHOOT THRU THE REGION BETWEEN 00Z AND 12Z FRI.
FOLLOWED LATEST HRRR FOR TIMING OF HOURLY POPS IN GRIDS TONIGHT AS
THIS MODEL SEEMS TO HAVE THE BEST HANDLE ON THE PRESENTLY EVOLVING
SHRA.
AFTER THIS FIRST UPR LVL WAVE AND ASSCTD LLJ PASSES E AND
WEAKENS BY 12Z...THERE WILL BE A LULL IN THE PRECIP FOR MUCH OF
FRI. I CAN SEE ISLD TO SCT SHRA ACVTY AT BEST AS WE WAIT FOR THE
NEXT LARGER SCALE UPR LVL WAVE TO MAKE A PUSH TO THE E INTO THE UPR
LAKES AND ONT BY 21Z FRI TO 00Z SAT. THIS WILL BE THE IMPETUS TO
PUSH THE SFC CD FRNT INTO WRN AND CNTRL NY LATE FRIDAY PM. HAVE
TRENDED POPS DOWNWARD FRI AM AND BRING THEM BACK UP BY LATE FRI AS
RESULT TO ACCOUNT FOR THIS LULL IN ACVTY. I MAY FURTHER REFINE THIS
WITH NEXT UPDATE AS WELL.
AS FOR PRECIP TYPE...I SEE ALL RAIN TONIGHT THRU FRI. MODEL
SOUNDING DATA IS QUITE WARM EVEN IN OUR COLDEST LOCATIONS IN THE
UPPER MOHAWK VALLEY AND CATSKILLS WHERE LL TEMPS ARE WELL ABV
FREEZING AT THE ONSET OF THIS EVE/S PRECIP. THE COLDER AIR DOES NOT
ARRIVE UNTIL FRI NGT TO TURN PRECIP TO SNOW BEFORE IT ENDS. SO
JUST PLAIN RAIN ALL DAY FRI.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
330 PM EST UPDATE...
THE CHANCE FOR RAIN SHOWERS WILL INCREASE EARLY FRIDAY MORNING
FROM WEST TO EAST AS THE ATMOSPHERIC COLUMN BECOMES SATURATED AND
STRONG ISENTROPIC LIFT REMAINS OVER NY/PA. THE BEST CHANCE FOR
RAIN SHOWERS FRIDAY MORNING WILL BE OVER THE WESTERN PORTIONS OF
THE CWA WHERE THE GREATEST UPPER LEVEL SUPPORT IS LOCATED. FRIDAY
AFTERNOON THERE WILL BE A BRIEF DECREASE IN ACTIVITY AHEAD OF AN
ADVANCING STRONG COLD FRONT/SFC TROUGH. THE COLD FRONT IS
EXPECTED TO PUSH INTO THE CWA BETWEEN 18 AND 00Z ON SATURDAY.
GUSTY WINDS AND COLDER AIR WILL FOLLOW THE FRONT.THE CHANCE FOR
RAIN SHOWERS WILL INCREASE OVER THE WESTERN PORTIONS OF THE CWA
WITH THE FROPA. VERY DRY AIR WILL QUICKLY FUNNEL INTO THE REGION
BEHIND THE FRONT... THUS THE CHANCE FOR SHOWERS WILL GREATLY
DIMINISH AFTER 03Z. RAIN IS EXPECTED FIRST AND AS THE COLDER AIR
MOVES IN... RAIN MAY TRANSITION OVER TO SNOW. BEHIND THE FROPA
THERE IS A BRIEF WINDOW FOR FREEZING DRIZZLE. THIS WINDOW IS
BETWEEN 06 AND 09Z SATURDAY AS VERY DRY AIR PUSHES IN. CONFIDENCE
IS NOT HIGH ON THIS SCENARIO... AND CLOSE ATTENTION WILL BE PAID
TO FUTURE MODEL RUNS TO DETERMINE IF THIS SITUATION IS
PLAUSIBLE... SO DECIDED TO LEAVE OUT OF CURRENT FORECAST FOR THE
TIME BEING.
EVEN THOUGH 850MB TEMPS WILL FALL TO -8 DEGREES CELSIUS MAKING
SATURDAY QUITE A CHILLY START... THE REAL COLD AIR WILL SURGE
INTO THE REGION LATE SATURDAY AFTERNOON/EARLY EVENING WITH A
SECONDARY COLD FRONT. 850MB TEMPS SUNDAY AFTERNOON WILL BE -19
DEGREES CELSIUS! THIS WILL BE A FIRST REAL TASTE OF COLD AIR OF
THE SEASON WITH TEMPERATURES REACHING THE UPPER TEENS TO LOW 20S
ACROSS THE CWA WITH WINDS SUSTAINED AROUND 15-20 MPH. WIND CHILL
VALUES WILL BE NEAR ZERO.
LE SNOW SHOWERS WILL BE LIKELY WITH RAPID COOLING ACROSS NY.
INITIAL FLOW BEHIND THE FROPA INDICATES A SINGLE BAND DEVELOPING
EAST OF LAKE ONTARIO THEN THE FLOW VEERING AND BECOMING MULTIBAND
ACROSS CENTRAL NY. MADE MINOR ADJUSTMENTS TO PREVIOUS FORECAST...
AND ADVISORY AND POTENTIALLY WARNING AMOUNT SNOWFALLS LOOK TO BE A
POSSIBILITY BY THE LATTER STAGE OF THE WEEKEND AND WILL CONTINUE
TO KEEP A CLOSE EYE ON THIS LE EVENT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
EXTENDED PERIOD WILL FEATURE AN UPPER LEVEL TROF ACROSS THE
NORTHEAST WHICH WILL RESULT IN A CONTINUATION OF MUCH COOLER THAN
NORMAL TEMPERATURES. SUNDAY NIGHT THE ONGOING LAKE EFFECT SNOW
SHOWERS WILL GRADUALLY DIMINISH AS IT LIFTS NORTH ACROSS THE
NORTHERN CWA. MONDAY LOOKS PRIMARILY DRY AS SFC LOW PRES MOVES INTO
EASTERN CANADA AND THE ASSOCIATED WARM FRONT BRINGS JUST A SLIGHT
CHC OF SNOW SHOWERS TO THE NRN CWA. MONDAY NIGHT THROUGH WEDNESDAY
CONTINUED WITH CHC POPS FOR SNOW SHOWERS AS A NORTHERN STREAM SYSTEM
CONTINUES TRACKING THROUGH EASTERN CANADA AND DRAGS A TRAILING COLD
FRONT THROUGH THE REGION TUE NIGHT. BEHIND THIS FEATURE MORE COLD
AIR AND NORTHWEST FLOW IS EXPECTED WITH SCATTERED SNOW SHOWERS
ESPECIALLY SOUTHEAST OF LAKE ONTARIO.
LATEST ECMWF NOW SHOWS MORE PHASING WITH NRN/SRN STREAM TUE NIGHT
AND WED WITH A COASTAL SYSTEM BRUSHING THE REGION. ITS ALSO WARMER
INDICATING THE POTENTIAL FOR RAIN OVER THE E/SE PTN OF THE FA. THE
GFS CONTINUES TO SHOW SYSTEM PASSING WELL SOUTH OF THE AREA AND NOT
AFFECTING CENTRAL NY/NE PA. FOLLOWED WPC GUIDANCE WHICH KEEPS SYSTEM
SOUTHEAST OF FA AND POPS ONLY IN THE CHC CATEGORY.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
06Z UPDATE...
LIGHT VFR SHOWERS MOVING ACROSS NY TERMINALS TONIGHT. MVFR CIGS AT
KAVP EARLY ON WITH LITTLE IN THE WAY OF SHOWERS BUT -SHRA SHOULD
MOVE INTO TERMINAL AFTER 10Z WITH MVFR RESTRICTIONS CONTINUING
THROUGH THE DAY.
FURTHER NORTH ACROSS NY TERMINALS, CONDITIONS EXPECTED TO
DETERIORATE TO MVFR AFTER 08Z OR 09Z DUE TO CIGS. MVFR
RESTRICTIONS EXPECTED THROUGH END OF TAF VALID TIME, THOUGH
POSSIBLE THAT CONDITIONS COULD IMPROVE TO VFR IMMEDIATELY
FOLLOWING COLD FRONTAL PASSAGE CLOSE TO 06Z. POTENTIAL WILL BE
POSSIBLE FOR IFR CIGS TOWARD 12Z THIS MORNING BUT CONFIDENCE IS
STILL TOO LOW AT THIS TIME TO INCLUDE MENTION IN TERMINALS.
COLD FRONT PASSAGE LOOKS TO OCCUR IN THE 00Z-03Z TIMEFRAME WITH
SHOWERS/MVFR CIGS EXPECTED ALONG THE FRONT.
LIGHT S-SE WINDS TONIGHT WILL BECOME SOUTHWESTERLY BTWN 5-10KTS
DURING THE AFTERNOON AHEAD OF CDFNT. FOLLOWING FROPA, WINDS QUICKLY
SHIFT AROUND TO THE NW WITH SUSTAINED 10-15KTS WITH GUSTS AROUND
20KTS.
OUTLOOK...
SAT...PRIMARILY VFR.
SAT NGT AND SUN...RESTRICTIONS LIKELY FROM LAKE EFFECT
SHSN...ESPECIALLY CENTRAL NY TERMINALS.
SUN NIGHT AND MON...MOSTLY VFR.
MON NIGHT/TUE...SOME RESTRICTIONS PSBL IN SCTD -SHSN.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...KAH
LONG TERM...PVN/RRM
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1238 AM EST FRI NOV 22 2013
.SYNOPSIS...
A COASTAL TROUGH WILL BRING PERIODS OF ATLANTIC CLOUD COVER ONSHORE
THROUGH FRIDAY. A COLD FRONT WILL CROSS THE AREA SATURDAY FOLLOWED
BY A BRIEF PERIOD OF VERY COLD AIR. A SIGNIFICANT RAIN EVENT IS
BECOMING MORE LIKELY TOWARD THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 1230 AM FRIDAY...QUITE A FEW CHANGES TO THE FORECAST ARE
NEEDED AT THE CURRENT TIME. FIRST OF ALL...SKIES ARE OVERCAST IN A
COMBINATION OF LOW AND MID LEVEL CLOUDS AND SHOULD REMAIN THAT WAY
THROUGH DAYBREAK FOR ALL BUT PERHAPS WILLIAMSBURG AND GEORGETOWN
COUNTIES IN SOUTH CAROLINA. THIS WILL PREVENT ANYTHING APPROACHING
IDEAL RADIATIONAL COOLING AND I HAVE THEREFORE RAISED LOW
TEMPERATURES BY SEVERAL DEGREES. ISENTROPIC LIFT OCCURRING WITHIN
THE LAYER OF ALTOCUMULUS ACROSS THE SANDHILLS REGION IS PRODUCING
LIGHT SHOWERS BLOSSOMING ON RADAR NEAR BENNETTSVILLE AND LUMBERTON.
MODELS REVEAL THIS IS ASSOCIATED WITH AN AREA OF ISENTROPIC LIFT
ALONG THE 295-300K SURFACES WHICH SHOULD GRADUALLY DIMINISH OVER THE
NEXT 3 HOURS. I HAVE PLACED A 20-30 POP HERE THROUGH 09Z.
ELSEWHERE...VERY LOW CEILINGS THAT HAVE DEVELOPED ACROSS THE
"DOWNEAST" PORTION OF EXTREME EASTERN NC ARE ADVECTING WESTWARD WITH
THE ONSHORE WINDS. CEILINGS IN WILMINGTON...JACKSONVILLE AND
KENANSVILLE ARE DOWN TO 200-300 FT. THIS LOW CLOUD DECK MAY PUSH
WEST AND UNDERCUT THE MID-LEVEL CLOUDS FARTHER INLAND. CLOUD DEPTH
IS PROBABLY TOO THIN FOR DRIZZLE ACCORDING TO THE WELL-INITIALIZED
00Z NAM.
PREVIOUS DISCUSSION FROM 1030 PM FOLLOWS...
LATEST HRRR AND SREF PROBABILITY FOR MEASURABLE PRECIP...KEEP THE
BEST CHANCES...ALBEIT SMALL...OVER THE ADJACENT ATL WATERS MAINLY
JUST OFFSHORE AND ALONG A WEAK INVERTED SFC TROF. LOOKING AT VARIOUS
MODEL TIME HEIGHT DISPLAYS ACROSS THE FA...YIELDS AN ABUNDANCE OF
LOW LEVEL MOISTURE THAT WILL BE CONDUCIVE FOR STRATOCU AND STRATUS
BELOW 1K FT. THEREFORE...SKY CONDITIONS WILL REMAIN MOSTLY OR
VARIABLY CLOUDY FOR THE REMAINDER OF THE OVERNIGHT. THIS WILL PLACE
THE FOG POTENTIAL ON THE LOWER/LESSER SIDE OF OCCURRENCE BUT
NEVERTHELESS ENOUGH TO CONTINUE WITH PATCHY AND/OR AREAS OF FOG.
LATEST NAM AND GFS MODEL MOS GUIDANCE ARE QUITE SIMILAR WITH THEIR
LOWS FOR TONIGHT AND SEE NO REASON TO DETOUR FROM THEIR OVERALL
NUMBERS. THE ONLY CHANGE WILL ALONG THE IMMEDIATE BEACHES WHERE SFC
DEWPOINTS ARE RUNNING HIGHER THAN GUIDANCE WHICH WILL KEEP THE MINS
A FEW DEGREES HIGHER OVERNIGHT.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
AS OF 230 PM THURSDAY...HIGH PRESSURE REMAINS ACROSS THE AREA ON
FRIDAY WITH A WEAK TROUGHINESS EVIDENT JUST OFF THE COAST. THE
FORMER WILL SPONSOR UNSEASONABLY WARM TEMPERATURES WHILE THE LATTER
MAKES IT TOUGH TO RULE OUT THE OCCASIONAL SPRINKLE. HAVE NOT LIMITED
THE VERY LOW POPS TO JUST THE COAST HOWEVER AS SOME GUIDANCE SHOWING
VERY GOOD SIGNAL FOR SHALLOW CONVECTION FURTHER INLAND ALONG A LATE
SEASON SEA BREEZE. COLD FRONT WILL BE APPROACHING FROM THE NORTHWEST
AND THIS WILL HELP TO KEEP TEMPS QUITE MILD FRIDAY NIGHT WITH LOWS
ONLY DIPPING INTO THE MID OR UPPER 50S. THE CHANCE FOR MAINLY
NON-MEASURABLE PRECIP WILL CONTINUE. ARCTIC FRONT NOW A LITTLE
FASTER AND LOOKS TO BLAST THROUGH FAR NW ZONES BY MORNING AND AROUND
MIDDAY FURTHER SOUTH AND EAST. THIS HAS CAST SOME SERIOUS DOUBTS ON
SATURDAY`S HIGH TEMPERATURE FORECAST. ALTHOUGH THE MORNING HOURS
SHOULD FEATURE A RAPID JUMP OFF OF NIGHTTIME LOWS THE PASSAGE OF THE
FRONT WILL OBVIOUSLY SHARPLY REVERSE THAT TREND. HOW SOON THIS
HAPPENS WILL HAVE A GREAT IMPACT ON WHAT TEMPS ARE ACHIEVED...BEFORE
THEY START TO TUMBLE EARLIER THAN NORMAL BEHIND THE BOUNDARY. HAVE
TRIMMED HIGHS SOME FOR THIS REASON. A LOT OF TIMES THE STRONG CAA
LAGS A BIT BEHIND THE BOUNDARY HERE IN THE EASTERN CAROLINAS AS THE
PASSAGE ACROSS THE MOUNTAINS FRACTURES THE BOUNDARY IN THE VERTICAL.
THIS WILL ALSO PROBABLY YIELD QUITE A SPREAD IN THE ACTUAL HIGHS
ACHIEVED FROM NW TO SE AND HAVE ADJUSTED FCST ACCORDINGLY.
PREFRONTAL MOISTURE ADVECTION IS LACKLUSTER AND DYNAMICS ALOFT STAY
WELL REMOVED TO OUR NORTH. RAINFALL CHANCES APPEAR TO ONLY WARRANT
CHANCE AND QPF SHOULD BE QUITE MINIMAL.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 230 PM THURSDAY...PERIOD BEGINS QUIET AND COLD WITH HIGH
PRESSURE BUILDING IN FROM THE NORTHWEST. STRONG COLD ADVECTION SUN
WILL HELP KEEP HIGHS FROM REACHING 50 IN MOST PLACES. PROXIMITY TO
SURFACE RIDGE AXIS SUN NIGHT WILL ALLOW SOME RADIATIONAL EFFECT. HOW
STRONG REMAINS IN QUESTION BUT LOWS WILL FALL INTO THE MID 20S.
SURFACE RIDGE AXIS SLOWLY SHIFTS OFFSHORE MON BUT RETURN FLOW NEVER
REALLY DEVELOPS WITH WEAK WEDGE SETTING UP. MON AND MON NIGHT WILL
AGAIN BE COOL AND DRY WITH TEMPERATURES REMAINING BELOW CLIMO. LATE
MON INTO MON NIGHT INCREASING MOISTURE ALOFT AHEAD OF GULF COAST
SYSTEM LEADS TO INCREASING AND SLOWLY LOWERING CLOUD DECK.
SOUTHERN STREAM SYSTEM EMERGING FROM THE SOUTHWEST EARLY NEXT WEEK
WILL BE PROVIDE THE NEXT BATCH OF SIGNIFICANT WEATHER FOR THE
SOUTHEAST DURING THE MIDDLE OF NEXT WEEK. AS THE UPPER LOW EMERGES
OVER THE NORTHERN GULF OF MEXICO IT WILL START TO OPEN UP. THE
LOCATION AND TIMING OF THIS FEATURE REMAINS IN QUESTION AND IS THE
SOURCE OF CONSIDERABLE FORECAST UNCERTAINTY. AT THE SAME TIME A WEAK
COASTAL TROUGH STARTS TO DEVELOP OFF THE CAROLINA COAST. INCREASING
MOISTURE AHEAD OF THE 5H LOW AND ISENTROPIC LIFT ARE LIKELY TO LEAD
TO LIGHT RAIN INCREASING OVER THE AREA TUE AND TUE NIGHT. HAVE
INCREASED POP TO LIKELY. ALSO HAVE QUESTIONS ABOUT HOW THE MID LEVEL
AND SURFACE PATTERN EVOLVE TUE INTO WED. CANNOT RULE OUT A COASTAL
LOW DEVELOPING ALONG THE TROUGH...SOMETHING THE GFS HAS BEEN
SHOWING. THE ECMWF ON THE OTHER HAND MOVES THE TROUGH INLAND WITH
THE SURFACE LOW TRACKING WEST OF THE AREA INSTEAD OF JUMPING OFF THE
COAST. WHILE EITHER SOLUTION IS LIKELY TO RESULT IN PRECIP FALLING
IN THE AREA THE DIFFERENCE LIES IN THE TIMING AND TEMPERATURE
POTENTIAL. GIVEN THE UNCERTAINTY WILL NOT MAKE A LOT OF CHANGES TO
THE EXTENDED. HAVE MAINTAINED POP INTO WED NIGHT WITH HIGHS BELOW
CLIMO AND LOWS NEAR CLIMO.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...LOW LEVEL EAST WIND IS BRINGING PLENTY OF ATLANTIC
MOISTURE ONSHORE. IN SE NORTH CAROLINA A LAYER OF VERY LOW STRATUS
(200-300 FOOT CEILINGS) HAS DEVELOPED OVER ILM EXTENDING NORTH
TOWARD NEW BERN AND MOREHEAD CITY. LINEAR EXTRAPOLATION SHOWS THIS
CLOUD DECK COULD GET INTO LBT AFTER 09Z...AND MAY EVEN CLIP CRE FOR
A FEW HOURS BEFORE WINDS JUST ABOVE THE SURFACE VEER MORE
SOUTHEASTERLY AROUND 10Z. A HEFTY MID LEVEL DECK OF ALTOCUMULUS ALOFT
SHOULD PREVENT ANYTHING APPROACHING IDEAL RADIATIONAL COOLING
THROUGH DAYBREAK. THIS IS NOT TO SAY LOW VSBY IN FOG AND/OR
ADDITIONAL LOW CEILINGS WON`T OCCUR...JUST THAT THE PROBABILITY IS
MUCH LOWER THAN IF WE HAD CLEAR MID LEVELS. A BATCH OF LIGHT SHOWERS
IN THE LBT VCNTY IS FALLING FROM THE MID LEVEL ALTOCUMULUS CLOUDS
AND SHOULD NOT SUBSTANTIALLY AFFECT VSBY.
AFTER DAYBREAK FLIGHT CATEGORY SHOULD IMPROVE TO VFR BY 13-15Z AS
SURFACE WINDS VEER TO THE SOUTH AND SOUTHWEST.
EXTENDED OUTLOOK...CHANCE OF SHOWERS/MVFR CIGS ON SATURDAY WITH A
COLD FRONT. VFR SUNDAY AND MONDAY. EXPECT GUSTY NORTH WINDS ON
SUNDAY BEHIND THE FRONT. INCREASING CHANCE FOR SHOWERS ON TUESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 AM FRIDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE
FORECAST. PREVIOUS DISCUSSION FROM 1030 PM FOLLOWS...
THE BORDERLINE SCA FOR THE NC COASTAL WATERS CONTINUES THROUGH 3
AM...MAINLY DUE TO SIGNIFICANT SEAS STAYING RIGHT AT SCA THRESHOLDS
ACROSS THE OUTER WATERS OFF CAPE FEAR. THE BASIC TREND FOR THE
OVERNIGHT PERIOD WILL LIE WITH THE BROAD CENTER OF HIGH PRESSURE
DROPPING SOUTH AND EVENTUALLY PARKING ITSELF ACROSS THE CAROLINAS
AND ADJACENT ATL WATERS BY DAYTIME FRIDAY. THE WEAK INVERTED SFC
TROF THIS EVENING WILL AID THE ENE-E WIND DIRECTION. DEPENDING ON
HOW THE BROAD CENTER OF HIGH PRESSURE ORIENTS ITSELF ACROSS THE
FORECAST AREA...ONSHORE WINDS SHOULD PREVAIL WITH DIMINISHED SPEEDS
IE. 10-15 KT OVERNIGHT DUE TO A RELAXING SFC PG. SIGNIFICANT SEAS
WILL HOLD IN THE 3 TO 6 FOOT RANGE OVERNIGHT...WITH THE 6 FOOTERS
PRIMARILY OCCURRING ACROSS THE OUTER WATERS OFF CAPE FEAR INTO THE
PRE-DAWN HOURS. DOMINANT PERIODS WILL RANGE BETWEEN 8 AND 10 SECONDS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 PM THURSDAY...THE PERIOD STARTS OFF RATHER QUIET WITH HIGH
PRESSURE CENTERED OVER GA AND WEAKENING. MEANWHILE A WEAK
TROUGHINESS WILL BE FOUND ALONG THE COAST. WINDS SHOULD BE CAPPED AT
JUST 10 KT OUT OF THE SOUTH. SOME VEERING ON FRIDAY NIGHT IS IN
RESPONSE TO BOTH THE FURTHER WEAKENING OF THE HIGH AS WELL AS THE
APPROACH OF A STRONG COLD FRONT. THIS BOUNDARY WILL PUSH ACROSS THE
WATERS SATURDAY EVENING LEADING TO A VERY SHARP VEER. THE INCREASE
IN WIND SPEEDS HOWEVER WILL BE MORE GRADUAL. ANY HEADLINE OR
ADVISORY CONDITIONS...IF THEY OCCUR...APPEAR SLATED FOR THE LONG
TERM.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 230 PM THURSDAY...STRONG COLD ADVECTION AND PINCHED GRADIENT
ON SUN WILL RESULT IN NORTH TO NORTHWEST FLOW APPROACHING 25 KT AT
TIMES SUN INTO SUN NIGHT. HEADLINES WILL LIKELY BE REQUIRED THOUGH
SEAS MAY END UP REMAINING UNDER 6 FT GIVEN THE OFFSHORE TRAJECTORY.
COLD ADVECTION WEAKENS LATE SUN NIGHT AND GRADIENT RELAXES WITH
WINDS VEERING TO NORTHEAST AND DECREASING AS RIDGE AXIS MOVES CLOSER
TO THE COAST. LIGHT NORTHEAST FLOW WILL CONTINUE MON INTO TUE WITH
SURFACE HIGH RIDGING DOWN THE COAST. SPEEDS WILL DROP UNDER 10 KT BY
AFTERNOON WITH SEAS DROPPING TO 2 TO 3 FT. WEAK COASTAL TROUGH
DEVELOPS EARLY TUE WITH WINDS BECOMING VARIABLE ALONG THE TROUGH
AXIS. SOUTHEAST FLOW DEVELOPS OVER THE WATERS LATER TUE AND STARTS
TO INCREASE AS THE TROUGH MOVES CLOSER TO THE COAST. INCREASE IN
WINDS COMBINED WITH ONSHORE TRAJECTORY PUSHES SEAS TO 3 TO 4 FT BY
THE END OF THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 3 AM EST FRIDAY FOR AMZ250-252.
&&
$$
SYNOPSIS...MBB
NEAR TERM...DCH/TRA
SHORT TERM...MBB
LONG TERM...III
AVIATION...SGL/TRA
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1150 PM CST THU NOV 21 2013
.AVIATION...
HAVING TO MAKE SOME TWEAKS TO THE FCST BASED ON CURRENT TRENDS OF
THE COLD FRONT. HAVE LEANED HEAVILY ON THE HRRR FOR THESE TAFS AS
ALL THE OTHERS HAVE KEPT WITH THE MUCH SLOWER MOVEMENT. AS SUCH A
WET/COLD/BREEZY FCST DAY WILL PREVAIL FRI. 41
&&
.PREV DISCUSSION... /ISSUED 931 PM CST THU NOV 21 2013/
FRONT IS MAKING GOOD SWD PROGRESS AND EXPECT IT TO BE ALONG A
LINE FROM ROUGHLY COLUMBUS-TRINITY BY 6 AM AND ALONG THE BEACHES
BY NOON. ONGOING TEMPERATURES AND TIMING MATCH UP PRETTY WELL WITH
THE RAW NAM12 DATA AND ADJUSTED SHORT TERM GRIDS AND GAVE THAT
MODELS SOME PRETTY HEAVY WEIGHT.
SHRA/TSTMS CONTINUE DEVELOPING IN N TX AHEAD OF THE FRONT. SVR WX
THREAT FAIRLY MINIMAL BUT THERE HAVE BEEN SOME ISOLATED STRONG/SEVERE
CELLS UP THERE AND ANTICIPATE SIMILAR HERE AHEAD OF THE BOUNDARY.
SOME HEAVY DOWNPOURS MORE LIKELY WITH RESIDENT PW`S AROUND 1.7"
BEING ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL FOR THIS TIME OF
YEAR. NEXT SHIFT MAY BE ABLE TO REDUCE MID/LATE AFTN POPS AS
INCOMING 0Z GUIDANCE ISN`T QUITE AS BULLISH WITH OVERRUNNING
PRECIP ACCUMULATIONS BUT WILL LEAVE THAT DECISION TO THEM AFTER
SEEING THE FULL MODEL SUITE. SHOULD BE A CLOUDY COLD BREEZY NASTY
AFTERNOON REGARDLESS. 47
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 56 56 38 45 36 / 70 70 50 40 20
HOUSTON (IAH) 72 74 43 51 41 / 50 70 60 50 20
GALVESTON (GLS) 71 73 50 55 45 / 40 70 60 50 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...99
AVIATION/MARINE...41
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
1119 PM CST THU NOV 21 2013
.DISCUSSION...
SEE AVIATION FOR THE 06Z TAF DISCUSSION.
&&
.AVIATION...
AT 05Z THE COLD FRONT WAS MOVING SOUTH ACROSS BURNET AND LLANO
COUNTIES. THE LATEST RUC13 MODEL GUIDANCE HAS THE BEST HANDLE ON
THE MOVEMENT OF THE COLD FRONT. BASED ON CURRENT TRENDS AND MODEL
GUIDANCE HAVE MOVED UP THE FROPA 1 HOUR AT THE I-35 TERMINALS.
MVFR CONDITIONS WILL PREVAIL IN ADVANCE OF THE FROPA LOWERING TO
IFR A FEW HOURS AFTER FROPA. THERE WILL BE A BRIEF IMPROVEMENT
TO MVFR FRIDAY AFTERNOON BEFORE LOWERING TO IFR ONCE AGAIN FRIDAY
EVENING. SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE FROPA WITH
POST-FRONTAL ELEVATED SHOWERS TRANSITIONING TO LIGHT RAIN AND
DRIZZLE ON FRIDAY. POST-FRONTAL SFC WINDS WILL BE NORTHERLY AT 15
TO 25 KTS WITH GUSTS OF 30 KTS.
&&
.PREV DISCUSSION... /ISSUED 856 PM CST THU NOV 21 2013/
UPDATE...
ARCTIC FRONT ALONG A PECOS TO SAN ANGELO TO STEPHENVILLE LINE WAS
SURGING SOUTH AHEAD OF SCHEDULE. NOW EXPECT FRONT WILL ENTER THE
NORTHERN HILL COUNTRY AROUND MIDNIGHT...MOVE ACROSS THE AUSTIN AND
SAN ANTONIO AREAS BETWEEN 2 AND 4 AM AND EXIT SOUTH CENTRAL TEXAS
BY SUNRISE. AS A RESULT...HAVE LOWERED TEMPERATURES AND DEW POINTS
FOR OVERNIGHT INTO FRIDAY ALONG WITH AN EARLIER ONSET OF MODERATE
GUSTY NORTHERLY WINDS. ALSO...HAVE REMOVED MENTION OF THUNDER FOR
FRIDAY AS INSTABILITY IS GONE AND CHANGED SHOWERS TO LIGHT RAIN.
REMAINDER OF SOUTH CENTRAL TEXAS FORECAST IS ON TRACK. 18Z MODEL
SUITE AND NEW 00Z NAM CONTINUE TO SUGGEST A MIX OF LIGHT SLEET AND
RAIN DURING THE OVERNIGHT INTO EARLY MORNING HOURS FRIDAY NIGHT
THROUGH MONDAY MORNING.
PREV DISCUSSION... /ISSUED 535 PM CST THU NOV 21 2013/
DISCUSSION...
SEE AVIATION FOR THE 00Z TAF DISCUSSION.
AVIATION...
AT 23Z THE COLD FRONT WAS MOVING SOUTHWARD ACROSS NORTH TEXAS. THE
FRONT WILL MOVE INTO THE HILL COUNTRY AFTER MIDNIGHT...REACHING
THE TEXAS COAST BY EARLY AFTERNOON ON FRIDAY. THE TIMING OF THE
FROPA AND ASSOCIATED WIND SHIFT AT THE TERMINALS WILL BE BASED ON
A BLEND OF THE LATEST RUC AND LAMP GUIDANCE. NUMEROUS SHOWERS AND
ISOLATED THUNDERSTORMS WILL OCCUR IN THE VICINITY OF THE FRONTAL
BOUNDARY AS IT INTERACTS WITH THE MOISTURE LADEN GULF AIRMASS.
POST-FRONTAL PCPN WILL BE MAINLY ELEVATED SHOWERS.
I-35 TERMINALS...VFR CONDITIONS WILL LOWER TO MVFR BETWEEN 02Z AND
04Z...LOWERING TO IFR BY 15Z. THE BEST CHANCE FOR CONVECTION TO
IMPACT THE TAFS SITES WILL BE A FEW HOURS BEFORE AND DURING THE
FROPA. WINDS WILL SHIFT TO THE NORTH AT 12 TO 15 KTS WITH GUSTS OF
25 KTS. FROPA AT KAUS...08Z...KSAT AND KSSF AROUND 10Z.
THE KDRT TERMINAL...VFR CONDITIONS WILL LOWER TO MVFR BY 01Z...IFR
BY 08Z...IMPROVING TO MVFR BY 22Z. ORGANIZED CONVECTION IS EXPECTED
TO STAY EAST OF THE TERMINAL. WINDS WILL SHIFT TO THE NORTH AT 15
TO 20 KTS WITH GUSTS OF 25 KTS FOLLOWING THE FROPA. FROPA IS EXPECTED
AROUND 08Z.
PREV DISCUSSION... /ISSUED 318 PM CST THU NOV 21 2013/
SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...
THE STRONG COLD FRONT HAS REACHED THE PANHANDLE. THE COLD AIR
ADVECTION IN THE WAKE OF THE FRONT IS CLEARLY EVIDENT...SFC OBS
INDICATE TEMPERATURES PLUMMETING BY 20 DEGREES OR MORE IN THE WAKE
OF THE FROPA. THE FRONT WILL CONTINUE TO PUSH SOUTHWARD ACROSS THE
STATE TONIGHT AND WILL REACH THE HILL COUNTRY BEFORE SUNRISE. THE
FRONT WILL CONTINUE TO QUICKLY MOVE THROUGH THE AREA...AND IS
EXPECTED TO REACH OUR SOUTHERN COUNTIES BEFORE NOON. DUE TO THE
TIMING OF THE FROPA...CALENDAR DAY "HIGH" TEMPERATURES FOR FRIDAY
WILL OCCUR DURING THE OVERNIGHT HOURS TONIGHT. TEMPERATURES DURING
THE DAY ON FRIDAY WILL FALL BEHIND THE FRONT...WITH AFTERNOON
TEMPERATURES REMAINING IN THE 40S (UPPER 30S HILL COUNTRY). STRONG
NORTHERLY WINDS OF 15 TO 25 MPH WILL LEAD TO WIND CHILLS IN THE
LOW TO MID 30S ACROSS MUCH OF THE AREA...AND INTO THE MID/UPPER
20S ACROSS THE HILL COUNTRY.
CHANCES FOR RAIN WILL INCREASE TONIGHT AND PERSIST THROUGH THE
WEEKEND. ISOLATED THUNDERSTORMS ARE POSSIBLE THIS EVENING THROUGH
FRIDAY. TEMPERATURES FRIDAY NIGHT WILL FALL INTO THE MID-30S ACROSS
THE HILL COUNTRY...BRINGING THE POTENTIAL FOR ISOLATED LIGHT SLEET
TO MIX-IN WITH THE COLD RAIN. NO SLEET ACCUMULATIONS ARE EXPECTED.
THE LINGERING MOISTURE/CHANCES FOR RAIN/CLOUD COVER WILL OTHERWISE
KEEP LOW TEMPERATURES IN THE UPPER 30S TO LOW 40S FRIDAY NIGHT.
LONG TERM (SATURDAY THROUGH THURSDAY)...
A DEEP UPPER LOW PARKED OVER THE SOUTHWESTERN U.S. WILL KEEP CLOUDY
SKIES AND GOOD CHANCES FOR RAIN OVER THE WEEKEND AND INTO EARLY
NEXT WEEK. HIGH TEMPERATURES WILL REMAIN UNSEASONABLY COLD. THERE
IS A RENEWED CHANCE FOR ISOLATED LIGHT SLEET TO MIX-IN WITH THE
RAIN ACROSS THE HILL COUNTRY SATURDAY NIGHT/SUNDAY MORNING AND
AGAIN SUNDAY NIGHT/MONDAY MORNING. SURFACE TEMPERATURES ARE
EXPECTED TO REMAIN ABOVE FREEZING AND THEREFORE SLEET
ACCUMULATIONS ARE AGAIN NOT EXPECTED.
THE UPPER LOW WILL EJECT EASTWARD ON MONDAY. CHANCES FOR RAIN WILL
BEGIN TO DECREASE MONDAY NIGHT AND WILL END LATE TUESDAY AS THE
UPPER LOW MOVES TO OUR EAST. SKIES WILL BEGIN TO CLEAR FROM THE
WEST LATE TUESDAY...WITH SUNSHINE FINALLY RETURNING ON WEDNESDAY.
HIGH TEMPERATURES WILL BEGIN TO WARM...BUT MOSTLY CLEAR SKIES
DURING THE OVERNIGHT HOURS WILL ALLOW LOW TEMPERATURES TO FALL
INTO THE 30S ACROSS MUCH OF THE CWA. SPOTTY FREEZING TEMPERATURES
ARE POSSIBLE THANKSGIVING MORNING.
CLIMATE...
RECORD COLD HIGH TEMPERATURES FOR NOV 23 THROUGH 24:
23RD 24TH
AUSTIN CAMP MABRY...40/1937...42/1982
AUSTIN BERGSTROM....43/1957...44/1972
SAN ANTONIO.........41/1932...44/1982
DEL RIO.............40/1957...42/1918
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 43 45 39 43 38 / 90 70 70 60 60
AUSTIN BERGSTROM INTL AIRPORT 45 46 38 45 40 / 80 70 70 60 60
NEW BRAUNFELS MUNI AIRPORT 47 51 37 44 38 / 80 70 70 60 60
BURNET MUNI AIRPORT 39 39 34 41 34 / 90 70 70 60 60
DEL RIO INTL AIRPORT 46 52 38 42 36 / 50 60 60 50 50
GEORGETOWN MUNI AIRPORT 40 40 34 42 34 / 90 70 70 60 60
HONDO MUNI AIRPORT 49 53 40 46 39 / 70 70 70 60 60
SAN MARCOS MUNI AIRPORT 46 48 38 43 38 / 80 70 70 60 60
LA GRANGE - FAYETTE REGIONAL 51 56 43 48 43 / 70 70 70 60 60
SAN ANTONIO INTL AIRPORT 48 54 40 45 39 / 70 70 70 60 60
STINSON MUNI AIRPORT 52 56 42 48 42 / 70 70 70 60 60
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...13
SYNOPTIC/GRIDS...04
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
1036 PM CST THU NOV 21 2013
.DISCUSSION...PLEASE SEE THE AVIATION DISCUSSION BELOW FOR MORE
DETAILS.
&&
.AVIATION...WIDESPREAD MVFR STRATUS WL PREVAIL GIVEN THE VERY
MOIST BOUNDARY LAYER AND ONSHORE FLOW EXPECTED TNT. IFR
CONDITIONS WL BE POSSIBLE FOR PRIMARILY THE VCT AREA. THE 18Z AND
00Z GUIDANCE HAVE CAUGHT ON TO A FASTER MOVEMENT WITH THE STRONG COLD
FRONT CURRENTLY MOVING INTO THE NORTHERN HILL COUNTRY. THIS IS IN
LINE WITH THE OBSERVED FAST SWD MOVEMENT WITH MSAS SHOWING 5-8 MB
PRESSURE RISES OVER THE PAST SVRL HOURS BEHIND THE FRONT. WL THUS
GO WITH FROPA SLIGHTLY FASTER THAN THE PRIOR TAF FCST. WL GO WITH
FROPA AROUND 12Z FOR VCT AND AROUND 15Z ELSEWHERE. SUFFICIENT
MOISTURE AND LIFTING ALONG AND BEHIND THE FRONT WL PRODUCE
SCATTERED TO NUMEROUS SHOWERS. CAPES BETWEEN 1500 AND 2000 J/KG
WITH A WEAK CAP AND MODERATE LIFT WL BE ENOUGH FOR THUNDERSTORMS
ALONG AND BEHIND THE FRONT. AFTER THE INITIAL AREA OF PCPN
ASSOCIATED WITH THE FRONT...THE PCPN WL TEND TO TAPER OFF FROM
NORTH TO SOUTH BY THE AFTN/EVE AS THE FORCING DIMINISHES.
&&
.PREV DISCUSSION... /ISSUED 923 PM CST THU NOV 21 2013/
DISCUSSION...ARCTIC COLD FRONT...JUST SOUTH OF A LINE FROM
DALLAS TO SAN ANGELO AT 03Z...CONTINUES TO SURGE SOUTH AT AROUND
25 MPH. LATEST MSAS ANALYSIS SHOWS 3 HOURLY PRESSURE RISES OF
6 TO 8 MBS OVER THE BIG COUNTRY AND CROSS TIMBERS REGIONS IN
NORTHWEST TEXAS. BELIEVE 00Z RUC/RAPID REFRESH MODEL ALONG WITH
THE LATEST SREF AND 3KM TEXAS TECH MODEL HAVE A BETTER HANDLE
ON THE PROGRESSION OF THIS STRONG SHALLOW ARCTIC AIR MASS. WENT
WITH 00Z RUC WITH BRINGING IN THE FRONT SHORTLY AFTER 12Z INTO
THE NORTHERN COUNTIES AND FRONTAL PASSAGE THROUGH THE SOUTHERN
COASTAL BEND BY 18Z FRIDAY AND THROUGH THE COASTAL WATERS BY 21Z.
STRONG COLD AIR ADVECTION BEHIND THE FRONT WILL BRING DOWN THE
TEMPERATURES INTO THE 40S ACROSS THE INLAND AREAS BY AFTERNOON
AND LOWER 50S ALONG THE COAST. LOWERED THE MINIMUM TEMPS JUST
SLIGHTLY FOR FRIDAY NIGHT. NO ADJUSTMENTS WERE MADE TO THE
CURRENT WEATHER/POPS CONFIGURATION FOR FRIDAY.
PREV DISCUSSION... /ISSUED 534 PM CST THU NOV 21 2013/
DISCUSSION...PLEASE SEE THE AVIATION DISCUSSION BELOW FOR MORE
DETAILS.
AVIATION...MVFR STRATUS WL QUICKLY DEVELOP OVER THE NEXT FEW
HOURS AS A VERY MOIST BOUNDARY LAYER ALONG WITH SUBTLE COOLING WL
PROMOTE RAPID STRATUS DEVELOPMENT. A FEW ISOLATED STREAMER SHRAS
WL BE POSSIBLE TNT...MAINLY THE VCT AREA. PATCHY IFR CONDITIONS WL
ALSO BE POSSIBLE MAINLY THE VCT AREA AFTER 04Z. THE MAIN STORY WL
BE THE SLIGHTLY FASTER TIMING OF THE STRONG COLD FRONT WHICH IS
CURRENTLY MOVING RAPIDLY THROUGH NORTH TEXAS. THE 18Z MODELS HAVE
PICKED UP ON THIS FASTER MOVEMENT AND WL THUS LEAN TWDS THIS
QUICKER FROPA TIMING. AS A RESULT...WL SHOW FROPA AROUND 13Z FOR
VCT AND AROUND 16Z ELSEWHERE. SUFFICIENT MOISTURE AND LIFTING
ALONG AND BEHIND THE FRONT WL PRODUCE SCATTERED TO NUMEROUS
SHOWERS WITH EMBEDDED THUNDERSTORMS ACROSS MOST OF SOUTH TX ON
FRIDAY. THE PCPN WL TEND TO TAPER OFF FROM NORTH TO SOUTH BY THE
AFTN.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 74 75 41 49 46 / 30 70 60 70 40
VICTORIA 65 69 40 51 44 / 40 70 60 60 40
LAREDO 73 73 41 48 43 / 20 70 60 40 40
ALICE 74 75 41 48 44 / 30 70 60 60 40
ROCKPORT 72 72 46 51 47 / 30 70 60 70 40
COTULLA 65 66 40 45 42 / 50 70 60 40 30
KINGSVILLE 74 77 41 48 45 / 20 70 60 60 40
NAVY CORPUS 73 73 46 51 48 / 20 70 60 70 40
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
MB/80...AVIATION
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
801 AM CST FRI NOV 22 2013
.DISCUSSION...
335 AM CST
THE MAIN FORECAST CONCERNS THIS MORNING WILL FOCUS ON THE ARCTIC AIR
EXPECTED TO SPILL IN ACROSS THE AREA ON SATURDAY AND SUNDAY.
THE FIRST OF TWO COLD FRONTS HAS PUSHED ACROSS THE AREA OVERNIGHT.
HOWEVER...LIGHT PRECIPITATION CONTINUES ON THE BACK SIDE OF THIS
FRONT IN ASSOCIATION WITH SOME FORCING FOR ASCENT FROM SEVERAL WEAK
MID LEVEL SHORT WAVE DISTURBANCES...WHICH ARE BEING EJECTED EASTWARD
ACROSS THE MIDDLE MISSISSIPPI VALLEY WITHIN A RAPIDLY STRENGTHENING
120+ KT WESTERLY UPPER LEVEL JET. THIS DISTURBED MID LEVEL FLOW...IN
COMBINATION WITH SOME ENHANCED LOWER LEVEL FRONTOGENESIS ASSOCIATED
WITH THE BAROCLINIC ZONE DROPPING ACROSS THE AREA WILL LIKELY
CONTINUE TO PRODUCE SOME LIGHT PRECIP ACROSS THE AREA THROUGH MID TO
LATE MORNING.
IT APPEARS THAT COLDER AIR WILL WILL ARRIVE IN TIME TO LEAD TO A
CHANGE OVER TO SOME LIGHT SNOW EARLY THIS MORNING BEFORE THE PRECIP
ENDS. THE BEST CHANCES FOR THIS TO OCCUR LOOKS TO REMAIN MAINLY
ALONG AND NORTHEAST OF A LINE FROM NEAR PONTIAC NORTHEASTWARD
THROUGH CHICAGO. REGIONAL RADAR IMAGERY ACROSS EASTERN IOWA...WHERE
SNOW IS NOW FALLING INDICATES THAT THE PRECIP IS LIGHT...WITH ONLY A
FEW SLIGHTLY HEAVIER POCKETS OF SNOW EMBEDDED. I EXPECT THESE TRENDS
TO SHIFT OVER NORTHERN ILLINOIS THROUGH THE MORNING. SNOW SHOULD
BEGIN FALLING IN OR NEAR ROCKFORD AND MUCH OF NORTH CENTRAL ILLINOIS
BY AROUND 11 TO 12 UTC...AND IN THE CHICAGO AREA AFTER 13- 14 UTC.
PLACES TO THE SOUTHEAST ACROSS NORTHWESTERN INDIANA AND EAST CENTRAL
ILLINOIS WILL LIKELY REMAIN IN THE FORM OF RAIN. OVERALL...THIS
SHOULD NOT BE A BIG DEAL AS THE SNOW WILL REMAIN LIGHT AND
TEMPERATURES WILL LIKELY HOVER AROUND OR JUST ABOVE FREEZING THROUGH
THE MORNING. THEREFORE...NO REAL ACCUMULATION IS EXPECTED.
THINGS WILL DRY OUT BY THIS AFTERNOON...THEN ATTENTION TURNS TO THE
NEXT ARCTIC FRONT...WHICH SHOULD DROP ACROSS THE AREA EARLY ON
SATURDAY. THIS FRONT WILL MARK A QUICK SHIFT TO MUCH MUCH COLDER AIR
AS AN IMPRESSIVE 1048+ MB HIGH BUILDS SOUTHWARD ACROSS THE DAKOTAS.
TEMPERATURES AT 850 MB ARE PROGGED TO DROP DOWN AROUND -18 CELSIUS
ACROSS FAR NORTHERN ILLINOIS BY SATURDAY AFTERNOON VIA SOME STIFF
NORTHWESTERLY WINDS. OVERALL THIS WILL RESULT IN AN UGLY DAY...WITH
TEMPERATURES LIKELY REMAINING NEARLY STEADY OR EVEN DROPPING IN THE
20S THROUGH THE DAY. THIS COMBINED WITH A NORTHWEST WINDS OF 15 TO
25 MPH AND GUSTS UP TO 35 MPH WILL CREATE WIND CHILL VALUES IN THE
UPPER SINGLE DIGITS NORTH TO THE MID TO UPPER TEENS SOUTH. THE RAPID
TRANSITION TO THIS COLDER AIRMASS COULD EVEN SQUEEZE OUT A FEW
FLURRIES EARLY SATURDAY...MAKING IT FEEL MORE LIKE
MID-WINTER.
THESE VERY COLD TEMPERATURES WILL ALSO SET UP VERY FAVORABLE
THERMODYNAMIC CONDITIONS OVER LAKE MICHIGAN TO RESULT IN LAKE EFFECT
SNOW SATURDAY AND SATURDAY NIGHT. EQUILIBRIUM HEIGHTS ARE EXPECTED TO
TOP 12,000 FEET...AS LAKE TO 850 MB TEMPERATURE DEVIATIONS CLIMB IN
EXCESS OF 22 DEGREES CELSIUS. THIS SHOULD ULTIMATELY LEAD TO THE
POSSIBILITIES FOR SOME DECENT LAKE EFFECT SNOW. AT THIS TIME IT
APPEARS THAT THE NORTHWEST FLOW OVER LAKE MICHIGAN WILL FAVOR AREAS
ACROSS THE EASTERN SHORES...LIKELY EAST OF PORTER COUNTY INDIANA AS
WELL. I DID...HOWEVER...LEAVE SOME SLIGHT CHANCE MENTIONS FOR SNOW
SHOWERS FOR FAR NORTHEASTERN PORTER LATE SATURDAY AND SATURDAY
NIGHT.
SATURDAY NIGHT INTO SUNDAY MORNING APPEARS TO BE ONE OF THE COLDEST
NIGHTS THUS FAR THIS SEASON. GUIDANCE CONTINUES TO BUILD THE STRONG
1040 MB HIGH RIGHT ACROSS THE MID MISSISSIPPI VALLEY BY DAYBREAK
SUNDAY. ALTHOUGH THIS LOOKS TO RESULT IN ENOUGH OF A GRADIENT TO
KEEP SOME NORTHERLY WINDS GOING ACROSS NORTHEASTERN ILLINOIS AND
NORTHWESTERN INDIANA INTO SUNDAY MORNING...IT APPEARS THAT
TEMPERATURES WILL LIKELY FALL INTO THE SINGLE DIGITS IN SOME OF THE
COLDER SPOTS OF THE FOX VALLEY AND PORTIONS OF NORTH CENTRAL
ILLINOIS. IT APPEARS THAT EVEN THE CITY OF CHICAGO WILL DROP INTO
THE MID TEENS SUNDAY MORNING.
THIS COLD START TO SUNDAY WILL LIKELY ONLY ALLOW TEMPS TO REBOUND
INTO THE MIDDLE TO PERHAPS UPPER 20S SUNDAY AFTERNOON. THE SURFACE
FLOW SHOULD TURN SOUTHWESTERLY SUNDAY AFTERNOON AS THE SURFACE HIGH
CONTINUES TO SHIFT SOUTHEASTWARD TOWARDS THE TENNESSEE VALLEY. WIND
SPEEDS WILL LIKELY INCREASE SUNDAY NIGHT INTO MONDAY...SO THIS
SHOULD NOT ALLOW TEMPS TO DROP OFF MUCH SUNDAY NIGHT.
THE EXTENDED PERIOD APPEARS TO BE MAINLY DRY ACROSS THE REGION.
HOWEVER...THERE COULD BE SOME LIGHT SNOW ACROSS THE AREA ON MONDAY
AS GOOD ISENTROPIC ASCENT SETS UP ACROSS THE AREA IN ASSOCIATION
WITH A CLIPPER SYSTEM EXPECTED TO PUSH ACROSS SOUTHERN ONTARIO. I AM
NOT TO EXCITED ABOUT THIS CHANCE AS THE BEST DYNAMICS SHOULD REMAIN
NORTH OF THE AREA...BUT I HAVE LEFT SLIGHT CHANCE MENTIONS IN THE
FORECAST.
ANOTHER REINFORCING SHOT OF COLD AIR LOOKS TO DROP DOWN IN THE WAKE
OF THIS CLIPPER SYSTEM FOR MID WEEK...SO NO BIG IMPROVEMENTS IN
TEMPERATURES ARE EXPECTED. WITH THIS NEXT COLD PUSH...ANOTHER
SURFACE HIGH WILL LIKELY SHIFT SOUTHEAST SOMEWHERE ACROSS THE GREAT
LAKES ON OR AROUND THANKSGIVING. THE NORTHERLY FLOW THIS SETS UP
COULD PRODUCE SOME MORE LAKE EFFECT SNOW...AND IF THE FLOW TURNS
NORTHEAST AS THE GUIDANCE SUGGESTS BY THURSDAY...SOME OF THIS LAKE
EFFECT SNOW COULD AFFECT PORTIONS OF NORTHEASTERN ILLINOIS BEFORE IT
FADES. THIS IS STILL FAR OUT...BUT THE OVERALL SET UP FOR GOOD LAKE
EFFECT SNOW MAY NOT BE AS GOOD...ESPECIALLY BY THANKSGIVING...AS IT
APPEARS WARMER MID LEVEL TEMPERATURES MAY TRY TO QUICKLY OVERSPREAD
THE AREA IN RESPONSE TO RISING HEIGHTS ALOFT LATER NEXT WEEK. THIS
COULD ULTIMATELY LIMIT THE HEIGHT OF THE EQUILIBRIUM LEVELS FOR
PARCELS MODIFIED BY LAKE MICHIGAN. THIS WILL NEED TO BE WATCHED.
OTHERWISE IT JUST LOOKS UNSEASONABLY COLD AND DRY ACROSS MUCH OF THE
AREA THROUGH THANKSGIVING.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* NORTHERLY WINDS GUSTING TO AROUND 20 KT THROUGH MID-AFTERNOON.
* MVFR CIGS THROUGH MID-DAY.
* LIGHT RAIN ENDING AROUND 15Z...POSSIBLY BRIEFLY MIXING WITH -SN
BEFORE ENDING.
* NORTHWEST WINDS GUSTING TO 25-30 KT SATURDAY MORNING.
RATZER
//DISCUSSION...UPDATED 12Z...
AN UPPER LEVEL DISTURBANCE PASSING OVER THE AREA EARLY THIS
MORNING WILL CONTINUE LIGHT RAIN THROUGH DAYBREAK BEFORE ENDING
WITHIN AN HOUR OR TWO. WHILE THERE HAS BEEN A MIX WITH LIGHT SNOW
OR PELLETS ACROSS NORTHWEST IL AND EASTERN IA IN THE PAST SEVERAL
HOURS...THE SATURATION LAYER FOR SNOWFLAKES IS QUICKLY DRYING OUT
IN THE WAKE OF THIS DISTURBANCE. SO IF IT OCCURS IT SHOULD BE
LIGHT WITH NO ACCUMULATION. CLOUDS WILL GRADUALLY LIFT AND SCATTER
THROUGH EARLY TO MID AFTERNOON. NORTHERLY WINDS WILL CONTINUE WITH
GUSTS AT OR JUST ABOVE 20 KT THIS MORNING. A SECOND BUT MORE
POTENT COLD FRONT WILL SURGE SOUTHWARD ACROSS THE REGION LATE
TONIGHT INTO EARLY SATURDAY WHICH WILL BRING AN EVEN STRONGER
NORTHWEST WIND FOR SATURDAY MORNING WITH GUSTS IN THE 30 KT
BALLPARK. A SHORT PERIOD OF MVFR CIGS WITH FLURRIES IS POSSIBLE IN
THE IMMEDIATE POST FRONTAL PASSAGE AIRMASS.
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN WIND SPEEDS AND IN THE DIRECTION REMAINING
JUST SLIGHTLY WEST OF DUE NORTH.
* HIGH CONFIDENCE IN CIGS 1000 FT OR HIGHER IMPROVING ABOVE 1500
FT BY MID-MORNING.
* MEDIUM-HIGH CONFIDENCE IN PRECIP ENDING TIME AND LOW CONFIDENCE
IF A BRIEF MIX WITH SNOW WILL OCCUR.
* HIGH CONFIDENCE IN GUSTY NORTHWEST WINDS SATURDAY MORNING.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT-SUNDAY...VFR.
MONDAY...CHC OF -SN AND MVFR.
TUESDAY- WEDNESDAY...VFR.
THURSDAY...SLIGHT CHANCE OF LAKE EFFECT SNOW SHOWERS.
MTF
&&
.MARINE...
204 AM CST
AN ACTIVE LATE AUTUMN/EARLY WINTER PATTERN WILL PREVAIL ACROSS THE
LAKE THROUGH AT LEAST THE FIRST HALF OF NEXT WEEK. A COLD FRONT
WHICH PASSED LATE THURSDAY NIGHT HAS USHERED IN STIFF NORTH TO
NORTHWEST WINDS OVER THE LAKE WHICH WILL CONTINUE THROUGH MIDDAY
BEFORE EASING AND BACKING. WHILE THERE MAY BE A TEMPORARY BREAK IN
SMALL CRAFT ADVISORY CRITERIA TONIGHT...IT IS EXPECTED TO BE
BRIEF...SO HAVE CONTINUED THAT HEADLINE FOR THE IL AND IN
NEARSHORE.
ANOTHER COLD FRONT IS SET TO CROSS THE LAKE LATE TONIGHT WHICH WILL
BRING A PUNCH OF EVEN COLDER AIR. THIS WILL LEAD TO STEEPER LAPSE
RATES AND GREATER TRANSFER OF WIND MOMENTUM. IN RESPONSE...NORTHWEST
GALES ARE EXPECTED TO QUICKLY SPREAD DOWN THE LAKE PRIOR TO DAYBREAK
ON SATURDAY. GALES LOOK DEFINITE...MAYBE A FEW TO EVEN 40 KT. GALES
MAY EVEN BE EXPERIENCED IN NEAR SHORE AREAS OF INDIANA GIVEN THE
GREATER COMPONENT OF ONSHORE WIND DIRECTION AND REALIZED FETCH. AS
FOR FREEZING SPRAY SATURDAY...IT CONTINUES TO LOOK POSSIBLE BUT
MAINLY LIGHT DUE TO TOO WARM OF WATER TEMPERATURES.
A LARGE AND STRONG CANADIAN HIGH WILL MOVE TO THE SOUTH OF THE LAKE
ON SUNDAY AND THE PRESSURE GRADIENT ON ITS BACKSIDE WILL BE ENHANCED
BY LOW PRESSURE RACING ACROSS CANADA ON SUNDAY NIGHT INTO EARLY
MONDAY. THIS WILL AGAIN SET THE STAGE FOR POTENTIAL GALES...THIS
TIME FROM THE SOUTHWEST/WEST. HIGH PRESSURE LOOKS TO SLOWLY BUILD IN
THROUGH THE MIDWEEK TIME FRAME THEN...WITH INCREASING POTENTIAL FOR
LAKE EFFECT SNOWS ON THE CENTRAL...EASTERN...AND SOUTHERN PARTS OF
THE LAKE.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 AM SATURDAY TO 9 PM
SATURDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 9 AM SATURDAY.
GALE WATCH...LMZ744-LMZ745...9 AM SATURDAY TO 9 PM SATURDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 9 PM
SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
[top]
Area Forecast Discussion
National Weather Service Lincoln IL
547 AM CST Fri Nov 22 2013
.DISCUSSION...
ISSUED 220 AM CST Fri Nov 22 2013
The cold front has pushed through much of the forecast area early
this morning...and is about to clear the far southeast as of 2 am.
Some light post-frontal showers continue over the northwest half
of the area, while radar and surface obs showed some fairly
widespread light snow across much of central and eastern Iowa,
back where temperatures are mainly in the 20s. Have been seeing
some dense fog along and just behind the front, but this should
continue to lift as the front moves further east.
Main forecast concern involves the cold weekend weather, and
timing of the ending of the remaining precipitation today.
SHORT TERM...Today through Sunday:
Latest model trends continue to get the area largely dry by
midday. Colder air will make more of a surge later today, and most
areas should see steady or falling afternoon temperatures.
Arctic air mass over central Canada poised to surge southeast
through the Great Lakes this weekend. Brunt of the coldest air
still progged to stay to our north, but 850 mb temperatures drop
to around -14C here, so sub-freezing highs likely. Rather blustery
conditions expected Saturday ahead of strong Canadian high
pressure, but winds will subside on Sunday as the high drifts into
south central Illinois.
LONG TERM...Monday through Thanksgiving Day:
Large cutoff low, currently seen in water vapor imagery centered
near Los Angeles, should finally start to push eastward early next
week, as the deep trough in the northern stream finally pushes
to New England. Next shortwave in the northern stream is looking
to come through mainly dry Monday afternoon/night, as a storm
system develops along the Gulf. Deformation precipitation with
this system progged to reach about as far as the Ohio River as the
storm slowly moves into the Carolinas by midweek. This will
largely keep the Midwest dry from Tuesday through Thanksgiving,
except for some lake effect snow south of Lake Michigan. Second
Arctic surge at mid week is not quite as bitter as the upcoming
cold wave, but highs in the lower to mid 30s will be common for
the pre-Thanksgiving travel rush.
Geelhart
&&
.AVIATION...
ISSUED 545 AM CST Fri Nov 22 2013
Ifr conditions over region in the post frontal area over central
IL. IR satellite and moisture channel depicts minor wave moving
through central IL with debris from the AR pcpn. Very light pcpn
with this wave is gradually moving eastward over eastern CWA.
Expect cigs to only slowly raise til mid morning and then improve.
Drier air finally moves in during afternoon per the HRRR models
and then show increase cigs. The patchy vsbs in fog to improve
early this morning to vfr.
Goetsch
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
620 AM EST FRI NOV 22 2013
.SYNOPSIS...
A WEAK WAVE OF LOW PRESSURE WILL APPROACH TODAY AND CROSS THE AREA
TONIGHT. HIGH PRESSURE WILL BUILD IN FROM THE WEST OVER THE
WEEKEND AS LOW PRESSURE STRENGTHENING IN EASTERN CANADA PULLS ARCTIC
AIR INTO THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
620 AM UPDATE...THERE IS AN AREA OF OVERRUNNING PRECIPITATION
ACROSS CENTRAL AND EASTERN NY STATE INTO WESTERN NEW ENGLAND.
THIS IS ASSOCIATED WITH A WEAK WARM FRONT. THE HRRR HAS A PRETTY
GOOD HANDLE ON THE PRECIP SHIELD AS OF 11Z. THE AREA OF
PRECIPITATION IS EXPECTED TO PASS TO THE SOUTH OF THE AREA THIS
MORNING. FOR OUR CWA THE MAIN SYSTEM STILL LOOKS TO BE FROM LATE
THIS EVENING THROUGH THE EARLY MORNING HOURS SATURDAY. MADE SOME
MINOR ADJUSTMENTS TO THE GRIDS BASED ON THE LATEST CONDITIONS...MAINLY
TO INCREASE THE CLOUD COVER THIS MORNING...BUT OVERALL ONLY SOME
MINOR TWEAKS.
PREVIOUS DISCUSSION...
HIGH PRESSURE CONTINUES TO RETREAT TO THE SOUTH OF THE REGION
EARLY THIS MORNING. LOW PRESSURE IS EXPECTED TO DEEPEN TODAY IN
DIFFLUENT FLOW ALOFT ACROSS QUEBEC WITH THE LOW TO BE WEST OF THE
ST LAWRENCE BY 00Z THIS EVENING. THE LOW WILL CONTINUE TO DEEPEN
TONIGHT AS IT PASSES NORTH OF MAINE. THIS WILL BRING A PERIOD OF
OVERRUNNING ACROSS THE NORTHERN AND WESTERN ZONES. THE BUFKIT
SOUNDINGS FROM BOTH THE NAM AND GFS INDICATE A SMALL LAYER ABOVE
FREEZING DURING THE EVENING BUT WITH MOST OF THE QPF TO BE LATER
IN THE EVENING AND OVERNIGHT ANY SCATTERED RAIN SHOWERS WILL
QUICKLY CHANGE TO SNOW. THE HIGHEST SNOW ACCUMULATION IS EXPECTED
ACROSS THE ST JOHN VALLEY WHERE SNOW ACCUMULATION OF AROUND 3
INCHES IS EXPECTED. AMOUNTS IN THE CARIBOU/PRESQUE ISLE AREAS ARE
EXPECTED TO BE AROUND 2 INCHES...AND THEN DROP OFF TO AROUND 1
INCH IN THE HOULTON AREA...WITH LITTLE/NO SNOW ACCUMULATION SOUTH
OF MILLINOCKET. IT LOOKS TO BE JUST SHY OF AN ADVISORY EVENT IN
THE ST JOHN VALLEY. WITH MOST OF THE SNOW FALLING AT NIGHT AND
HEADING INTO A SATURDAY MORNING WILL NOT HOIST ANY ADVISORIES.
THIS AREA ALSO ALREADY HAD A 3 TO 4 INCH SNOWFALL BACK IN OCTOBER.
THE COLD FRONT ASSOCIATED WITH THE LOW SWEEPS ACROSS THE AREA LATE
TONIGHT WITH A GUSTY NORTHWEST WIND TO KICK IN TOWARD MORNING THAT
MAY CAUSE THE SNOW TO BLOW AROUND SOME IN THE FAR NORTH.
TEMPERATURES TODAY WILL BE A BIT COOLER THAN YESTERDAY DESPITE A
WARMER START TO THE DAY. THERE WILL BE A BIT OF COOLING ALOFT IN
THE WAKE OF THE WEAK SURFACE TROUGH MOVING THROUGH OVERNIGHT. ALSO
AN INCREASE IN CLOUDS THIS AFTERNOON WILL CUT OFF THE HEATING.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
SOME VERY BLUSTERY AND COLD WEATHER IS ON THE WAY FOR THIS WEEKEND.
AN UPPER LEVEL TROUGH MOVING INTO THE AREA COMBINED WITH LOW
PRESSURE IN THE MARITIMES AND A LARGE HIGH BUILDING INTO THE NATIONS
MID SECTION WILL BRING GUSTY NORTHWEST WINDS ON SATURDAY. SOME
FLURRIES WILL BE POSSIBLE IN NORTHERN AND WESTERN AREAS. OTHERWISE
SATURDAY WILL BE PARTLY CLOUDY AND CHILLY WITH HIGHS A COUPLE
DEGREES BELOW FREEZING NORTH TO NEAR 40 DOWNEAST. A WEAK
SHORTWAVE WILL SLIDE SOUTH OF THE REGION SATURDAY NIGHT. THE
GRADIENT WILL THEN TIGHTEN BETWEEN LOW PRESSURE IN EASTERN CANADA
AND THE HIGH BUILDING IN. A STRONG GUSTY NORTHWEST WIND WILL
USHER IN EVEN COLDER AIR ON SUNDAY. HIGHS WILL LIKELY BE IN THE 20S
ACROSS THE ENTIRE REGION AND WIND CHILLS MAY REMAIN IN THE SINGLE
DIGITS ALL DAY OVER MUCH OF THE AREA. MOISTURE POOLED IN THE
UPPER TROUGH WILL LIKELY BRING SNOW SHOWERS AND POSSIBLY SOME SNOW
SQUALLS TO NORTHERN AND WESTERN AREAS ON SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
COLD GUSTY WINDS WILL LIKELY CONTINUE SUNDAY NIGHT WITH LOW PRESSURE
REMAINING IN THE NORTHERN MARITIMES. FLURRIES AND SNOW SHOWERS MAY
CONTINUE ACROSS THE NORTH AND WEST. A SMALL SHORTWAVE RIDGE OF HIGH
PRESSURE WILL THEN MOVE IN ON MONDAY BRINGING A MOSTLY SUNNY DAY. A
NEW SHORTWAVE TROUGH AND WEAK SURFACE LOW MOVING ACROSS SOUTHERN
QUEBEC ON TUESDAY WILL BRING CLOUDS AND A CHANCE FOR A PERIOD OF
LIGHT SNOW OR SNOW SHOWERS TUESDAY, ESPECIALLY ACROSS THE NORTH. OUR
ATTENTION THEN FOCUSES ON A LARGE STORM SYSTEM MOVING THROUGH THE
DEEP SOUTH TUESDAY AND ONTO THE SOUTHEAST COAST TUESDAY NIGHT.
MODELS CONTINUE TO SHOW VARIATION ON THE TRACK OF THIS STORM, BUT
ARE COMING INTO AGREEMENT ON THE POTENTIAL THAT THIS SYSTEM WILL
MOVE UP THE COAST BRINGING A SIGNIFICANT PRECIPITATION EVENT. A
TRACK JUST EAST OF CAPE COD AND INTO THE GULF OF MAINE WOULD BRING
SNOW AND WIND TO NORTHERN AREAS AND SNOW OR SLEET GOING OVER TO
RAIN DOWNEAST. THIS ALL DEPENDS ON THE TIMING OF A NEW TROUGH OF
LOW PRESSURE DIGGING INTO THE PLAINS STATES AS THE SOUTHERN LOW
MOVES ONTO THE EAST COAST. IF THE TROUGH DIGS IN TOO QUICKLY THE
SOUTHERN LOW MAY BE PUSHED OUT TO SEA WHICH IS WHAT EARLIER GFS
MODELS WERE FORECASTING. IF THE TROUGH DIGS IN TOO SLOW THE LOW
MAY TAKE A MORE WESTERN TRACK AND BRING RAIN TO THE ENTIRE REGION
WHICH IS WHAT THE OLD ECMWF HAS BEEN FORECASTING. EITHER WAY,
THERE IS A POTENTIAL FOR A SIGNIFICANT STORM DURING THE MID WEEK
PERIOD AND THOSE WITH TRAVEL PLANS SHOULD STAY TUNED TO FORECAST
UPDATES THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: VFR TODAY AT ALL TERMINALS. CONDITION WILL LOWER TO
IFR/LOW END MVFR IN SNOW TONIGHT AT THE NORTHERN TERMINALS...AND
TO MVFR AT THE SOUTHERN TERMINALS IN RAIN/SNOW SHOWERS.
SHORT TERM: VFR CONDITIONS ARE EXPECTED DOWNEAST OVER THE WEEKEND
WITH MVFR CONDITIONS IN SNOW SHOWERS ACROSS THE NORTH. VFR
CONDITIONS ARE EXPECTED TUESDAY AS A WEAK HIGH MOVES OVER.
CONDITIONS WILL THEN LOWER TO MVFR, AND POSSIBLY IFR ACROSS THE
NORTH ON TUESDAY. VFR CONDITIONS EARLY WEDNESDAY MAY DROP TO IFR
FROM SOUTH TO NORTH AS CLOUDS AND PRECIPITATION MOVE IN.
&&
.MARINE...
NEAR TERM: COLD AIR ADVECTION KICKS IN ALONG THE COASTAL WATERS EARLY
SATURDAY MORNING AND HAVE STARTED A SCA AT 10Z. EXPECT FREQUENT
GUSTS TO 30 KT AND A FEW GUSTS TO AROUND 35 KTS.
SHORT TERM: A GALE MAY BE NEEDED SATURDAY MORNING. GALES WILL THEN
LIKELY BE NEEDED FOR COLD GUSTY NORTHWEST WINDS SUNDAY INTO SUNDAY
NIGHT. WINDS MAY DIMINISH TO SCA VALUES MONDAY INTO EARLY
WEDNESDAY BEFORE GALES RETURN LATE WEDNESDAY INTO WEDNESDAY NIGHT
IN A STORM SYSTEM MOVING UP THE COAST.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 5 AM TO 7 PM EST SATURDAY FOR
ANZ050>052.
&&
$$
NEAR TERM...CB
SHORT TERM...BLOOMER
LONG TERM...BLOOMER
AVIATION...CB/BLOOMER
MARINE...CB/BLOOMER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
644 AM EST FRI NOV 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 444 AM EST FRI NOV 22 2013
BROAD AREA OF LIGHT SNOW ASSOCIATED WITH A COUPLED UPPER
JET...SHORTWAVE ENERGY AND MID-LEVEL Q-VECTOR CONVERGENCE CONTINUES
TO SLIDE EAST EARLY THIS MORNING ACROSS UPPER MICHIGAN AND
WISCONSIN. GENERALLY LIGHT SNOW WITH VISIBILITIES IN MOST LOCATIONS
OF 2 TO 5 MILES. WE SAW FINE FLAKES AT OUR OFFICE MOST OF THE
NIGHT...WHICH HAS BEEN HELPFUL IN REDUCING VISIBILITIES. ONE REPORT
FROM NORTHERN WISCONSIN INDICATED A HALF AN INCH OF SNOW
ACCUMULATION AND OUR OFFICE HAD 0.6 INCH AS OF 1AM. THE SNOW HAS
ALREADY ENDED OVER WESTERN UPPER MICHIGAN (KCMX/KIWD OBS) AND
STARTING TO SEE THE REFLECTIVITIES QUICKLY DIMINISH OVER BARAGA
AND IRON COUNTIES. AS THE UPPER LEVEL FEATURES CONTINUE TO SHIFT
EAST THIS MORNING...EXPECT THE SYNOPTIC SNOWFALL TO QUICKLY
DIMINISH THROUGH MID MORNING.
OVER NORTHERN UPPER MICHIGAN...LOW LEVEL 925-850MB NORTH-NORTHWEST
FLOW (ON KMQT VAD AND RAP ANALYSIS) ACROSS LAKE SUPERIOR...ALONG
WITH 850MB TEMPS OF -7C TO -11C FROM EAST TO WEST HAS LED TO SOME
LAKE ENHANCEMENT EARLY THIS MORNING...WITH THE STRONGEST RETURNS ON
RADAR AND OBS INDICATING THE HEAVIEST SNOW OVER EASTERN
MARQUETTE AND WESTERN ALGER COUNTIES. THIS ENHANCEMENT
WILL ALSO BE DIMINISHING QUICKLY THIS MORNING AS A HIGH PRESSURE
RIDGE FROM NORTHERN MINNESOTA NOSES INTO THE AREA. VERY DRY AIR
ABOVE THE INVERSION AT 920MB ON THE 00Z KINL SOUNDING WILL BE WHAT
IS MOVING INTO THE AREA AND REALLY DIMINISH THE INTENSITY OF THE
LAKE ENHANCEMENT OVER THE NORTH CENTRAL THIS MORNING. THIS WILL ALSO
LEAD TO A DIMINISHING TREND TO THE LAKE EFFECT CLOUDS FROM WEST TO
EAST TODAY AS THE LAKE INDUCED INSTABILITY AND MOISTURE IS PINCHED
BY THAT LOWERING INVERSION FROM THE HIGH PRESSURE RIDGE. EXPECT THE
LAKE CLOUDS TO HANG ON THE LONGEST OVER THE KEWEENAW AND THE EAST
WHERE THE BACKING WINDS WINDS WILL STAY FAVORABLE THE LONGEST. THE
REST OF THE AREA SHOULD SEE SKIES BECOMING PARTLY CLOUDY IF NOT
MOSTLY SUNNY LATE THIS MORNING THROUGH THE AFTERNOON.
FOCUS THEN TURNS TO THE MAIN WEATHER MAKER FOR THE FORECAST
PERIOD...WHICH IS ASSOCIATED WITH A LOW THAT IS CURRENTLY LOCATED
NEAR LAKE WINNIPEG. THIS LOW AND POTENT SHORTWAVE NOTED ON WV
IMAGERY WILL QUICKLY SWEEP SOUTHEAST ACROSS LAKE SUPERIOR LATE THIS
AFTERNOON AND EVENING. STRONG CONVERGENCE ALONG TWO ASSOCIATED
TROUGHS WILL LEAD TO A COUPLE MODERATE TO POTENTIALLY HEAVY PERIODS
OF SNOW BEFORE THE LAKE EFFECT REALLY KICKS IN OVERNIGHT.
THE FIRST TROUGH WILL SHIFT WINDS TO THE NORTHWEST AND MOVE INTO THE
KEWEENAW AND WESTERN UPPER MICHIGAN AROUND DINNER TIME AND THE REST
OF THE CWA DURING THE EVENING HOURS. EXPECT THE STRONGEST SNOW TO
OCCUR OVER THE WEST WITH THE FAVORABLE UPSLOPE WINDS AND LEAD TO A
COUPLE HOUR PERIOD OF STRONG SNOW SHOWERS. THEN THERE MAY BE
A SHORT PERIOD OF LIGHTER SNOW AS THE DEEPER MOISTURE CUTS OUT FOR
A FEW HOURS. THE SECONDARY TROUGH (WITH ANOTHER BURST OF
MODERATE TO HEAVY SNOWFALL) WILL THEN DROP SOUTH ACROSS THE KEWEENAW
AND WESTERN UPPER MICHIGAN AROUND OR SHORTLY AFTER
MIDNIGHT...SHIFTING THE WINDS TO ALMOST NORTHERLY AND THE LAKE
EFFECT SNOW SHOULD REALLY KICK IN. EXPECT A SIMILAR OCCURRENCE
ACROSS THE REST OF NORTHERN UPPER MICHIGAN WITH MORE OF A DELAY ON
THE SECONDARY TROUGH UNTIL THE 08-09Z TIME FRAME. IN ADDITION...WITH
THE FIRST FRONT SHIFTING WINDS TO LESS FAVORABLE NORTHWESTERLY
DOWNSLOPING FLOW FOR THE NORTH CENTRAL...THEY WILL LIKELY NOT SEE
MUCH SNOW ACCUMULATION UNTIL THE SECONDARY TROUGH MOVES THROUGH AND
LAKE EFFECT DEVELOPS.
BEHIND THE TROUGHS...850MB TEMPS WILL FALL FROM AROUND -10C AT 18Z
TODAY TO -20C AT 12Z SATURDAY. THIS WILL PROVIDE SIGNIFICANT OVER
THE LAKE INSTABILITY (DELTA-T VALUES APPROACHING 25) AND LEAD TO
LAKE INDUCED CAPE AND EQL LEVELS OF 800 J/KG AND 13-14K
FT RESPECTIVELY. BEST DEEP MOISTURE WILL BE FOCUSED OVER THE EAST
CLOSER TO THE LOW MOVING THROUGH. THUS...EXPECT REALLY GOOD
CONDITIONS FOR MODERATE TO HEAVY LAKE EFFECT SNOW DURING THE
OVERNIGHT HOURS AND CONTINUING INTO SATURDAY. SNOW RATIOS WILL BE
ON THE INCREASE THROUGH THE FORECAST PERIOD...STARTING AROUND
10-15 TO 1 BEFORE INCREASING TO THE LOW 20S ONCE THE LAKE EFFECT
KICKS IN. WITH THE BEST LAKE INDUCED LIFT RIGHT IN THE DGZ...THERE
IS THE POTENTIAL THAT SNOW RATIOS COULD BE HIGHER IN THE STRONGER
BANDS (ESPECIALLY TOWARDS IRONWOOD WHERE THE WINDS ARE LIGHTER) AND
MAY BE SOMETHING TO MONITOR.
AS FOR SNOW AMOUNTS FOR THE WEST FIRST. WHILE THERE WILL BE SOME
BURSTS LATE THIS AFTERNOON AND EVENING...OVERALL AMOUNTS SHOULD BE
IN THE 1-3 INCH RANGE. THEN AS THE LAKE EFFECT KICKS IN
TONIGHT...HAVE ANOTHER 2-4 INCHES OVER THE HIGHER TERRAIN FROM THE
KEWEENAW THROUGH GOGEBIC COUNTIES. THIS PRODUCES TOTALS BY 12Z
SATURDAY OF 3-7 INCHES...WITH THE HIGHEST FOR GOGEBIC/ONTONAGON
DUE TO THE LONGER FETCH AND WEAKER WINDS INCREASING RESIDENCE
TIME OVER THE LAKE. ALSO...IT APPEARS THE INITIAL TROUGH WILL BECOME
HUNG UP IN THAT AREA THIS EVENING...WHICH WOULD ALLOW THE SNOW TO
PERSIST FOR MUCH OF THE EVENING HOURS. MARQUETTE/BARAGA COUNTY AND
LOCATIONS EASTWARD WILL LIKELY NOT REALLY SEE THE SNOW PICKING UP
UNTIL AFTER MIDNIGHT AND LIKELY AROUND 08-09Z WHEN THE TROUGH
FINALLY SHIFTS THROUGH AND SWITCHES THE WINDS MORE NORTH-NORTHWEST.
THIS BECOMES FAIRLY FAVORABLE FOR NORTH CENTRAL AND EASTERN PARTS OF
MARQUETTE COUNTY AND FOCUSED INTO ALGER COUNTY LATE TONIGHT...SO
EXPECT CONDITIONS TO DETERIORATE VERY QUICKLY THERE. WITH AN INCH
AN HOUR SNOW OVER MARQUETTE COUNTY LATE TONIGHT...EXPECT TOTALS IN
THE 2-5 INCH RANGE FROM THE HURON MOUNTAINS THROUGH
NEGAUNEE/SKANDIA BY 12Z. FARTHER EAST...THE DELAYED ARRIVAL WILL
LIKELY KEEP AMOUNTS IN THE 1-3 INCH RANGE.
ALONG WITH THE SNOW...WINDS WILL ALSO INCREASE BEHIND THE
FRONTS...GUSTING TO 40KT GALES OVER CENTRAL AND EASTERN LAKE
SUPERIOR DURING THE OVERNIGHT HOURS. GUSTS TO 35-40MPH WILL BE
COMMON OVER THE KEWEENAW STARTING LATE THIS EVENING AND LATE
TONIGHT EAST OF MARQUETTE. AS THE SNOW STARTS TO
ACCUMULATE...BLOWING SNOW BECOMES A LARGER ISSUE THROUGH THE NIGHT
AND INTO SATURDAY WITH SNOW BEING ON THE GROUND.
AS FOR HEADLINES...COORDINATION WITH THE LONG TERM SHIFT LED TO
SWITCHING GOGEBIC/ONTONAGON AND ALGER/LUCE...NORTHERN SCHOOLCRAFT
TO LAKE EFFECT SNOW WARNINGS DUE TO THEIR FAVORABLE CONDITIONS AND
EXPECTED SNOW ACCUMULATIONS. THERE WAS ENOUGH UNCERTAINTY ON
SNOWFALL AMOUNTS FOR THE KEWEENAW PENINSULA TO OPT FOR AN ADVISORY
AT THIS POINT...SINCE THE LIMITED FETCH (AND UPSLOPE) WITH THE
WINDS WILL KEEP AMOUNTS LOWER. THOSE WINDS COULD ALSO MAKE FOR
WORSE VISIBILITIES AND COULD ALMOST JUSTIFY A WARNING. MARQUETTE
WAS SIMILAR (AND MAY NEED TO BE UPGRADED WITH THE DAY SHIFT)...SINCE
AMOUNTS IN 12 HOURS ARE JUST UNDER WARNING CRITERIA AND THERE IS
SOME UNCERTAINTY ON THE EXACT LOCATION OF THE STRONGER BANDS OFF
LAKE NIPIGON. FINALLY...THE REST OF THE AREAS IN THE WATCH WERE
SWITCHED TO AN ADVISORY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 503 AM EST FRI NOV 22 2013
THE MAIN FCST CONCERNS ARE THE LES POTENTIAL FROM SAT INTO EARLY
SUNDAY ALONG WITH BLOWING SNOW AND WIND CHILLS IN THE VERY COLD
ARCTIC AIRMASS.
SAT INTO SAT NIGHT...
WITH MODEL FCST 850MB TEMPS FALLING TO -18 TO -21C BY 12Z
SAT...VIGOROUS NW/NNW FLOW ORIENTED LAKE EFFECT SNOW BANDS WILL BE
ONGOING IN THE WAKE OF THE ARCTIC FRONT. MODELS SUGGEST THAT THE
DEEPER MOISTURE TO AROUND 8K TO 10K FEET WILL PERSIST LONGER OVER
THE ERN FCST AREA. THE FAVORABLE MOISTURE PROFILE AND THE DGZ WITHIN
THE CONVECTIVE LAYER WILL SUPPORT SNOWFALL RATES OF AT LEAST 1 TO 2
INCHES PER HOUR IN THE STRONGER BANDS. HOWEVER...SNOWFLAKE
FRACTURING AND COMPACTION WITH TEH STRONG WINDS SHOULD LIMIT
SNOW/WATER RATIOS TO AROUND 20/1.
AS IS OFTEN THE CASE...THE MOST INTENSE DOMINANT BAND SHOULD
ORIGINATE WITH PRECONDITIONING OFF OF LAKE NIPIGON. THERE IS LESS
CONFIDENCE ON WHERE THAT BAND WILL SET UP AND HOW LONG IT WILL LAST
IN ANY ONE LOCATION. THE HIGHER RESOLUTION MODELS SUGGEST THAT THE
BAND MAY START OUT NEAR MARQUETTE AND THEN SHIFT EAST TOWARD SHOT
POINT AND INTO ALGER COUNTY BY LATE SATURDAY MORNING WHERE THE
HEAVIER LES WILL THEN PERSIST FROM SAT AFTERNOON INTO SAT NIGHT. 12
HOUR SNOWFALL AMOUNTS OF AROUND 8 INCHES ARE EXPECTED BOTH SATURDAY
AND SAT NIGHT FOR ALGER AND NRN SCHOOLCRAFT COUNTIES WHERE LES
WARNINGS WERE POSTED. THERE WAS GREATER UNCERTAINTY FOR MARQUETTE
COUNTY WHERE AN ADVISORY WAS POSTED. SNOWFALL TOTALS SHOULD BE
GREATEST IN THE 6Z-18Z/SAT PERIOD WHEN AMOUNTS IN THE 3 TO 7 INCH RANGE
ARE EXPECTED. AN UPGRADE TO A WARNING MAY BE NEEDED IF ANY STRONG
BANDS PERSIST LONGER THAN EXPECTED.
OVER THE WEST...INVERSION HEIGHTS DROPPING TO AROUND 5K-6K FT WILL
LIMIT LES INTENSITY. HOWEVER...WITH STRONG NRLY UPSLOPE FLOW INTO
THE HIGHER TERRAIN WILL SUPPORT ADDITIONAL SNOWFALL AMOUNTS OF 3 TO
5 INCHES SATURDAY WITH ANOTHER 2 TO 4 INCHES SAT NIGHT.
GUSTY WINDS TO 30-40 MPH WILL ALSO PRODUCE CONSIDERABLE BLOWING SNOW
WITH SHARPLY REDUCED VISIBILITY IN THE HEAVIER SNOW BANDS.
THE LES SHOULD MOSTLY END SUNDAY FROM W TO E AS WINDS BACK TO THE SW
AHEAD OF THE NEXT CLIPPER SHORTWAVE TROUGH DIVING SE THROUGH SOUTH
CNTRL CANADA. HOWEVER...A DEVELOPING WAA PATTERN WITH STRONG
285K-295K ISENTROPIC LIFT WILL PROBABLY LEAD TO AN AREA OF -SN
STREAKING SE INTO THE AREA SUN AFTN/NIGHT. HOWEVER...SINCE THE
STRONGER 700-300 MB QVECTOR CONV REMAINS WELL TO THE NORTH WITH THE
TRACK OF THE SHRTWV AND LOWER LEVELS ARE VERY DRY...ONLY CHANCE POPS
WERE INCLUDED FOR SNOWFALL AMOUNTS THAT WOULD AMOUNT TO LESS THAN AN
INCH OVER MOST OF THE CWA.
TUE-THU...THE GFS/GEFS/ECMWF WERE IN REASONABLE AGREEMENT THAT
ANOTHER BATCH OF ARCTIC AIR IS EXPECTED TO MOVE INTO THE NRN GREAT
LAKES IN THE WAKE OF A STRONGER SHORTWAVE MOVING THROUGH NRN ONTARIO
ON TUE. WITH 850 MB TEMPS DROPPING TO AROUND -17C...ANOTHER EXTENDED
PERIOD OF LES WITH AT LEAST MODERATE ACCUMULATIONS IS LIKELY FOR NW
TO N FLOW FAVORED LOCATIONS. THE LES SHOULD DIMINISH BY THU AS THE
SFC HIGH BUILDS INTO THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 643 AM EST FRI NOV 22 2013
MVFR CEILINGS WILL GRADUALLY IMPROVE TO VFR THIS MORNING FROM WEST TO
EAST AS A HIGH PRESSURE RIDGE MOVES ACROSS UPPER MICHIGAN. THE MVFR
CEILINGS WILL HOLD ON THE LONGEST AT KCMX AS WINDS BACK AND STILL
REMAIN FAVORABLE FOR LAKE EFFECT CLOUDS.
A LOW PRESSURE SYSTEM THAT IS JUST NORTH OF THE LAKE OF THE WOODS
IN MINNESOTA WILL DIVE SOUTHEAST ACROSS LAKE SUPERIOR THIS
AFTERNOON AND DRAG A COLD FRONT ACROSS THE AREA LATE THIS AFTERNOON
AND EVENING. THERE WILL LIKELY BE A BRIEF PERIOD OF STRONGER SNOW
SHOWERS WITH THIS FRONT OVER THE WEST...THEN LIGHT TO MODERATE LAKE
EFFECT SNOW DURING THE REST OF THE EVENING WITH MVFR CONDITIONS.
BY THE TIME THE FRONT REACHES KSAW...THE IMPACT FROM THE SNOW
SHOWERS WILL BE LIMITED. A SECONDARY FRONT WILL DROP SOUTH ACROSS
THE TAF SITES BETWEEN 06-08Z AND BRING ANOTHER BURST OF HEAVY SNOW.
THIS SNOW WILL TRANSITION TO LAKE EFFECT UNDER NNW WINDS AND LIKELY
BRING ALTERNATE TO NEARLY AIRFIELD LANDING MINIMUM VISIBILITIES TO
THE THREE SITES INTO SATURDAY MORNING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 444 AM EST FRI NOV 22 2013
A FAIRLY ACTIVE NEXT COUPLE DAYS IS IN STORE FOR LAKE SUPERIOR. A
TROUGH THAT MOVED THROUGH LAKE SUPERIOR THIS PAST EVENING WILL
CONTINUE EAST EARLY THIS MORNING...WHILE A HIGH PRESSURE RIDGE
MOVES ACROSS THE LAKE THROUGH EARLY AFTERNOON. THERE WERE A FEW
GALE FORCE GUSTS TO 35KTS SHORTLY AFTER MIDNIGHT...BUT THEY HAVE
SINCE DIMINISHED AND EXPECT A DIMINISHING TREND TO THE WINDS THIS
MORNING. AS THE HIGH PRESSURE RIDGE SHIFTS EAST THIS AFTERNOON
SOUTHWESTERLY WINDS WILL BE ON THE INCREASE OVER WESTERLY LAKE
SUPERIOR AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. THIS SYSTEM
WILL QUICKLY DIVE SOUTHEAST ACROSS LAKE SUPERIOR LATE THIS AFTERNOON
AND EVENING...QUICKLY SHIFTING WINDS TO THE NORTH-NORTHWEST AND
PRODUCING GALE FORCE WINDS TO 40KTS. THERE COULD EVEN BE SOME GUSTS
TO 45KTS RIGHT AS WINDS SHIFT TO THE NORTH-NORTHWEST AFTER MIDNIGHT
OVER EASTERN LAKE SUPERIOR. THE GALE WARNING THAT IS IN PLACE LOOKS
TO BE IN GOOD SHAPE. A STRONG HIGH DROPPING SOUTH THROUGH THE
NORTHERN PLAINS ON SATURDAY WILL BEGIN TO NOSE A RIDGE OVER WESTERN
LAKE SUPERIOR ON SATURDAY AFTERNOON AND THEN PUSH ACROSS THE ENTIRE
LAKE SATURDAY NIGHT AND SUNDAY. THIS WILL LEAD TO DIMINISHING AND
BACKING WINDS DURING THAT PERIOD. THAT DIMINISHING TREND WILL BE
SHORT LIVED AS WINDS WILL INCREASE ON SUNDAY NIGHT OUT OF THE
SOUTHWEST (TO 30KTS) AHEAD OF LOW MOVING SOUTHEAST THROUGH ONTARIO
LATE SUNDAY NIGHT AND MONDAY. THIS LOW WILL DRAG A COUPLE TROUGHS
ACROSS LAKE SUPERIOR MONDAY AND MONDAY NIGHT...WITH THE SECOND ONE
STALLING OVER SOUTHEAST LAKE SUPERIOR THROUGH WEDNESDAY. AT THIS
POINT...NORTHWEST WINDS UP TO 30KTS ARE EXPECTED BEHIND THE
TROUGHS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 1 AM EST
SUNDAY FOR MIZ004-084.
LAKE EFFECT SNOW WARNING FROM MIDNIGHT TONIGHT TO NOON EST
SUNDAY FOR MIZ006-007-085.
LAKE EFFECT SNOW ADVISORY FROM 5 PM THIS AFTERNOON TO 7 AM EST
SUNDAY FOR MIZ001-003.
LAKE EFFECT SNOW WARNING FROM 6 PM EST /5 PM CST/ THIS EVENING
TO 7 AM EST /6 AM CST/ SUNDAY FOR MIZ002-009.
LAKE EFFECT SNOW ADVISORY FROM 1 AM TO 10 PM EST SATURDAY FOR
MIZ005.
LAKE EFFECT SNOW ADVISORY FROM 1 AM SATURDAY TO 7 AM EST SUNDAY
FOR MIZ014.
LAKE EFFECT SNOW ADVISORY FROM 1 AM SATURDAY TO 5 AM EST SUNDAY
FOR MIZ013.
LAKE SUPERIOR...
GALE WARNING FROM 11 PM THIS EVENING TO 1 AM EST SUNDAY FOR
LSZ266-267.
GALE WARNING FROM 1 AM TO 10 PM EST SATURDAY FOR LSZ248>251-265.
GALE WARNING FROM 10 PM THIS EVENING TO 10 PM EST SATURDAY FOR
LSZ264.
GALE WARNING FROM 10 PM THIS EVENING TO 7 PM EST SATURDAY FOR
LSZ244-245.
GALE WARNING FROM 10 PM THIS EVENING TO 7 AM EST SATURDAY FOR
LSZ242-243.
GALE WARNING FROM 10 PM THIS EVENING TO 10 AM EST SATURDAY FOR
LSZ263.
LAKE MICHIGAN...
GALE WARNING FROM 4 AM TO 10 PM EST SATURDAY FOR LMZ221-248-250.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
538 AM CST FRI NOV 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 242 AM CST FRI NOV 22 2013
SURFACE ANALYSIS THIS MORNING IS DOMINATED BY HIGH PRESSURE. THERE
ARE TWO HIGH CENTERS OVER CENTRAL NOAM...A 1043 MB HIGH WAS CENTERED
OVER WRN NEB WITH A HIGH OF SIMILAR STRENGTH OVER NRN ALBERTA. IN
BETWEEN THESE TWO HIGHS WAS AN AREA OF LOWER PRESSURE OVER LAKE
WINNIPEG THAT CHECKS IN AT 1028 MB...WHICH UNDER NORMAL
CIRCUMSTANCES WOULD BE THE PRESSURE SEEN AT THE CENTER OF HIGH.
THE NEBRASKA HIGH HAS A RIDGE AXIS THAT STRETCHES NE TO NEAR INL.
WITH THIS AXIS SITTING OVER WEST CENTRAL MN UNDER CLEAR SKIES...HAVE
SEEN SITES OUT BY THE SODAK BORDER DROP TO NEAR ZERO THIS MORNING.
AS FOR THAT CANADIAN HIGH...TEMPERATURES HAVE FOUND THEIR WAY DOWN
TO AROUND -30F ACROSS NRN ALBERTA AND SASKATCHEWAN...WELCOME TO
WINTER.
FOR TODAY...WE WILL SEE BREEZY WSW WINDS DEVELOP OUT AHEAD OF THE
ARCTIC BOUNDARY THAT WILL SLIP INTO THE NW CWA AROUND 18Z...REACH
THE TWIN CITIES AROUND 00Z AND EXIT THE MPX CWA BY 6Z. AS YOU CAN
IMAGINE...WITH SFC PRESSURE VALUES UP NEAR 1030 MB...PRECIP WILL BE
HARD TO COME BY. WITH THAT SAID...IT DOES LOOK LIKE RIGHT BEHIND THE
FRONT THERE WILL BE THE POTENTIAL FOR A QUICK HIT OF LIGHT SNOW.
BOTH THE NAM/GFS SHOW A BAND OF FGEN IN THE H7-H6 LAYER WORKING DOWN
BEHIND THE FRONT. IN ADDITION...FORECAST SOUNDINGS SHOW DEEP
DENDRITIC GROWTH ZONES BECOMING SATURATED AS THE FRONT PASSES...SO
WILL NOT TAKE MUCH LIFT TO GENERATE SOME LIGHT SNOW. HRRR AND
HIRES-NMM REFLECTIVITY FORECASTS INDICATE A LIGHT BAND OF SNOW
DEVELOPING BEHIND THE FRONT AS WELL. FOR NOW...BEEFED UP SKY COVER
THIS EVENING WITH THE FRONT AND WORKED SOME OCCASIONAL FLURRY
WORDING DOWN WITH IT AS WELL.
BEHIND THE FRONT...NAM BUFR SOUNDINGS SHOW THE POTENTIAL FOR NW
WINDS TO BE GUSTING UP AROUND 30 MPH...BUT MORE IMPRESSIVE THAN THAT
IS THE 1050 MB HIGH ALL MODELS SHOW MOVING INTO NODAK LATE TONIGHT.
TO GO ALONG WITH THAT HIGH...BY 12Z SATURDAY...H85 TEMPS WILL
ALREADY BE DOWN IN THE -16 TO -20 C RANGE. 22.00 MODELS ALL CAME IN
A BIT FASTER WITH THE FROPA THIS EVENING AND MOST CAME IN A FEW DEGS
COOLER FOR LOWS SATURDAY MORNING THAN WHAT THEY WERE SHOWING WITH
EARLIER RUNS...SO DID KNOCK A COUPLE OF DEGREES OFF EXISTING LOWS
FOR SATURDAY MORNING. WITH LOWS CURRENTLY FORECAST TO RANGE FROM 2
TO 12...WE WILL BE LAYING A NICE FOUNDATION FOR WHAT WILL BE A
FRIGID SATURDAY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 242 AM CST FRI NOV 22 2013
THE LONG TERM FORECAST LOOKS COLD AND DRY AS BOTH MN/WI REMAIN
ENTRENCHED IN NORTHWEST FLOW. NORTHERN MN WILL BE CLOSER TO THE
CORE OF COLDEST ARCTIC AIR DROPPING SOUTH OUT OF CANADA
THROUGHOUT THE WEEKEND. AS A RESULT...THE NORTHERN HALF OF THE
STATE HAS A MUCH BETTER CHANCE OF KEEPING CLOUD COVER AND A
CHANCE FOR SNOW FLURRIES AROUND. THE DENDRITE GROWTH ZONE IS NEAR THE
SURFACE WITH AN AIR MASS THIS COLD...SO IF YOU END UP WITH STRATUS
CLOUDS...YOU OFTEN END UP WITH FLURRIES OR LIGHT SNOW. THE
SOUTHERN HALF OF MN AND WEST CENTRAL WI LOOKS A DRIER DOWN LOW
AND SHOULD SEE MORE SUNSHINE. THIS WILL BE OF LITTLE CONSOLATION
AS A BRISK NORTHERLY FLOW BEHIND THE AFOREMENTIONED COLD FRONT
KEEPS TEMPERATURES IN THE TEENS ON SATURDAY WITH WIND CHILLS NEAR
ZERO. THE STRONG COLD ADVECTION WILL CREATE STEEP LAPSE RATES ON
SATURDAY BELOW 900MB AND ENOUGH MIXING TO KEEP GUSTY WINDS UP NEAR
20 MPH. MIXING TO 925MB SHOULD YIELD MID TO UPPER TEENS FOR HIGHS.
BEFORE A SLIGHTLY WARMER WESTERLY FLOW RETURNS ON
SUNDAY...SATURDAY NIGHT WILL BE THE COLDEST NIGHT OF THE FALL
SEASON SO FAR WITH THE ARCTIC HIGH SLIPPING JUST SOUTH OF THE
FORECAST AREA. THE LACK OF SNOW COVER DOESN`T HELP...BUT HARD TO
IMAGINE WE WOULDN`T HAVE MULTIPLE SITES DROP BELOW ZERO.
THERE IS GOOD MODEL AGREEMENT WITH RESPECT TO TEMPERATURES THROUGH
THE EXTENDED. THE DRY PROFILES AND LACK OF CLOUD COVER ACROSS THE
FORECAST AREA OVER THE NEXT 7 DAYS IS HELPING TO KEEP A TIGHTER
ENVELOPE OF MODELED TEMPERATURES /WITHIN 4-7 DEGREES/.
THEREFORE...THERE IS HIGH CONFIDENCE IN BELOW NORMAL TEMPERATURES
OVER THE NEXT 7-10 DAYS. I SUPPOSE YOU COULD ALSO SAY THERE IS
HIGH CONFIDENCE IN BELOW NORMAL PRECIP /NEAR ZERO/ OVER AT LEAST
THE NEXT 7 DAYS AS WELL. THE TIME HEIGHTS OFF THE GFS AND ECMWF
DON`T EVEN CARRY ENOUGH RH TO JUSTIFY MUCH CLOUD COVER...LET ALONE
PRECIP.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 523 AM CST FRI NOV 22 2013
ANOTHER ARCTIC BOUNDARY SLIPPING ACROSS NODAK THIS MORNING WILL
PROVIDE THE ONLY EXCITEMENT THIS TAF PERIOD. ALREADY SEEING WINDS
BACK TO THE SW OUT AHEAD OF THE FRONT OVER NW MN AND THIS TREND
WILL CONTINUE DOWN INTO THE MPX TERMINALS THIS MORNING AS THE
FRONT APPROACHES. MODEL TIMING OF THE FROPA HAS NOT CHANGED MUCH
SO CONFIDENCE REMAINS HIGH IN ITS TIMING. MIXING PROFILES SUPPORT
SOME GUSTS INTO THE MID 20S BEHIND THE FRONT SAT NIGHT. IN
ADDITION...HRRR REFLECTIVITY FORECAST CONTINUES TO SHOW A BAND OF
LIGHT SNOW AND LOWER CIGS WORKING SOUTH JUST BEHIND THE FRONT.
THIS WILL NOT BE ALL THAT IMPRESSIVE...BUT SHOULD PROVIDE AN HOUR
OR TWO OF LIGHT SNOW...ESPECIALLY FOR CENTRAL MN. HAVE CONTINUED
WITH THE TEMPO -SN GROUPS AT TERMINALS AS A RESULT.
KMSP...WITH WINDS UP AROUND FARGO COMING OUT AT 190
DIRECTION...WILL HAVE TO WATCH DIRECTION CLOSELY BETWEEN 17Z AND
21Z AS THE COULD BACK FAR ENOUGH SOUTH TO LEAD TO THE POSSIBILITY
OF HAVING TO BRIEFLY SWAP OUT OF THE 30S. AS FOR SNOW...NOT
EXPECTING MUCH...BUT ENOUGH OF A POSSIBILITY EXISTS TO KEEP THE
TEMPO GROUP GOING.
/OUTLOOK FOR KMSP/
SAT...VFR. WINDS NNW AT 10G15KTS.
SUN...VFR. WINDS LIGHT AND VRB IN MRNG...BCMG S AT 15G25KTS.
MON...VFR. WINDS WNW AT 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...CLF
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
416 AM CST FRI NOV 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 242 AM CST FRI NOV 22 2013
SURFACE ANALYSIS THIS MORNING IS DOMINATED BY HIGH PRESSURE. THERE
ARE TWO HIGH CENTERS OVER CENTRAL NOAM...A 1043 MB HIGH WAS CENTERED
OVER WRN NEB WITH A HIGH OF SIMILAR STRENGTH OVER NRN ALBERTA. IN
BETWEEN THESE TWO HIGHS WAS AN AREA OF LOWER PRESSURE OVER LAKE
WINNIPEG THAT CHECKS IN AT 1028 MB...WHICH UNDER NORMAL
CIRCUMSTANCES WOULD BE THE PRESSURE SEEN AT THE CENTER OF HIGH.
THE NEBRASKA HIGH HAS A RIDGE AXIS THAT STRETCHES NE TO NEAR INL.
WITH THIS AXIS SITTING OVER WEST CENTRAL MN UNDER CLEAR SKIES...HAVE
SEEN SITES OUT BY THE SODAK BORDER DROP TO NEAR ZERO THIS MORNING.
AS FOR THAT CANADIAN HIGH...TEMPERATURES HAVE FOUND THEIR WAY DOWN
TO AROUND -30F ACROSS NRN ALBERTA AND SASKATCHEWAN...WELCOME TO
WINTER.
FOR TODAY...WE WILL SEE BREEZY WSW WINDS DEVELOP OUT AHEAD OF THE
ARCTIC BOUNDARY THAT WILL SLIP INTO THE NW CWA AROUND 18Z...REACH
THE TWIN CITIES AROUND 00Z AND EXIT THE MPX CWA BY 6Z. AS YOU CAN
IMAGINE...WITH SFC PRESSURE VALUES UP NEAR 1030 MB...PRECIP WILL BE
HARD TO COME BY. WITH THAT SAID...IT DOES LOOK LIKE RIGHT BEHIND THE
FRONT THERE WILL BE THE POTENTIAL FOR A QUICK HIT OF LIGHT SNOW.
BOTH THE NAM/GFS SHOW A BAND OF FGEN IN THE H7-H6 LAYER WORKING DOWN
BEHIND THE FRONT. IN ADDITION...FORECAST SOUNDINGS SHOW DEEP
DENDRITIC GROWTH ZONES BECOMING SATURATED AS THE FRONT PASSES...SO
WILL NOT TAKE MUCH LIFT TO GENERATE SOME LIGHT SNOW. HRRR AND
HIRES-NMM REFLECTIVITY FORECASTS INDICATE A LIGHT BAND OF SNOW
DEVELOPING BEHIND THE FRONT AS WELL. FOR NOW...BEEFED UP SKY COVER
THIS EVENING WITH THE FRONT AND WORKED SOME OCCASIONAL FLURRY
WORDING DOWN WITH IT AS WELL.
BEHIND THE FRONT...NAM BUFR SOUNDINGS SHOW THE POTENTIAL FOR NW
WINDS TO BE GUSTING UP AROUND 30 MPH...BUT MORE IMPRESSIVE THAN THAT
IS THE 1050 MB HIGH ALL MODELS SHOW MOVING INTO NODAK LATE TONIGHT.
TO GO ALONG WITH THAT HIGH...BY 12Z SATURDAY...H85 TEMPS WILL
ALREADY BE DOWN IN THE -16 TO -20 C RANGE. 22.00 MODELS ALL CAME IN
A BIT FASTER WITH THE FROPA THIS EVENING AND MOST CAME IN A FEW DEGS
COOLER FOR LOWS SATURDAY MORNING THAN WHAT THEY WERE SHOWING WITH
EARLIER RUNS...SO DID KNOCK A COUPLE OF DEGREES OFF EXISTING LOWS
FOR SATURDAY MORNING. WITH LOWS CURRENTLY FORECAST TO RANGE FROM 2
TO 12...WE WILL BE LAYING A NICE FOUNDATION FOR WHAT WILL BE A
FRIGID SATURDAY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 242 AM CST FRI NOV 22 2013
THE LONG TERM FORECAST LOOKS COLD AND DRY AS BOTH MN/WI REMAIN
ENTRENCHED IN NORTHWEST FLOW. NORTHERN MN WILL BE CLOSER TO THE
CORE OF COLDEST ARCTIC AIR DROPPING SOUTH OUT OF CANADA
THROUGHOUT THE WEEKEND. AS A RESULT...THE NORTHERN HALF OF THE
STATE HAS A MUCH BETTER CHANCE OF KEEPING CLOUD COVER AND A
CHANCE FOR SNOW FLURRIES AROUND. THE DENDRITE GROWTH ZONE IS NEAR THE
SURFACE WITH AN AIR MASS THIS COLD...SO IF YOU END UP WITH STRATUS
CLOUDS...YOU OFTEN END UP WITH FLURRIES OR LIGHT SNOW. THE
SOUTHERN HALF OF MN AND WEST CENTRAL WI LOOKS A DRIER DOWN LOW
AND SHOULD SEE MORE SUNSHINE. THIS WILL BE OF LITTLE CONSOLATION
AS A BRISK NORTHERLY FLOW BEHIND THE AFOREMENTIONED COLD FRONT
KEEPS TEMPERATURES IN THE TEENS ON SATURDAY WITH WIND CHILLS NEAR
ZERO. THE STRONG COLD ADVECTION WILL CREATE STEEP LAPSE RATES ON
SATURDAY BELOW 900MB AND ENOUGH MIXING TO KEEP GUSTY WINDS UP NEAR
20 MPH. MIXING TO 925MB SHOULD YIELD MID TO UPPER TEENS FOR HIGHS.
BEFORE A SLIGHTLY WARMER WESTERLY FLOW RETURNS ON
SUNDAY...SATURDAY NIGHT WILL BE THE COLDEST NIGHT OF THE FALL
SEASON SO FAR WITH THE ARCTIC HIGH SLIPPING JUST SOUTH OF THE
FORECAST AREA. THE LACK OF SNOW COVER DOESN`T HELP...BUT HARD TO
IMAGINE WE WOULDN`T HAVE MULTIPLE SITES DROP BELOW ZERO.
THERE IS GOOD MODEL AGREEMENT WITH RESPECT TO TEMPERATURES THROUGH
THE EXTENDED. THE DRY PROFILES AND LACK OF CLOUD COVER ACROSS THE
FORECAST AREA OVER THE NEXT 7 DAYS IS HELPING TO KEEP A TIGHTER
ENVELOPE OF MODELED TEMPERATURES /WITHIN 4-7 DEGREES/.
THEREFORE...THERE IS HIGH CONFIDENCE IN BELOW NORMAL TEMPERATURES
OVER THE NEXT 7-10 DAYS. I SUPPOSE YOU COULD ALSO SAY THERE IS
HIGH CONFIDENCE IN BELOW NORMAL PRECIP /NEAR ZERO/ OVER AT LEAST
THE NEXT 7 DAYS AS WELL. THE TIME HEIGHTS OFF THE GFS AND ECMWF
DON`T EVEN CARRY ENOUGH RH TO JUSTIFY MUCH CLOUD COVER...LET ALONE
PRECIP.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1150 PM CST THU NOV 21 2013
BAND OF SNOW CONTINUES ACROSS FAR SOUTHERN MN AND INTO WESTERN
WISCONSIN AT TAF ISSUANCE TIME. THIS BAND WILL SHIFT SOUTHEAST
DURING THE NEXT FEW HOURS AS DRIER AIR FEEDS IN. CIGS WILL
CONTINUE TO IMPROVE OVERNIGHT WITH CLEAR SKIES EXPECTED BY EARLY
FRIDAY MORNING. ANOTHER ARCTIC COLD FRONT WILL PUSH THROUGH LATE
FRIDAY... AND MODELS INDICATE SOME CHANCE OF SNOW SHOWERS WITH THE
FROPA AS TEMPERATURES DROP INTO THE OPTIMAL RANGE FOR SNOWFLAKE
FORMATION IN A HIGH RH PROFILE. WINDY NORTHWEST WINDS AND DRIER
AIR WILL QUICKLY FOLLOW FRIDAY NIGHT.
KMSP...VFR CONDITIONS UNTIL LATE FRIDAY WHEN A BAND OF MVFR CIGS
AND SNOW SHOWERS MAY ACCOMPANY AN ARCTIC COLD FRONT.
/OUTLOOK FOR KMSP/
SAT...VFR. WINDS NNW AT 10G15KTS.
SUN...VFR. WINDS LIGHT AND VRB...BECOMING S AT 10G15KTS LATE.
MON...VFR. WINDS NW AT 15KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...CLF
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
635 AM EST FRI NOV 22 2013
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL WEAKEN AND SHIFT SOUTH ACROSS THE
CAROLINAS LATER TODAY. A STRONG ARCTIC COLD FRONT WILL CROSS THE
AREA LATE SATURDAY FOLLOWED BY THE COLDEST TEMPERATURES OF THE
SEASON. A SIGNIFICANT RAIN EVENT APPEARS LIKELY FOR THE MIDDLE OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...A SURFACE RIDGE OF HIGH PRESSURE EXTENDING
FROM NORTHERN NORTH CAROLINA TO A FEW HUNDRED MILES EAST OF THE NEW
JERSEY COAST WILL SINK SOUTH TODAY WHILE WEAKENING...MOVING ACROSS
OUR PORTION OF THE EASTERN CAROLINAS DURING THE AFTERNOON HOURS. THE
LOW LEVEL WINDS REMAIN ONSHORE...THEREFORE I ANTICIPATE ANOTHER MILD
DAY FOR MID-NOVEMBER WITH 850 MB TEMPS AROUND +10C. YESTERDAY`S
MAJOR CONCERN WAS CLOUD COVER...AND THIS IS AGAIN A CONCERN FOR
TODAY. MOISTURE POOLED AT THE BASE OF A SUBSIDENCE INVERSION ALOFT
IS MAINTAINING EXPANSIVE AREAS OF ALTOCUMULUS ACROSS THE CAROLINAS
EARLY THIS MORNING. THIS SUBSIDENCE INVERSION SHOULD DISSIPATE
DURING THE AFTERNOON HOURS...AND WEAK 300-305K ISENTROPIC LIFT MAY
NOT BE ENOUGH TO PRODUCE AN OVERCAST SKY BY ITSELF. FOR THIS REASON
I AM FORECASTING SKIES TO BECOME PARTLY CLOUDY BY AFTERNOON
IN ALL BUT THE INTERIOR PORTIONS OF SE NORTH CAROLINA AND THE
NORTHERN PEE DEE REGION.
ASSUMING WE GET THE AMOUNT OF SUNSHINE I AM ANTICIPATING...HIGHS
SHOULD REACH 72-75 AWAY FROM THE BEACHES TODAY. THIS IS VERY CLOSE
TO THE 00Z NAM WHICH PERFORMED EXTREMELY WELL WITH YESTERDAY`S
TRICKY FORECAST. THE 06Z MODELS DID NOT CHANGE APPRECIABLY VERSUS
THEIR 00Z COUNTERPARTS. THE NAM STILL LOOKS GOOD AND NOW HAS SUPPORT
FROM THE 10Z RUC WITH REGARD TO TEMPERATURES.
TONIGHT THE SURFACE RIDGE WILL WEAKEN FURTHER AND SHIFT WELL SOUTH
OF THE CAROLINAS...PRODUCING A LIGHT SOUTHWEST SURFACE WIND MOST OF
THE NIGHT. INCREASING DEEP-LAYER MOISTURE SHOULD RESULT IN SKIES
BECOMING INCREASINGLY CLOUDY OVERNIGHT...AND A FEW SHOWERS COULD
DEVELOP LATE. A WEAK LOW LEVEL JET WILL HELP HOLD TEMPERATURES
WELL-ABOVE NORMAL FOR THE DATE: LOWS ARE EXPECTED TO REACH THE MID
50S INLAND WITH SOME UPPER 50S NEAR THE COAST.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...SWEEPING MID LEVEL TROUGH FROM THE NORTHERN
BRANCH OF THE SPLIT FLOW WILL BE THE MAIN FOCUS FOR THE SHORT TERM.
THE COLD FRONT ASSOCIATED WITH THIS FEATURE MOVES ACROSS SATURDAY.
THE LATEST GUIDANCE HAS TRENDED LOWER ON MAX TEMPERATURES FOR
SATURDAY DUE TO LESS INSOLATION. GUIDANCE POPS...MOST NOTABLY THE
MET NUMBERS HAVE JUMPED UP AND ARE NOW IN THE CATEGORICAL RANGE FOR
ALL STATIONS. FOR THIS REASON I HAVE INCREASED POPS TO LIKELY VALUES
FOR SATURDAY AFTERNOON. BY 0000 UTC SUNDAY THE FRONT HAS MOVED SOUTH
OF THE AREA AND THE COLD AIR ADVECTION ARRIVES IN FORCE. LATEST
850MB TEMPERATURES VIA THE GFS ARE NOT QUIET AS COLD SO IT SHOULD
NOT BE A BRUTAL DAY SUNDAY BUT MAX TEMPERATURES STILL LOOK TO REMAIN
BELOW 50 ACROSS ALL AREAS. FOR MONDAY MORNING LOWS...THE STORY WILL
BE WARM AIR ADVECTION ALOFT WITH THE VERY DRY/SHALLOW AND COLD
AIRMASS AT THE SURFACE. WITH A COUPLE OF DAYS IN THE 70S GROUND
TEMPERATES SHOULD KEEP LOWS IN THE MID 20S AREA WIDE.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 AM FRIDAY...FOCUS REMAINS ON THE SOUTHERN STREAM SYSTEM TO
IMPACT THE AREA TUESDAY AND WEDNESDAY. MEDIUM RANGE GUIDANCE REMAINS
CONSISTENT ON A SLOW MOVING MID LEVEL LOW MOVING OUT OF THE FOUR
CORNERS REGION WITH A SURFACE LOW DEVELOPING IN THE GULF OF MEXICO.
THERE REMAINS UNCERTAINTY AS TO WHICH TYPE OF SURFACE LOW
DEVELOPS... A MILLER A OR B SCENARIO BUT ONCE AGAIN THIS FAR OUT IN
TIME...THIS ISN/T CRITICAL AS OF YET. AS WE MOVE CLOSER...THE TRACK
AND TYPE WILL BECOME INCREASINGLY IMPORTANT AS TO THE TYPE AND
AMOUNT OF QPF. I HAVE MAINTAINED THE LIKELY POPS FOR TUESDAY AND
WEDNESDAY WHILE SHOWING RESTRAINT FROM INCREASING POPS THIS FAR OUT
IN TIME. TEMPERATURE TRENDS REMAIN ALL BUT UNCHANGED AS THE MOISTURE
WILL LIMIT VOLATILITY. I SUPPOSE THE BIG STORY RELATIVELY SPEAKING
IS THANKSGIVING DAY SHOULD BE DRY AS THE SYSTEM DEPARTS.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 12Z...SURFACE OBS INDICATE PATCHY AREAS OF DENSE FOG AND
STRATUS HAVE DEVELOPED WITHIN OUR CWA. KILM...KCRE AND KMYR ARE ALL
REPORTING LIFR CONDITIONS THIS MORNING. WHILE VSBYS SHOULD IMPROVE
BY 13-14Z...LIFR/IFR CIGS COULD PERSIST ALONG THE COAST THROUGH MID
MORNING. KCRE/KMYR HAVE HAD THE MOST PERSISTENT LIFR FOG/STRATUS...
SO THESE TERMS WILL LIKELY BE THE LAST TO BECOME VFR. AFTERWARDS...
VFR WILL PREVAIL TODAY WITH LIGHT AND VARIABLE WINDS EARLY BECOMING
SOUTH 5-8 KTS IN THE AFTN. LOW TO MID LEVEL CLOUDS WILL INCREASE
OVERNIGHT AS THE COLUMN MOISTENS AHEAD OF A COLD FRONT. CONDITIONS
AT KLBT/KFLO/KILM WILL LIKELY DETERIORATE TO AT LEAST MVFR BY THE
END OF THE PERIOD AS THE FRONT APPROACHES. HAVE ALSO ADDED VCSH FOR
THESE SITES AFTER 09Z SATURDAY. SHOWERS AT KCRE/KMYR WILL LIKELY
HOLD OFF UNTIL AFTER 12Z.
EXTENDED OUTLOOK...SCATTERED SHOWERS AND MVFR/IFR CIGS POSSIBLE
SATURDAY WITH A COLD FRONT. EXPECT BREEZY CONDITIONS FOLLOWING FROPA
ON SUNDAY. VFR ON MONDAY. SHOWERS LIKELY ON TUESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...A WEAKENING RIDGE OF HIGH PRESSURE EXTENDING
FROM NORTHERN NORTH CAROLINA TO A FEW HUNDRED MILES EAST OF NEW
JERSEY WILL SETTLE SOUTH ACROSS THE CAROLINA COASTAL WATERS LATE
THIS AFTERNOON. UNTIL THIS RIDGE AXIS GETS HERE WIND DIRECTIONS WILL
REMAIN GENERALLY EAST TO NORTHEASTERLY WITH SPEEDS DIMINISHING
THROUGHOUT THE DAY. THE RIDGE SHOULD SINK SOUTH OF THE AREA THIS
EVENING WITH OUR WINDS VEERING TO THE SOUTHWEST AND EVENTUALLY WEST
LATE TONIGHT IN ADVANCE OF A STRONG ARCTIC FRONT SCHEDULED FOR
TOMORROW.
MODELS HAVE MINOR TIMING DIFFERENCES WITH REGARDS TO WHEN THE RIDGE
AXIS MOVES ACROSS THE AREA...BUT NONE CHANGE THE FORECAST
APPRECIABLY. SEAS HAVE FALLEN TO 5 FEET OUT AT THE FRYING PAN SHOALS
BUOY...AND SHOULD SUBSIDE TO 4 FT TONIGHT...WITH A 10-11 SECOND
EASTERLY SWELL PROVIDING MOST OF THE WAVE ENERGY OBSERVED TODAY.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...THE FORECAST CHALLENGE FOR THE COASTAL WATERS
IS THE STRONG WINDS ARRIVING SATURDAY NIGHT IN THE WAKE OF A STRONG
COLD FRONT. SUSTAINED WINDS HAVE BACKED OFF EVER SO SLIGHTLY AND
GUSTS NOW ARE JUST BELOW GALE CRITERIA. CERTAINLY A SMALL CRAFT
ADVISORY IS A SLAM DUNK BUT A BRIEF GALE WARNING IS A LITTLE MORE IN
QUESTION. STILL LATE SATURDAY AND SUNDAY WILL NOT BE PLEASANT FOR
MARINERS WITH SUSTAINED NORTH WINDS OF 25-30 KNOTS EARLY DROPPING TO
15-20 KNOTS LATE SUNDAY. FOR MOST OF THE DAY SATURDAY A PRE FRONTAL
WESTERLY FLOW OF 10-15 KNOTS SHOULD PREVAIL. SIGNIFICANT SEAS ARE
MANAGEABLE MOST OF SATURDAY WITH 1-3 FEET. HOWEVER BY EARLY SUNDAY
HEIGHTS BUILD WITH THE STRONGER WINDS TO 4-6 FEET WITH THE HIGHER
SEAS ACROSS THE OUTER WATERS.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 300 AM FRIDAY...COASTAL WATERS WILL BE IN TRANSITION AS THE
SMALL CRAFT AND POSSIBLY GALE HEADLINE FROM SUNDAY WILL BE LONG
GONE. A MODEST NORTHEAST FLOW WILL BE IN PLACE EARLY MONDAY ON THE
ORDER OF 10-15 KNOTS DROPPING TO AROUND TEN KNOTS OR LESS BY DAYS
END. FOR TUESDAY A WEAK EAST TO SOUTHEAST FLOW WILL DEVELOP AS THE
HIGH MOVES OFF AND THE STORM SYSTEM IN THE GULF OF MEXICO MAKES ITS
MOVE. SPEEDS REMAIN TEPID TEN KNOTS OR LESS. RESIDUAL SEAS OF 2-4
FEET WILL BE IN PLACE MONDAY MORNING DROPPING TO 1-3 FEET LATE
MONDAY AND CONTINUING INTO TUESDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
935 AM EST FRI NOV 22 2013
.DISCUSSION...SPOTTY PATCHES OF LIGHT RAIN MOVING ACROSS THE
FORECAST AREA WELL AHEAD OF THE MORE SIGNIFICANT SHOWERS CLOSER TO
THE COLD FRONT. LATEST RUC MODEL RUN ADVANCES THE SHOWERS ACROSS THE
PLATEAU AND INTO SE TN BY NOON...THEN THE SHOWERS SPREAD TO THE FAR
ERN COUNTIES OF E TN AND SW VA BY MID TO LATE AFTERNOON. FORECAST
GRIDS COVER THIS SCENARIO QUITE WELL.
12Z SOUNDINGS FROM OHX AND RNK ARE WARM ALOFT WITH OHX SOUNDING
SATURATED FROM SURFACE TO 600 MBS. BETTER UPPER LEVEL SUPPORT IS TO
OUR NORTH...SO EXPECTING JUST SHOWERS (NO THUNDERSTORMS) AHEAD OF
THE FRONT.
PLAN TO FRESHEN THE HOURLY GRIDS AND DROP ANY MORNING WORDING FROM
THE ZFPMRX PRODUCT AROUND 11 AM EST.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 63 49 56 28 40 / 90 90 50 0 0
KNOXVILLE AIRPORT, TN 63 48 55 25 37 / 90 90 50 0 0
OAK RIDGE, TN 63 47 53 25 37 / 90 90 40 0 0
TRI CITIES AIRPORT, TN 63 45 52 22 33 / 90 90 50 0 0
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
TG
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
949 AM CST FRI NOV 22 2013
.DISCUSSION...
STRONG COLD FRONT WILL CONTINUE TO MOVE OFF THE COAST THIS MORNING AND
ACROSS THE COASTAL WATERS THIS AFTERNOON. BEHIND THE FRONT...SEEING
SOME 1 TO 2 INCH RAINFALL TOTALS ACROSS THE HOUSTON AREA ON THE HARRIS
COUNTY FLOOD WARNING SYSTEM WEBSITE AS A BAND OF SHOWERS AND THUNDERSTORMS
MOVES ACROSS THE AREA. TEMPERATURES BEHIND THE FRONT HAVE FALLEN INTO
THE 40S AND 50S...AND DO NOT EXPECT TO SEE ANY WARMUP FOR THE REMAINDER
OF THE DAY. CURRENT FORECAST AND DISCUSSIONS BELOW ARE RIGHT ON TRACK...AND
AT THIS TIME WILL NOT ISSUE A MORNING UPDATE. 42
&&
.PREV DISCUSSION... /ISSUED 609 AM CST FRI NOV 22 2013/
DISCUSSION...
SEE AVIATION FOR 12Z TAF DISCUSSION
AVIATION...
A STRONG COLD FRONT IS MOVING ACROSS SOUTHEAST TEXAS THIS MORNING
AND WILL APPROACH IAH WITHIN THE NEXT HOUR. THE FRONT IS MAKING A
QUICKER PUSH THROUGH OUR WESTERN COUNTIES SO THE BOUNDARY MAY
LIKELY MAKE IT THROUGH SGR BEFORE HOU AND WILL CLEAR MATAGORDA BAY
BEFORE MOVING THROUGH GLS. EXPECT SCATTERED SHOWERS AND
THUNDERSTORMS WITH THE FRONTAL PASSAGE AND THEN LINGERING LIGHT
RAIN AND IFR CIGS PERSISTING THROUGH THE TAF PERIOD. 38
.PREV DISCUSSION... /ISSUED 451 AM CST FRI NOV 22 2013/
DISCUSSION...
THE COLD FRONT HAS PUSHED INTO SE TX THIS MORNING AND BASICALLY
LOCATED FROM BRENHAM TO HUNTSVILLE TO JUST WEST OF NACOGDOCHES.
TEMPS AT COLLEGE STATION HAVE DROPPED FROM LOW 70S TO LOW 50S IN
AN HOUR AND NOW HOVERING AROUND 50F. FRONT HAS JUST PUSHED THROUGH
HUNTSVILLE SO EXPECT A SIMILAR DROP IN TEMPS THE NEXT HOUR OR TWO.
MAIN CONCERN TODAY WILL BE THE FRONTAL PASSAGE AND TEMPS DROPPING
BEHIND IT. THE 06Z HRRR SEEMS TO BE ABOUT AN HOUR SLOW WITH THE
FRONT. WITH THAT IN MIND...THINK FRONT REACHES KCXO AROUND 12Z AND
THEN KIAH AROUND 14-15Z. FRONT MAY REACH MATAGORDA BAY AROUND
16-17Z WHICH IS ABOUT THE SAME TIME IT SHOULD PUSH THROUGH KHOU.
FRONT WILL SLOWLY PUSH OFF THE COAST AROUND 18Z. TEMPS SHOULD DROP
BEHIND THE FRONT THROUGH THE AFTERNOON. TEMPS CLOSELY FOLLOW
RECENT RAP/NAM RUNS WHICH ALSO SEEM TO HAVE A GOOD HANDLE ON THE
FRONT AND POST FRONTAL TEMPS. THIS MEANS THAT TEMPS WILL BE IN THE
40S FOR THE COLLEGE STATION AREA DURING THE AFTERNOON WITH 50S FOR
HOUSTON AREA. TEMPS WILL DROP QUICKLY INTO THE 40S OVERNIGHT.
THUNDERSTORM CHANCES HAVE BEEN KEPT HIGH AROUND 70/80 PERCENT AND
THEN HIGHER BEHIND THE FRONT FOR POST FRONTAL RAIN. WILL KEEP SOME
RAIN CHANCES GOING FRI NIGHT INTO SAT AS A WEAK VORTICITY MAX
MOVES OVER THE AREA AND FRONTOGENESIS FROM 850MB FRONT INCREASES.
DEEPER COLD AIR MOVES INTO THE AREA SAT NIGHT INTO SUN AND
BOUNDARY LAYER ALSO DRIES OUT BASED ON MODEL SOUNDINGS. HAVE LOWER
POPS FROM NE TO SW FOR SAT NIGHT AND SUN. SUNDAY EXPECT A STRONGER
VORTICITY MAX TO MOVE OVER THE AREA WHICH WILL BE IN ADVANCE OF
MAIN UPPER LEVEL LOW OVER THE DESERT SW. UPPER LOW WILL SLOWLY
MOVE ACROSS THE S ROCKIES SUN NIGHT INTO MON. IN RESPONSE...EXPECT
INCREASES ISENTROPIC LIFT EVIDENT AT 290K/295K SURFACES. SO RAIN
CHANCES WILL BE ON THE INCREASE SUN NIGHT INTO MON. INCREASED POPS
TO 70 PERCENT ON MONDAY BUT COULD VERY WELL HAVE GONE HIGHER.
DECIDED TO WAIT FOR A COUPLE MORE RUNS BUT EVERYTHING POINTS TO A
VERY WET MONDAY. COULD SEE 1-2 INCHES OF RAIN AREAWIDE FOR SE TX
FOR MONDAY. MOISTURE WILL BE STREAMING OVER THE FRONTAL SURFACE
FOR LIFT AS WELL AS INCREASED OMEGA AS THE UPPER LOW MOVES INTO
TX. LARGE SCALE ASCENT WILL NOT BE LACKING ON MONDAY AND WILL
PERSIST INTO MON NIGHT. THE HARDEST DETAILS WILL BE TO DETERMINE
EXACTLY WHERE/HOW RAIN BANDS SET UP. ALSO NOTE THAT THE BOUNDARY
LAYER WILL BE QUITE COLD UNDER THE FRONTAL SURFACE. NAM/GFS MODEL
SOUNDINGS WILL BE QUITE BORDERLINE FOR RAIN/FREEZING RAIN FROM
KCLL TO KLFK. NOT GOING TO GO WITH FROZEN PRECIP YET AS THINK SFC
WILL STAY WARM ENOUGH AND THERE IS A SOLID WARM NOSE OF 5-8C
THROUGH A 8000FT LAYER BETWEEN 925-700MB.
THERE ARE STILL SOME TIMING DIFFERENCES BETWEEN THE
NAM/GFS/ECMWF. NAM/ECMWF SOLUTIONS ARE A BIT FASTER WITH TAKING
THE COASTAL LOW FROM THE NW GULF INTO LA COAST. THEY ALSO BRING
THE SFC LOW CLOSER TO THE UPPER TX COAST WHICH WOULD ONLY ADD TO
RAINFALL POTENTIAL. GFS IS ABOUT 6 HRS SLOWER AND FARTHER OFF THE
COAST WITH THE LOW. WITH THIS IN MIND HELD ONTO SOME HIGHER POPS
FOR MON NIGHT AS THERE STILL COULD BE THE POTENTIAL FOR RAINBANDS
TO SET UP WITH MODERATE/HEAVY RAIN.
SURFACE HIGH PRESSURE WILL BUILD INTO TX LATE TUE THROUGH
THANKSGIVING HOLIDAY. TEMPS WILL BE A SOLID 10-15 DEGREES BELOW
NORMAL FOR THE HOLIDAY. ALSO NOT EXPECTING ANY HOLIDAY TRAVEL
ISSUES FOR THE HOUSTON AREA ON WEDNESDAY. HOWEVER IF YOU ARE
TRAVELING FROM HOUSTON EAST TOWARDS DCA/PHL/JFK/BOS...YOU MAY
WANT TO KEEP TRACK OF FUTURE FORECASTS. IT IS NOT LOOKING GOOD.
&&
.MARINE...
STRONG COLD FRONT HAS MOVED INTO SOUTHEAST TEXAS THIS MORNING AND
WILL BEGIN PUSHING INTO THE BAYS LATE THIS MORNING. HAVE ISSUED
ADVISORIES FOR ALL WATERS BEGINNING THIS AFTERNOON AS STRONG
OFFSHORE WINDS AND BUILDING SEAS ARE EXPECTED IN THE WAKE OF THE
FRONT. SOME GUSTS TO GALE FORCE WILL BE POSSIBLE TODAY. STRONG
OFFSHORE WINDS WILL PERSIST THROUGH THE WEEKEND AND ADVISORIES
WILL LIKELY BE EXTENDED INTO SATURDAY OR SUNDAY. A COASTAL LOW IS
FORECAST TO DEVELOP AND MOVE ACROSS THE UPPER TEXAS COASTAL WATERS
ON MONDAY...WITH STRONG OFFSHORE WINDS THEN PERSISTING IN ITS WAKE
THROUGH MID WEEK. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 47 38 46 36 44 / 70 50 60 20 60
HOUSTON (IAH) 69 43 50 42 50 / 80 50 50 20 30
GALVESTON (GLS) 68 50 55 44 53 / 70 50 50 40 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE
FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS
FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60
NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT
20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...42
AVIATION/MARINE...23
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
451 AM CST FRI NOV 22 2013
.DISCUSSION...
THE COLD FRONT HAS PUSHED INTO SE TX THIS MORNING AND BASICALLY
LOCATED FROM BRENHAM TO HUNTSVILLE TO JUST WEST OF NACOGDOCHES.
TEMPS AT COLLEGE STATION HAVE DROPPED FROM LOW 70S TO LOW 50S IN
AN HOUR AND NOW HOVERING AROUND 50F. FRONT HAS JUST PUSHED THROUGH
HUNTSVILLE SO EXPECT A SIMILAR DROP IN TEMPS THE NEXT HOUR OR TWO.
MAIN CONCERN TODAY WILL BE THE FRONTAL PASSAGE AND TEMPS DROPPING
BEHIND IT. THE 06Z HRRR SEEMS TO BE ABOUT AN HOUR SLOW WITH THE
FRONT. WITH THAT IN MIND...THINK FRONT REACHES KCXO AROUND 12Z AND
THEN KIAH AROUND 14-15Z. FRONT MAY REACH MATAGORDA BAY AROUND
16-17Z WHICH IS ABOUT THE SAME TIME IT SHOULD PUSH THROUGH KHOU.
FRONT WILL SLOWLY PUSH OFF THE COAST AROUND 18Z. TEMPS SHOULD DROP
BEHIND THE FRONT THROUGH THE AFTERNOON. TEMPS CLOSELY FOLLOW
RECENT RAP/NAM RUNS WHICH ALSO SEEM TO HAVE A GOOD HANDLE ON THE
FRONT AND POST FRONTAL TEMPS. THIS MEANS THAT TEMPS WILL BE IN THE
40S FOR THE COLLEGE STATION AREA DURING THE AFTERNOON WITH 50S FOR
HOUSTON AREA. TEMPS WILL DROP QUICKLY INTO THE 40S OVERNIGHT.
THUNDERSTORM CHANCES HAVE BEEN KEPT HIGH AROUND 70/80 PERCENT AND
THEN HIGHER BEHIND THE FRONT FOR POST FRONTAL RAIN. WILL KEEP SOME
RAIN CHANCES GOING FRI NIGHT INTO SAT AS A WEAK VORTICITY MAX
MOVES OVER THE AREA AND FRONTOGENESIS FROM 850MB FRONT INCREASES.
DEEPER COLD AIR MOVES INTO THE AREA SAT NIGHT INTO SUN AND
BOUNDARY LAYER ALSO DRIES OUT BASED ON MODEL SOUNDINGS. HAVE LOWER
POPS FROM NE TO SW FOR SAT NIGHT AND SUN. SUNDAY EXPECT A STRONGER
VORTICITY MAX TO MOVE OVER THE AREA WHICH WILL BE IN ADVANCE OF
MAIN UPPER LEVEL LOW OVER THE DESERT SW. UPPER LOW WILL SLOWLY
MOVE ACROSS THE S ROCKIES SUN NIGHT INTO MON. IN RESPONSE...EXPECT
INCREASES ISENTROPIC LIFT EVIDENT AT 290K/295K SURFACES. SO RAIN
CHANCES WILL BE ON THE INCREASE SUN NIGHT INTO MON. INCREASED POPS
TO 70 PERCENT ON MONDAY BUT COULD VERY WELL HAVE GONE HIGHER.
DECIDED TO WAIT FOR A COUPLE MORE RUNS BUT EVERYTHING POINTS TO A
VERY WET MONDAY. COULD SEE 1-2 INCHES OF RAIN AREAWIDE FOR SE TX
FOR MONDAY. MOISTURE WILL BE STREAMING OVER THE FRONTAL SURFACE
FOR LIFT AS WELL AS INCREASED OMEGA AS THE UPPER LOW MOVES INTO
TX. LARGE SCALE ASCENT WILL NOT BE LACKING ON MONDAY AND WILL
PERSIST INTO MON NIGHT. THE HARDEST DETAILS WILL BE TO DETERMINE
EXACTLY WHERE/HOW RAIN BANDS SET UP. ALSO NOTE THAT THE BOUNDARY
LAYER WILL BE QUITE COLD UNDER THE FRONTAL SURFACE. NAM/GFS MODEL
SOUNDINGS WILL BE QUITE BORDERLINE FOR RAIN/FREEZING RAIN FROM
KCLL TO KLFK. NOT GOING TO GO WITH FROZEN PRECIP YET AS THINK SFC
WILL STAY WARM ENOUGH AND THERE IS A SOLID WARM NOSE OF 5-8C
THROUGH A 8000FT LAYER BETWEEN 925-700MB.
THERE ARE STILL SOME TIMING DIFFERENCES BETWEEN THE
NAM/GFS/ECMWF. NAM/ECMWF SOLUTIONS ARE A BIT FASTER WITH TAKING
THE COASTAL LOW FROM THE NW GULF INTO LA COAST. THEY ALSO BRING
THE SFC LOW CLOSER TO THE UPPER TX COAST WHICH WOULD ONLY ADD TO
RAINFALL POTENTIAL. GFS IS ABOUT 6 HRS SLOWER AND FARTHER OFF THE
COAST WITH THE LOW. WITH THIS IN MIND HELD ONTO SOME HIGHER POPS
FOR MON NIGHT AS THERE STILL COULD BE THE POTENTIAL FOR RAINBANDS
TO SET UP WITH MODERATE/HEAVY RAIN.
SURFACE HIGH PRESSURE WILL BUILD INTO TX LATE TUE THROUGH
THANKSGIVING HOLIDAY. TEMPS WILL BE A SOLID 10-15 DEGREES BELOW
NORMAL FOR THE HOLIDAY. ALSO NOT EXPECTING ANY HOLIDAY TRAVEL
ISSUES FOR THE HOUSTON AREA ON WEDNESDAY. HOWEVER IF YOU ARE
TRAVELING FROM HOUSTON EAST TOWARDS DCA/PHL/JFK/BOS...YOU MAY
WANT TO KEEP TRACK OF FUTURE FORECASTS. IT IS NOT LOOKING GOOD.
&&
.MARINE...
STRONG COLD FRONT HAS MOVED INTO SOUTHEAST TEXAS THIS MORNING AND
WILL BEGIN PUSHING INTO THE BAYS LATE THIS MORNING. HAVE ISSUED
ADVISORIES FOR ALL WATERS BEGINNING THIS AFTERNOON AS STRONG
OFFSHORE WINDS AND BUILDING SEAS ARE EXPECTED IN THE WAKE OF THE
FRONT. SOME GUSTS TO GALE FORCE WILL BE POSSIBLE TODAY. STRONG
OFFSHORE WINDS WILL PERSIST THROUGH THE WEEKEND AND ADVISORIES
WILL LIKELY BE EXTENDED INTO SATURDAY OR SUNDAY. A COASTAL LOW IS
FORECAST TO DEVELOP AND MOVE ACROSS THE UPPER TEXAS COASTAL WATERS
ON MONDAY...WITH STRONG OFFSHORE WINDS THEN PERSISTING IN ITS WAKE
THROUGH MID WEEK. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 47 38 46 36 44 / 70 50 60 20 60
HOUSTON (IAH) 69 43 50 42 50 / 80 50 50 20 30
GALVESTON (GLS) 68 50 55 44 53 / 70 50 50 40 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY FROM NOON TODAY TO MIDNIGHT CST TONIGHT FOR
THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS
FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60
NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT
20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...39
AVIATION/MARINE...38
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
936 AM MST FRI NOV 22 2013
.UPDATE...
ISSUED AT 935 AM MST FRI NOV 22 2013
RAIN BUT LITTLE IF ANY SNOW HAS BEEN OBSERVED IN THE DURANGO AREA
(CO ZONE 22) THIS MORNING. A COUPLE CALLS TO SPOTTERS AROUND 7000 FT
ELEV THERE THIS MORNING INDICATED RAIN...OR RAIN/SNOW MIX BUT NO
ACCUMULATIONS. NAM AND RUC MODELS BUFKIT FORECAST SOUNDINGS TELLING
DIFFERENT PRECIP STORIES FOR TODAY...WITH THE NAM FAVORING SNOW AND
THE RUC FAVORING RAIN. CURRENT TEMPS FROM MESONET SHOWED TEMPS
MOSTLY ABOVE FREEZING...AND WITH TEMPS AND DEWPOINTS EXPECTED TO
STAY ABOVE FREEZING THERE TODAY...I WILL LEAN TOWARD RAIN OR
RAIN/SNOW MIX BUT WITH LITTLE ACCUMULATION. THUS...PLAN TO CANCEL
THE WINTER STORM WARNING FOR THE DURANGO AREA (CO ZONE 22) AND
REPLACE WITH A WINTER WEATHER ADVISORY FOR TONIGHT. NEW HIGHLIGHT
STATEMENT AND UPDATED GRIDDED/WORDED FORECAST OUT SHORTLY.
UPDATE ISSUED AT 750 AM MST FRI NOV 22 2013
CANCELLED THE WINTER WEATHER ADVISORY FOR THE I-70 CORRIDOR FROM
GRAND JCT TO RIFLE. LITTLE IF ANY SNOW OCCURRED OVERNIGHT. RADAR
INDICATES SOME SNOW WAS POSSIBLE FROM ABOUT WHITEWATER TO THE MESA-
DELTA COUNTY LINE. SNOW CONTINUED TO BE REPORTED AT THE DELTA AND
MONTROSE AIRPORTS SO WILL KEEP THE ADVISORY FOR CO ZONE 11 INTACT.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 356 AM MST FRI NOV 22 2013
HEALTHY AREA OF PRECIPITATION HAS MOVED INTO SW CO OVERNIGHT PRODUCING
LIGHT TO MODERATE RAIN AND SNOW FROM ABOUT OLATHE TO GATEWAY AND
SOUTH. SNOWFALL RATES VIA SNOTELS IN THE SAN JUANS LOOK TO BE
ABOUT ONE INCH PER HOUR FOR THE LAST FEW HOURS...AND MUCH SLOWER
AS YOU GO NORTH. KEPT THE ADVISORIES GOING FOR ZONES 6 AND
7...BUT A LITTLE BIT CONCERNED ABOUT MOISTURE BEING SHADOWED OVER
THE UNCOMPAHGRE AND REACHING AS FAR NORTH AS RIFLE TO MAKE MUCH IN
THE WAY OF SNOW ACCUMULATION. RADAR RETURNS ARE CREEPING TOWARD
THE VALLEY SO A TRACE OF SNOW IS EXPECTED BY THE BEGINNING OF THE
WORKDAY AND POTENTIALLY MORE BY MID-MORNING. EXPECTING TEMPS TO
WARM UP ENOUGH FOR VALLEYS TO CHANGE BACK OVER TO RAIN DURING THE
DAY AND POTENTIALLY BACK TO SNOW AGAIN TONIGHT FOR A FUN WINTRY
MIX.
THE HEAVIEST SNOW DURING THE FIRST HALF OF TODAY WILL OCCUR ALONG
SOUTHWEST FACING SLOPES FROM AN AREA STRETCHING WEST TO EAST
ENCOMPASSING ELEVATIONS ABOVE 7000 FT IN LA PLATA...SAN
JUAN...HINSDALE...AND ARCHULETA COUNTIES. STILL STRUGGLING WITH
SNOW LEVELS AS THE FORECAST MODELS STILL SHOW A SHALLOW COLD FRONT
GETTING ALL THE WAY DOWN TO THE 4 CORNERS AROUND NOON FRI. THIS
COULD BRING TEMPS DOWN A FEW DEGREES IN THE VALLEYS...AND COMBINED
WITH MOIST SOUTHWEST FLOW ALOFT...PRODUCE SNOW IN THE VALLEYS AS WELL.
MOISTURE TRANSPORT VECTORS SHOW MOISTURE CURRENTLY WRAPPING INTO
THE FOUR CORNERS AREA AHEAD OF THE UPPER LEVEL LOW CURRENTLY
SPINNING OVER SOUTHERN CALIFORNIA. THOUGH IR SATELLITE OVERNIGHT
SHOWS THIS SYSTEM BECOMING A LITTLE LESS ORGANIZED...IT IS STILL
PACKING A BIG PUNCH OF MOISTURE WHICH WILL COME IN A FEW DIFFERENT
WAVES THROUGH SATURDAY NIGHT. THE UPPER LEVEL LOW CAUSING THIS
PROLONGED PERIOD OF CLOUDS AND PRECIPITATION IS EXPECTED TO SHIFT
SOUTHEAST SLIGHTLY BEFORE MAKING AN EAST NORTHEAST TURN INTO THE 4
CORNERS REGION SUNDAY...ALLOWING A COUPLE OF PUSHES OF ENERGY
THROUGH BETWEEN NOW AND THEN.
MOISTURE IS EXPECTED TO REMAIN MAINLY IN THE SAN JUANS REGION
EARLY THIS MORNING...AND GRADUALLY MOVE NORTH INTO THE CENTRAL
MTNS INCLUDING ASPEN AND VAIL AROUND NOON OR EARLY THIS AFTERNOON.
MODELS INDICATE SHOWERS TAPERING OFF TONIGHT EXCEPT IN THE LA SALS
AND ABAJOS WHERE IT WILL CONTINUE THROUGH THE NIGHT. AS THE LOW
PUSHES EAST SATURDAY...ANOTHER SWATH OF MOISTURE AND VORT MAX WILL
PUSH BACK INTO THE AREA ACCOMPANIED BY A 85 KT JET...ONCE AGAIN
DUMPING THE HEAVIEST PRECIPITATION OVER SW CO.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 356 AM MST FRI NOV 22 2013
STILL EXPECTING SHOWERS TO CONTINUE THROUGH SATURDAY NIGHT...BUT
WILL BEGIN TO TAPER OFF WITH THE LOW PRESSURE CENTER FINALLY
MAKING A PUSH TOWARD THE AREA.
SUNDAY THROUGH THURSDAY...THE MID-RANGE MODELS REMAIN IN GOOD
AGREEMENT WITH THE CLOSED LOW OVER THE SWRN U.S. BEGINNING TO LIFT
ENE OVER CENTRAL AZ SUNDAY. THE NAM12...GFS AND ECMWF SHOW A
LARGE BAND OF CLOUDS AND PCPN WRAPPING AROUND THE N AND NW
QUADRANTS OF THE 500 MB LOW WITH MOISTURE CONTINUING TO FEED INTO
THE SYSTEM FROM THE SOUTH. AS THE UPPER LOW SLIDES OVER THE TX/OK
PANHANDLE EARLY MONDAY MORNING...THIS BAND REMAINS SOMEWHAT
STATIONARY OVER CENTRAL AND SW CO...AND SE UT. THE MODELS SHOW THE
PCPN AREA GLIDING SE AND EXITING THE FORECAST AREA BY MONDAY
EVENING. THE BEST FOCUSES FOR SIGNIFICANT PCPN WILL REMAIN BENEATH
THIS BAND...AND OVER THE SAN JAN MOUNTAINS DUE TO THE ADDED
INGREDIENT OF SOUTHERLY WINDS AT MID LEVELS ENHANCING THE
OROGRAPHIC COMPONENT OF THE PCPN. ONE MITIGATING FACTOR WILL BE
THE INDICATION OF A DRIER SLOT MOVING OVER THE AREA SUNDAY BEHIND
THE SURFACE COLD FRONT WHICH WILL HAVE MOVED OVER ERN NM AND WRN
TX SUNDAY.
DRY RIDGING WILL BRING A WARMING TREND TO THE AREA TUESDAY THROUGH
WEDNESDAY...THEN THE NEXT STORM WILL APPROACH FROM THE PACNW WED
NIGHT AND THURSDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 356 AM MST FRI NOV 22 2013
WIDESPREAD RAIN AND SNOW WILL CONTINUE THROUGH SAT MORNING. MVFR
CIGS AND VSBYS WILL BE COMMON AT ALL TAF SITES AND AIRPORTS ACROSS
THE AREA...WITH MOUNTAINS AND HIGH PASSES OBSCURED. EXPECT PERIODS
OF IFR CONDITIONS AT KASE...KEGE...KMTJ...KTEX...KDRO AND KCEZ...
AS WILL AS ALL AIRPORTS FROM KMTJ SOUTH. BRIEF LIFR IS POSSIBLE AT
KTEX...KDRO...KCEZ AND KPSO.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR COZ014.
WINTER STORM WARNING UNTIL 6 PM MST SATURDAY FOR COZ018-019.
WINTER WEATHER ADVISORY UNTIL 11 AM MST THIS MORNING FOR COZ011.
WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR COZ009-010-
012-017.
WINTER STORM WARNING UNTIL 6 AM MST SATURDAY FOR COZ023.
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 6 AM MST
SATURDAY FOR COZ022.
UT...WINTER STORM WARNING UNTIL 6 PM MST SATURDAY FOR UTZ028.
&&
$$
UPDATE...JAD
SHORT TERM...JAM
LONG TERM...JAM/CC
AVIATION...CC
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
202 PM CST FRI NOV 22 2013
.DISCUSSION...
335 AM CST
THE MAIN FORECAST CONCERNS THIS MORNING WILL FOCUS ON THE ARCTIC AIR
EXPECTED TO SPILL IN ACROSS THE AREA ON SATURDAY AND SUNDAY.
THE FIRST OF TWO COLD FRONTS HAS PUSHED ACROSS THE AREA OVERNIGHT.
HOWEVER...LIGHT PRECIPITATION CONTINUES ON THE BACK SIDE OF THIS
FRONT IN ASSOCIATION WITH SOME FORCING FOR ASCENT FROM SEVERAL WEAK
MID LEVEL SHORT WAVE DISTURBANCES...WHICH ARE BEING EJECTED EASTWARD
ACROSS THE MIDDLE MISSISSIPPI VALLEY WITHIN A RAPIDLY STRENGTHENING
120+ KT WESTERLY UPPER LEVEL JET. THIS DISTURBED MID LEVEL FLOW...IN
COMBINATION WITH SOME ENHANCED LOWER LEVEL FRONTOGENESIS ASSOCIATED
WITH THE BAROCLINIC ZONE DROPPING ACROSS THE AREA WILL LIKELY
CONTINUE TO PRODUCE SOME LIGHT PRECIP ACROSS THE AREA THROUGH MID TO
LATE MORNING.
IT APPEARS THAT COLDER AIR WILL WILL ARRIVE IN TIME TO LEAD TO A
CHANGE OVER TO SOME LIGHT SNOW EARLY THIS MORNING BEFORE THE PRECIP
ENDS. THE BEST CHANCES FOR THIS TO OCCUR LOOKS TO REMAIN MAINLY
ALONG AND NORTHEAST OF A LINE FROM NEAR PONTIAC NORTHEASTWARD
THROUGH CHICAGO. REGIONAL RADAR IMAGERY ACROSS EASTERN IOWA...WHERE
SNOW IS NOW FALLING INDICATES THAT THE PRECIP IS LIGHT...WITH ONLY A
FEW SLIGHTLY HEAVIER POCKETS OF SNOW EMBEDDED. I EXPECT THESE TRENDS
TO SHIFT OVER NORTHERN ILLINOIS THROUGH THE MORNING. SNOW SHOULD
BEGIN FALLING IN OR NEAR ROCKFORD AND MUCH OF NORTH CENTRAL ILLINOIS
BY AROUND 11 TO 12 UTC...AND IN THE CHICAGO AREA AFTER 13- 14 UTC.
PLACES TO THE SOUTHEAST ACROSS NORTHWESTERN INDIANA AND EAST CENTRAL
ILLINOIS WILL LIKELY REMAIN IN THE FORM OF RAIN. OVERALL...THIS
SHOULD NOT BE A BIG DEAL AS THE SNOW WILL REMAIN LIGHT AND
TEMPERATURES WILL LIKELY HOVER AROUND OR JUST ABOVE FREEZING THROUGH
THE MORNING. THEREFORE...NO REAL ACCUMULATION IS EXPECTED.
THINGS WILL DRY OUT BY THIS AFTERNOON...THEN ATTENTION TURNS TO THE
NEXT ARCTIC FRONT...WHICH SHOULD DROP ACROSS THE AREA EARLY ON
SATURDAY. THIS FRONT WILL MARK A QUICK SHIFT TO MUCH MUCH COLDER AIR
AS AN IMPRESSIVE 1048+ MB HIGH BUILDS SOUTHWARD ACROSS THE DAKOTAS.
TEMPERATURES AT 850 MB ARE PROGGED TO DROP DOWN AROUND -18 CELSIUS
ACROSS FAR NORTHERN ILLINOIS BY SATURDAY AFTERNOON VIA SOME STIFF
NORTHWESTERLY WINDS. OVERALL THIS WILL RESULT IN AN UGLY DAY...WITH
TEMPERATURES LIKELY REMAINING NEARLY STEADY OR EVEN DROPPING IN THE
20S THROUGH THE DAY. THIS COMBINED WITH A NORTHWEST WINDS OF 15 TO
25 MPH AND GUSTS UP TO 35 MPH WILL CREATE WIND CHILL VALUES IN THE
UPPER SINGLE DIGITS NORTH TO THE MID TO UPPER TEENS SOUTH. THE RAPID
TRANSITION TO THIS COLDER AIRMASS COULD EVEN SQUEEZE OUT A FEW
FLURRIES EARLY SATURDAY...MAKING IT FEEL MORE LIKE
MID-WINTER.
THESE VERY COLD TEMPERATURES WILL ALSO SET UP VERY FAVORABLE
THERMODYNAMIC CONDITIONS OVER LAKE MICHIGAN TO RESULT IN LAKE EFFECT
SNOW SATURDAY AND SATURDAY NIGHT. EQUILIBRIUM HEIGHTS ARE EXPECTED TO
TOP 12,000 FEET...AS LAKE TO 850 MB TEMPERATURE DEVIATIONS CLIMB IN
EXCESS OF 22 DEGREES CELSIUS. THIS SHOULD ULTIMATELY LEAD TO THE
POSSIBILITIES FOR SOME DECENT LAKE EFFECT SNOW. AT THIS TIME IT
APPEARS THAT THE NORTHWEST FLOW OVER LAKE MICHIGAN WILL FAVOR AREAS
ACROSS THE EASTERN SHORES...LIKELY EAST OF PORTER COUNTY INDIANA AS
WELL. I DID...HOWEVER...LEAVE SOME SLIGHT CHANCE MENTIONS FOR SNOW
SHOWERS FOR FAR NORTHEASTERN PORTER LATE SATURDAY AND SATURDAY
NIGHT.
SATURDAY NIGHT INTO SUNDAY MORNING APPEARS TO BE ONE OF THE COLDEST
NIGHTS THUS FAR THIS SEASON. GUIDANCE CONTINUES TO BUILD THE STRONG
1040 MB HIGH RIGHT ACROSS THE MID MISSISSIPPI VALLEY BY DAYBREAK
SUNDAY. ALTHOUGH THIS LOOKS TO RESULT IN ENOUGH OF A GRADIENT TO
KEEP SOME NORTHERLY WINDS GOING ACROSS NORTHEASTERN ILLINOIS AND
NORTHWESTERN INDIANA INTO SUNDAY MORNING...IT APPEARS THAT
TEMPERATURES WILL LIKELY FALL INTO THE SINGLE DIGITS IN SOME OF THE
COLDER SPOTS OF THE FOX VALLEY AND PORTIONS OF NORTH CENTRAL
ILLINOIS. IT APPEARS THAT EVEN THE CITY OF CHICAGO WILL DROP INTO
THE MID TEENS SUNDAY MORNING.
THIS COLD START TO SUNDAY WILL LIKELY ONLY ALLOW TEMPS TO REBOUND
INTO THE MIDDLE TO PERHAPS UPPER 20S SUNDAY AFTERNOON. THE SURFACE
FLOW SHOULD TURN SOUTHWESTERLY SUNDAY AFTERNOON AS THE SURFACE HIGH
CONTINUES TO SHIFT SOUTHEASTWARD TOWARDS THE TENNESSEE VALLEY. WIND
SPEEDS WILL LIKELY INCREASE SUNDAY NIGHT INTO MONDAY...SO THIS
SHOULD NOT ALLOW TEMPS TO DROP OFF MUCH SUNDAY NIGHT.
THE EXTENDED PERIOD APPEARS TO BE MAINLY DRY ACROSS THE REGION.
HOWEVER...THERE COULD BE SOME LIGHT SNOW ACROSS THE AREA ON MONDAY
AS GOOD ISENTROPIC ASCENT SETS UP ACROSS THE AREA IN ASSOCIATION
WITH A CLIPPER SYSTEM EXPECTED TO PUSH ACROSS SOUTHERN ONTARIO. I AM
NOT TO EXCITED ABOUT THIS CHANCE AS THE BEST DYNAMICS SHOULD REMAIN
NORTH OF THE AREA...BUT I HAVE LEFT SLIGHT CHANCE MENTIONS IN THE
FORECAST.
ANOTHER REINFORCING SHOT OF COLD AIR LOOKS TO DROP DOWN IN THE WAKE
OF THIS CLIPPER SYSTEM FOR MID WEEK...SO NO BIG IMPROVEMENTS IN
TEMPERATURES ARE EXPECTED. WITH THIS NEXT COLD PUSH...ANOTHER
SURFACE HIGH WILL LIKELY SHIFT SOUTHEAST SOMEWHERE ACROSS THE GREAT
LAKES ON OR AROUND THANKSGIVING. THE NORTHERLY FLOW THIS SETS UP
COULD PRODUCE SOME MORE LAKE EFFECT SNOW...AND IF THE FLOW TURNS
NORTHEAST AS THE GUIDANCE SUGGESTS BY THURSDAY...SOME OF THIS LAKE
EFFECT SNOW COULD AFFECT PORTIONS OF NORTHEASTERN ILLINOIS BEFORE IT
FADES. THIS IS STILL FAR OUT...BUT THE OVERALL SET UP FOR GOOD LAKE
EFFECT SNOW MAY NOT BE AS GOOD...ESPECIALLY BY THANKSGIVING...AS IT
APPEARS WARMER MID LEVEL TEMPERATURES MAY TRY TO QUICKLY OVERSPREAD
THE AREA IN RESPONSE TO RISING HEIGHTS ALOFT LATER NEXT WEEK. THIS
COULD ULTIMATELY LIMIT THE HEIGHT OF THE EQUILIBRIUM LEVELS FOR
PARCELS MODIFIED BY LAKE MICHIGAN. THIS WILL NEED TO BE WATCHED.
OTHERWISE IT JUST LOOKS UNSEASONABLY COLD AND DRY ACROSS MUCH OF THE
AREA THROUGH THANKSGIVING.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* PATCHY MVFR CIGS 2200-2500 FT DISSIPATING BY LATE AFTERNOON.
* GUSTY NORTH WINDS 15-20 KT EARLY THIS AFTERNOON DIMINISHING BY
EVENING.
* STRONG COLD FRONTAL PASSAGE EARLY SATURDAY MORNING. GUSTY NORTH-
NORTHWEST WINDS 25-30 KT. MVFR CIGS 2500-3000 FT DEVELOPING
BEHIND FRONT WITH A FEW SNOW FLURRIES.
RATZER
//DISCUSSION...UPDATED 18Z...
DRYING/SUBSIDENCE ERODING CLOUD COVER FROM THE NORTH-NORTHWEST
EARLY THIS AFTERNOON. MVFR CIGS HAVE SHOWN SLOW BUT STEADY
IMPROVEMENT...AND SHOULD CONTINUE TO LIFT/SCATTER TO VFR BY MID-
AFTERNOON. NORTH WINDS GUSTING 15-20 KT WILL GRADUALLY DECREASE
LATER THIS AFTERNOON...DROPPING TO LESS THAN 10 KT AFTER SUNSET AS
WEAK HIGH PRESSURE RIDGE DEVELOPS ACROSS THE TERMINALS.
LOW PRESSURE OVER SOUTHERN ONTARIO WILL DEEPEN AS IT MOVES
SOUTHEAST ACROSS THE NORTHERN GREAT LAKES TONIGHT...WITH A STRONG
ARCTIC COLD FRONT PUSHING SOUTHEAST ACROSS THE MIDWEST EARLY
SATURDAY. AFTER BACKING MORE WESTERLY OVERNIGHT...WINDS WILL VEER
NORTH-NORTHWEST AND GUST 25-30 KT BEHIND THE FRONT AFTER 10-13Z.
STRONG COLD ADVECTION WILL PRODUCE A FAIRLY SOLID MVFR STRATOCU
DECK WHICH LOOKS TO BE AROUND 2500 FT INITIALLY PERHAPS LIFTING
CLOSER TO 3000 FT IN THE AFTERNOON. WHILE NO ORGANIZED
PRECIPITATION IS EXPECTED...THE STRATOCU DECK WILL LIKELY PRODUCE
SOME FLURRIES AS THE COLUMN COOLS DURING THE DAY SATURDAY.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN CIGS ABOVE 2000 FT AND TRENDING TO VFR
CONDITIONS BY EVENING.
* HIGH CONFIDENCE IN WIND TRENDS AND GUSTY CONDITIONS SATURDAY.
* MEDIUM-HIGH CONFIDENCE IN MVFR CIGS SATURDAY.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT-SUNDAY...VFR.
MONDAY...CHC OF -SN AND MVFR.
TUESDAY- WEDNESDAY...VFR.
THURSDAY...SLIGHT CHANCE OF LAKE EFFECT SNOW SHOWERS.
MTF
&&
.MARINE...
204 AM CST
AN ACTIVE LATE AUTUMN/EARLY WINTER PATTERN WILL PREVAIL ACROSS THE
LAKE THROUGH AT LEAST THE FIRST HALF OF NEXT WEEK. A COLD FRONT
WHICH PASSED LATE THURSDAY NIGHT HAS USHERED IN STIFF NORTH TO
NORTHWEST WINDS OVER THE LAKE WHICH WILL CONTINUE THROUGH MIDDAY
BEFORE EASING AND BACKING. WHILE THERE MAY BE A TEMPORARY BREAK IN
SMALL CRAFT ADVISORY CRITERIA TONIGHT...IT IS EXPECTED TO BE
BRIEF...SO HAVE CONTINUED THAT HEADLINE FOR THE IL AND IN
NEARSHORE.
ANOTHER COLD FRONT IS SET TO CROSS THE LAKE LATE TONIGHT WHICH WILL
BRING A PUNCH OF EVEN COLDER AIR. THIS WILL LEAD TO STEEPER LAPSE
RATES AND GREATER TRANSFER OF WIND MOMENTUM. IN RESPONSE...NORTHWEST
GALES ARE EXPECTED TO QUICKLY SPREAD DOWN THE LAKE PRIOR TO DAYBREAK
ON SATURDAY. GALES LOOK DEFINITE...MAYBE A FEW TO EVEN 40 KT. GALES
MAY EVEN BE EXPERIENCED IN NEAR SHORE AREAS OF INDIANA GIVEN THE
GREATER COMPONENT OF ONSHORE WIND DIRECTION AND REALIZED FETCH. AS
FOR FREEZING SPRAY SATURDAY...IT CONTINUES TO LOOK POSSIBLE BUT
MAINLY LIGHT DUE TO TOO WARM OF WATER TEMPERATURES.
A LARGE AND STRONG CANADIAN HIGH WILL MOVE TO THE SOUTH OF THE LAKE
ON SUNDAY AND THE PRESSURE GRADIENT ON ITS BACKSIDE WILL BE ENHANCED
BY LOW PRESSURE RACING ACROSS CANADA ON SUNDAY NIGHT INTO EARLY
MONDAY. THIS WILL AGAIN SET THE STAGE FOR POTENTIAL GALES...THIS
TIME FROM THE SOUTHWEST/WEST. HIGH PRESSURE LOOKS TO SLOWLY BUILD IN
THROUGH THE MIDWEEK TIME FRAME THEN...WITH INCREASING POTENTIAL FOR
LAKE EFFECT SNOWS ON THE CENTRAL...EASTERN...AND SOUTHERN PARTS OF
THE LAKE.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 AM SATURDAY TO 9 PM
SATURDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 9 AM SATURDAY.
GALE WATCH...LMZ744-LMZ745...9 AM SATURDAY TO 9 PM SATURDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 9 PM
SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
[top]
Area Forecast Discussion
National Weather Service Lincoln IL
130 PM CST Fri Nov 22 2013
.DISCUSSION...
ISSUED 120 PM CST Fri Nov 22 2013
SHORT TERM...Tonight through Monday
Temperatures and wind chills the main forecast concern this period
as Arctic high pressure settles over the region.
Models in good agreement in the short term with respect to the track
of the surface high pressure through the Midwest with our western
areas seeing the coldest temps late Sat night into Sunday morning,
and then our far east and southeast may see their coldest early
morning readings early Monday morning. With the surface high forecast
just to our west Saturday night, north to northwest winds will hold
up enough to drop wind chills down close to zero. As the high settles
across our area on Sunday, winds will be much lighter so wind chills
won`t be as much of a factor until towards dawn Monday across our far
west and northwest areas as the return flow sets up.
Moisture streaming northeast from the cutoff low across the southwest
U.S. will move through our area tonight, especially across the south.
Overnight lows will range from the mid teens far northwest to the mid
20s far southeast. With a gusty northerly wind on Saturday, afternoon
temperatures will stuggle thru the mid 20s north the mid 30s south
with wind chills in the 10 to 15 degree range north and low 20s far
south. Lows early Sunday morning will dip into the 5 to 10 degree
range north to the low/mid teens far south with single digit wind
chills in most of our area.
LONG TERM...Tuesday through Friday
Cold pattern to hold through most of the week with minor warm ups
in advance of shortwaves approaching from the northwest about every
couple of days. Little in the way of significant rain or snow seen
as a cutoff low, currently over the southwest U.S., tracks across
the southern Plains and lower Mississippi Valley, keeping most of
the significant precip south of our I-70 corridor early next week.
Meanwhile, return flow ahead of a northern stream wave may generate
some warm advection snow/rain on Monday but with such dry air at
the low levels thanks to the departing Arctic high, have opted to
keep the pops out of our area on Monday for now. Another shot of
Arctic air will follow the northern stream shortwave late Tuesday
into Wednesday with 850 temps from both the operational GFS and
12z ECMWF showing -10 to -14 degrees C pouring south into our
area. If those numbers do verify late in the week, our going highs
and lows for Wed and Thu may be too optimistic.
Smith
&&
.AVIATION...
ISSUED 1140 AM CST Fri Nov 22 2013
IFR ceilings will linger at both KBMI and KCMI for the next hour
or two before slowly improving to MVFR for the balance of the
afternoon. Back edge of cloud cover remains across far northwest
Illinois into eastern Iowa and has shown little to no
southeastward progress over the past several hours. NAM forecast
soundings try to clear skies at KPIA too early, so have trended
toward the more pessimistic HRRR for this aviation forecast. As
such, have maintained MVFR ceilings until 23z at KPIA...and 01z
further southeast at the I-72 terminals. Once low clouds depart,
plenty of high cloudiness currently over the Plains will stream
eastward tonight. This high cloudiness will gradually settle
southward overnight, resulting in mostly sunny skies by Saturday
morning. Strong northwesterly winds gusting to around 20kt will
persist through the afternoon before subsiding to less than 10kt
this evening. The winds will once again increase after 15z
Saturday, with numeric guidance suggesting gusts to between 20 and
25kt.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1137 AM CST FRI NOV 22 2013
.DISCUSSION...
335 AM CST
THE MAIN FORECAST CONCERNS THIS MORNING WILL FOCUS ON THE ARCTIC AIR
EXPECTED TO SPILL IN ACROSS THE AREA ON SATURDAY AND SUNDAY.
THE FIRST OF TWO COLD FRONTS HAS PUSHED ACROSS THE AREA OVERNIGHT.
HOWEVER...LIGHT PRECIPITATION CONTINUES ON THE BACK SIDE OF THIS
FRONT IN ASSOCIATION WITH SOME FORCING FOR ASCENT FROM SEVERAL WEAK
MID LEVEL SHORT WAVE DISTURBANCES...WHICH ARE BEING EJECTED EASTWARD
ACROSS THE MIDDLE MISSISSIPPI VALLEY WITHIN A RAPIDLY STRENGTHENING
120+ KT WESTERLY UPPER LEVEL JET. THIS DISTURBED MID LEVEL FLOW...IN
COMBINATION WITH SOME ENHANCED LOWER LEVEL FRONTOGENESIS ASSOCIATED
WITH THE BAROCLINIC ZONE DROPPING ACROSS THE AREA WILL LIKELY
CONTINUE TO PRODUCE SOME LIGHT PRECIP ACROSS THE AREA THROUGH MID TO
LATE MORNING.
IT APPEARS THAT COLDER AIR WILL WILL ARRIVE IN TIME TO LEAD TO A
CHANGE OVER TO SOME LIGHT SNOW EARLY THIS MORNING BEFORE THE PRECIP
ENDS. THE BEST CHANCES FOR THIS TO OCCUR LOOKS TO REMAIN MAINLY
ALONG AND NORTHEAST OF A LINE FROM NEAR PONTIAC NORTHEASTWARD
THROUGH CHICAGO. REGIONAL RADAR IMAGERY ACROSS EASTERN IOWA...WHERE
SNOW IS NOW FALLING INDICATES THAT THE PRECIP IS LIGHT...WITH ONLY A
FEW SLIGHTLY HEAVIER POCKETS OF SNOW EMBEDDED. I EXPECT THESE TRENDS
TO SHIFT OVER NORTHERN ILLINOIS THROUGH THE MORNING. SNOW SHOULD
BEGIN FALLING IN OR NEAR ROCKFORD AND MUCH OF NORTH CENTRAL ILLINOIS
BY AROUND 11 TO 12 UTC...AND IN THE CHICAGO AREA AFTER 13- 14 UTC.
PLACES TO THE SOUTHEAST ACROSS NORTHWESTERN INDIANA AND EAST CENTRAL
ILLINOIS WILL LIKELY REMAIN IN THE FORM OF RAIN. OVERALL...THIS
SHOULD NOT BE A BIG DEAL AS THE SNOW WILL REMAIN LIGHT AND
TEMPERATURES WILL LIKELY HOVER AROUND OR JUST ABOVE FREEZING THROUGH
THE MORNING. THEREFORE...NO REAL ACCUMULATION IS EXPECTED.
THINGS WILL DRY OUT BY THIS AFTERNOON...THEN ATTENTION TURNS TO THE
NEXT ARCTIC FRONT...WHICH SHOULD DROP ACROSS THE AREA EARLY ON
SATURDAY. THIS FRONT WILL MARK A QUICK SHIFT TO MUCH MUCH COLDER AIR
AS AN IMPRESSIVE 1048+ MB HIGH BUILDS SOUTHWARD ACROSS THE DAKOTAS.
TEMPERATURES AT 850 MB ARE PROGGED TO DROP DOWN AROUND -18 CELSIUS
ACROSS FAR NORTHERN ILLINOIS BY SATURDAY AFTERNOON VIA SOME STIFF
NORTHWESTERLY WINDS. OVERALL THIS WILL RESULT IN AN UGLY DAY...WITH
TEMPERATURES LIKELY REMAINING NEARLY STEADY OR EVEN DROPPING IN THE
20S THROUGH THE DAY. THIS COMBINED WITH A NORTHWEST WINDS OF 15 TO
25 MPH AND GUSTS UP TO 35 MPH WILL CREATE WIND CHILL VALUES IN THE
UPPER SINGLE DIGITS NORTH TO THE MID TO UPPER TEENS SOUTH. THE RAPID
TRANSITION TO THIS COLDER AIRMASS COULD EVEN SQUEEZE OUT A FEW
FLURRIES EARLY SATURDAY...MAKING IT FEEL MORE LIKE
MID-WINTER.
THESE VERY COLD TEMPERATURES WILL ALSO SET UP VERY FAVORABLE
THERMODYNAMIC CONDITIONS OVER LAKE MICHIGAN TO RESULT IN LAKE EFFECT
SNOW SATURDAY AND SATURDAY NIGHT. EQUILIBRIUM HEIGHTS ARE EXPECTED TO
TOP 12,000 FEET...AS LAKE TO 850 MB TEMPERATURE DEVIATIONS CLIMB IN
EXCESS OF 22 DEGREES CELSIUS. THIS SHOULD ULTIMATELY LEAD TO THE
POSSIBILITIES FOR SOME DECENT LAKE EFFECT SNOW. AT THIS TIME IT
APPEARS THAT THE NORTHWEST FLOW OVER LAKE MICHIGAN WILL FAVOR AREAS
ACROSS THE EASTERN SHORES...LIKELY EAST OF PORTER COUNTY INDIANA AS
WELL. I DID...HOWEVER...LEAVE SOME SLIGHT CHANCE MENTIONS FOR SNOW
SHOWERS FOR FAR NORTHEASTERN PORTER LATE SATURDAY AND SATURDAY
NIGHT.
SATURDAY NIGHT INTO SUNDAY MORNING APPEARS TO BE ONE OF THE COLDEST
NIGHTS THUS FAR THIS SEASON. GUIDANCE CONTINUES TO BUILD THE STRONG
1040 MB HIGH RIGHT ACROSS THE MID MISSISSIPPI VALLEY BY DAYBREAK
SUNDAY. ALTHOUGH THIS LOOKS TO RESULT IN ENOUGH OF A GRADIENT TO
KEEP SOME NORTHERLY WINDS GOING ACROSS NORTHEASTERN ILLINOIS AND
NORTHWESTERN INDIANA INTO SUNDAY MORNING...IT APPEARS THAT
TEMPERATURES WILL LIKELY FALL INTO THE SINGLE DIGITS IN SOME OF THE
COLDER SPOTS OF THE FOX VALLEY AND PORTIONS OF NORTH CENTRAL
ILLINOIS. IT APPEARS THAT EVEN THE CITY OF CHICAGO WILL DROP INTO
THE MID TEENS SUNDAY MORNING.
THIS COLD START TO SUNDAY WILL LIKELY ONLY ALLOW TEMPS TO REBOUND
INTO THE MIDDLE TO PERHAPS UPPER 20S SUNDAY AFTERNOON. THE SURFACE
FLOW SHOULD TURN SOUTHWESTERLY SUNDAY AFTERNOON AS THE SURFACE HIGH
CONTINUES TO SHIFT SOUTHEASTWARD TOWARDS THE TENNESSEE VALLEY. WIND
SPEEDS WILL LIKELY INCREASE SUNDAY NIGHT INTO MONDAY...SO THIS
SHOULD NOT ALLOW TEMPS TO DROP OFF MUCH SUNDAY NIGHT.
THE EXTENDED PERIOD APPEARS TO BE MAINLY DRY ACROSS THE REGION.
HOWEVER...THERE COULD BE SOME LIGHT SNOW ACROSS THE AREA ON MONDAY
AS GOOD ISENTROPIC ASCENT SETS UP ACROSS THE AREA IN ASSOCIATION
WITH A CLIPPER SYSTEM EXPECTED TO PUSH ACROSS SOUTHERN ONTARIO. I AM
NOT TO EXCITED ABOUT THIS CHANCE AS THE BEST DYNAMICS SHOULD REMAIN
NORTH OF THE AREA...BUT I HAVE LEFT SLIGHT CHANCE MENTIONS IN THE
FORECAST.
ANOTHER REINFORCING SHOT OF COLD AIR LOOKS TO DROP DOWN IN THE WAKE
OF THIS CLIPPER SYSTEM FOR MID WEEK...SO NO BIG IMPROVEMENTS IN
TEMPERATURES ARE EXPECTED. WITH THIS NEXT COLD PUSH...ANOTHER
SURFACE HIGH WILL LIKELY SHIFT SOUTHEAST SOMEWHERE ACROSS THE GREAT
LAKES ON OR AROUND THANKSGIVING. THE NORTHERLY FLOW THIS SETS UP
COULD PRODUCE SOME MORE LAKE EFFECT SNOW...AND IF THE FLOW TURNS
NORTHEAST AS THE GUIDANCE SUGGESTS BY THURSDAY...SOME OF THIS LAKE
EFFECT SNOW COULD AFFECT PORTIONS OF NORTHEASTERN ILLINOIS BEFORE IT
FADES. THIS IS STILL FAR OUT...BUT THE OVERALL SET UP FOR GOOD LAKE
EFFECT SNOW MAY NOT BE AS GOOD...ESPECIALLY BY THANKSGIVING...AS IT
APPEARS WARMER MID LEVEL TEMPERATURES MAY TRY TO QUICKLY OVERSPREAD
THE AREA IN RESPONSE TO RISING HEIGHTS ALOFT LATER NEXT WEEK. THIS
COULD ULTIMATELY LIMIT THE HEIGHT OF THE EQUILIBRIUM LEVELS FOR
PARCELS MODIFIED BY LAKE MICHIGAN. THIS WILL NEED TO BE WATCHED.
OTHERWISE IT JUST LOOKS UNSEASONABLY COLD AND DRY ACROSS MUCH OF THE
AREA THROUGH THANKSGIVING.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* PATCHY MVFR CIGS 1600-2000 FT DISSIPATING EARLY THIS AFTERNOON.
* GUSTY NORTH WINDS 15-20 KT THIS AFTERNOON. GUSTS DIMINISHING BY
EARLY EVENING.
* STRONG COLD FRONTAL PASSAGE EARLY SATURDAY MORNING. GUSTY NORTH-
NORTHWEST WINDS 25-30 KT. MVFR CIGS 2500-3000 FT DEVELOPING
BEHIND FRONT WITH A FEW SNOW FLURRIES.
RATZER
//DISCUSSION...UPDATED 18Z...
DRYING/SUBSIDENCE ERODING CLOUD COVER FROM THE NORTH-NORTHWEST
EARLY THIS AFTERNOON. MVFR CIGS HAVE SHOWN SLOW BUT STEADY
IMPROVEMENT...AND SHOULD CONTINUE TO LIFT/SCATTER TO VFR BY MID-
AFTERNOON. NORTH WINDS GUSTING 15-20 KT WILL GRADUALLY DECREASE
LATER THIS AFTERNOON...DROPPING TO LESS THAN 10 KT AFTER SUNSET AS
WEAK HIGH PRESSURE RIDGE DEVELOPS ACROSS THE TERMINALS.
LOW PRESSURE OVER SOUTHERN ONTARIO WILL DEEPEN AS IT MOVES
SOUTHEAST ACROSS THE NORTHERN GREAT LAKES TONIGHT...WITH A STRONG
ARCTIC COLD FRONT PUSHING SOUTHEAST ACROSS THE MIDWEST EARLY
SATURDAY. AFTER BACKING MORE WESTERLY OVERNIGHT...WINDS WILL VEER
NORTH-NORTHWEST AND GUST 25-30 KT BEHIND THE FRONT AFTER 10-13Z.
STRONG COLD ADVECTION WILL PRODUCE A FAIRLY SOLID MVFR STRATOCU
DECK WHICH LOOKS TO BE AROUND 2500 FT INITIALLY PERHAPS LIFTING
CLOSER TO 3000 FT IN THE AFTERNOON. WHILE NO ORGANIZED
PRECIPITATION IS EXPECTED...THE STRATOCU DECK WILL LIKELY PRODUCE
SOME FLURRIES AS THE COLUMN COOLS DURING THE DAY SATURDAY.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN TREND TO VFR CONDITIONS THIS AFTERNOON. CIGS
STARTING OUT ABOVE 1500 FT.
* HIGH CONFIDENCE IN WIND TRENDS AND GUSTY CONDITIONS SATURDAY.
* MEDIUM-HIGH CONFIDENCE IN MVFR CIGS SATURDAY.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT-SUNDAY...VFR.
MONDAY...CHC OF -SN AND MVFR.
TUESDAY- WEDNESDAY...VFR.
THURSDAY...SLIGHT CHANCE OF LAKE EFFECT SNOW SHOWERS.
MTF
&&
.MARINE...
204 AM CST
AN ACTIVE LATE AUTUMN/EARLY WINTER PATTERN WILL PREVAIL ACROSS THE
LAKE THROUGH AT LEAST THE FIRST HALF OF NEXT WEEK. A COLD FRONT
WHICH PASSED LATE THURSDAY NIGHT HAS USHERED IN STIFF NORTH TO
NORTHWEST WINDS OVER THE LAKE WHICH WILL CONTINUE THROUGH MIDDAY
BEFORE EASING AND BACKING. WHILE THERE MAY BE A TEMPORARY BREAK IN
SMALL CRAFT ADVISORY CRITERIA TONIGHT...IT IS EXPECTED TO BE
BRIEF...SO HAVE CONTINUED THAT HEADLINE FOR THE IL AND IN
NEARSHORE.
ANOTHER COLD FRONT IS SET TO CROSS THE LAKE LATE TONIGHT WHICH WILL
BRING A PUNCH OF EVEN COLDER AIR. THIS WILL LEAD TO STEEPER LAPSE
RATES AND GREATER TRANSFER OF WIND MOMENTUM. IN RESPONSE...NORTHWEST
GALES ARE EXPECTED TO QUICKLY SPREAD DOWN THE LAKE PRIOR TO DAYBREAK
ON SATURDAY. GALES LOOK DEFINITE...MAYBE A FEW TO EVEN 40 KT. GALES
MAY EVEN BE EXPERIENCED IN NEAR SHORE AREAS OF INDIANA GIVEN THE
GREATER COMPONENT OF ONSHORE WIND DIRECTION AND REALIZED FETCH. AS
FOR FREEZING SPRAY SATURDAY...IT CONTINUES TO LOOK POSSIBLE BUT
MAINLY LIGHT DUE TO TOO WARM OF WATER TEMPERATURES.
A LARGE AND STRONG CANADIAN HIGH WILL MOVE TO THE SOUTH OF THE LAKE
ON SUNDAY AND THE PRESSURE GRADIENT ON ITS BACKSIDE WILL BE ENHANCED
BY LOW PRESSURE RACING ACROSS CANADA ON SUNDAY NIGHT INTO EARLY
MONDAY. THIS WILL AGAIN SET THE STAGE FOR POTENTIAL GALES...THIS
TIME FROM THE SOUTHWEST/WEST. HIGH PRESSURE LOOKS TO SLOWLY BUILD IN
THROUGH THE MIDWEEK TIME FRAME THEN...WITH INCREASING POTENTIAL FOR
LAKE EFFECT SNOWS ON THE CENTRAL...EASTERN...AND SOUTHERN PARTS OF
THE LAKE.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 AM SATURDAY TO 9 PM
SATURDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 9 AM SATURDAY.
GALE WATCH...LMZ744-LMZ745...9 AM SATURDAY TO 9 PM SATURDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 9 PM
SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
1035 AM CST Fri Nov 22 2013
.DISCUSSION...
ISSUED 1035 AM CST Fri Nov 22 2013
Cold front continues to push eastward toward the Appalachians,
while gusty northwesterly winds bring much colder air into central
Illinois. Light showers/drizzle from earlier this morning has now
shifted into far eastern Illinois and will exit into Indiana over
the next couple of hours. Cloudy skies currently blanket the
entire area: however, clearing is noted as close as eastern Iowa.
Latest visible satellite imagery shows additional diurnal clouds
developing along the back edge of the main cloud deck, thus
slowing the eastward progression of the clearing. Despite this new
development, think skies will become partly to mostly sunny by mid
to late afternoon along and northwest of a Rushville to Minonk
line. Further southeast, cloudy skies will prevail throughout the
day. Temperatures will remain steady or slowly fall into the 30s.
Zone update to remove morning POPs and better define the clearing
trend has already been issued.
Barnes
&&
.AVIATION...
ISSUED 545 AM CST Fri Nov 22 2013
Ifr conditions over region in the post frontal area over central
IL. IR satellite and moisture channel depicts minor wave moving
through central IL with debris from the AR pcpn. Very light pcpn
with this wave is gradually moving eastward over eastern CWA.
Expect cigs to only slowly raise til mid morning and then improve.
Drier air finally moves in during afternoon per the HRRR models
and then show increase cigs. The patchy vsbs in fog to improve
early this morning to vfr.
Goetsch
&&
.PREV DISCUSSION...
ISSUED 220 AM CST Fri Nov 22 2013
The cold front has pushed through much of the forecast area early
this morning...and is about to clear the far southeast as of 2 am.
Some light post-frontal showers continue over the northwest half
of the area, while radar and surface obs showed some fairly
widespread light snow across much of central and eastern Iowa,
back where temperatures are mainly in the 20s. Have been seeing
some dense fog along and just behind the front, but this should
continue to lift as the front moves further east.
Main forecast concern involves the cold weekend weather, and
timing of the ending of the remaining precipitation today.
SHORT TERM...Today through Sunday:
Latest model trends continue to get the area largely dry by
midday. Colder air will make more of a surge later today, and most
areas should see steady or falling afternoon temperatures.
Arctic air mass over central Canada poised to surge southeast
through the Great Lakes this weekend. Brunt of the coldest air
still progged to stay to our north, but 850 mb temperatures drop
to around -14C here, so sub-freezing highs likely. Rather blustery
conditions expected Saturday ahead of strong Canadian high
pressure, but winds will subside on Sunday as the high drifts into
south central Illinois.
LONG TERM...Monday through Thanksgiving Day:
Large cutoff low, currently seen in water vapor imagery centered
near Los Angeles, should finally start to push eastward early next
week, as the deep trough in the northern stream finally pushes
to New England. Next shortwave in the northern stream is looking
to come through mainly dry Monday afternoon/night, as a storm
system develops along the Gulf. Deformation precipitation with
this system progged to reach about as far as the Ohio River as the
storm slowly moves into the Carolinas by midweek. This will
largely keep the Midwest dry from Tuesday through Thanksgiving,
except for some lake effect snow south of Lake Michigan. Second
Arctic surge at mid week is not quite as bitter as the upcoming
cold wave, but highs in the lower to mid 30s will be common for
the pre-Thanksgiving travel rush.
Geelhart
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1237 PM EST FRI NOV 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 444 AM EST FRI NOV 22 2013
BROAD AREA OF LIGHT SNOW ASSOCIATED WITH A COUPLED UPPER
JET...SHORTWAVE ENERGY AND MID-LEVEL Q-VECTOR CONVERGENCE CONTINUES
TO SLIDE EAST EARLY THIS MORNING ACROSS UPPER MICHIGAN AND
WISCONSIN. GENERALLY LIGHT SNOW WITH VISIBILITIES IN MOST LOCATIONS
OF 2 TO 5 MILES. WE SAW FINE FLAKES AT OUR OFFICE MOST OF THE
NIGHT...WHICH HAS BEEN HELPFUL IN REDUCING VISIBILITIES. ONE REPORT
FROM NORTHERN WISCONSIN INDICATED A HALF AN INCH OF SNOW
ACCUMULATION AND OUR OFFICE HAD 0.6 INCH AS OF 1AM. THE SNOW HAS
ALREADY ENDED OVER WESTERN UPPER MICHIGAN (KCMX/KIWD OBS) AND
STARTING TO SEE THE REFLECTIVITIES QUICKLY DIMINISH OVER BARAGA
AND IRON COUNTIES. AS THE UPPER LEVEL FEATURES CONTINUE TO SHIFT
EAST THIS MORNING...EXPECT THE SYNOPTIC SNOWFALL TO QUICKLY
DIMINISH THROUGH MID MORNING.
OVER NORTHERN UPPER MICHIGAN...LOW LEVEL 925-850MB NORTH-NORTHWEST
FLOW (ON KMQT VAD AND RAP ANALYSIS) ACROSS LAKE SUPERIOR...ALONG
WITH 850MB TEMPS OF -7C TO -11C FROM EAST TO WEST HAS LED TO SOME
LAKE ENHANCEMENT EARLY THIS MORNING...WITH THE STRONGEST RETURNS ON
RADAR AND OBS INDICATING THE HEAVIEST SNOW OVER EASTERN
MARQUETTE AND WESTERN ALGER COUNTIES. THIS ENHANCEMENT
WILL ALSO BE DIMINISHING QUICKLY THIS MORNING AS A HIGH PRESSURE
RIDGE FROM NORTHERN MINNESOTA NOSES INTO THE AREA. VERY DRY AIR
ABOVE THE INVERSION AT 920MB ON THE 00Z KINL SOUNDING WILL BE WHAT
IS MOVING INTO THE AREA AND REALLY DIMINISH THE INTENSITY OF THE
LAKE ENHANCEMENT OVER THE NORTH CENTRAL THIS MORNING. THIS WILL ALSO
LEAD TO A DIMINISHING TREND TO THE LAKE EFFECT CLOUDS FROM WEST TO
EAST TODAY AS THE LAKE INDUCED INSTABILITY AND MOISTURE IS PINCHED
BY THAT LOWERING INVERSION FROM THE HIGH PRESSURE RIDGE. EXPECT THE
LAKE CLOUDS TO HANG ON THE LONGEST OVER THE KEWEENAW AND THE EAST
WHERE THE BACKING WINDS WINDS WILL STAY FAVORABLE THE LONGEST. THE
REST OF THE AREA SHOULD SEE SKIES BECOMING PARTLY CLOUDY IF NOT
MOSTLY SUNNY LATE THIS MORNING THROUGH THE AFTERNOON.
FOCUS THEN TURNS TO THE MAIN WEATHER MAKER FOR THE FORECAST
PERIOD...WHICH IS ASSOCIATED WITH A LOW THAT IS CURRENTLY LOCATED
NEAR LAKE WINNIPEG. THIS LOW AND POTENT SHORTWAVE NOTED ON WV
IMAGERY WILL QUICKLY SWEEP SOUTHEAST ACROSS LAKE SUPERIOR LATE THIS
AFTERNOON AND EVENING. STRONG CONVERGENCE ALONG TWO ASSOCIATED
TROUGHS WILL LEAD TO A COUPLE MODERATE TO POTENTIALLY HEAVY PERIODS
OF SNOW BEFORE THE LAKE EFFECT REALLY KICKS IN OVERNIGHT.
THE FIRST TROUGH WILL SHIFT WINDS TO THE NORTHWEST AND MOVE INTO THE
KEWEENAW AND WESTERN UPPER MICHIGAN AROUND DINNER TIME AND THE REST
OF THE CWA DURING THE EVENING HOURS. EXPECT THE STRONGEST SNOW TO
OCCUR OVER THE WEST WITH THE FAVORABLE UPSLOPE WINDS AND LEAD TO A
COUPLE HOUR PERIOD OF STRONG SNOW SHOWERS. THEN THERE MAY BE
A SHORT PERIOD OF LIGHTER SNOW AS THE DEEPER MOISTURE CUTS OUT FOR
A FEW HOURS. THE SECONDARY TROUGH (WITH ANOTHER BURST OF
MODERATE TO HEAVY SNOWFALL) WILL THEN DROP SOUTH ACROSS THE KEWEENAW
AND WESTERN UPPER MICHIGAN AROUND OR SHORTLY AFTER
MIDNIGHT...SHIFTING THE WINDS TO ALMOST NORTHERLY AND THE LAKE
EFFECT SNOW SHOULD REALLY KICK IN. EXPECT A SIMILAR OCCURRENCE
ACROSS THE REST OF NORTHERN UPPER MICHIGAN WITH MORE OF A DELAY ON
THE SECONDARY TROUGH UNTIL THE 08-09Z TIME FRAME. IN ADDITION...WITH
THE FIRST FRONT SHIFTING WINDS TO LESS FAVORABLE NORTHWESTERLY
DOWNSLOPING FLOW FOR THE NORTH CENTRAL...THEY WILL LIKELY NOT SEE
MUCH SNOW ACCUMULATION UNTIL THE SECONDARY TROUGH MOVES THROUGH AND
LAKE EFFECT DEVELOPS.
BEHIND THE TROUGHS...850MB TEMPS WILL FALL FROM AROUND -10C AT 18Z
TODAY TO -20C AT 12Z SATURDAY. THIS WILL PROVIDE SIGNIFICANT OVER
THE LAKE INSTABILITY (DELTA-T VALUES APPROACHING 25) AND LEAD TO
LAKE INDUCED CAPE AND EQL LEVELS OF 800 J/KG AND 13-14K
FT RESPECTIVELY. BEST DEEP MOISTURE WILL BE FOCUSED OVER THE EAST
CLOSER TO THE LOW MOVING THROUGH. THUS...EXPECT REALLY GOOD
CONDITIONS FOR MODERATE TO HEAVY LAKE EFFECT SNOW DURING THE
OVERNIGHT HOURS AND CONTINUING INTO SATURDAY. SNOW RATIOS WILL BE
ON THE INCREASE THROUGH THE FORECAST PERIOD...STARTING AROUND
10-15 TO 1 BEFORE INCREASING TO THE LOW 20S ONCE THE LAKE EFFECT
KICKS IN. WITH THE BEST LAKE INDUCED LIFT RIGHT IN THE DGZ...THERE
IS THE POTENTIAL THAT SNOW RATIOS COULD BE HIGHER IN THE STRONGER
BANDS (ESPECIALLY TOWARDS IRONWOOD WHERE THE WINDS ARE LIGHTER) AND
MAY BE SOMETHING TO MONITOR.
AS FOR SNOW AMOUNTS FOR THE WEST FIRST. WHILE THERE WILL BE SOME
BURSTS LATE THIS AFTERNOON AND EVENING...OVERALL AMOUNTS SHOULD BE
IN THE 1-3 INCH RANGE. THEN AS THE LAKE EFFECT KICKS IN
TONIGHT...HAVE ANOTHER 2-4 INCHES OVER THE HIGHER TERRAIN FROM THE
KEWEENAW THROUGH GOGEBIC COUNTIES. THIS PRODUCES TOTALS BY 12Z
SATURDAY OF 3-7 INCHES...WITH THE HIGHEST FOR GOGEBIC/ONTONAGON
DUE TO THE LONGER FETCH AND WEAKER WINDS INCREASING RESIDENCE
TIME OVER THE LAKE. ALSO...IT APPEARS THE INITIAL TROUGH WILL BECOME
HUNG UP IN THAT AREA THIS EVENING...WHICH WOULD ALLOW THE SNOW TO
PERSIST FOR MUCH OF THE EVENING HOURS. MARQUETTE/BARAGA COUNTY AND
LOCATIONS EASTWARD WILL LIKELY NOT REALLY SEE THE SNOW PICKING UP
UNTIL AFTER MIDNIGHT AND LIKELY AROUND 08-09Z WHEN THE TROUGH
FINALLY SHIFTS THROUGH AND SWITCHES THE WINDS MORE NORTH-NORTHWEST.
THIS BECOMES FAIRLY FAVORABLE FOR NORTH CENTRAL AND EASTERN PARTS OF
MARQUETTE COUNTY AND FOCUSED INTO ALGER COUNTY LATE TONIGHT...SO
EXPECT CONDITIONS TO DETERIORATE VERY QUICKLY THERE. WITH AN INCH
AN HOUR SNOW OVER MARQUETTE COUNTY LATE TONIGHT...EXPECT TOTALS IN
THE 2-5 INCH RANGE FROM THE HURON MOUNTAINS THROUGH
NEGAUNEE/SKANDIA BY 12Z. FARTHER EAST...THE DELAYED ARRIVAL WILL
LIKELY KEEP AMOUNTS IN THE 1-3 INCH RANGE.
ALONG WITH THE SNOW...WINDS WILL ALSO INCREASE BEHIND THE
FRONTS...GUSTING TO 40KT GALES OVER CENTRAL AND EASTERN LAKE
SUPERIOR DURING THE OVERNIGHT HOURS. GUSTS TO 35-40MPH WILL BE
COMMON OVER THE KEWEENAW STARTING LATE THIS EVENING AND LATE
TONIGHT EAST OF MARQUETTE. AS THE SNOW STARTS TO
ACCUMULATE...BLOWING SNOW BECOMES A LARGER ISSUE THROUGH THE NIGHT
AND INTO SATURDAY WITH SNOW BEING ON THE GROUND.
AS FOR HEADLINES...COORDINATION WITH THE LONG TERM SHIFT LED TO
SWITCHING GOGEBIC/ONTONAGON AND ALGER/LUCE...NORTHERN SCHOOLCRAFT
TO LAKE EFFECT SNOW WARNINGS DUE TO THEIR FAVORABLE CONDITIONS AND
EXPECTED SNOW ACCUMULATIONS. THERE WAS ENOUGH UNCERTAINTY ON
SNOWFALL AMOUNTS FOR THE KEWEENAW PENINSULA TO OPT FOR AN ADVISORY
AT THIS POINT...SINCE THE LIMITED FETCH (AND UPSLOPE) WITH THE
WINDS WILL KEEP AMOUNTS LOWER. THOSE WINDS COULD ALSO MAKE FOR
WORSE VISIBILITIES AND COULD ALMOST JUSTIFY A WARNING. MARQUETTE
WAS SIMILAR (AND MAY NEED TO BE UPGRADED WITH THE DAY SHIFT)...SINCE
AMOUNTS IN 12 HOURS ARE JUST UNDER WARNING CRITERIA AND THERE IS
SOME UNCERTAINTY ON THE EXACT LOCATION OF THE STRONGER BANDS OFF
LAKE NIPIGON. FINALLY...THE REST OF THE AREAS IN THE WATCH WERE
SWITCHED TO AN ADVISORY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 503 AM EST FRI NOV 22 2013
THE MAIN FCST CONCERNS ARE THE LES POTENTIAL FROM SAT INTO EARLY
SUNDAY ALONG WITH BLOWING SNOW AND WIND CHILLS IN THE VERY COLD
ARCTIC AIRMASS.
SAT INTO SAT NIGHT...
WITH MODEL FCST 850MB TEMPS FALLING TO -18 TO -21C BY 12Z
SAT...VIGOROUS NW/NNW FLOW ORIENTED LAKE EFFECT SNOW BANDS WILL BE
ONGOING IN THE WAKE OF THE ARCTIC FRONT. MODELS SUGGEST THAT THE
DEEPER MOISTURE TO AROUND 8K TO 10K FEET WILL PERSIST LONGER OVER
THE ERN FCST AREA. THE FAVORABLE MOISTURE PROFILE AND THE DGZ WITHIN
THE CONVECTIVE LAYER WILL SUPPORT SNOWFALL RATES OF AT LEAST 1 TO 2
INCHES PER HOUR IN THE STRONGER BANDS. HOWEVER...SNOWFLAKE
FRACTURING AND COMPACTION WITH TEH STRONG WINDS SHOULD LIMIT
SNOW/WATER RATIOS TO AROUND 20/1.
AS IS OFTEN THE CASE...THE MOST INTENSE DOMINANT BAND SHOULD
ORIGINATE WITH PRECONDITIONING OFF OF LAKE NIPIGON. THERE IS LESS
CONFIDENCE ON WHERE THAT BAND WILL SET UP AND HOW LONG IT WILL LAST
IN ANY ONE LOCATION. THE HIGHER RESOLUTION MODELS SUGGEST THAT THE
BAND MAY START OUT NEAR MARQUETTE AND THEN SHIFT EAST TOWARD SHOT
POINT AND INTO ALGER COUNTY BY LATE SATURDAY MORNING WHERE THE
HEAVIER LES WILL THEN PERSIST FROM SAT AFTERNOON INTO SAT NIGHT. 12
HOUR SNOWFALL AMOUNTS OF AROUND 8 INCHES ARE EXPECTED BOTH SATURDAY
AND SAT NIGHT FOR ALGER AND NRN SCHOOLCRAFT COUNTIES WHERE LES
WARNINGS WERE POSTED. THERE WAS GREATER UNCERTAINTY FOR MARQUETTE
COUNTY WHERE AN ADVISORY WAS POSTED. SNOWFALL TOTALS SHOULD BE
GREATEST IN THE 6Z-18Z/SAT PERIOD WHEN AMOUNTS IN THE 3 TO 7 INCH RANGE
ARE EXPECTED. AN UPGRADE TO A WARNING MAY BE NEEDED IF ANY STRONG
BANDS PERSIST LONGER THAN EXPECTED.
OVER THE WEST...INVERSION HEIGHTS DROPPING TO AROUND 5K-6K FT WILL
LIMIT LES INTENSITY. HOWEVER...WITH STRONG NRLY UPSLOPE FLOW INTO
THE HIGHER TERRAIN WILL SUPPORT ADDITIONAL SNOWFALL AMOUNTS OF 3 TO
5 INCHES SATURDAY WITH ANOTHER 2 TO 4 INCHES SAT NIGHT.
GUSTY WINDS TO 30-40 MPH WILL ALSO PRODUCE CONSIDERABLE BLOWING SNOW
WITH SHARPLY REDUCED VISIBILITY IN THE HEAVIER SNOW BANDS.
THE LES SHOULD MOSTLY END SUNDAY FROM W TO E AS WINDS BACK TO THE SW
AHEAD OF THE NEXT CLIPPER SHORTWAVE TROUGH DIVING SE THROUGH SOUTH
CNTRL CANADA. HOWEVER...A DEVELOPING WAA PATTERN WITH STRONG
285K-295K ISENTROPIC LIFT WILL PROBABLY LEAD TO AN AREA OF -SN
STREAKING SE INTO THE AREA SUN AFTN/NIGHT. HOWEVER...SINCE THE
STRONGER 700-300 MB QVECTOR CONV REMAINS WELL TO THE NORTH WITH THE
TRACK OF THE SHRTWV AND LOWER LEVELS ARE VERY DRY...ONLY CHANCE POPS
WERE INCLUDED FOR SNOWFALL AMOUNTS THAT WOULD AMOUNT TO LESS THAN AN
INCH OVER MOST OF THE CWA.
TUE-THU...THE GFS/GEFS/ECMWF WERE IN REASONABLE AGREEMENT THAT
ANOTHER BATCH OF ARCTIC AIR IS EXPECTED TO MOVE INTO THE NRN GREAT
LAKES IN THE WAKE OF A STRONGER SHORTWAVE MOVING THROUGH NRN ONTARIO
ON TUE. WITH 850 MB TEMPS DROPPING TO AROUND -17C...ANOTHER EXTENDED
PERIOD OF LES WITH AT LEAST MODERATE ACCUMULATIONS IS LIKELY FOR NW
TO N FLOW FAVORED LOCATIONS. THE LES SHOULD DIMINISH BY THU AS THE
SFC HIGH BUILDS INTO THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1236 PM EST FRI NOV 22 2013
A LOW PRESSURE SYSTEM THAT IS JUST NORTHWEST OF LAKE SUPERIOR WILL
DIVE SOUTHEAST ACROSS LAKE SUPERIOR THIS AFTERNOON AND DRAG A COLD
FRONT ACROSS THE AREA LATE THIS AFTERNOON AND EVENING. THERE WILL
LIKELY BE A BRIEF PERIOD OF STRONGER SNOW SHOWERS WITH THIS FRONT
OVER THE WEST...THEN LIGHT TO MODERATE LAKE EFFECT SNOW DURING THE
REST OF THE EVENING WITH MVFR CONDITIONS. BY THE TIME THE FRONT
REACHES KSAW...THE IMPACT FROM THE SNOW SHOWERS WILL BE LIMITED. A
SECONDARY FRONT WILL DROP SOUTH ACROSS THE TAF SITES BETWEEN 06-08Z
AND BRING ANOTHER BURST OF HEAVY SNOW. THIS SNOW WILL TRANSITION TO
LAKE EFFECT UNDER NNW WINDS AND LIKELY BRING ALTERNATE TO NEARLY
AIRFIELD LANDING MINIMUM VISIBILITIES TO THE THREE SITES INTO
SATURDAY MORNING. SHOULD SEE SOME IMPROVEMENT INTO SATURDAY
AFTERNOON AS DRIER AIR WORKS INTO THE IWD AND CMX AREAS AND WINDS
MAY SHIFT BEST LAKE EFFECT SNOW JUST E OF SAW...BUT THERE CONFIDENCE
IN EXACT CIGS AND VIS IS LOW THAT LATE IN THE TAF PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 444 AM EST FRI NOV 22 2013
A FAIRLY ACTIVE NEXT COUPLE DAYS IS IN STORE FOR LAKE SUPERIOR. A
TROUGH THAT MOVED THROUGH LAKE SUPERIOR THIS PAST EVENING WILL
CONTINUE EAST EARLY THIS MORNING...WHILE A HIGH PRESSURE RIDGE
MOVES ACROSS THE LAKE THROUGH EARLY AFTERNOON. THERE WERE A FEW
GALE FORCE GUSTS TO 35KTS SHORTLY AFTER MIDNIGHT...BUT THEY HAVE
SINCE DIMINISHED AND EXPECT A DIMINISHING TREND TO THE WINDS THIS
MORNING. AS THE HIGH PRESSURE RIDGE SHIFTS EAST THIS AFTERNOON
SOUTHWESTERLY WINDS WILL BE ON THE INCREASE OVER WESTERLY LAKE
SUPERIOR AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. THIS SYSTEM
WILL QUICKLY DIVE SOUTHEAST ACROSS LAKE SUPERIOR LATE THIS AFTERNOON
AND EVENING...QUICKLY SHIFTING WINDS TO THE NORTH-NORTHWEST AND
PRODUCING GALE FORCE WINDS TO 40KTS. THERE COULD EVEN BE SOME GUSTS
TO 45KTS RIGHT AS WINDS SHIFT TO THE NORTH-NORTHWEST AFTER MIDNIGHT
OVER EASTERN LAKE SUPERIOR. THE GALE WARNING THAT IS IN PLACE LOOKS
TO BE IN GOOD SHAPE. A STRONG HIGH DROPPING SOUTH THROUGH THE
NORTHERN PLAINS ON SATURDAY WILL BEGIN TO NOSE A RIDGE OVER WESTERN
LAKE SUPERIOR ON SATURDAY AFTERNOON AND THEN PUSH ACROSS THE ENTIRE
LAKE SATURDAY NIGHT AND SUNDAY. THIS WILL LEAD TO DIMINISHING AND
BACKING WINDS DURING THAT PERIOD. THAT DIMINISHING TREND WILL BE
SHORT LIVED AS WINDS WILL INCREASE ON SUNDAY NIGHT OUT OF THE
SOUTHWEST (TO 30KTS) AHEAD OF LOW MOVING SOUTHEAST THROUGH ONTARIO
LATE SUNDAY NIGHT AND MONDAY. THIS LOW WILL DRAG A COUPLE TROUGHS
ACROSS LAKE SUPERIOR MONDAY AND MONDAY NIGHT...WITH THE SECOND ONE
STALLING OVER SOUTHEAST LAKE SUPERIOR THROUGH WEDNESDAY. AT THIS
POINT...NORTHWEST WINDS UP TO 30KTS ARE EXPECTED BEHIND THE
TROUGHS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 1 AM EST
SUNDAY FOR MIZ004-084.
LAKE EFFECT SNOW WARNING FROM MIDNIGHT TONIGHT TO NOON EST
SUNDAY FOR MIZ006-007-085.
LAKE EFFECT SNOW ADVISORY FROM 5 PM THIS AFTERNOON TO 7 AM EST
SUNDAY FOR MIZ001-003.
LAKE EFFECT SNOW WARNING FROM 6 PM EST /5 PM CST/ THIS EVENING
TO 7 AM EST /6 AM CST/ SUNDAY FOR MIZ002-009.
LAKE EFFECT SNOW ADVISORY FROM 1 AM TO 10 PM EST SATURDAY FOR
MIZ005.
LAKE EFFECT SNOW ADVISORY FROM 1 AM SATURDAY TO 7 AM EST SUNDAY
FOR MIZ014.
LAKE EFFECT SNOW ADVISORY FROM 1 AM SATURDAY TO 5 AM EST SUNDAY
FOR MIZ013.
LAKE SUPERIOR...
GALE WARNING FROM 11 PM THIS EVENING TO 1 AM EST SUNDAY FOR
LSZ266-267.
GALE WARNING FROM 1 AM TO 10 PM EST SATURDAY FOR LSZ248>251-265.
GALE WARNING FROM 10 PM THIS EVENING TO 10 PM EST SATURDAY FOR
LSZ264.
GALE WARNING FROM 10 PM THIS EVENING TO 7 PM EST SATURDAY FOR
LSZ244-245.
GALE WARNING FROM 10 PM THIS EVENING TO 7 AM EST SATURDAY FOR
LSZ242-243.
GALE WARNING FROM 10 PM THIS EVENING TO 10 AM EST SATURDAY FOR
LSZ263.
LAKE MICHIGAN...
GALE WARNING FROM 4 AM TO 10 PM EST SATURDAY FOR LMZ221-248-250.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...TITUS
MARINE...SRF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1144 AM CST FRI NOV 22 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 242 AM CST FRI NOV 22 2013
SURFACE ANALYSIS THIS MORNING IS DOMINATED BY HIGH PRESSURE. THERE
ARE TWO HIGH CENTERS OVER CENTRAL NOAM...A 1043 MB HIGH WAS CENTERED
OVER WRN NEB WITH A HIGH OF SIMILAR STRENGTH OVER NRN ALBERTA. IN
BETWEEN THESE TWO HIGHS WAS AN AREA OF LOWER PRESSURE OVER LAKE
WINNIPEG THAT CHECKS IN AT 1028 MB...WHICH UNDER NORMAL
CIRCUMSTANCES WOULD BE THE PRESSURE SEEN AT THE CENTER OF HIGH.
THE NEBRASKA HIGH HAS A RIDGE AXIS THAT STRETCHES NE TO NEAR INL.
WITH THIS AXIS SITTING OVER WEST CENTRAL MN UNDER CLEAR SKIES...HAVE
SEEN SITES OUT BY THE SODAK BORDER DROP TO NEAR ZERO THIS MORNING.
AS FOR THAT CANADIAN HIGH...TEMPERATURES HAVE FOUND THEIR WAY DOWN
TO AROUND -30F ACROSS NRN ALBERTA AND SASKATCHEWAN...WELCOME TO
WINTER.
FOR TODAY...WE WILL SEE BREEZY WSW WINDS DEVELOP OUT AHEAD OF THE
ARCTIC BOUNDARY THAT WILL SLIP INTO THE NW CWA AROUND 18Z...REACH
THE TWIN CITIES AROUND 00Z AND EXIT THE MPX CWA BY 6Z. AS YOU CAN
IMAGINE...WITH SFC PRESSURE VALUES UP NEAR 1030 MB...PRECIP WILL BE
HARD TO COME BY. WITH THAT SAID...IT DOES LOOK LIKE RIGHT BEHIND THE
FRONT THERE WILL BE THE POTENTIAL FOR A QUICK HIT OF LIGHT SNOW.
BOTH THE NAM/GFS SHOW A BAND OF FGEN IN THE H7-H6 LAYER WORKING DOWN
BEHIND THE FRONT. IN ADDITION...FORECAST SOUNDINGS SHOW DEEP
DENDRITIC GROWTH ZONES BECOMING SATURATED AS THE FRONT PASSES...SO
WILL NOT TAKE MUCH LIFT TO GENERATE SOME LIGHT SNOW. HRRR AND
HIRES-NMM REFLECTIVITY FORECASTS INDICATE A LIGHT BAND OF SNOW
DEVELOPING BEHIND THE FRONT AS WELL. FOR NOW...BEEFED UP SKY COVER
THIS EVENING WITH THE FRONT AND WORKED SOME OCCASIONAL FLURRY
WORDING DOWN WITH IT AS WELL.
BEHIND THE FRONT...NAM BUFR SOUNDINGS SHOW THE POTENTIAL FOR NW
WINDS TO BE GUSTING UP AROUND 30 MPH...BUT MORE IMPRESSIVE THAN THAT
IS THE 1050 MB HIGH ALL MODELS SHOW MOVING INTO NODAK LATE TONIGHT.
TO GO ALONG WITH THAT HIGH...BY 12Z SATURDAY...H85 TEMPS WILL
ALREADY BE DOWN IN THE -16 TO -20 C RANGE. 22.00 MODELS ALL CAME IN
A BIT FASTER WITH THE FROPA THIS EVENING AND MOST CAME IN A FEW DEGS
COOLER FOR LOWS SATURDAY MORNING THAN WHAT THEY WERE SHOWING WITH
EARLIER RUNS...SO DID KNOCK A COUPLE OF DEGREES OFF EXISTING LOWS
FOR SATURDAY MORNING. WITH LOWS CURRENTLY FORECAST TO RANGE FROM 2
TO 12...WE WILL BE LAYING A NICE FOUNDATION FOR WHAT WILL BE A
FRIGID SATURDAY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 242 AM CST FRI NOV 22 2013
THE LONG TERM FORECAST LOOKS COLD AND DRY AS BOTH MN/WI REMAIN
ENTRENCHED IN NORTHWEST FLOW. NORTHERN MN WILL BE CLOSER TO THE
CORE OF COLDEST ARCTIC AIR DROPPING SOUTH OUT OF CANADA
THROUGHOUT THE WEEKEND. AS A RESULT...THE NORTHERN HALF OF THE
STATE HAS A MUCH BETTER CHANCE OF KEEPING CLOUD COVER AND A
CHANCE FOR SNOW FLURRIES AROUND. THE DENDRITE GROWTH ZONE IS NEAR THE
SURFACE WITH AN AIR MASS THIS COLD...SO IF YOU END UP WITH STRATUS
CLOUDS...YOU OFTEN END UP WITH FLURRIES OR LIGHT SNOW. THE
SOUTHERN HALF OF MN AND WEST CENTRAL WI LOOKS A DRIER DOWN LOW
AND SHOULD SEE MORE SUNSHINE. THIS WILL BE OF LITTLE CONSOLATION
AS A BRISK NORTHERLY FLOW BEHIND THE AFOREMENTIONED COLD FRONT
KEEPS TEMPERATURES IN THE TEENS ON SATURDAY WITH WIND CHILLS NEAR
ZERO. THE STRONG COLD ADVECTION WILL CREATE STEEP LAPSE RATES ON
SATURDAY BELOW 900MB AND ENOUGH MIXING TO KEEP GUSTY WINDS UP NEAR
20 MPH. MIXING TO 925MB SHOULD YIELD MID TO UPPER TEENS FOR HIGHS.
BEFORE A SLIGHTLY WARMER WESTERLY FLOW RETURNS ON
SUNDAY...SATURDAY NIGHT WILL BE THE COLDEST NIGHT OF THE FALL
SEASON SO FAR WITH THE ARCTIC HIGH SLIPPING JUST SOUTH OF THE
FORECAST AREA. THE LACK OF SNOW COVER DOESN`T HELP...BUT HARD TO
IMAGINE WE WOULDN`T HAVE MULTIPLE SITES DROP BELOW ZERO.
THERE IS GOOD MODEL AGREEMENT WITH RESPECT TO TEMPERATURES THROUGH
THE EXTENDED. THE DRY PROFILES AND LACK OF CLOUD COVER ACROSS THE
FORECAST AREA OVER THE NEXT 7 DAYS IS HELPING TO KEEP A TIGHTER
ENVELOPE OF MODELED TEMPERATURES /WITHIN 4-7 DEGREES/.
THEREFORE...THERE IS HIGH CONFIDENCE IN BELOW NORMAL TEMPERATURES
OVER THE NEXT 7-10 DAYS. I SUPPOSE YOU COULD ALSO SAY THERE IS
HIGH CONFIDENCE IN BELOW NORMAL PRECIP /NEAR ZERO/ OVER AT LEAST
THE NEXT 7 DAYS AS WELL. THE TIME HEIGHTS OFF THE GFS AND ECMWF
DON`T EVEN CARRY ENOUGH RH TO JUSTIFY MUCH CLOUD COVER...LET ALONE
PRECIP.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1134 AM CST FRI NOV 22 2013
A BAND OF MVFR CIGS/VSBYS DEVELOPED BEHIND A SHARP COLD FRONT
ACROSS NW MN EARLIER TODAY...WHICH WILL AFFECT KAXN BY
1930Z...THEN AT KSTC BY 21-22Z. EVENTUALLY THE MVFR CIGS/VSBYS
WILL ABATE WITH ONLY FLURRIES POSSIBLE AS MOST OF THE MOISTURE
WILL BE LIMITED AFT 23Z. SOME GUSTY WINDS HAVE DEVELOPED AHEAD OF
THIS FRONT SO DECIDED TO ADD GUSTY WINDS DURING THE AFTN ARND
16-18 KTS. MOST OF THE STRONGER GUSTY WINDS OCCUR BEHIND THE FRONT
LATER THIS EVENING...BEFORE DECREASING SATURDAY AFTN.
KMSP...
VFR CONDS SHOULD PREVAIL THRU THE TAF PERIOD WITH ONLY A SMALL
WINDOW OF MVFR VSBY IN -SN ARND 00-02Z AS A SHARP COLD FRONT MOVES
THROUGH. SOME GUSTY WINDS WILL OCCUR AHEAD OF THIS FRONT...BUT
MOST OF THE STRONGER GUSTS WILL BE BEHIND THE FRONT LATER THIS
EVENING AND OVERNIGHT...BEFORE DECREASING SATURDAY AFTN.
/OUTLOOK FOR KMSP/
SUN...VFR. WINDS LIGHT AND VRB IN MRNG...BCMG S AT 15G25KTS.
MON...VFR. WINDS WNW AT 10KTS.
TUE...VFR. WINDS NNW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...CLF
AVIATION...JLT
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1233 PM EST FRI NOV 22 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA TODAY. THIS WILL BE FOLLOWED
BY AN ARCTIC FRONT ON SATURDAY...WHICH WILL USHER IN MUCH COLDER
CONDITIONS AND PRODUCE LAKE EFFECT SNOW IN THE SNOWBELT SATURDAY
NIGHT INTO SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS MOSTLY CONFINED TO THE EASTERN HALF OF THE FORECAST AREA
AT THIS TIME AS DRIER AIR ARRIVES BEHIND THE FRONT. THE HRRR SHOWS
A BAND OF LIGHT SHOWERS RE-DEVELOPING THIS AFTERNOON ACROSS LAKE
ERIE AND NRN OHIO AS THE 850MB TROUGH SWINGS THROUGH. THERE IS
ALREADY SOME SUPPORT OF THIS SHOWING UP ON REGIONAL RADARS AND
WILL HOLD ONTO A LOW CHANCE OF SHOWERS...ALTHOUGH EXPECTED TO BE
BRIEF. NORTHWEST WINDS WILL INCREASE BEHIND THE FRONT THIS
AFTERNOON TO 10 TO 20 MPH IN THE WEST.
PREVIOUS DISCUSSION...
THE KILN SOUNDING THIS MORNING SHOWED DEEP MOISTURE IN
PLACE OVER THE REGION THROUGH 550MB. SHOWERS ARE FILLING IN ON THE
RADAR AS MOISTURE CONTINUES TO STREAM NORTHWARD IN ADVANCE OF THE
STRONG FRONT APPROACHING FROM THE NORTHWEST. RAISED POPS TO NEAR
100 PERCENT AS THIS WILL BE THE TREND FOR THE NEXT SEVERAL HOURS
EXCEPT FOR EXTREME NW OHIO WHERE DRIER AIR IS ALREADY SNEAKING IN
FROM THE WEST. HIGHS WILL OCCUR THIS MORNING WITH TEMPERATURES
SLOWLY FALLING BEHIND THE FRONT. WILL KEEP PRECIP TYPE AS ALL RAIN
AS WE LOSE OUR MOISTURE ALOFT BY THE TIME THE BOUNDARY LAYER COOLS
ENOUGH FOR SNOW.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
FRONT SHOULD BE WELL SOUTH OF THE AREA BY THIS EVENING TAKING THE
RAIN WITH IT. EXPECT DRY SLOT FOR TONIGHT INTO SATURDAY UNTIL
ARCTIC FRONT PUSHES THROUGH BY EARLY AFTERNOON. EXPECT SOME LIGHT
SNOW WITH THE FRONT...THEN A LULL BEFORE THE LAKE EFFECT SNOW
SHOWERS KICK IN. TEMPERATURES ON SATURDAY WILL PEAK BY LATE MORNING
WITH STEADY OR FALLING TEMPS IN THE AFTERNOON.
COLDEST AIR MOVES OVER THE LAKE SATURDAY NIGHT AS MODELS CONTINUE
PLUNGING THE 850MB TEMPS TO MINUS 18C BY SUNDAY MORNING. WATCH
OVER NW PA AND ASHTABULA COUNTY OHIO CONTINUES. SEVERAL INGREDIENTS
ADDING TO POTENTIAL FOR WARNING IN WATCH AREA. MODERATE INSTABILITY
OVER THE LAKE. IN ADDITION MODELS HAVE BEEN CONSISTENT WITH NW FLOW
SETTING UP AND CONTINUING INTO SUNDAY AFTERNOON. DEFINITE POTENTIAL
FOR A HURON CONNECTION SETTING UP WHICH COULD LAST INTO SUNDAY. THAT
COMBINED WITH THE HIGHER TERRAIN AWAY FROM THE LAKESHORE ALL POINT
TO THE POTENTIAL OF 6 TO 10 INCHES ACROSS THE HIGHER TERRAIN.
STILL SOME DOUBT IN MY MIND...HOW LONG WILL IT TAKE FOR THE LAKE
EFFECT TO START AFTER ARCTIC FRONT...AND THE DEPTH OF THE SYNOPTIC
MOISTURE. FOR NOW LOOKS LIKE LAKE EFFECT SNOW WILL CONTINUE INTO
SUNDAY AFTERNOON...WHEN SURFACE RIDGING FINALLY FORCES WINDS TO THE
SOUTHWEST.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
A COLD FRONT WILL CROSS THE AREA TUESDAY...MOISTURE IS OK...SO
EXPANDING THE CHANCE POPS TO MOST OF THE FORECAST AREA. AN
ONSHORE...MAINLY NORTHERLY FLOW WILL DEVELOP TUESDAY NIGHT AND
CONTINUE INTO THURSDAY. MOISTURE IS LIMITED...IT IS COLD...THE LAKE
AND 850 MB TEMPERATURE DIFFERENCE WILL BE OVER 20C AT TIMES. FOR THE
TIME BEING JUST KEPT CHANCE POPS OVER THE EASTERN HALF OF THE
FORECAST AREA. A RIDGE WILL BEGIN BUILDING IN BY LATE THURSDAY AND
ANY LAKE EFFECT SNOW SHOWERS WILL BE ENDING THURSDAY NIGHT AS THE
FLOW BECOMES SOUTHWEST. USED A BLEND OF GUIDANCE FOR THE
TEMPERATURES.
&&
.AVIATION /17Z FRIDAY THROUGH TUESDAY/...
A SLOW IMPROVEMENT IN CONDITIONS CONTINUES IN THE WEST WHERE VSBYS
HAVE IMPROVED AND CIGS HAVE JUMPED TO MVFR. EXPECT THIS TREND TO
CONTINUE TO THE EAST THIS AFTERNOON AS THE COLD FRONT EXITS THE
AREA. EXPECT ALL BUT THE FAR EASTERN END OF THE AREA TO HAVE MVFR
CIGS BY SUNSET. A CLEARING LINE OVER THE WESTERN GREAT LAKES WILL
REACH WESTERN AREAS THIS EVENING. EVEN IN THE EAST CONDITIONS
SHOULD BECOME VFR THIS EVENING. EXPECT ABOUT THE SW 2/3 OF THE
AREA TO LOSE CIGS OVERNIGHT WHILE LAKE CLOUDS REMAIN FROM KCLE
EAST TO KYNG AND UP THE LAKE TO NW PA. WEST FLOW WILL BECOME NW
THIS AFTERNOON AND SOME GUSTS TO 20 KNOTS ARE LIKELY INTO THE
EVENING HOURS. VFR WEATHER IS EXPECTED THE SECOND HALF OF THE
PERIOD.
OUTLOOK...NON VFR MAINLY OVER NE OH AND NW PA SATURDAY THROUGH
SUNDAY BECAUSE OF LAKE EFFECT. NON VFR RETURNING LATE MONDAY
NIGHT INTO TUESDAY.
&&
.MARINE...
AN ACTIVE WEATHER PATTERN FOR THE LAKE...TODAY THROUGH LATE NEXT
WEEK.
A COLD FRONT WILL MOVE ACROSS THE LAKE THIS MORNING AND CONDITIONS
SHOULD REACH SMALL CRAFT ADVISORY CRITERIA BY LATE AFTERNOON...THUS
A SMALL CRAFT ADVISORY WILL BE IN EFFECT STARTING AT 4 PM. THERE
COULD BE A PERIOD OF SEVERAL HOURS AROUND DAYBREAK SATURDAY WHEN WE
WILL BE BELOW SMALL CRAFT ADVISORY CRITERIA BUT THEN THE ARCTIC
FRONT MOVES THROUGH SATURDAY MORNING. THUS THE SMALL CRAFT ADVISORY
IS IN EFFECT THROUGH SUNDAY EVENING. AT THIS TIME IT DOESN`T LOOK
LIKE WILL WE MAKE GALES. WE WILL JUST BE BELOW THE GALE CRITERIA.
THE WINDS ALOFT JUST AREN`T STRONG ENOUGH AND THE COLD ADVECTION IS
SOMEWHAT GRADUAL.
HIGH PRESSURE WILL PASS TO THE SOUTH OF THE LAKE SUNDAY NIGHT
SHIFTING THE WINDS TO THE SOUTHWEST. THE WINDS WILL BE ON THE STRONG
SIDE...SO IT IS POSSIBLE A SMALL CRAFT ADVISORY COULD BE NEEDED ON
THE EAST END. A COLD FRONT WILL CROSS THE LAKE LATE TUESDAY AND A
SMALL CRAFT ADVISORY COULD BE NEEDED ON THE ENTIRE NEARSHORE TUESDAY
NIGHT INTO EARLY THURSDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...LAKE EFFECT SNOW WATCH FROM SATURDAY EVENING THROUGH SUNDAY
EVENING FOR OHZ014-089.
PA...LAKE EFFECT SNOW WATCH FROM SATURDAY EVENING THROUGH SUNDAY
EVENING FOR PAZ001>003.
MARINE...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 7 PM EST
SUNDAY FOR LEZ142>149.
&&
$$
SYNOPSIS...DJB
NEAR TERM...KEC
SHORT TERM...DJB
LONG TERM...KIELTYKA
AVIATION...KUBINA
MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS NORMAN OK
300 PM CST FRI NOV 22 2013
.DISCUSSION...
TWO MAIN FORECAST CONCERNS TO COVER...-FZRA/SLEET TODAY AND
SNOW/SLEET CHANCES LATE SATURDAY THROUGH MONDAY.
CURRENTLY...ACTIVE WINTER WEATHER CONTINUES TO IMPACT MUCH OF
OKLAHOMA AND NRN TEXAS. FREEZING RAIN AND SLEET CONTINUE TO FALL
ACROSS PORTIONS OF WRN N TX AND THROUGH WRN AND CENTRAL OK THIS
AFTERNOON...THE IMPACTS OF WHICH HAVE PROMPTED A FEW TO SAY...WELL
THAT ESCALATED QUICKLY. WITH SFC TEMPS HOLDING AT OR NEAR
FREEZING...ROADS HAVE BECOME HAZARDOUS IN SOME PLACES ACROSS THE
REGION...WITH NUMEROUS TRAFFIC ACCIDENTS REPORTED VIA SOCIAL
MEDIA/LOCAL MEDIA/AND SPOTTERS. MOST ROADS REMAIN WET...NOT
FROZEN...WITH ELEVATED SURFACES...SUCH AS BRIDGES AND OVERPASSES THE
MOST LIKELY TO HAVE ICING. BEST ADVICE...SLOW DOWN. 18Z SPECIAL
RELEASE FROM OUN SHOWS A DECENT SLEET/FZRA SOUNDING...WITH BOTH
PRECIP TYPES FALLING AT VARIOUS TIMES AT THE OFFICE AND ACROSS THE
OKC METRO/REGION THROUGH THE PAST FEW HOURS. MOST IMPRESSIVE...THE
NEAR SFC FREEZING LAYER HAS REMAINED AS DEEP...-7 C AT BOTH 12 AND
18Z APPROXIMATELY 430M AGL. MESOSCALE MODELS...SUCH AS THE HRRR AND
RAP SEEM TO HAVE A DECENT HANDLE ON THE OVERALL PROGRESSION OF THE
SYSTEM. STARTING THIS MORNING...700MB WINDS BEGAN TO VEER BACK TO
THE SW...WITH GOOD WAA AND MOISTURE RETURN. WITH THE GOOD ISENTROPIC
RESPONSE...WELL VISUALIZED AT THE 305K LEVEL...ABOUT THE HEIGHT OF
THE 750-700MB LEVEL...FZRA AND SLEET WILL CONTINUE THROUGH THE
AFTN/EARLY EVENING HRS...SLOWLY SHIFTING S/SE THROUGH 00Z AS THE
ARCTIC HIGH CONTINUES TO PROTRUDE INTO NRN OK. AREAS OF -FZRA/-FZDZ
WILL LIKELY LINGER ACROSS CENTRAL OK THROUGH MIDNIGHT...WITH THE
REMAINDER OF ACTIVITY CONTINUING TO SHIFT SOUTHWARD THROUGH EARLY
SATURDAY MORNING...WITH AREAS OF -FZRA/-FZDZ/-RA NEAR/ALONG THE RED
RIVER VALLEY THROUGH SUNRISE.
SATURDAY DURING THE DAY SHOULD BE DRY...BUT COLD...WITH HIGHS ONLY
CLIMBING INTO THE MID/UPPER 30S...WITH WIND CHILLS IN THE TEENS AS
NORTH WINDS PERSIST. WINTER WEATHER WILL THEN MAKE A RETURN LATE
SATURDAY NIGHT AND CONTINUE THROUGH MONDAY. A DEEPENING UPPER
LOW...A BOWLING BALL IF YOU WILL...CONTINUES TO DIG DOWN THE WEST
COAST THIS AFTERNOON...WELL VISUALIZED ON WV IMAGERY. THIS
DEEPENING H500 TROUGH WILL CONTINUE TO DIG S/SE AND SWING EWRD
ACROSS THE DESERT SOUTHWEST. AS KG MENTIONED LAST NIGHT...THERE IS
NO APPARENT KICKER TO FORCE THIS FEATURE QUICKLY ACROSS THE SRN
PLAINS...SO ITS A RELATIVELY SLOW MOVING...BUT STRONG TROUGH.
GUIDANCE REMAINS IN DECENT AGREEMENT WITH THE TRANSITION OF THE
UPPER TROUGH...WITH A DECENT REGION OF ISENTROPIC LIFT DEVELOPING
ACROSS THE PANHANDLES AND FAR WRN OK SATURDAY NIGHT. GFS AND NAM
BUFR PROFILES TAKEN ACROSS THE REGION CONTINUE TO SHOW A SNOW/SLEET
MIX TO START...WITH A TRANSITION TO SNOW THROUGH SUNDAY...SPREADING
EASTWARD ACROSS THE REGION. GIVEN IT IS WINTER IN THE SRN
PLAINS...TIMING AND IMPACTS ARE LIKELY TO CHANGE BETWEEN NOW AND
THEN. HOWEVER...CONFIDENCE IS GROWING IN MUCH OF WRN N TX AND
CENTRAL AND WRN OK TO SEE THERE FIRST SNOW FLAKES OF THE YEAR. BEST
CHANCES WILL BE FROM WRN N TX THROUGH CENTRAL OK...WITH MOST
LOCATIONS SEEING A TRACE TO 2 INCHES...WITH SOME SEEING AS MUCH AS
3. OF COURSE...SOME LOCATIONS MAY SEE MORE SLEET THAN SNOW. LIGHT
SNOW/SLEET CHANCES WILL CONTINUE THROUGH MONDAY...WITH A TRANSITION
TO RAIN/SNOW MIX POSSIBLE...AND RAIN ACROSS SRN OK/NRN TX THROUGH
TUESDAY MORNING.
DRY...CALM WEATHER WILL THEN PERSIST FOR THE REMAINDER OF THE
HOLIDAY WEEK...WITH HIGHS WARMING BACK INTO THE LOWER 50S BY
THANKSGIVING DAY...CONTINUING THROUGH THE WEEKEND.
JTK
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 29 38 26 32 / 40 10 20 50
HOBART OK 27 38 26 31 / 30 10 30 50
WICHITA FALLS TX 30 39 28 34 / 50 10 30 70
GAGE OK 21 34 21 30 / 30 0 30 50
PONCA CITY OK 28 37 20 34 / 20 0 10 30
DURANT OK 34 42 31 38 / 60 20 10 60
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...WINTER WEATHER ADVISORY UNTIL 6 AM CST SATURDAY FOR OKZ004>047-
050-051.
TX...WINTER WEATHER ADVISORY UNTIL 6 AM CST SATURDAY FOR TXZ083>090.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1113 AM CST FRI NOV 22 2013
.DISCUSSION...
SEE AVIATION FOR 18Z TAF ISSUANCE.
&&
.AVIATION...
IFR CONDITIONS ACROSS THE AREA TODAY WITH THE SURFACE COLD FRONT
JUST MAKING IT TO KGLS. THERE IS A LINE OF THUNDERSTORMS CROSSING
KLBX AND APPROACHING KGLS. IN THESE THUNDERSTORMS EXPECT GUSTY
WINDS AND HEAVY RAIN. BEHIND THE MAIN LINE OF STORMS WE ARE
GETTING SOME REDEVELOPMENT OF LIGHT SHOWERS. THESE LIGHT TO
MODERATE SHOWERS WILL BE POSSIBLE THROUGH THE DAY INTO SATURDAY
MORNING AS THE 850MB FRONT TRIES TO MAKE IT DOWN INTO THE AREA.
BEST CHANCE OF THESE LIGHTER SHOWERS SEEMS TO TOWARDS THE NORTH.
CAN`T RULE IT OUT ACROSS THE ENTIRE AREA THOUGH. 23
&&
.PREV DISCUSSION... /ISSUED 949 AM CST FRI NOV 22 2013/
DISCUSSION...
STRONG COLD FRONT WILL CONTINUE TO MOVE OFF THE COAST THIS MORNING AND
ACROSS THE COASTAL WATERS THIS AFTERNOON. BEHIND THE FRONT...SEEING
SOME 1 TO 2 INCH RAINFALL TOTALS ACROSS THE HOUSTON AREA ON THE HARRIS
COUNTY FLOOD WARNING SYSTEM WEBSITE AS A BAND OF SHOWERS AND THUNDERSTORMS
MOVES ACROSS THE AREA. TEMPERATURES BEHIND THE FRONT HAVE FALLEN INTO
THE 40S AND 50S...AND DO NOT EXPECT TO SEE ANY WARMUP FOR THE REMAINDER
OF THE DAY. CURRENT FORECAST AND DISCUSSIONS BELOW ARE RIGHT ON TRACK...AND
AT THIS TIME WILL NOT ISSUE A MORNING UPDATE. 42
PREV DISCUSSION... /ISSUED 609 AM CST FRI NOV 22 2013/
DISCUSSION...
SEE AVIATION FOR 12Z TAF DISCUSSION
AVIATION...
A STRONG COLD FRONT IS MOVING ACROSS SOUTHEAST TEXAS THIS MORNING
AND WILL APPROACH IAH WITHIN THE NEXT HOUR. THE FRONT IS MAKING A
QUICKER PUSH THROUGH OUR WESTERN COUNTIES SO THE BOUNDARY MAY
LIKELY MAKE IT THROUGH SGR BEFORE HOU AND WILL CLEAR MATAGORDA BAY
BEFORE MOVING THROUGH GLS. EXPECT SCATTERED SHOWERS AND
THUNDERSTORMS WITH THE FRONTAL PASSAGE AND THEN LINGERING LIGHT
RAIN AND IFR CIGS PERSISTING THROUGH THE TAF PERIOD. 38
PREV DISCUSSION... /ISSUED 451 AM CST FRI NOV 22 2013/
DISCUSSION...
THE COLD FRONT HAS PUSHED INTO SE TX THIS MORNING AND BASICALLY
LOCATED FROM BRENHAM TO HUNTSVILLE TO JUST WEST OF NACOGDOCHES.
TEMPS AT COLLEGE STATION HAVE DROPPED FROM LOW 70S TO LOW 50S IN
AN HOUR AND NOW HOVERING AROUND 50F. FRONT HAS JUST PUSHED THROUGH
HUNTSVILLE SO EXPECT A SIMILAR DROP IN TEMPS THE NEXT HOUR OR TWO.
MAIN CONCERN TODAY WILL BE THE FRONTAL PASSAGE AND TEMPS DROPPING
BEHIND IT. THE 06Z HRRR SEEMS TO BE ABOUT AN HOUR SLOW WITH THE
FRONT. WITH THAT IN MIND...THINK FRONT REACHES KCXO AROUND 12Z AND
THEN KIAH AROUND 14-15Z. FRONT MAY REACH MATAGORDA BAY AROUND
16-17Z WHICH IS ABOUT THE SAME TIME IT SHOULD PUSH THROUGH KHOU.
FRONT WILL SLOWLY PUSH OFF THE COAST AROUND 18Z. TEMPS SHOULD DROP
BEHIND THE FRONT THROUGH THE AFTERNOON. TEMPS CLOSELY FOLLOW
RECENT RAP/NAM RUNS WHICH ALSO SEEM TO HAVE A GOOD HANDLE ON THE
FRONT AND POST FRONTAL TEMPS. THIS MEANS THAT TEMPS WILL BE IN THE
40S FOR THE COLLEGE STATION AREA DURING THE AFTERNOON WITH 50S FOR
HOUSTON AREA. TEMPS WILL DROP QUICKLY INTO THE 40S OVERNIGHT.
THUNDERSTORM CHANCES HAVE BEEN KEPT HIGH AROUND 70/80 PERCENT AND
THEN HIGHER BEHIND THE FRONT FOR POST FRONTAL RAIN. WILL KEEP SOME
RAIN CHANCES GOING FRI NIGHT INTO SAT AS A WEAK VORTICITY MAX
MOVES OVER THE AREA AND FRONTOGENESIS FROM 850MB FRONT INCREASES.
DEEPER COLD AIR MOVES INTO THE AREA SAT NIGHT INTO SUN AND
BOUNDARY LAYER ALSO DRIES OUT BASED ON MODEL SOUNDINGS. HAVE LOWER
POPS FROM NE TO SW FOR SAT NIGHT AND SUN. SUNDAY EXPECT A STRONGER
VORTICITY MAX TO MOVE OVER THE AREA WHICH WILL BE IN ADVANCE OF
MAIN UPPER LEVEL LOW OVER THE DESERT SW. UPPER LOW WILL SLOWLY
MOVE ACROSS THE S ROCKIES SUN NIGHT INTO MON. IN RESPONSE...EXPECT
INCREASES ISENTROPIC LIFT EVIDENT AT 290K/295K SURFACES. SO RAIN
CHANCES WILL BE ON THE INCREASE SUN NIGHT INTO MON. INCREASED POPS
TO 70 PERCENT ON MONDAY BUT COULD VERY WELL HAVE GONE HIGHER.
DECIDED TO WAIT FOR A COUPLE MORE RUNS BUT EVERYTHING POINTS TO A
VERY WET MONDAY. COULD SEE 1-2 INCHES OF RAIN AREAWIDE FOR SE TX
FOR MONDAY. MOISTURE WILL BE STREAMING OVER THE FRONTAL SURFACE
FOR LIFT AS WELL AS INCREASED OMEGA AS THE UPPER LOW MOVES INTO
TX. LARGE SCALE ASCENT WILL NOT BE LACKING ON MONDAY AND WILL
PERSIST INTO MON NIGHT. THE HARDEST DETAILS WILL BE TO DETERMINE
EXACTLY WHERE/HOW RAIN BANDS SET UP. ALSO NOTE THAT THE BOUNDARY
LAYER WILL BE QUITE COLD UNDER THE FRONTAL SURFACE. NAM/GFS MODEL
SOUNDINGS WILL BE QUITE BORDERLINE FOR RAIN/FREEZING RAIN FROM
KCLL TO KLFK. NOT GOING TO GO WITH FROZEN PRECIP YET AS THINK SFC
WILL STAY WARM ENOUGH AND THERE IS A SOLID WARM NOSE OF 5-8C
THROUGH A 8000FT LAYER BETWEEN 925-700MB.
THERE ARE STILL SOME TIMING DIFFERENCES BETWEEN THE
NAM/GFS/ECMWF. NAM/ECMWF SOLUTIONS ARE A BIT FASTER WITH TAKING
THE COASTAL LOW FROM THE NW GULF INTO LA COAST. THEY ALSO BRING
THE SFC LOW CLOSER TO THE UPPER TX COAST WHICH WOULD ONLY ADD TO
RAINFALL POTENTIAL. GFS IS ABOUT 6 HRS SLOWER AND FARTHER OFF THE
COAST WITH THE LOW. WITH THIS IN MIND HELD ONTO SOME HIGHER POPS
FOR MON NIGHT AS THERE STILL COULD BE THE POTENTIAL FOR RAINBANDS
TO SET UP WITH MODERATE/HEAVY RAIN.
SURFACE HIGH PRESSURE WILL BUILD INTO TX LATE TUE THROUGH
THANKSGIVING HOLIDAY. TEMPS WILL BE A SOLID 10-15 DEGREES BELOW
NORMAL FOR THE HOLIDAY. ALSO NOT EXPECTING ANY HOLIDAY TRAVEL
ISSUES FOR THE HOUSTON AREA ON WEDNESDAY. HOWEVER IF YOU ARE
TRAVELING FROM HOUSTON EAST TOWARDS DCA/PHL/JFK/BOS...YOU MAY
WANT TO KEEP TRACK OF FUTURE FORECASTS. IT IS NOT LOOKING GOOD.
MARINE...
STRONG COLD FRONT HAS MOVED INTO SOUTHEAST TEXAS THIS MORNING AND
WILL BEGIN PUSHING INTO THE BAYS LATE THIS MORNING. HAVE ISSUED
ADVISORIES FOR ALL WATERS BEGINNING THIS AFTERNOON AS STRONG
OFFSHORE WINDS AND BUILDING SEAS ARE EXPECTED IN THE WAKE OF THE
FRONT. SOME GUSTS TO GALE FORCE WILL BE POSSIBLE TODAY. STRONG
OFFSHORE WINDS WILL PERSIST THROUGH THE WEEKEND AND ADVISORIES
WILL LIKELY BE EXTENDED INTO SATURDAY OR SUNDAY. A COASTAL LOW IS
FORECAST TO DEVELOP AND MOVE ACROSS THE UPPER TEXAS COASTAL WATERS
ON MONDAY...WITH STRONG OFFSHORE WINDS THEN PERSISTING IN ITS WAKE
THROUGH MID WEEK. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 47 38 46 36 44 / 70 50 60 20 60
HOUSTON (IAH) 69 43 50 42 50 / 80 50 50 20 30
GALVESTON (GLS) 68 50 55 44 53 / 70 50 50 40 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE
FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS
FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60
NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT
20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
AVIATION/MARINE...23