Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/18/12
AREA FORECAST DISCUSSION
NWS ALBANY NY
1030 PM EDT MON SEP 17 2012
.SYNOPSIS...
THE WEATHER WILL DETERIORATE QUICKLY TONIGHT AND THROUGH TUESDAY AS A
POWERFUL LOW PRESSURE SYSTEM WILL APPROACH FROM THE SOUTH AND
WEST. THIS SYSTEM WILL BRING INCREASINGLY STRONG SOUTHERLY WINDS
AND A WIDESPREAD SOAKING RAINFALL. IN ITS WAKE...COOLER WEATHER FOR
THE REGION FOR THE MID WEEK PERIOD. SEE THE SHORT TERM FOR
INFORMATION ON THIS STORM.
&&
.NEAR TERM /UNTIL 6AM TUESDAY/...
AS OF 1030 PM...STILL DRY ACROSS OUR ENTIRE REGION...AND REALLY NO
RAIN UNTIL ONE GETS DOWN INTO THE MID ATLANTIC. BASED ON THE LATEST
00Z NAM AND HRRR GUIDANCE AND THE FACT THAT OUR 00Z ALY RAOB IS
QUITE DRY...WENT AHEAD AND SLOWED DOWN THE ARRIVAL OF THE INITIAL
SHOWERS BY A FEW HOURS OVERNIGHT. SLIGHT POPS REACH THE GREATER
CAPITAL DISTRICT AT 09Z...WITH 30 POPS BY 11Z...QUICKLY ROMPING UP
TO LIKELY SHORTLY THEREAFTER. STILL LOOKING LIKE A GOOD BET FOR A
WET MORNING COMMUTE...ESPECIALLY FROM THE CAPITAL REGION SOUTHWEST.
TWEAKED A FEW OVERNIGHT LOWS AS IN SOME CASES...TEMPERATURES HAVE
APPROACHED OUR PREVIOUS OVERNIGHT LOWS. ANY TWEAKING WAS MINOR AS
WE FEEL PRETTY CONFIDENT WITH A SLOW INCREASE IN DEWPOINT/RELATIVE
HUMIDITY OVERNIGHT...TEMPERATURES WILL NOT DROP ALL THAT
MUCH...GENERALLY BOTTOMING OUT FROM THE UPPER 40S IN OUR FAR
NORTHWESTERN AREAS...TO MAINLY 50S ACROSS THE VAST MAJORITY OF THE
REGION.
IT STILL LOOKS AS IF WE WILL SEE PHASING OF THE NORTHERN AND
SOUTHERN STREAMS (MUCH LIKE A WINTER STORM)...ULTIMATELY DEVELOPING
INTO AN UNSEASONABLY POWERFUL LOW PRESSURE SYSTEM TRACKING FROM THE
OHIO VALLEY INTO THE SAINT LAWRENCE VALLEY...DRAGGING A COLD FRONT
THROUGH THE REGION LATE WEDNESDAY.
&&
.SHORT TERM /MIDNIGHT TONIGHT THROUGH WEDNESDAY NIGHT/...
A POTENT STORM WILL IMPACT THE REGION TUESDAY-TUESDAY NIGHT...
NCEP MODEL SUITE CONTINUES TO ADVERTISE A PHASING OF THE NORTH AND
SOUTHERN STREAM DURING TUESDAY WITH SURFACE CYCLOGENESIS EXPECTED
OVER THE OHIO RIVER VALLEY AND TRACKING INTO THE ST LAWRENCE VALLEY
AND EASTERN CANADA TUESDAY EVENING. PRECEDING THIS WILL BE A PASSAGE
OF A WARM FRONT WITH HIGHER THETA-E AIR AND BROAD ISENTROPIC LIFT
THROUGH THE DAY TUESDAY AS STRENGTHENING COLD FRONT APPROACHES.
DURING TUESDAY AND TUESDAY EVENING...LOW LEVEL JET INCREASES TO
BETWEEN 50-70 KTS WITH 0-30AGL WINDS BETWEEN 50-60KTS. THE MAIN
QUESTION WILL BE HOW MUCH OF THIS HIGHER MOMENTUM AIR WILL BE MIXED
TO THE SURFACE?
BASED ON LOCAL RESEARCH AND EXCELLENT COORDINATION AMONG
NEIGHBORING OFFICES AND SPC...OUR CONFIDENCE IS A BIT HIGHER THAT
WE MAY SEE A COMBINATION OF SYNOPTIC GRADIENT WINDS INITIALLY THAT
COULD RESULT IN SOME DAMAGE AS TREES STILL REMAIN FULL WITH LEAVES
AND TO BE FOLLOWED BY A NARROW AND STRONG THUNDER-LESS LINE OF
CONVECTION RACE ACROSS THE REGION WITH FROPA. SPC SWODY2 CONTINUES
TO HIGHLIGHT THE SOUTHERN 1/2 OF THE CWA WITH SLIGHT RISK WITH THE
30% CONTOUR POTENTIAL ACROSS ULSTER...DUTCHESS AND LITCHFIELD
COUNTIES. HERE THERE IS A LITTLE MORE INSTABILITY POTENTIAL AS
DCAPES CLIMB TO BETWEEN 500-900 J/KG AND SHOWALTERS NEAR -1C
/WHICH EXPANDS ACROSS THE ENTIRE REGION ALONG AND JUST AHEAD OF
THE FROPA/. HOWEVER...MID LEVEL LAPSE RATES REMAIN QUITE POOR WITH
VALUES OF AROUND 5.5 C/KM. WHILE SEVERE THUNDERSTORM THREAT
REMAINS LOW...THE COMBINATION OF THOSE HIGHER MOMENTUM WINDS JUST
ABOVE 2K FEET WITH ANY CONVECTIVE ELEMENTS WILL HAVE THE POTENTIAL
TO MIX DOWN TO THE SURFACE. FOR THESE REASONS...WE WILL ISSUE A
HIGH WIND WATCH FOR THE ENTIRE REGION.
TIMING OF THE FROPA APPEARS TO BE BETWEEN 21Z TUESDAY AND 03Z
WEDNESDAY...THIS WILL BE THE MAIN THREAT WINDOW FOR DAMAGE FROM
WINDS. THEREAFTER...STRONG ISALLOBARIC RISES ARE FORECAST AS WINDS
ABRUPTLY SHIFT TO THE WEST WITH +6MB/3HR. THERE COULD BE SOME
ADDITIONAL FUNNELING DOWN THE MOHAWK THAT WILL NEED TO BE MONITORED.
AS FOR RAINFALL TOTALS...850MB/925MB SOUTH-SOUTHEAST WINDS OF
STANDARD DEVIATIONS OF GREATER THAN 5 WILL BE OVER THE REGION FOR A
FEW HOURS IN THE AFTERNOON AND EVENING. FAVORED SOUTHEAST FACING
LOCATIONS WILL BE FAVORED FOR ENHANCED RAINFALL WITH MOST AREAS
BETWEEN 1 AND 3 INCHES. MORE DETAILS IN THE HYDRO SECTION BELOW.
IN THE WAKE OF THE FROPA AND DEPARTING STORM...COLD ADVECTION AND
HIGH PRESSURE SETTLE IN THE REGION FOR WEDNESDAY AND THURSDAY. IN
FACT...PER THE THERMAL PROFILES AND 850MB TEMPS DROPPING BACK INTO
THE LOWER SINGLE DIGITS...COULD BE RATHER CHILLY ACROSS THE CWFA
INTO THURSDAY MORNING WITH NEAR IDEAL RADIATIONAL COOLING.
TEMPERATURES AT OR BELOW 30F ARE EXPECTED ACROSS THE DACKS WITH
LOW-MID 30S FOR THE REMAINDER OF THE TERRAIN AND LOWER 40S FOR THE
MID AND LOWER HUDSON RIVER VALLEY WITHIN THE CWA.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THE PERIOD STARTS OUT WITH HIGH PRESSURE ANCHORED ALONG THE EASTERN
SEABOARD FROM MAINE TO THE GULF COAST...WITH A SOUTHERLY FLOW
STARTING TO DEVELOP IN OUR REGION. SO AFTER A COOL START THURSDAY
MORNING...TEMPS SHOULD WARM TO NEAR NORMAL DURING THE AFTERNOON WITH
ABUNDANT SUNSHINE. AS A BROAD UPPER LEVEL TROUGH GETS CARVED OUT
OVER THE UPPER GREAT LAKES AND MIDWEST...THE PATTERN WILL BECOME
MORE AMPLIFIED WHICH WILL ALLOW FOR HIGH PRESSURE TO REMAIN ANCHORED
OVER OR JUST EAST OF OUR AREA THROUGH FRIDAY NIGHT. SUNSHINE SHOULD
CONTINUE WITH A MODEST SOUTHERLY FLOW RESULTING IN TEMPS WARMING TO
THE MID 70S IN VALLEYS.
DURING THE WEEKEND UPPER LEVEL ENERGY IS FORECAST TO START MOVING
EASTWARD ACROSS THE GREAT LAKES...AND WILL PUSH A COLD FRONT THROUGH
THE EASTERN GREAT LAKES AND APPROACHING OUR AREA BY LATE SATURDAY.
WILL MENTION CHANCE POPS...BUT WILL DELAY MENTION UNTIL THE LATTER
HALF OF THE DAY ACROSS CENTRAL AND EASTERN AREAS. THERE COULD BE
ENOUGH SUNSHINE TO AGAIN SEND TEMPS WARMING INTO THE 70S.
THE MAIN FORECAST CHALLENGE FOR THE END OF THE WEEKEND INTO EARLY
NEXT WEEK IS HOW QUICKLY THE FRONTAL BOUNDARY CAN MOVE THROUGH...AS
THE ECMWF INDICATING A WAVE OF LOW PRESSURE MAY DEVELOP ALONG THE
FRONT WITH THE UPPER TROUGH PIVOTING EASTWARD. THERE IS ENOUGH OF A
PROBABILITY TO MENTION CHANCE POPS THROUGH SUNDAY NIGHT...ALTHOUGH
IF THE MORE PROGRESSIVE GFS SOLUTION VERIFIES IT WOULD DRY OUR
SOONER. TEMPS LOOKS TO COOL DOWN CONSIDERABLY IN WAKE OF THE COLD
FRONT PASSAGE SUNDAY INTO EARLY NEXT WEEK.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS WILL PREVAIL THROUGH AT LEAST THE EVENING HOURS. HIGH
CLOUDS WILL THICKEN THROUGHOUT THE NIGHT. THE THICKENING CLOUDS AND
A SLIGHT BREEZE SHOULD MITIGATE THE FORMATION OF ANY RADIATIONAL FOG
THROUGHOUT THE NIGHTTIME HOURS.
WHILE THE CURRENT TAFS DO NOT CARRY ANY REAL STRATUS OVERNIGHT...WE
ARE NOTICING SOME DEVELOPING OFF THE SOUTH JERSEY COAST OFF OUR
11U-3.U IFR SATELLITE IMAGES. CONFIDENCE WAS NOT HIGH ENOUGH THAT
THIS STRATUS WOULD IMPACT THE TAFS BY THE MORNING PEAK...BUT IT IS A
POSSIBILITY. FOR NOW...WE KEPT VFR CONDITIONS THROUGH 11Z...GOING TO
MVFR AT THAT AS THE CIGS LOWER TO AROUND 3000 FEET.
A HIGH WIND WATCH HAS BEEN ISSUED FOR THE ENTIRE AREA STARTING 16Z.
LOOK FOR AN INCREASING SOUTH OR SOUTHEASTERLY WIND THROUGHOUT THE
DAY. AS USUAL WITH THESE SITUATIONS...THE BIG QUESTION IS WHETHER OR
A LOW LEVEL OF NEARLY 50KT JET WILL TRANSLATE TO THE SURFACE...OR
REMAIN ALOFT. THE BEST CHANCES FOR THE WIND TO MIX TO THE GROUND
WOULD BE ALBANY...SO THERE WE CARRY PREVAILING GUSTS TO 30KTS
STARTING AT 16Z. AT THE OTHER TAF SITES...WE CARRY 20KT GUSTS.
KEEP IN MIND...WIND GUSTS UP TO 40KTS OR MORE IS POSSIBLE...MAINLY
DURING THE LATER AFTERNOON AND EARLY EVENING HOURS. FOR NOW...WE
TOOK THE LOW LEVEL WIND SHEAR OUT OF OUR ALBANY TAF AS THE
DIFFERENCE IN WIND SPEED FROM THE LOW LEVEL JET TO THE SURFACE...
LOOKS TO FALL SHORT OF THE THRESHOLD FOR SIGNIFICANT WIND SHEAR. WE
DID HOWEVER...ASSIGN WS020/16045KT TO THE OTHER TAFS FROM 14Z
(KPOU)-15Z (KPSF) AND 16Z (KGFL).
CONDITIONS LOOK TO BE GENERALLY LOW MVFR AT THE TAF SITES BY
14Z-16Z...ALTHOUGH KALB AND ESPECIALLY KGFL TEND TO HIGH MARGINALLY
HIGH CIGS WITH A SE WIND. FOR NOW...HAVE KEPT BOTH THESE AIRPORTS
JUST ABOVE THE THRESHOLD THAT REQUIRES THE CARRYING OF EXTRA FUEL.
HOWEVER...CONFIDENCE IS ONLY MODERATE (A LITTLE OVER 50 PERCENT) OF
THIS HAPPENING...AND CERTAINLY CIGS/VSBY COULD OCCASIONALLY DIP INTO
THE LOW MVFR OR EVEN IFR ESPECIALLY LATER IN THE AFTERNOON AND
EVENING AS THE HEAVIEST RAIN APPROACHES. JUST TOO HARD TO
SPECIFICALLY TIME THIS...BUT AS ALWAYS...WE ENCOURAGE YOU CHECK BACK
LATER THIS EVENING OR EARLY MORNING IF YOU ARE FLYING IN/OUT OF OUR
TAF SITES ANYTIME TOMORROW.
THERE IS A SLIGHT CHANCE FOR A THUNDERSTORMS...BUT NOT ENOUGH TO
MENTION IN THE TAFS AT THIS SITE. EVEN IN THE ABSENCE OF
THUNDERSTORMS...AGAIN THE POTENTIAL IS THERE FOR WIND GUSTS TO
BRIEFLY REACH UP TO OR EVEN OVER 40KTS LATE TOMORROW AND CONDITIONS
AT LEAST GOING BRIEFLY TO IFR.
OUTLOOK...
TUE NIGHT...SUB-VFR. RAIN. WINDY.
WED...SUB-VFR TO VFR. -SHRA MAINLY IN THE MORNING.
WED NIGHT-FRI...VFR. NO SIG WX.
SAT...VFR. SLIGHT CHC SUB-VFR IN -SHRAS.
&&
.FIRE WEATHER...
RAINFALL POTENTIAL INCREASES OVERNIGHT AND THROUGH THE DAY
TUESDAY WITH A SOAKING RAINFALL EXPECTED. THIS WILL KEEP RELATIVE
HUMIDITIES HIGH WITH LITTLE TO NO FIRE WEATHER CONCERNS THROUGH
TUESDAY NIGHT.
&&
.HYDROLOGY...
A WIDESPREAD SOAKING RAINFALL IS EXPECTED LATE TONIGHT THROUGH
TUESDAY NIGHT. ONE TO 3 INCHES OF RAIN ARE ANTICIPATED WITH HIGHER
AMOUNTS POSSIBLE ACROSS THE HIGHER TERRAIN IN AREAS WHERE A SOUTH
TO SOUTHEAST FLOW ENHANCES RAINFALL WITH 4-5 INCHES POSSIBLE. SINCE
ANTECEDENT CONDITIONS HAVE BEEN DRY...FLOODING IS NOT EXPECTED ON
THE MAIN STEM RIVERS AT THIS TIME. THE ZONAL FLASH FLOOD GUIDANCE
VALUES REMAIN HIGH WITH 6-HOUR VALUES RANGING FROM 3.0 TO 4.0
INCHES. SOME PONDING OF WATER ON ROADWAYS AND POOR DRAINAGE
FLOODING MAY BE POSSIBLE. RESERVOIRS LEVELS ARE EXTREMELY LOW FOR
THE LATE SUMMER AND THE RAINFALL WILL BE BENEFICIAL.
MAY HAVE SOME LINGERING SHOWERS EARLY WEDNESDAY MORNING THEN DRY
WEATHER IS EXPECTED INTO FRIDAY WITH OUR NEXT CHANCE FOR WET
WEATHER ARRIVING OVER THE WEEKEND.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...HIGH WIND WATCH FROM TUESDAY AFTERNOON THROUGH LATE TUESDAY
NIGHT FOR CTZ001-013.
NY...HIGH WIND WATCH FROM TUESDAY AFTERNOON THROUGH LATE TUESDAY
NIGHT FOR NYZ032-033-038>043-047>054-058>061-063>066-
082>084.
MA...HIGH WIND WATCH FROM TUESDAY AFTERNOON THROUGH LATE TUESDAY
NIGHT FOR MAZ001-025.
VT...HIGH WIND WATCH FROM TUESDAY AFTERNOON THROUGH LATE TUESDAY
NIGHT FOR VTZ013>015.
&&
$$
SYNOPSIS...BGM
NEAR TERM...HWJIV/BGM
SHORT TERM...BGM
LONG TERM...JPV
AVIATION...HWJIV
FIRE WEATHER...BGM
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1022 AM EDT SUN SEP 16 2012
.SYNOPSIS...
A NEARLY STATIONARY FRONTAL BOUNDARY ALONG WITH A SERIES OF UPPER
IMPULSES WILL PROVIDE A CHANCE OF SHOWERS AND A POSSIBLE
THUNDERSTORM MAINLY ACROSS NORTHERN PORTIONS OF THE FORECAST AREA
TODAY AND TONIGHT. AN UPPER LEVEL TROUGH AND INCREASING
ATMOSPHERIC MOISTURE WILL PROVIDE INCREASING CHANCES OF
PRECIPITATION FOR THE REGION LATE MONDAY THROUGH TUESDAY. A COLD
FRONT WILL MOVE THROUGH TUESDAY NIGHT OR EARLY WEDNESDAY BRINGING
DRIER AIR INTO THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE: MID-MORNING SATELLITE IMAGE AND RADAR INDICATING THE
SURFACE BOUNDARY STILL JUST NORTH OF THE FORECAST AREA. STILL
APPEARS THE BEST CHANCE OF SHOWERS WILL BE NORTH OF THE AREA THIS
AFTERNOON. NEAR ZONAL FLOW ALOFT. RUC MODEL SHOWS A WEAK UPPER
LEVEL RIPPLE TO CROSS THE NORTHERN/CENTRAL MIDLANDS THIS AFTERNOON.
SO..POPS AND TEMPS LOOK GOOD. MADE SLIGHT ADJUSTMENTS TO SKY
COVER...MAINLY SOUTH.
PREVIOUS DISCUSSION:
SURFACE BOUNDARY CURRENTLY STRETCHED TO OUR NORTH ACROSS TN AND
NC MAY REMAIN NEARLY STATIONARY OR SHIFT SLIGHTLY SOUTH TODAY AND
TONIGHT...AS HIGH PRESSURE CURRENTLY CENTERED OVER OHIO SHIFTS
EAST TO THE NE/MID ATLANTIC COAST. THE BOUNDARY ALONG WITH DAYTIME
HEATING AND A SERIES OF UPPER IMPULSES TO PROVIDE A CHANCE OF
PRECIPITATION...MAINLY ACROSS THE NORTHERN FORECAST AREA.
CONVECTIVE ANALYSIS INDICATES WEAK INSTABILITY AND WEAK WIND
FIELDS. WILL MENTION ISOLATED TO SLIGHT CHANCE THUNDER TO
ACCOMPANY THE CHANCE POPS MAINLY NORTH...BUT SEVERE NOT EXPECTED.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
CUTOFF UPPER LOW CURRENTLY OVER W TX...WILL OPEN AND SHIFT TO THE
ENE MON/TUE AHEAD OF NORTHERN STREAM KICKER TROUGH DIGGING SE INTO
THE PLAINS AND MIDWEST. SURFACE HIGH PRESSURE WILL SHIFT OFF THE EAST
COAST WHILE SURFACE LOW DEVELOPS ALONG THE GULF COAST AND SHIFTS
RAPIDLY NE AHEAD OF A COLD FRONT. THIS WILL BRING INCREASING
MOISTURE INTO OUR REGION. LATEST MODEL RUNS ARE TRENDING A LITTLE
SLOWER WITH THE BEST MOISTURE AND POPS. MODELS INDICATE MODERATE
INSTABILITY AND SIGNIFICANT 850MB JET AROUND 40KTS. SPC HAS REGION
OUTLOOKED IN SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY. DRIER
AIR WILL ENTER THE REGION BEHIND A COLD FRONT THAT IS PROGGED TO
COME THROUGH EITHER LATE TUESDAY NIGHT OR EARLY WED.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
NO CHANGES WERE MADE TO THE ONGOING FORECAST FOR THIS TIME PERIOD.
PREVIOUS DISCUSSION...A DEEP MEAN TROUGH WILL HOLD OVER THE CONUS
EAST OF THE ROCKY MOUNTAINS THROUGH THE LONG TERM. COOL AND DRY HIGH
PRESSURE WILL BUILD EAST FROM THE MIDWEST WEDNESDAY THROUGH FRIDAY.
A CLIPPER SYSTEM WILL CROSS THE GREAT LAKES REGION NEXT WEEKEND. THE
MAIN MOISTURE SHOULD REMAIN NORTH OF THE AREA. THE WEATHER SHOULD BE
DRY. EXPECT HIGHS IN THE MID 70S TO MID 80S WITH LOWS IN THE MID 50S
TO MID 60S.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS EXPECTED THROUGH THE EVENING HOURS.
LIGHT WINDS TO BECOME MORE SOUTH TO SOUTHEAST THIS AFTERNOON.
WEAK SURFACE FRONT TO SET UP ACROSS THE NORTHERN MIDLANDS THIS
AFTERNOON AND BECOME A FOCUS FOR SHOWERS. EXPECT BULK OF SHOWERS
TO REMAIN MAINLY NORTH OF THE TAF SITES. LATE NIGHT FOG/STRATUS
COULD DEVELOP TOWARD THE END OF THE TAF PERIOD. SINCE CONFIDENCE
IS LOW...WILL NOT INCLUDE AT THIS TIME.
EXTENDED AVIATION OUTLOOK...VSBY/CIG RESTRICTIONS ASSOCIATED WITH
RAIN POSSIBLE MONDAY INTO EARLY WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
330 AM CDT SUN SEP 16 2012
.SHORT TERM /TODAY/...
COUPLE OF CHALLENGES FOR TODAYS FORECAST INCLUDE LOW STRATUS MOVING
NORTH FROM MISSOURI AND KANSAS IN RIBBON OF LOW LEVEL MOISTURE FROM
H925 TO H850 EARLY TODAY. SUBJECTIVE H850 ANALYSIS AT 00Z SUN SHOWED
RAPID EXPANSION OF 50 TO 60F DEW POINTS AT THE SFC JUST TO OUR WEST
NOSING NORTH INTO EASTERN NEBRASKA WHILE ALOFT 0 TO 10C DEW POINTS
RAPIDLY HEADING NORTH AS WELL. WARM AIR ADVECTION IS ALSO EXPECTED
TO INCREASE THROUGH THE DAY...ESPECIALLY JUST AHEAD OF SLOW MOVING
COLD FRONT WHICH WILL BE NEAR THE IOWA AND MINNESOTA BORDERS BY
00Z. WITH H850 TEMPS INCREASING TO 13C SOUTH TO 16C ALONG THE
NORTHERN BORDER...AFTERNOON HIGH TEMPS WILL RISE INTO THE LOWER TO
MID 80S NORTH HALF...TEMPERED BY STRATOCU THAT SHOULD TAKE OVER ONCE
HEATING COMMENCES THIS MORNING. STILL SOME QUESTIONS EVEN AT THIS
HOUR... 07Z SUN...AS TO HOW WIDESPREAD LOW CLOUDS WILL BE BY
12Z...THOUGH THE AREA SOUTH IS DEFINITELY DEVELOPING SLOWLY NORTH.
NAM BUFR SOUNDING NEAR CRESTON IN THE SOUTHWEST SUGGESTS CEILINGS
MAY BEGIN THE MORNING NEAR 1000 FT WITH ONLY A SLIGHT IMPROVEMENT BY
15Z TO 2 TO 3KFT...EVENTUALLY BECOMING PARTLY CLOUDY BY THE NOON
HOUR. WILL MONITOR THROUGH 12Z FOR POSSIBLE UPDATES TO SKY GRIDS
ACROSS THE WEST AND SOUTH WHICH MAY NEED HIGHER VALUES. THOUGH SFC
DEW POINTS WILL RISE THIS AFTERNOON ALONG WITH HIGH TEMPS...AND
MLCAPE WILL RISE TO 600 TO 800 J/KG ALONG OVER THE NORTHWEST HALF
TOWARD 00Z... THERE IS LITTLE FORCING AHEAD OF THE BOUNDARY AND A
WEAK CAP NEAR H800 SHOULD INHIBIT CONVECTION. THUS...THUNDER CHANCES
REMAIN NIL UNTIL LATER THIS EVENING AS FRONT APPROACHES THE NORTHERN
BORDER. SOUTHWEST FLOW WILL DEVELOP AHEAD OF THE BOUNDARY TODAY BUT
MIXING REMAINS QUITE MEAGER WITH WINDS OF 12 TO 15 MPH THROUGH THE
BOUNDARY LAYER AHEAD OF THE BOUNDARY.
.LONG TERM /TONIGHT THROUGH SATURDAY/...
NO LARGE SCALE CHANGES TO THE EXTENDED WITH THE FORECAST CONCERNS
BEING THE PRECIP CHANCES TONIGHT THROUGH MONDAY FOLLOWED BY THE COLD
TEMPS AND FROST POTENTIAL. MODELS ARE STILL DEPICTING A SLOWER
MOVEMENT TO THE FRONT WITH LIMITED MOISTURE. THERE WILL BE CAPPING
AHEAD OF THE FRONT FURTHER LIMITING CONVECTIVE POTENTIAL. EVEN THE
FRONTOGENETICAL FORCING WHICH WAS DECENT YESTERDAY IS A LITTLE
SLOWER...A LITTLE WEAKER AND FALLS APART AS IT SHIFTS ACROSS IOWA.
THERE IS A NARROW AREA OF CAPE...MAINLY RIGHT ALONG AND IMMEDIATELY
BEHIND THE FRONT AND THIS WILL BE THE BEST OPPORTUNITY TO SEE
THUNDER. I HAVE KEPT THE ISOLATED WORDING AS A RESULT. PRECIP
SHOULD BEGIN OVER THE DAKOTAS AND MN THIS EVENING BUT SHOULD STAY
OUT OF IA UNTIL AFTER MIDNIGHT. I WAS GENEROUS IN POPS BEFORE 09Z
TO STAY IN COLLABORATION BUT SOUNDINGS REALLY DO NOT MOISTEN
SUFFICIENTLY UNTIL THE 09Z-12Z PERIOD REACHING A PEAK BETWEEN
15Z-18Z THEN DRYING OUT AGAIN. I BACKED OFF ON QPF JUST A BIT BASED
ON THE LACK OF MOISTURE IN THE FORECAST SOUNDINGS.
POST FRONTAL WE WILL EXPERIENCE STRONG COLD ADVECTION MONDAY NIGHT
AND AS SKIES CLEAR NORTH AND WEST TEMPS OVERNIGHT WILL BE THE
COLDEST WE HAVE SEEN YET THIS SEASON. READINGS ESPECIALLY IN LOW
LYING AREAS SHOULD DROP INTO THE MID TO UPPER 30S...ENOUGH TO SEE AT
LEAST SOME PATCHY FROST. AT THIS POINT IT IS NOT HEADLINE WORTHY
BUT THERE WILL BE A MENTION IN THE HWO FOR PEOPLE WHO DO WANT TO
THINK ABOUT PROTECTING PLANTS.
BENIGN WEATHER UNTIL WEDNESDAY/THURSDAY WHEN A FAIRLY STRONG
SHORTWAVE DROPS DOWN IN THE NORTHERLY FLOW OVER THE REGION. THERE
IS SOME DISCREPANCY AS TO HOW MUCH THE WAVE WILL DIG AND HOW IT WILL
MOVE BUT FOR NOW IT LOOKS LIKE NORTHEAST IOWA WILL GET A GLANCING
BLOW FROM THIS FEATURE AND I HAVE RELEGATED POPS WITH THIS FEATURE
MAINLY TO THE NORTHEAST AND EAST. REINFORCING COLD AIR WILL THEN
PUSH BACK INTO IOWA BUT THERE IS LARGE DISCREPANCIES AS TO HOW COLD
NEXT WEEKEND WILL BE AND THE EVOLUTION OF THE UPPER PATTERN. THE
EURO WANTS TO DROP ANOTHER STRONG WAVE OVER US AND DEVELOP A CLOSED
LOW JUST TO THE EAST. WHEN THE GFS IS MUCH WEAKER WITH THE WAVE AND
DOES NOT DEVELOP A CLOSED LOW WITH IT. FOR NOW I KEPT THE WEEKEND
DRY BUT THIS THERE WILL OBVIOUSLY BE SOME ADJUSTMENTS WITH TIME.
&&
.AVIATION...16/06Z
MVFR STRATUS DECK STILL PROGGED TO MOVE NORTHWARD OVERNIGHT AND
MAINLY AFFECT DSM AND FOD BY AROUND 10Z. CLOUD DECK MAY PUSH AS FAR
EAST AS OTM...BUT HAD LOW CONFIDENCE WITH ANY MENTION OF MVFR AS
LATEST HRRR AND WRF MODELS KEEP DECK TO THE WEST. ENOUGH MIXING
SUNDAY AFTERNOON FOR GUSTS IN THE MID-UPPER TEENS.
OTHERWISE...INCREASING HIGH CLOUDS TOMORROW NIGHT WITH APPROACHING
TROUGH.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...REV
LONG TERM...FAB
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1154 PM CDT SAT SEP 15 2012
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TONIGHT/...
HIGH PRESSURE CENTERED OVER NORTHEAST MO WILL CONTINUE EAST WITH
RETURN FLOW OF MORE MOIST AIR COMING AROUND THE BACK SIDE. THEREIN
LIES THE PROBLEM FOR TONIGHT. HOW FAR TO BRING THE CLOUDS INTO
SOUTHWEST IA AND THEN EVENTUALLY SPREADING THEM NORTHEAST. THE
NAM/WRF AND EXPERIMENTAL SATELLITE PRODUCTS SEEM TO HAVE A PRETTY
GOOD HANDLE ON IT AND WILL BRING CLOUDS TO JUST WEST OF
OTTUMWA...THROUGH ABOUT AMES...TO FORT DODGE...THEN BACK TO
DENISON. LOW TEMPS SUN SHOULD BE 5 TO 10 DEG WARMER THAN THIS
MORNING.
.LONG TERM /SUNDAY THROUGH SATURDAY/...
THE COOLEST TEMPERATURES THUS FAR THIS SEASON WILL AFFECT OUR
REGION BY THE MIDDLE OF THIS COMING WEEK...BUT NOT BEFORE A
CHANCE OF RAINFALL SUNDAY NIGHT INTO MONDAY.
SUNDAY IS A CHALLENGING DAY TO FORECAST...GIVEN THAT WE WILL BE
IN THE TRANSITION ZONE BETWEEN A DEPARTING SFC HIGH AND THE
APPROACHING NEXT WX SYSTEM. A LONG WAVE TROF WILL BRING THE NEXT
WX SYSTEM TO OUR REGION...WITH BEST CHANCES OF PRECIP LATE SUNDAY
NIGHT INTO MONDAY. MODELS HAVE BEEN TRENDING SLIGHTLY SLOWER WITH
THIS SYSTEM. ALTHOUGH THE BEST FRONTOGENETICAL FORCING REMAINS
NORTH OF IA-MN BORDER...PRECIP IS STILL EXPECTED IN OUR CWA. IN
TERMS OF CONVECTION...ONLY ISOLATED TSRA ARE EXPECTED AT BEST.
STRONG CAA BEHIND THIS SYSTEM WILL BRING OUR COOLEST TEMPS THUS
FAR THIS SEASON TO OUR CWA MONDAY NIGHT. HAVE TRENDED SLIGHTLY
COOLER ON MONDAY NIGHT/S LOWS FROM THE PREVIOUS FCST. PATCHY
FROST WILL BE A POSSIBILITY IN OUR NORTHWESTERN CWA...GIVEN TEMPS
IN THE MIDDLE 30S...ALONG WITH MINIMAL CLOUD COVER AND WIND. HAVE
INSERTED PATCHY FROST WORDING THERE.
TUESDAY WILL BRING RELATIVELY COOL TEMPS DURING THE DAYTIME
TOO...AT LEAST ACROSS THE EASTERN HALF OF THE CWA...AS THE LONG
WAVE TROF WILL BE SLOW TO LEAVE. TEMPS ARE A CHALLENGE...WITH THE
POSSIBILITY OF THE WESTERN THIRD OF THE CWA SEEING A DECENT WARM
UP ESPECIALLY IF THE CLOUDS MOVE OUT.
REINFORCING SHOT OF COOL AIR WILL ARRIVE WEDNESDAY NIGHT INTO
THURSDAY...IN CONJUNCTION WITH A POTENT SHORTWAVE DROPPING SOUTH
FROM CANADA.
MODELS SHOW CONSIDERABLE DIVERGENCE LATE IN THE FORECAST PERIOD
AND BEYOND. ECMWF BRINGS ANOTHER LONG WAVE TROF SOUTH INTO THE
NORTH CENTRAL U.S. FRIDAY NIGHT INTO SATURDAY...AND THEN ATTEMPTS
TO DEVELOP A CLOSED H5 LOW OVER ARKANSAS BY SUNDAY NIGHT. THE GFS
IS FASTER WITH THE LONG WAVE TROF...BRINGING IT INTO THE NORTH
CENTRAL U.S. DURING THE DAY ON FRIDAY...AND THEN PUSHES IT TO OUR
EAST WITHOUT A CLOSED LOW DEVELOPING. IF THE ECMWF WERE TO VERIFY
THEN THE UNSETTLED WX MAY LINGER LONGER IN OUR AREA.
&&
.AVIATION...16/06Z
MVFR STRATUS DECK STILL PROGGED TO MOVE NORTHWARD OVERNIGHT AND
MAINLY AFFECT DSM AND FOD BY AROUND 10Z. CLOUD DECK MAY PUSH AS FAR
EAST AS OTM...BUT HAD LOW CONFIDENCE WITH ANY MENTION OF MVFR AS
LATEST HRRR AND WRF MODELS KEEP DECK TO THE WEST. ENOUGH MIXING
SUNDAY AFTERNOON FOR GUSTS IN THE MID-UPPER TEENS.
OTHERWISE...INCREASING HIGH CLOUDS TOMORROW NIGHT WITH APPROACHING
TROUGH.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...MS SEP 12
LONG TERM...ZOGG
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1245 PM CDT SUN SEP 16 2012
...UPDATED FOR THE 18Z TAF AND AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 1230 PM CDT SUN SEP 16 2012
A WEAK UPPER LEVEL CYCLONE WAS EVIDENT OVER SOUTHWEST TEXAS WITH A
TROUGH EXTENDING INTO SOUTHEAST MISSOURI THIS MORNING. A WEAK
SURFACE HIGH PRESSURE SYSTEM WAS CENTERED IN WEST VIRGINIA WITH A
RIDGE EXTENDING ACROSS THE SOUTHERN PLAINS INTO SOUTH TEXAS. A
MOIST, STAGNANT AIR MASS COVERED MUCH OF THE SOUTHERN AND CENTRAL PLAINS,
AND WIDESPREAD LOW CLOUDINESS WAS EVIDENT EAST OF A LINE FROM SAN
ANGELO TO CENTRAL KANSAS LATE THIS MORNING. FOG WAS EXTENSIVE IN
CENTRAL AND WESTERN KANSAS EARLY IN THE DAY BUT ERODED BY MID
MORNING. THE MID LEVELS OF THE ATMOSPHERE WERE QUITE WARM IN THE
CENTRAL PLAINS WITH H7 TEMPERATURES NEAR 10C OVER WESTERN KANSAS.
A PLUME OF LOW LEVEL WARM AIR COVERED EASTERN COLORADO AND
SOUTHWEST NEBRASKA WITH H8 TEMPERATURES IN EXCESS OF 20C.
A DEEP CYCLONE WAS CENTERED NEAR THE SOUTHWEST COAST OF ALASKA THIS
MORNING, AND STRONG WARM AIR ADVECTION WAS ENHANCING UPPER LEVEL
RIDGING IN ALASKA AND WESTERN CANADA AND AMPLIFICATION OF THE
DOWNSTREAM LONG WAVE TROUGH EVOLVING IN THE MISSISSIPPI VALLEY. A
STRONG UPPER LEVEL JET WITH H25 WINDS IN EXCESS OF 140 KNOTS WAS
EVIDENT IN ADVANCE OF THE ALASKAN UPPER LEVEL CYCLONE, AND A JET
STREAK WITH WINDS EXCEEDING 130 KNOTS EXTENDED FROM THE NORTHWEST
TERRITORIES INTO SASKATCHEWAN. A VIGOROUS UPPER LEVEL TROUGH
EXTENDED FROM AN UPPER LEVEL LOW NEAR THE NORTH SHORE OF HUDSON BAY
INTO SOUTHERN SASKATCHEWAN, AND A DEEP SURFACE CYCLONE WAS OVER THE
NORTHERN PART OF HUDSON BAY. A COLD FRONT WAS EXTENDED FROM THE
HUDSON BAY LOW ACROSS CENTRAL MANITOBA TO NEAR THE NORTHERN NEBRASKA
BORDER THEN BACK INTO ALBERTA ALONG THE HIGHER TERRAIN. TEMPERATURES
BEHIND THE COLD FRONT AT 16Z WERE COOL WITH READINGS IN THE LOWER
50S FROM NORTH DAKOTA INTO THE PRAIRIE PROVINCES.
AN UPPER LEVEL TROUGH WAS EVIDENT IN A DEFORMATION ZONE OVER OREGON,
AND A PLUME OF HIGH LEVEL TROPICAL MOISTURE WAS FLOWING FROM THE
DEEP TROPICS INTO NORTHERN CALIFORNIA ON THE EAST SIDE OF AN UPPER
LEVEL CYCLONE CENTERED NEAR 138W/34N. ANOTHER JET STREAK WAS EVIDENT
IN MORNING RAOBS FROM NORTHERN CALIFORNIA TO WESTERN UTAH.
&&
.UPDATE...
ISSUED AT 955 AM CDT SUN SEP 16 2012
UPDATED THE FORECAST FOR MAINLY MAX TEMPS TODAY, LOWERING THEM A
BIT IN MY EASTERN ZONES. DENSE FOG THIS MORNING AND LINGERING
LOWER CLOUDS THROUGH NOON TO 1 PM CDT WILL SLOW DOWN DAY TIME
HEATING. ALSO, THE HRRR, RUC AND NAM MODELS ALL HAVE UPPER 70S FOR
HIGH IN THE LARNED AND PRATT AREAS. BUMPED HIGHS DOWN IN THE
JETMORE, DODGE CITY AND ASHLAND AREAS TO LOWER 80S.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 310 AM CDT SUN SEP 16 2012
THE MAIN FORECAST CHALLENGES ARE AREAS OF DENSE FOG THIS MORNING.
LIGHT MOIST UPSLOPE FLOW AHEAD OF A LEE TROUGH THIS MORNING WILL
CONTINUE TO ADVECT HIGHER DEWPOINTS WESTWARD INTO OUR WESTERN
COUNTIES UNDER CLEAR SKIES. A WEAK WARM FRONT AND WIND SHIFT TO THE
SOUTH BY 12Z FROM WAKEENEY SOUTH TO DODGE CITY AND ASHLAND MAY
HOWEVER LIMIT DENSE FOG FORMATION WEST OF THAT LINE AS UPSLOPE ENDS.
ALREADY PRATT SHOWING 2 MILES AND OVERCAST 100 FEET. NEW REPORTS UNDER
1/4 MILE AND FOG COMING IN FROM PRATT AND HAYS SO WILL GO AHEAD
AND ISSUE A DENSE FOG ADVISORY FROM HAYS SOUTH TO GREENSBURG AND
EAST TO PRATT THROUGH 10 AM. THE DENSE FOG SHOULD QUICKLY CLEAR BY
MID MORNING AS LIGHT SOUTH WINDS CONTINUE AND WITH A VERY SHALLOW
MOIST LAYER.
A STRONG UPPER LEVEL SHORTWAVE TROUGH WILL DIG INTO THE NORTHERN
HIGH PLAINS BY THIS EVENING AND THEN DIG INTO THE CENTRAL PLAINS BY
MONDAY MORNING. THIS FEATURE WILL PUSH A STRONG COLD FRONT ACROSS
WESTERN KANSAS BY EARLY MORNING WITH THE FRONT RUNNING FROM NEAR
SAINT JOHN TO ASHLAND. SOUTH WINDS OVERNIGHT WILL SHIFT ABRUPTLY TO
THE NORTH AT 20 TO 35 MPH AND GUSTY WITH THE COLD FRONT. ONLY SOME
MID TO HIGH LEVEL CLOUDS ARE FORECAST WITH AND BEHIND THE COLD FRONT.
HIGHS WILL BE WARMER WITH 850 TEMPS RISING TO AROUND 20C WITH A WEAK
WARM FRONT AND RANGE FROM THE MID 80S TO UPPER 80S WEST TO LOW TO
MID 80S EAST. OVERNIGHT LOWS WILL RANGE FROM THE UPPER 40S TO
LOWER 50S WEST AND NORTH BEHIND THE COLD FRONT TO THE MID TO UPPER
50S IN OUR SOUTHEAST FA FROM SAINT JOHN TO ASHLAND AND EAST.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 310 AM CDT SUN SEP 16 2012
THE COLD FRONT EXPECTED MONDAY MORNING APPEARS THE HAVE A RELATIVELY
TIGHT SURFACE PRESSURE GRADIENT OF AROUND 8 MB ACROSS WESTERN
KANSAS. LARGE DIFFERENCES EXIST IN THE WIND SPEED OUTPUT BETWEEN
THE GFS MOS - ECMWF AND NAM MODELS. IT IS PROBABLE THAT A FEW HOURS
OF WIND ADVISORY CRITERIA WIND SPEEDS WILL BE MET. HOWEVER, GIVEN
THE LACK LUSTER SPEEDS OF THE ECMWF AND EVEN THE MOS IN CENTRAL
KANSAS, WE WILL HOLD OFF ON ANY ADVISORY ISSUING NOW AND DEFER TO
CLOSER TO THE EVENT. IT DOES APPEAR TO BE SHAPING UP AS A TYPICAL
MARGINAL OR LOW END WIND EPISODE.
THE COOLER AIR USHERED IN WILL LIKELY TEMPER HIGHS ON MONDAY INTO
THE UPPER 60S. SOUTH CENTRAL KANSAS WILL PROBABLY BE WARMER SINCE
THE AREA WOULD REMAIN IN THE WARM SECTOR LONGER. THE DRY AIR LEFT IN
THE WAKE OF THE FRONT SHOULD PROMOTE STRONG LONGWAVE RADIATIONAL
COOLING OVERNIGHT, BUT THIS ALSO COULD BE MODIFIED SLIGHTLY BY MID
TO UPPER LEVEL CLOUDS ASSOCIATED WITH THE STRONG UPPER JET MOVING
THROUGH THE CENTRAL PLAINS. TEMPERATURES BY EARLY TUESDAY SHOULD
FALL INTO THE LOW 40S ACROSS A BROAD AREA. NORTHWEST FLOW WILL
PERSIST ALOFT ACROSS THE AREA. THE SURFACE RESPONSE WILL BE TO
CREATE TROUGHING ACROSS EASTERN COLORADO, AND A WARMING TREND AS
HIGHER TEMPERATURE BOUNDARY LAYER AIR OVERSPREADS SOUTHWEST KANSAS.
WEDNESDAY CONTINUES TO LOOK LIKE THE WARMEST DAY WITH POTENTIAL FOR
ADIABATICALLY WARMED AIR FROM DOWNSLOPE WINDS. THE REMAINDER OF
THE EXTENDED PERIOD LOOKS TO REMAIN DRY WITH NEAR NORMAL
TEMPERATURES FOR MID TO LATE SEPTEMBER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1240 PM CDT SUN SEP 16 2012
AFTER THE STRATOCU CLOUDS AND DENSE FOG LIFTED THIS MORNING
BETWEEN 15 AND 16Z, HIGH PRESSURE STARTED BUILDING, BRINGING CLEAR
SKIES WITH BRIGHT SUNSHINE, AND SOUTH WINDS OF 10 TO 15 KTS. A
STRONG COLD FRONT WILL BARREL SOUTHWARD EARLY MONDAY MORNING,
SHIFTING WINDS ABRUPTLY TO THE NORTH AND QUICKLY INCREASING TO
20G30KTS. MID LEVEL CLOUDS ARE ALSO EXPECTED ALONG AND BEHIND THE
FRONT, AND SHOULD BE IN THE 150-180 THOUSAND FOOT RANGE. THE MAY
BE SOME LOW LEVEL WIND SHEAR MONDAY MORNING, BUT VERY BRIEFLY AS
THE FRONT WILL BE TRAVELING TO THE SOUTH RAPIDLY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 82 50 68 42 / 0 0 10 10
GCK 85 49 68 42 / 0 0 10 0
EHA 87 50 68 47 / 0 0 20 10
LBL 86 49 69 44 / 0 0 20 10
HYS 80 49 69 42 / 0 10 20 10
P28 82 59 77 46 / 0 0 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BURKE
SYNOPSIS...RUTHI
SHORT TERM...KRUSE
LONG TERM...RUSSELL
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1232 PM CDT SUN SEP 16 2012
...SYNOPSIS UPDATED AT 1730Z...
.SYNOPSIS...
ISSUED AT 1230 PM CDT SUN SEP 16 2012
A WEAK UPPER LEVEL CYCLONE WAS EVIDENT OVER SOUTHWEST TEXAS WITH A
TROUGH EXTENDING INTO SOUTHEAST MISSOURI THIS MORNING. A WEAK
SURFACE HIGH PRESSURE SYSTEM WAS CENTERED IN WEST VIRGINIA WITH A
RIDGE EXTENDING ACROSS THE SOUTHERN PLAINS INTO SOUTH TEXAS. A
MOIST, STAGNANT AIR MASS COVERED MUCH OF THE SOUTHERN AND CENTRAL PLAINS,
AND WIDESPREAD LOW CLOUDINESS WAS EVIDENT EAST OF A LINE FROM SAN
ANGELO TO CENTRAL KANSAS LATE THIS MORNING. FOG WAS EXTENSIVE IN
CENTRAL AND WESTERN KANSAS EARLY IN THE DAY BUT ERODED BY MID
MORNING. THE MID LEVELS OF THE ATMOSPHERE WERE QUITE WARM IN THE
CENTRAL PLAINS WITH H7 TEMPERATURES NEAR 10C OVER WESTERN KANSAS.
A PLUME OF LOW LEVEL WARM AIR COVERED EASTERN COLORADO AND
SOUTHWEST NEBRASKA WITH H8 TEMPERATURES IN EXCESS OF 20C.
A DEEP CYCLONE WAS CENTERED NEAR THE SOUTHWEST COAST OF ALASKA THIS
MORNING, AND STRONG WARM AIR ADVECTION WAS ENHANCING UPPER LEVEL
RIDGING IN ALASKA AND WESTERN CANADA AND AMPLIFICATION OF THE
DOWNSTREAM LONG WAVE TROUGH EVOLVING IN THE MISSISSIPPI VALLEY. A
STRONG UPPER LEVEL JET WITH H25 WINDS IN EXCESS OF 140 KNOTS WAS
EVIDENT IN ADVANCE OF THE ALASKAN UPPER LEVEL CYCLONE, AND A JET
STREAK WITH WINDS EXCEEDING 130 KNOTS EXTENDED FROM THE NORTHWEST
TERRITORIES INTO SASKATCHEWAN. A VIGOROUS UPPER LEVEL TROUGH
EXTENDED FROM AN UPPER LEVEL LOW NEAR THE NORTH SHORE OF HUDSON BAY
INTO SOUTHERN SASKATCHEWAN, AND A DEEP SURFACE CYCLONE WAS OVER THE
NORTHERN PART OF HUDSON BAY. A COLD FRONT WAS EXTENDED FROM THE
HUDSON BAY LOW ACROSS CENTRAL MANITOBA TO NEAR THE NORTHERN NEBRASKA
BORDER THEN BACK INTO ALBERTA ALONG THE HIGHER TERRAIN. TEMPERATURES
BEHIND THE COLD FRONT AT 16Z WERE COOL WITH READINGS IN THE LOWER
50S FROM NORTH DAKOTA INTO THE PRAIRIE PROVINCES.
AN UPPER LEVEL TROUGH WAS EVIDENT IN A DEFORMATION ZONE OVER OREGON,
AND A PLUME OF HIGH LEVEL TROPICAL MOISTURE WAS FLOWING FROM THE
DEEP TROPICS INTO NORTHERN CALIFORNIA ON THE EAST SIDE OF AN UPPER
LEVEL CYCLONE CENTERED NEAR 138W/34N. ANOTHER JET STREAK WAS EVIDENT
IN MORNING RAOBS FROM NORTHERN CALIFORNIA TO WESTERN UTAH.
&&
.UPDATE...
ISSUED AT 955 AM CDT SUN SEP 16 2012
UPDATED THE FORECAST FOR MAINLY MAX TEMPS TODAY, LOWERING THEM A
BIT IN MY EASTERN ZONES. DENSE FOG THIS MORNING AND LINGERING
LOWER CLOUDS THROUGH NOON TO 1 PM CDT WILL SLOW DOWN DAY TIME
HEATING. ALSO, THE HRRR, RUC AND NAM MODELS ALL HAVE UPPER 70S FOR
HIGH IN THE LARNED AND PRATT AREAS. BUMPED HIGHS DOWN IN THE
JETMORE, DODGE CITY AND ASHLAND AREAS TO LOWER 80S.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 310 AM CDT SUN SEP 16 2012
THE MAIN FORECAST CHALLENGES ARE AREAS OF DENSE FOG THIS MORNING.
LIGHT MOIST UPSLOPE FLOW AHEAD OF A LEE TROUGH THIS MORNING WILL
CONTINUE TO ADVECT HIGHER DEWPOINTS WESTWARD INTO OUR WESTERN
COUNTIES UNDER CLEAR SKIES. A WEAK WARM FRONT AND WIND SHIFT TO THE
SOUTH BY 12Z FROM WAKEENEY SOUTH TO DODGE CITY AND ASHLAND MAY
HOWEVER LIMIT DENSE FOG FORMATION WEST OF THAT LINE AS UPSLOPE ENDS.
ALREADY PRATT SHOWING 2 MILES AND OVERCAST 100 FEET. NEW REPORTS UNDER
1/4 MILE AND FOG COMING IN FROM PRATT AND HAYS SO WILL GO AHEAD
AND ISSUE A DENSE FOG ADVISORY FROM HAYS SOUTH TO GREENSBURG AND
EAST TO PRATT THROUGH 10 AM. THE DENSE FOG SHOULD QUICKLY CLEAR BY
MID MORNING AS LIGHT SOUTH WINDS CONTINUE AND WITH A VERY SHALLOW
MOIST LAYER.
A STRONG UPPER LEVEL SHORTWAVE TROUGH WILL DIG INTO THE NORTHERN
HIGH PLAINS BY THIS EVENING AND THEN DIG INTO THE CENTRAL PLAINS BY
MONDAY MORNING. THIS FEATURE WILL PUSH A STRONG COLD FRONT ACROSS
WESTERN KANSAS BY EARLY MORNING WITH THE FRONT RUNNING FROM NEAR
SAINT JOHN TO ASHLAND. SOUTH WINDS OVERNIGHT WILL SHIFT ABRUPTLY TO
THE NORTH AT 20 TO 35 MPH AND GUSTY WITH THE COLD FRONT. ONLY SOME
MID TO HIGH LEVEL CLOUDS ARE FORECAST WITH AND BEHIND THE COLD FRONT.
HIGHS WILL BE WARMER WITH 850 TEMPS RISING TO AROUND 20C WITH A WEAK
WARM FRONT AND RANGE FROM THE MID 80S TO UPPER 80S WEST TO LOW TO
MID 80S EAST. OVERNIGHT LOWS WILL RANGE FROM THE UPPER 40S TO
LOWER 50S WEST AND NORTH BEHIND THE COLD FRONT TO THE MID TO UPPER
50S IN OUR SOUTHEAST FA FROM SAINT JOHN TO ASHLAND AND EAST.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 310 AM CDT SUN SEP 16 2012
THE COLD FRONT EXPECTED MONDAY MORNING APPEARS THE HAVE A RELATIVELY
TIGHT SURFACE PRESSURE GRADIENT OF AROUND 8 MB ACROSS WESTERN
KANSAS. LARGE DIFFERENCES EXIST IN THE WIND SPEED OUTPUT BETWEEN
THE GFS MOS - ECMWF AND NAM MODELS. IT IS PROBABLE THAT A FEW HOURS
OF WIND ADVISORY CRITERIA WIND SPEEDS WILL BE MET. HOWEVER, GIVEN
THE LACK LUSTER SPEEDS OF THE ECMWF AND EVEN THE MOS IN CENTRAL
KANSAS, WE WILL HOLD OFF ON ANY ADVISORY ISSUING NOW AND DEFER TO
CLOSER TO THE EVENT. IT DOES APPEAR TO BE SHAPING UP AS A TYPICAL
MARGINAL OR LOW END WIND EPISODE.
THE COOLER AIR USHERED IN WILL LIKELY TEMPER HIGHS ON MONDAY INTO
THE UPPER 60S. SOUTH CENTRAL KANSAS WILL PROBABLY BE WARMER SINCE
THE AREA WOULD REMAIN IN THE WARM SECTOR LONGER. THE DRY AIR LEFT IN
THE WAKE OF THE FRONT SHOULD PROMOTE STRONG LONGWAVE RADIATIONAL
COOLING OVERNIGHT, BUT THIS ALSO COULD BE MODIFIED SLIGHTLY BY MID
TO UPPER LEVEL CLOUDS ASSOCIATED WITH THE STRONG UPPER JET MOVING
THROUGH THE CENTRAL PLAINS. TEMPERATURES BY EARLY TUESDAY SHOULD
FALL INTO THE LOW 40S ACROSS A BROAD AREA. NORTHWEST FLOW WILL
PERSIST ALOFT ACROSS THE AREA. THE SURFACE RESPONSE WILL BE TO
CREATE TROUGHING ACROSS EASTERN COLORADO, AND A WARMING TREND AS
HIGHER TEMPERATURE BOUNDARY LAYER AIR OVERSPREADS SOUTHWEST KANSAS.
WEDNESDAY CONTINUES TO LOOK LIKE THE WARMEST DAY WITH POTENTIAL FOR
ADIABATICALLY WARMED AIR FROM DOWNSLOPE WINDS. THE REMAINDER OF
THE EXTENDED PERIOD LOOKS TO REMAIN DRY WITH NEAR NORMAL
TEMPERATURES FOR MID TO LATE SEPTEMBER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 627 AM CDT SUN SEP 16 2012
MOIST ADVECTION AND RADIATIONAL COOLING AHEAD OF A LEE SIDE TROUGH
IN EASTERN COLORADO HAS LED TO AREAS OF SHALLOW DENSE FOG WITH
VLIFR TO LIFR CONDITIONS. AS THE SUN COMES UP THE DENSE FOG IS
EXPECTED TO BURN OFF RAPIDLY BY AROUND 15Z WITH VFR CONDITIONS. A
NORTHERN BRANCH SHORTWAVE TROUGH IS FORECAST TO DIG INTO THE
CENTRAL PLAINS TONIGHT PUSHING A STRONG COLD FRONT ACROSS THE TAF
SITES WITH LIGHT SOUTH WINDS SHIFTING TO THE NORTH AT 20-35KT. THE
COLD FRONT IS FORECAST TO BE NEAR KHYS BY AROUND 09Z, KGCK BY 10Z,
AND KDDC BY AROUND 11Z MONDAY MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 82 50 68 42 / 0 0 10 10
GCK 85 49 68 42 / 0 0 10 0
EHA 87 50 68 47 / 0 0 20 10
LBL 86 49 69 44 / 0 0 20 10
HYS 80 49 69 42 / 0 10 20 10
P28 82 59 77 46 / 0 0 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BURKE
SYNOPSIS...RUTHI
SHORT TERM...KRUSE
LONG TERM...RUSSELL
AVIATION...KRUSE
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1000 AM CDT SUN SEP 16 2012
...UPDATED...
.UPDATE...
ISSUED AT 955 AM CDT SUN SEP 16 2012
UPDATED THE FORECAST FOR MAINLY MAX TEMPS TODAY, LOWERING THEM A
BIT IN MY EASTERN ZONES. DENSE FOG THIS MORNING AND LINGERING
LOWER CLOUDS THROUGH NOON TO 1 PM CDT WILL SLOW DOWN DAY TIME
HEATING. ALSO, THE HRRR, RUC AND NAM MODELS ALL HAVE UPPER 70S FOR
HIGH IN THE LARNED AND PRATT AREAS. BUMPED HIGHS DOWN IN THE
JETMORE, DODGE CITY AND ASHLAND AREAS TO LOWER 80S.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 310 AM CDT SUN SEP 16 2012
THE MAIN FORECAST CHALLENGES ARE AREAS OF DENSE FOG THIS MORNING.
LIGHT MOIST UPSLOPE FLOW AHEAD OF A LEE TROUGH THIS MORNING WILL
CONTINUE TO ADVECT HIGHER DEWPOINTS WESTWARD INTO OUR WESTERN
COUNTIES UNDER CLEAR SKIES. A WEAK WARM FRONT AND WIND SHIFT TO THE
SOUTH BY 12Z FROM WAKEENEY SOUTH TO DODGE CITY AND ASHLAND MAY
HOWEVER LIMIT DENSE FOG FORMATION WEST OF THAT LINE AS UPSLOPE ENDS.
ALREADY PRATT SHOWING 2 MILES AND OVERCAST 100 FEET. NEW REPORTS UNDER
1/4 MILE AND FOG COMING IN FROM PRATT AND HAYS SO WILL GO AHEAD
AND ISSUE A DENSE FOG ADVISORY FROM HAYS SOUTH TO GREENSBURG AND
EAST TO PRATT THROUGH 10 AM. THE DENSE FOG SHOULD QUICKLY CLEAR BY
MID MORNING AS LIGHT SOUTH WINDS CONTINUE AND WITH A VERY SHALLOW
MOIST LAYER.
A STRONG UPPER LEVEL SHORTWAVE TROUGH WILL DIG INTO THE NORTHERN
HIGH PLAINS BY THIS EVENING AND THEN DIG INTO THE CENTRAL PLAINS BY
MONDAY MORNING. THIS FEATURE WILL PUSH A STRONG COLD FRONT ACROSS
WESTERN KANSAS BY EARLY MORNING WITH THE FRONT RUNNING FROM NEAR
SAINT JOHN TO ASHLAND. SOUTH WINDS OVERNIGHT WILL SHIFT ABRUPTLY TO
THE NORTH AT 20 TO 35 MPH AND GUSTY WITH THE COLD FRONT. ONLY SOME
MID TO HIGH LEVEL CLOUDS ARE FORECAST WITH AND BEHIND THE COLD FRONT.
HIGHS WILL BE WARMER WITH 850 TEMPS RISING TO AROUND 20C WITH A WEAK
WARM FRONT AND RANGE FROM THE MID 80S TO UPPER 80S WEST TO LOW TO
MID 80S EAST. OVERNIGHT LOWS WILL RANGE FROM THE UPPER 40S TO
LOWER 50S WEST AND NORTH BEHIND THE COLD FRONT TO THE MID TO UPPER
50S IN OUR SOUTHEAST FA FROM SAINT JOHN TO ASHLAND AND EAST.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 310 AM CDT SUN SEP 16 2012
THE COLD FRONT EXPECTED MONDAY MORNING APPEARS THE HAVE A RELATIVELY
TIGHT SURFACE PRESSURE GRADIENT OF AROUND 8 MB ACROSS WESTERN
KANSAS. LARGE DIFFERENCES EXIST IN THE WIND SPEED OUTPUT BETWEEN
THE GFS MOS - ECMWF AND NAM MODELS. IT IS PROBABLE THAT A FEW HOURS
OF WIND ADVISORY CRITERIA WIND SPEEDS WILL BE MET. HOWEVER, GIVEN
THE LACK LUSTER SPEEDS OF THE ECMWF AND EVEN THE MOS IN CENTRAL
KANSAS, WE WILL HOLD OFF ON ANY ADVISORY ISSUING NOW AND DEFER TO
CLOSER TO THE EVENT. IT DOES APPEAR TO BE SHAPING UP AS A TYPICAL
MARGINAL OR LOW END WIND EPISODE.
THE COOLER AIR USHERED IN WILL LIKELY TEMPER HIGHS ON MONDAY INTO
THE UPPER 60S. SOUTH CENTRAL KANSAS WILL PROBABLY BE WARMER SINCE
THE AREA WOULD REMAIN IN THE WARM SECTOR LONGER. THE DRY AIR LEFT IN
THE WAKE OF THE FRONT SHOULD PROMOTE STRONG LONGWAVE RADIATIONAL
COOLING OVERNIGHT, BUT THIS ALSO COULD BE MODIFIED SLIGHTLY BY MID
TO UPPER LEVEL CLOUDS ASSOCIATED WITH THE STRONG UPPER JET MOVING
THROUGH THE CENTRAL PLAINS. TEMPERATURES BY EARLY TUESDAY SHOULD
FALL INTO THE LOW 40S ACROSS A BROAD AREA. NORTHWEST FLOW WILL
PERSIST ALOFT ACROSS THE AREA. THE SURFACE RESPONSE WILL BE TO
CREATE TROUGHING ACROSS EASTERN COLORADO, AND A WARMING TREND AS
HIGHER TEMPERATURE BOUNDARY LAYER AIR OVERSPREADS SOUTHWEST KANSAS.
WEDNESDAY CONTINUES TO LOOK LIKE THE WARMEST DAY WITH POTENTIAL FOR
ADIABATICALLY WARMED AIR FROM DOWNSLOPE WINDS. THE REMAINDER OF
THE EXTENDED PERIOD LOOKS TO REMAIN DRY WITH NEAR NORMAL
TEMPERATURES FOR MID TO LATE SEPTEMBER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 627 AM CDT SUN SEP 16 2012
MOIST ADVECTION AND RADIATIONAL COOLING AHEAD OF A LEE SIDE TROUGH
IN EASTERN COLORADO HAS LED TO AREAS OF SHALLOW DENSE FOG WITH
VLIFR TO LIFR CONDITIONS. AS THE SUN COMES UP THE DENSE FOG IS
EXPECTED TO BURN OFF RAPIDLY BY AROUND 15Z WITH VFR CONDITIONS. A
NORTHERN BRANCH SHORTWAVE TROUGH IS FORECAST TO DIG INTO THE
CENTRAL PLAINS TONIGHT PUSHING A STRONG COLD FRONT ACROSS THE TAF
SITES WITH LIGHT SOUTH WINDS SHIFTING TO THE NORTH AT 20-35KT. THE
COLD FRONT IS FORECAST TO BE NEAR KHYS BY AROUND 09Z, KGCK BY 10Z,
AND KDDC BY AROUND 11Z MONDAY MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 82 50 68 42 / 0 0 10 10
GCK 85 49 68 42 / 0 0 10 0
EHA 87 50 68 47 / 0 0 20 10
LBL 86 49 69 44 / 0 0 20 10
HYS 80 49 69 42 / 0 10 20 10
P28 82 59 77 46 / 0 0 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR KSZ030-031-
044>046-063>066-077>081-087>090.
&&
$$
UPDATE...BURKE
SHORT TERM...KRUSE
LONG TERM...RUSSELL
AVIATION...KRUSE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
745 AM MDT SUN SEP 16 2012
.UPDATE...
ISSUED AT 735 AM MDT SUN SEP 16 2012
WITH FIRST VISIBLE IMAGES COMING IN THIS MORNING GIVES A GOOD VIEW
TO THE EXTENT OF MORNING FOG COVER WHICH INDICATES MOST WIDESPREAD
FOG ACROSS THE EXTREME EASTERN FRINGE OF THE AREA. WITH LIGHT
WESTERLY FLOW EXTENDING FROM A TRENTON TO GRINNELL LINE...DO NOT
THINK FOG WOULD EXPAND ANY FARTHER WEST THAN THAT AND WITH SFC
HEATING DEVELOPING HAVE DOUBTS IF IT WILL EXPAND MUCH FROM CURRENT
POSITION. HAVE LOWERED COVERAGE TO PATCHY ACROSS WESTERN EXTEND OF
ADVISORY AREA AND WANT TO MONITOR AREA FOR POSSIBLE EXPANSION OF
FOG COVERAGE BEFORE CLEARING COUNTIES.
UPDATE ISSUED AT 513 AM MDT SUN SEP 16 2012
DENSE FOG BEING REPORTED AT HILL CITY (KHLC) PRESENTLY. THIS
AIRMASS EXPECTED TO SLOWLY DRIFT WEST PER HRRR WHICH SEEMS TO HAVE
A GOOD HANDLE ON CURRENT CONDITIONS. DENSE FOG ADVISORY HAS BEEN
ISSUED.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 200 AM MDT SUN SEP 16 2012
FIRST CONCERN THIS MORNING IS FOG. AT 07Z FOG NOW DEVELOPING IN
THE HILL CITY AND POSSIBLY NORTON AREAS NEAR A SFC TROUGH. EXPECT
THE FOG TO CONTINUE IN THESE AREAS...POSSIBLY A ROW OF COUNTIES
FURTHER WEST THROUGH MID MORNING BEFORE THE SFC LOW AND TROUGH
START TO MOVE EAST PUSHING THE ABUNDANT LOW LEVEL MOISTURE OUT OF
THE AREA. OTHERWISE FOR TODAY EXPECT A SLOWLY INCREASE IN MOSTLY
HIGH LEVEL CLOUDS WITH HIGH TEMPERATURES AROUND 85 IN THE NORTON
AND HILL CITY AREAS TO THE UPPER 80S TO MID 90S
ELSEWHERE...HOTTEST IN THE BENKELMAN AND SAINT FRANCIS AREAS.
FOR TONIGHT THROUGH MONDAY FOCUS REMAINS ON A STRONG COLD FRONT
AND THE CHANCE ALBEIT SMALL FOR SOME LIGHT RAIN SHOWERS. GOOD
AGREEMENT ON BRINGING THE FRONT INTO THE NORTHWEST CORNER OF THE
AREA AROUND MIDNIGHT THEN RAPIDLY SOUTH AND THROUGH THE ENTIRE
AREA BY SUNRISE MONDAY. STILL LOOKING AT 20 TO 30 MPH WINDS WITH
HIGHER GUSTS. THESE WINDS WILL CONTINUE THE EARLY PART OF THE DAY
MONDAY BEFORE SLOWLY SUBSIDING THROUGH THE REST OF THE DAY. HIGH
TEMPERATURES WILL BE MUCH COOLER WITH MID 60S TO AROUND 70. AS FAR
AS PRECIPITATION CHANCES...STILL LOOKING LIKE THE BEST CHANCE WILL
BE AFTER MIDNIGHT TONIGHT THROUGH EARLY MONDAY AFTERNOON AS A
WEATHER DISTURBANCE AND SOME JET ENERGY MOVE THROUGH THE NORTHWEST
FLOW ALOFT.
MONDAY NIGHT-TUESDAY NIGHT...HIGH PRESSURE MOVES OVER THE AREA
MONDAY NIGHT WITH OVERNIGHT LOWS IN THE UPPER 30S TO LOW 40S.
WARMER TEMPERATURES RETURN TUESDAY WITH 75 TO 80 ACROSS THE AREA.
LOWS TUESDAY NIGHT NEAR NORMAL. IT APPEARS TO BE DRY THROUGH THE
PERIOD.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 200 AM MDT SUN SEP 16 2012
THE PERIOD IS EXPECTED TO BE DRY AS A WEAK RIDGE PERSISTS OVER THE
DESERT SOUTHWEST AND A SERIES OF TROUGHS DIG IN THROUGH THE EASTERN
2/3RDS OF THE CONUS. MAY SEE A FEW WEAK AND DRY FRONTAL PASSAGES
WITH THE NORTHWEST FLOW OVER THE AREA. THE 12Z/15 AND 00Z/16 EC ARE
VERY AGGRESSIVE IN BRINGING A SHORTWAVE TROUGH DEEP INTO THE PLAINS
FRIDAY INTO SATURDAY WHICH COULD BRING A SLIGHT CHANCE OF
PRECIP...BUT HAVE DECIDED TO KEEP POPS SILENT AS THIS SOLUTION IS AN
OUTLIER WRT OTHER GUIDANCE. TEMPERATURES OVER THE PERIOD WILL BE
NEAR NORMAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 552 AM MDT SUN SEP 16 2012
VFR CONDITIONS ARE EXPECTED AT MCK THROUGH MOST OF THE TAF PERIOD.
DENSE FOG DEVELOPED EAST OF MCK OVERNIGHT. LOOKING AT THE GOES
FOG PRODUCT...REGIONAL OBSERVATIONS...AND REAL TIME OBS AT MCK IT
APPEARS THAT THE LOW LEVEL MOISTURE IS VERY CLOSE TO MCK. HAVE
INCLUDED A TEMPO GROUP FOR MVFR VISIBILITIES AS PATCHY FOG MAY
DEVELOP THIS MORNING DUE TO THE LOW LEVEL MOISTURE...BUT AT THIS
TIME DO NOT EXPECT DENSE FOG TO REACH THE AIRPORT. OTHERWISE TODAY
WILL HAVE MODERATE WINDS OUT OF THE SOUTH BEFORE A STRONG COLD
FRONT PASSAGE LATE TONIGHT. PRECIPITATION CHANCES ARE VERY LOW BUT
BEHIND THE FRONT WINDS WILL BE STRONG OUT OF THE NORTH- NORTHEAST
AT 20KTS WITH GUSTS TO 30KTS.
AT GLD VFR CONDITIONS ARE EXPECTED THROUGH THE ENTIRE PERIOD AS A
WEAK TROUGH SITS OVER THE AREA WHICH WILL LIMIT AFTERNOON WINDS. A
STRONG COLD FRONT WILL PASS LATE TONIGHT BRINGING CLOUDS AND STRONG
WINDS OUT OF THE NORTH WITH GUSTS UP TO 30KTS.
&&
.FIRE WEATHER...
ISSUED AT 200 AM MDT SUN SEP 16 2012
CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE THIS AFTERNOON
FOR COUNTIES INCLUDING HITCHCOCK AND RED WILLOW COUNTIES OF
NEBRASKA...RAWLINS...DECATUR...THOMAS AND SHERIDAN COUNTIES OF
KANSAS. IN THESE AREAS SOUTH WINDS HAVE THE POTENTIAL TO GUST
AROUND 25 MPH WHILE RELATIVE HUMIDITY DROPS BELOW 15 PERCENT.
CONFIDENCE NOT HIGH ENOUGH RIGHT NOW FOR A RED FLAG WARNING GIVEN
DISAGREEMENT ON THE HANDLING OF THE SFC TROUGH AND SPEED AT WHICH
IT MAY OR MAY NOT MOVE EAST ACROSS THE AREA TODAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...DENSE FOG ADVISORY UNTIL 11 AM CDT THIS MORNING FOR KSZ003-004-
015-016-029.
CO...NONE.
NE...DENSE FOG ADVISORY UNTIL 11 AM CDT THIS MORNING FOR NEZ081.
&&
$$
UPDATE...JRM
SHORT TERM...99
LONG TERM...JJM
AVIATION...99/JJM
FIRE WEATHER...99
AREA FORECAST DISCUSSION
NWS GOODLAND KS
553 AM MDT SUN SEP 16 2012
.UPDATE...
ISSUED AT 513 AM MDT SUN SEP 16 2012
DENSE FOG BEING REPORTED AT HILL CITY (KHLC) PRESENTLY. THIS
AIRMASS EXPECTED TO SLOWLY DRIFT WEST PER HRRR WHICH SEEMS TO HAVE
A GOOD HANDLE ON CURRENT CONDITIONS. DENSE FOG ADVISORY HAS BEEN
ISSUED.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 200 AM MDT SUN SEP 16 2012
FIRST CONCERN THIS MORNING IS FOG. AT 07Z FOG NOW DEVELOPING IN
THE HILL CITY AND POSSIBLY NORTON AREAS NEAR A SFC TROUGH. EXPECT
THE FOG TO CONTINUE IN THESE AREAS...POSSIBLY A ROW OF COUNTIES
FURTHER WEST THROUGH MID MORNING BEFORE THE SFC LOW AND TROUGH
START TO MOVE EAST PUSHING THE ABUNDANT LOW LEVEL MOISTURE OUT OF
THE AREA. OTHERWISE FOR TODAY EXPECT A SLOWLY INCREASE IN MOSTLY
HIGH LEVEL CLOUDS WITH HIGH TEMPERATURES AROUND 85 IN THE NORTON
AND HILL CITY AREAS TO THE UPPER 80S TO MID 90S
ELSEWHERE...HOTTEST IN THE BENKELMAN AND SAINT FRANCIS AREAS.
FOR TONIGHT THROUGH MONDAY FOCUS REMAINS ON A STRONG COLD FRONT
AND THE CHANCE ALBEIT SMALL FOR SOME LIGHT RAIN SHOWERS. GOOD
AGREEMENT ON BRINGING THE FRONT INTO THE NORTHWEST CORNER OF THE
AREA AROUND MIDNIGHT THEN RAPIDLY SOUTH AND THROUGH THE ENTIRE
AREA BY SUNRISE MONDAY. STILL LOOKING AT 20 TO 30 MPH WINDS WITH
HIGHER GUSTS. THESE WINDS WILL CONTINUE THE EARLY PART OF THE DAY
MONDAY BEFORE SLOWLY SUBSIDING THROUGH THE REST OF THE DAY. HIGH
TEMPERATURES WILL BE MUCH COOLER WITH MID 60S TO AROUND 70. AS FAR
AS PRECIPITATION CHANCES...STILL LOOKING LIKE THE BEST CHANCE WILL
BE AFTER MIDNIGHT TONIGHT THROUGH EARLY MONDAY AFTERNOON AS A
WEATHER DISTURBANCE AND SOME JET ENERGY MOVE THROUGH THE NORTHWEST
FLOW ALOFT.
MONDAY NIGHT-TUESDAY NIGHT...HIGH PRESSURE MOVES OVER THE AREA
MONDAY NIGHT WITH OVERNIGHT LOWS IN THE UPPER 30S TO LOW 40S.
WARMER TEMPERATURES RETURN TUESDAY WITH 75 TO 80 ACROSS THE AREA.
LOWS TUESDAY NIGHT NEAR NORMAL. IT APPEARS TO BE DRY THROUGH THE
PERIOD.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 200 AM MDT SUN SEP 16 2012
THE PERIOD IS EXPECTED TO BE DRY AS A WEAK RIDGE PERSISTS OVER THE
DESERT SOUTHWEST AND A SERIES OF TROUGHS DIG IN THROUGH THE EASTERN
2/3RDS OF THE CONUS. MAY SEE A FEW WEAK AND DRY FRONTAL PASSAGES
WITH THE NORTHWEST FLOW OVER THE AREA. THE 12Z/15 AND 00Z/16 EC ARE
VERY AGGRESSIVE IN BRINGING A SHORTWAVE TROUGH DEEP INTO THE PLAINS
FRIDAY INTO SATURDAY WHICH COULD BRING A SLIGHT CHANCE OF
PRECIP...BUT HAVE DECIDED TO KEEP POPS SILENT AS THIS SOLUTION IS AN
OUTLIER WRT OTHER GUIDANCE. TEMPERATURES OVER THE PERIOD WILL BE
NEAR NORMAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 552 AM MDT SUN SEP 16 2012
VFR CONDITIONS ARE EXPECTED AT MCK THROUGH MOST OF THE TAF PERIOD.
DENSE FOG DEVELOPED EAST OF MCK OVERNIGHT. LOOKING AT THE GOES
FOG PRODUCT...REGIONAL OBSERVATIONS...AND REAL TIME OBS AT MCK IT
APPEARS THAT THE LOW LEVEL MOISTURE IS VERY CLOSE TO MCK. HAVE
INCLUDED A TEMPO GROUP FOR MVFR VISIBILITIES AS PATCHY FOG MAY
DEVELOP THIS MORNING DUE TO THE LOW LEVEL MOISTURE...BUT AT THIS
TIME DO NOT EXPECT DENSE FOG TO REACH THE AIRPORT. OTHERWISE TODAY
WILL HAVE MODERATE WINDS OUT OF THE SOUTH BEFORE A STRONG COLD
FRONT PASSAGE LATE TONIGHT. PRECIPITATION CHANCES ARE VERY LOW BUT
BEHIND THE FRONT WINDS WILL BE STRONG OUT OF THE NORTH- NORTHEAST
AT 20KTS WITH GUSTS TO 30KTS.
AT GLD VFR CONDITIONS ARE EXPECTED THROUGH THE ENTIRE PERIOD AS A
WEAK TROUGH SITS OVER THE AREA WHICH WILL LIMIT AFTERNOON WINDS. A
STRONG COLD FRONT WILL PASS LATE TONIGHT BRINGING CLOUDS AND STRONG
WINDS OUT OF THE NORTH WITH GUSTS UP TO 30KTS.
&&
.FIRE WEATHER...
ISSUED AT 200 AM MDT SUN SEP 16 2012
CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE THIS AFTERNOON
FOR COUNTIES INCLUDING HITCHCOCK AND RED WILLOW COUNTIES OF
NEBRASKA...RAWLINS...DECATUR...THOMAS AND SHERIDAN COUNTIES OF
KANSAS. IN THESE AREAS SOUTH WINDS HAVE THE POTENTIAL TO GUST
AROUND 25 MPH WHILE RELATIVE HUMIDITY DROPS BELOW 15 PERCENT.
CONFIDENCE NOT HIGH ENOUGH RIGHT NOW FOR A RED FLAG WARNING GIVEN
DISAGREEMENT ON THE HANDLING OF THE SFC TROUGH AND SPEED AT WHICH
IT MAY OR MAY NOT MOVE EAST ACROSS THE AREA TODAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...DENSE FOG ADVISORY UNTIL 11 AM CDT THIS MORNING FOR KSZ003-004-
015-016-029.
CO...NONE.
NE...DENSE FOG ADVISORY UNTIL 11 AM CDT THIS MORNING FOR NEZ081.
&&
$$
UPDATE...99
SHORT TERM...99
LONG TERM...JJM
AVIATION...99/JJM
FIRE WEATHER...99
AREA FORECAST DISCUSSION
NWS GOODLAND KS
517 AM MDT SUN SEP 16 2012
.UPDATE...
ISSUED AT 513 AM MDT SUN SEP 16 2012
DENSE FOG BEING REPORTED AT HILL CITY (KHLC) PRESENTLY. THIS
AIRMASS EXPECTED TO SLOWLY DRIFT WEST PER HRRR WHICH SEEMS TO HAVE
A GOOD HANDLE ON CURRENT CONDITIONS. DENSE FOG ADVISORY HAS BEEN
ISSUED.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 200 AM MDT SUN SEP 16 2012
FIRST CONCERN THIS MORNING IS FOG. AT 07Z FOG NOW DEVELOPING IN
THE HILL CITY AND POSSIBLY NORTON AREAS NEAR A SFC TROUGH. EXPECT
THE FOG TO CONTINUE IN THESE AREAS...POSSIBLY A ROW OF COUNTIES
FURTHER WEST THROUGH MID MORNING BEFORE THE SFC LOW AND TROUGH
START TO MOVE EAST PUSHING THE ABUNDANT LOW LEVEL MOISTURE OUT OF
THE AREA. OTHERWISE FOR TODAY EXPECT A SLOWLY INCREASE IN MOSTLY
HIGH LEVEL CLOUDS WITH HIGH TEMPERATURES AROUND 85 IN THE NORTON
AND HILL CITY AREAS TO THE UPPER 80S TO MID 90S
ELSEWHERE...HOTTEST IN THE BENKELMAN AND SAINT FRANCIS AREAS.
FOR TONIGHT THROUGH MONDAY FOCUS REMAINS ON A STRONG COLD FRONT
AND THE CHANCE ALBEIT SMALL FOR SOME LIGHT RAIN SHOWERS. GOOD
AGREEMENT ON BRINGING THE FRONT INTO THE NORTHWEST CORNER OF THE
AREA AROUND MIDNIGHT THEN RAPIDLY SOUTH AND THROUGH THE ENTIRE
AREA BY SUNRISE MONDAY. STILL LOOKING AT 20 TO 30 MPH WINDS WITH
HIGHER GUSTS. THESE WINDS WILL CONTINUE THE EARLY PART OF THE DAY
MONDAY BEFORE SLOWLY SUBSIDING THROUGH THE REST OF THE DAY. HIGH
TEMPERATURES WILL BE MUCH COOLER WITH MID 60S TO AROUND 70. AS FAR
AS PRECIPITATION CHANCES...STILL LOOKING LIKE THE BEST CHANCE WILL
BE AFTER MIDNIGHT TONIGHT THROUGH EARLY MONDAY AFTERNOON AS A
WEATHER DISTURBANCE AND SOME JET ENERGY MOVE THROUGH THE NORTHWEST
FLOW ALOFT.
MONDAY NIGHT-TUESDAY NIGHT...HIGH PRESSURE MOVES OVER THE AREA
MONDAY NIGHT WITH OVERNIGHT LOWS IN THE UPPER 30S TO LOW 40S.
WARMER TEMPERATURES RETURN TUESDAY WITH 75 TO 80 ACROSS THE AREA.
LOWS TUESDAY NIGHT NEAR NORMAL. IT APPEARS TO BE DRY THROUGH THE
PERIOD.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 200 AM MDT SUN SEP 16 2012
THE PERIOD IS EXPECTED TO BE DRY AS A WEAK RIDGE PERSISTS OVER THE
DESERT SOUTHWEST AND A SERIES OF TROUGHS DIG IN THROUGH THE EASTERN
2/3RDS OF THE CONUS. MAY SEE A FEW WEAK AND DRY FRONTAL PASSAGES
WITH THE NORTHWEST FLOW OVER THE AREA. THE 12Z/15 AND 00Z/16 EC ARE
VERY AGGRESSIVE IN BRINGING A SHORTWAVE TROUGH DEEP INTO THE PLAINS
FRIDAY INTO SATURDAY WHICH COULD BRING A SLIGHT CHANCE OF
PRECIP...BUT HAVE DECIDED TO KEEP POPS SILENT AS THIS SOLUTION IS AN
OUTLIER WRT OTHER GUIDANCE. TEMPERATURES OVER THE PERIOD WILL BE
NEAR NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1111 PM MDT SAT SEP 15 2012
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT KGLD THROUGH THE TAF
PERIOD. MVFR CONDITIONS ARE POSSIBLE OVER KMCK AROUND 12Z AS
FOG/STRATUS DEVELOP EAST OF THE TERMINAL IN RESPONSE TO GOOD BL
MOISTURE ADVECTING IN FROM THE SE. CANT RULE OUT CONDITIONS LOWER
THAN MVFR...HOWEVER AT THIS POINT LATEST SHORT RANGE GUIDANCE
WOULD KEEP IFR/LIFR JUST EAST OF MCK. LIGHT SOUTHERLY WINDS WILL
INCREASE SOME DURING THE DAY SUNDAY WITH AFTERNOON GUSTS AROUND
15KT. WINDS WILL SHIFT TO THE NORTH/NORTHWEST LATE SUNDAY EVENING
AS A FRONT DROPS SOUTH OVER BOTH TERMINALS.
&&
.FIRE WEATHER...
ISSUED AT 200 AM MDT SUN SEP 16 2012
CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE THIS AFTERNOON
FOR COUNTIES INCLUDING HITCHCOCK AND RED WILLOW COUNTIES OF
NEBRASKA...RAWLINS...DECATUR...THOMAS AND SHERIDAN COUNTIES OF
KANSAS. IN THESE AREAS SOUTH WINDS HAVE THE POTENTIAL TO GUST
AROUND 25 MPH WHILE RELATIVE HUMIDITY DROPS BELOW 15 PERCENT.
CONFIDENCE NOT HIGH ENOUGH RIGHT NOW FOR A RED FLAG WARNING GIVEN
DISAGREEMENT ON THE HANDLING OF THE SFC TROUGH AND SPEED AT WHICH
IT MAY OR MAY NOT MOVE EAST ACROSS THE AREA TODAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...DENSE FOG ADVISORY UNTIL 11 AM CDT THIS MORNING FOR KSZ003-004-
015-016-029.
CO...NONE.
NE...DENSE FOG ADVISORY UNTIL 11 AM CDT THIS MORNING FOR NEZ081.
&&
$$
UPDATE...99
SHORT TERM...99
LONG TERM...JJM
AVIATION...DR
FIRE WEATHER...99
AREA FORECAST DISCUSSION...UPDATED
NWS DODGE CITY KS
536 AM CDT SUN SEP 16 2012
.UPDATE...
ISSUED AT 528 AM CDT SUN SEP 16 2012
WENT AHEAD AND EXPANDED THE DENSE FOG ADVISORY WEST TO TREGO, LANE,
FINNEY, GRAY, AND MEADE, THEN EAST TO MEDICINE LODGE. LOCAL CALLS
TO COUNTIES WERE GETTING WIDESPREAD AREAS OF DENSE FOG WITH
VISIBILITIES LESS THAN 1/4 OF A MILE. SATELLITE FOG PRODUCT AND
HRRR MESOSCALE MODEL CONFIRM THOSE AREAS THROUGH 10 AM THIS
MORNING. RECENTLY THE GARDEN CITY AIRPORT WENT BACK UP TO 3 MILES
AND FOG SO THE WESTERN EDGE LOOKS TO BE NEAR KGCK AT THIS TIME.
THE FOG DUE TO MOIST ADVECTION AND RADIATIONAL COOLING AHEAD OF
A LEE TROUGH IN EASTERN COLORADO.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 310 AM CDT SUN SEP 16 2012
THE MAIN FORECAST CHALLENGES ARE AREAS OF DENSE FOG THIS MORNING.
LIGHT MOIST UPSLOPE FLOW AHEAD OF A LEE TROUGH THIS MORNING WILL
CONTINUE TO ADVECT HIGHER DEWPOINTS WESTWARD INTO OUR WESTERN
COUNTIES UNDER CLEAR SKIES. A WEAK WARM FRONT AND WIND SHIFT TO THE
SOUTH BY 12Z FROM WAKEENEY SOUTH TO DODGE CITY AND ASHLAND MAY
HOWEVER LIMIT DENSE FOG FORMATION WEST OF THAT LINE AS UPSLOPE ENDS.
ALREADY PRATT SHOWING 2 MILES AND OVERCAST 100 FEET. NEW REPORTS UNDER
1/4 MILE AND FOG COMING IN FROM PRATT AND HAYS SO WILL GO AHEAD
AND ISSUE A DENSE FOG ADVISORY FROM HAYS SOUTH TO GREENSBURG AND
EAST TO PRATT THROUGH 10 AM. THE DENSE FOG SHOULD QUICKLY CLEAR BY
MID MORNING AS LIGHT SOUTH WINDS CONTINUE AND WITH A VERY SHALLOW
MOIST LAYER.
A STRONG UPPER LEVEL SHORTWAVE TROUGH WILL DIG INTO THE NORTHERN
HIGH PLAINS BY THIS EVENING AND THEN DIG INTO THE CENTRAL PLAINS BY
MONDAY MORNING. THIS FEATURE WILL PUSH A STRONG COLD FRONT ACROSS
WESTERN KANSAS BY EARLY MORNING WITH THE FRONT RUNNING FROM NEAR
SAINT JOHN TO ASHLAND. SOUTH WINDS OVERNIGHT WILL SHIFT ABRUPTLY TO
THE NORTH AT 20 TO 35 MPH AND GUSTY WITH THE COLD FRONT. ONLY SOME
MID TO HIGH LEVEL CLOUDS ARE FORECAST WITH AND BEHIND THE COLD FRONT.
HIGHS WILL BE WARMER WITH 850 TEMPS RISING TO AROUND 20C WITH A WEAK
WARM FRONT AND RANGE FROM THE MID 80S TO UPPER 80S WEST TO LOW TO
MID 80S EAST. OVERNIGHT LOWS WILL RANGE FROM THE UPPER 40S TO
LOWER 50S WEST AND NORTH BEHIND THE COLD FRONT TO THE MID TO UPPER
50S IN OUR SOUTHEAST FA FROM SAINT JOHN TO ASHLAND AND EAST.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 310 AM CDT SUN SEP 16 2012
THE COLD FRONT EXPECTED MONDAY MORNING APPEARS THE HAVE A RELATIVELY
TIGHT SURFACE PRESSURE GRADIENT OF AROUND 8 MB ACROSS WESTERN
KANSAS. LARGE DIFFERENCES EXIST IN THE WIND SPEED OUTPUT BETWEEN
THE GFS MOS - ECMWF AND NAM MODELS. IT IS PROBABLE THAT A FEW HOURS
OF WIND ADVISORY CRITERIA WIND SPEEDS WILL BE MET. HOWEVER, GIVEN
THE LACK LUSTER SPEEDS OF THE ECMWF AND EVEN THE MOS IN CENTRAL
KANSAS, WE WILL HOLD OFF ON ANY ADVISORY ISSUING NOW AND DEFER TO
CLOSER TO THE EVENT. IT DOES APPEAR TO BE SHAPING UP AS A TYPICAL
MARGINAL OR LOW END WIND EPISODE.
THE COOLER AIR USHERED IN WILL LIKELY TEMPER HIGHS ON MONDAY INTO
THE UPPER 60S. SOUTH CENTRAL KANSAS WILL PROBABLY BE WARMER SINCE
THE AREA WOULD REMAIN IN THE WARM SECTOR LONGER. THE DRY AIR LEFT IN
THE WAKE OF THE FRONT SHOULD PROMOTE STRONG LONGWAVE RADIATIONAL
COOLING OVERNIGHT, BUT THIS ALSO COULD BE MODIFIED SLIGHTLY BY MID
TO UPPER LEVEL CLOUDS ASSOCIATED WITH THE STRONG UPPER JET MOVING
THROUGH THE CENTRAL PLAINS. TEMPERATURES BY EARLY TUESDAY SHOULD
FALL INTO THE LOW 40S ACROSS A BROAD AREA. NORTHWEST FLOW WILL
PERSIST ALOFT ACROSS THE AREA. THE SURFACE RESPONSE WILL BE TO
CREATE TROUGHING ACROSS EASTERN COLORADO, AND A WARMING TREND AS
HIGHER TEMPERATURE BOUNDARY LAYER AIR OVERSPREADS SOUTHWEST KANSAS.
WEDNESDAY CONTINUES TO LOOK LIKE THE WARMEST DAY WITH POTENTIAL FOR
ADIABATICALLY WARMED AIR FROM DOWNSLOPE WINDS. THE REMAINDER OF
THE EXTENDED PERIOD LOOKS TO REMAIN DRY WITH NEAR NORMAL
TEMPERATURES FOR MID TO LATE SEPTEMBER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1230 AM CDT SUN SEP 16 2012
LIGHT MOIST UPSLOPE FLOW CONTINUES AHEAD OF A LEE SIDE TROUGH INTO
THIS MORNING. NEW HRRR MODEL UPDATE CONTINUES TO SHOW AREAS OF SHALLOW
ADVECTION/RADIATION FOG DEVELOPING AFTER 09Z TILL AROUND 15Z AT
THE TAF SITES THIS MORNING. HOWEVER NEW NAM SHOWING LIGHT UPSLOPE
BECOMING LIGHT SOUTH BY 09-12Z FROM KGCK TO KDDC WITH NOT AS MUCH
FOG. NEW RAP SHOWING POSSIBLE STRATUS AND DENSE FOG EAST OF A LINE
FROM WAKEENEY TO DODGE CITY AND ASHLAND. WILL KEEP A TEMPO GROUP
GOING FOR SOME IFR VSBYS BETWEEN 09-15Z FOR THE TAF SITES WITH RAPID
CLEARING AFTER THAT. LIGHT SSE WINDS CONTINUE AHEAD OF A COLD
FRONT FORECAST TO BE NEAR KGLD BY 06Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 84 50 68 42 / 0 0 10 10
GCK 86 49 68 42 / 0 0 10 0
EHA 87 50 68 47 / 0 0 20 10
LBL 86 49 69 44 / 0 0 20 10
HYS 85 49 69 42 / 0 10 20 10
P28 84 59 77 46 / 0 0 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR KSZ030-031-
044>046-063>066-077>081-087>090.
&&
$$
UPDATE...KRUSE
SHORT TERM...KRUSE
LONG TERM...RUSSELL
AVIATION...KRUSE
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
317 AM CDT SUN SEP 16 2012
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 310 AM CDT SUN SEP 16 2012
THE MAIN FORECAST CHALLENGES ARE AREAS OF DENSE FOG THIS MORNING.
LIGHT MOIST UPSLOPE FLOW AHEAD OF A LEE TROUGH THIS MORNING WILL
CONTINUE TO ADVECT HIGHER DEWPOINTS WESTWARD INTO OUR WESTERN
COUNTIES UNDER CLEAR SKIES. A WEAK WARM FRONT AND WIND SHIFT TO THE
SOUTH BY 12Z FROM WAKEENEY SOUTH TO DODGE CITY AND ASHLAND MAY
HOWEVER LIMIT DENSE FOG FORMATION WEST OF THAT LINE AS UPSLOPE ENDS.
ALREADY PRATT SHOWING 2 MILES AND OVERCAST 100 FEET. NEW REPORTS UNDER
1/4 MILE AND FOG COMING IN FROM PRATT AND HAYS SO WILL GO AHEAD
AND ISSUE A DENSE FOG ADVISORY FROM HAYS SOUTH TO GREENSBURG AND
EAST TO PRATT THROUGH 10 AM. THE DENSE FOG SHOULD QUICKLY CLEAR BY
MID MORNING AS LIGHT SOUTH WINDS CONTINUE AND WITH A VERY SHALLOW
MOIST LAYER.
A STRONG UPPER LEVEL SHORTWAVE TROUGH WILL DIG INTO THE NORTHERN
HIGH PLAINS BY THIS EVENING AND THEN DIG INTO THE CENTRAL PLAINS BY
MONDAY MORNING. THIS FEATURE WILL PUSH A STRONG COLD FRONT ACROSS
WESTERN KANSAS BY EARLY MORNING WITH THE FRONT RUNNING FROM NEAR
SAINT JOHN TO ASHLAND. SOUTH WINDS OVERNIGHT WILL SHIFT ABRUPTLY TO
THE NORTH AT 20 TO 35 MPH AND GUSTY WITH THE COLD FRONT. ONLY SOME
MID TO HIGH LEVEL CLOUDS ARE FORECAST WITH AND BEHIND THE COLD FRONT.
HIGHS WILL BE WARMER WITH 850 TEMPS RISING TO AROUND 20C WITH A WEAK
WARM FRONT AND RANGE FROM THE MID 80S TO UPPER 80S WEST TO LOW TO
MID 80S EAST. OVERNIGHT LOWS WILL RANGE FROM THE UPPER 40S TO
LOWER 50S WEST AND NORTH BEHIND THE COLD FRONT TO THE MID TO UPPER
50S IN OUR SOUTHEAST FA FROM SAINT JOHN TO ASHLAND AND EAST.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 310 AM CDT SUN SEP 16 2012
THE COLD FRONT EXPECTED MONDAY MORNING APPEARS THE HAVE A RELATIVELY
TIGHT SURFACE PRESSURE GRADIENT OF AROUND 8 MB ACROSS WESTERN
KANSAS. LARGE DIFFERENCES EXIST IN THE WIND SPEED OUTPUT BETWEEN
THE GFS MOS - ECMWF AND NAM MODELS. IT IS PROBABLE THAT A FEW HOURS
OF WIND ADVISORY CRITERIA WIND SPEEDS WILL BE MET. HOWEVER, GIVEN
THE LACK LUSTER SPEEDS OF THE ECMWF AND EVEN THE MOS IN CENTRAL
KANSAS, WE WILL HOLD OFF ON ANY ADVISORY ISSUING NOW AND DEFER TO
CLOSER TO THE EVENT. IT DOES APPEAR TO BE SHAPING UP AS A TYPICAL
MARGINAL OR LOW END WIND EPISODE.
THE COOLER AIR USHERED IN WILL LIKELY TEMPER HIGHS ON MONDAY INTO
THE UPPER 60S. SOUTH CENTRAL KANSAS WILL PROBABLY BE WARMER SINCE
THE AREA WOULD REMAIN IN THE WARM SECTOR LONGER. THE DRY AIR LEFT IN
THE WAKE OF THE FRONT SHOULD PROMOTE STRONG LONGWAVE RADIATIONAL
COOLING OVERNIGHT, BUT THIS ALSO COULD BE MODIFIED SLIGHTLY BY MID
TO UPPER LEVEL CLOUDS ASSOCIATED WITH THE STRONG UPPER JET MOVING
THROUGH THE CENTRAL PLAINS. TEMPERATURES BY EARLY TUESDAY SHOULD
FALL INTO THE LOW 40S ACROSS A BROAD AREA. NORTHWEST FLOW WILL
PERSIST ALOFT ACROSS THE AREA. THE SURFACE RESPONSE WILL BE TO
CREATE TROUGHING ACROSS EASTERN COLORADO, AND A WARMING TREND AS
HIGHER TEMPERATURE BOUNDARY LAYER AIR OVERSPREADS SOUTHWEST KANSAS.
WEDNESDAY CONTINUES TO LOOK LIKE THE WARMEST DAY WITH POTENTIAL FOR
ADIABATICALLY WARMED AIR FROM DOWNSLOPE WINDS. THE REMAINDER OF
THE EXTENDED PERIOD LOOKS TO REMAIN DRY WITH NEAR NORMAL
TEMPERATURES FOR MID TO LATE SEPTEMBER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1230 AM CDT SUN SEP 16 2012
LIGHT MOIST UPSLOPE FLOW CONTINUES AHEAD OF A LEE SIDE TROUGH INTO
THIS MORNING. NEW HRRR MODEL UPDATE CONTINUES TO SHOW AREAS OF SHALLOW
ADVECTION/RADIATION FOG DEVELOPING AFTER 09Z TILL AROUND 15Z AT
THE TAF SITES THIS MORNING. HOWEVER NEW NAM SHOWING LIGHT UPSLOPE
BECOMING LIGHT SOUTH BY 09-12Z FROM KGCK TO KDDC WITH NOT AS MUCH
FOG. NEW RAP SHOWING POSSIBLE STRATUS AND DENSE FOG EAST OF A LINE
FROM WAKEENEY TO DODGE CITY AND ASHLAND. WILL KEEP A TEMPO GROUP
GOING FOR SOME IFR VSBYS BETWEEN 09-15Z FOR THE TAF SITES WITH RAPID
CLEARING AFTER THAT. LIGHT SSE WINDS CONTINUE AHEAD OF A COLD
FRONT FORECAST TO BE NEAR KGLD BY 06Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 84 50 68 42 / 0 0 10 10
GCK 86 49 68 42 / 0 0 10 0
EHA 87 50 68 47 / 0 0 20 10
LBL 86 49 69 44 / 0 0 20 10
HYS 85 49 69 42 / 0 10 20 10
P28 84 59 77 46 / 0 0 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY FROM 3 AM TO 10 AM CDT THIS MORNING FOR
KSZ031-046-065-066-079>081.
&&
$$
SHORT TERM...KRUSE
LONG TERM...RUSSELL
AVIATION...KRUSE
AREA FORECAST DISCUSSION...UPDATED
NWS DODGE CITY KS
1242 AM CDT SUN SEP 16 2012
...UPDATED FOR AVIATION...
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 210 PM CDT SAT SEP 15 2012
FOR TONIGHT, HIGH PRESSURE OVERHEAD WILL ALLOW CLEAR OR CLEARING
SKIES, LIGHT SOUTHEAST WINDS IN OUR CENTRAL AND EAST, BUT A TROUGH
IN COLORADO SHOULD TURN WINDS LIGHT SOUTHWEST IN OUR WESTERN
COUNTIES. ALTHOUGH ONLY 5 TO 10 MPH SOUTHWEST WINDS WILL BE OVER
OUR WESTERN COUNTIES, THINK THE UPSLOPE FLOW AFFECT WILL HELP
TEMPERATURES FROM FALLING AS PREVIOUSLY FORECAST. I RAISED MINIMUM
TEMPERATURES IN OUR CENTRAL AND WEST, WHICH NOW FIT BETTER WITH OUR
ISC NEIGHBORS. REVIEWED LAST NIGHT LOWS, WITH GCK AND HYS BOTTOMING
OUT AT 41F, AND THINK THEY SHOULD BE NEAR THAT LEVEL IN THE WEST
TONIGHT. ALL MODEL GUIDANCE IS EVEN HIGHER, IN THE MID 40S OUT
WEST, BUT DID NOT WANT TO SEE-SAW BACK AND FORTH TOO MUCH. IN THE
NEARER TERM, THE NAM AND HRRR MODELS BOTH PRODUCED A LITTLE LIGHT
RAIN IN MY EXTREME SOUTHEAST BY 19Z TODAY. SINCE THIS HAS NOT
MATERIALIZED, DECIDED TO LEAVE POPS OUT OF OUR SOUTHEAST COUNTIES
SUCH AS COMANCHE AND BARBER.
SUNDAY WILL SEE THE SURFACE TROUGH IN OUR WESTERN COUNTIES, PERHAPS
AS FAR EAST AT KEARNY, GRANT AND STEVENS COUNTIES. WINDS WILL SHIFT
SOUTH AND BY AFTERNOON INCREASE INTO THE 12 TO 15 MPH RANGE, GUSTING
TO NEAR 20 MPH. THIS SOUTH WIND WILL AID IN TRANSPORTING WARMER AIR
INTO SOUTHWESTERN KANSAS, ALLOWING MAXIMUM TEMPERATURES TO WARM
APPROXIMATELY 10F DEGREES MORE THAN TODAY. SUNDAY`S HIGHS SHOULD
RANGE FROM 84F IN HAYS AND DODGE CITY TO 89F IN SYRACUSE. HIGH
PRESSURE ALOFT OVER THE PLAINS WILL STILL KEEP A LOT OF SUNSHINE
OVERHEAD, WHICH WILL ALSO AID IN WARMING UP THE SURFACE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 218 PM CDT SAT SEP 15 2012
AN UPPER LEVEL TROUGH WILL EXIT CANADA AND MOVE SOUTHEAST ACROSS THE
NORTHERN PLAINS SUNDAY NIGHT AND MONDAY. AS THIS SYSTEM CROSSES THE
NORTHERN PLAINS A COLD FRONT WILL MOVE ACROSS WESTERN KANSAS.
PRECIPITATION CHANCES WITH THIS COLD FRONT AT THIS TIME STILL
APPEARS SMALL. IF PRECIPITATION DOES OCCUR IT WILL BE ON MONDAY AS
THE UPPER TROUGH CROSSES PORTIONS OF NORTH CENTRAL KANSAS. ANOTHER
AREA WHERE A FEW SHOWERS OR EVEN A THUNDERSTORM MAY DEVELOP WILL BE
IN FAR SOUTHWEST KANSAS NEAR THE LEFT EXIT REGION OF AN UPPER LEVEL
JET. GIVEN THE EXPECTED CLOUD COVER AND THE COOLING THAT IS FORECAST
BEHIND THIS FRONT IN THE 925-850MB LEVEL WILL TREND HIGHS DOWN A
COUPLE OF DEGREES AND FAVOR THE COOLEST MODEL GUIDANCE. HIGHS MONDAY
MAY STRUGGLE TO REACH THE UPPER 60S ACROSS PORTIONS OF WESTERN AND
NORTH CENTRAL KANSAS. GUSTY NORTH WINDS WILL DEVELOP BEHIND THIS
FRONT EARLY MONDAY. NAM MEAN MIXED LAYER WINDS SUGGESTING SUSTAINED
WIND SPEEDS OF 30 TO 35 MPH AT 15Z AND 18Z MONDAY. GFS WAS A LITTLE
WEAKER WITH THESE MIXED LAYER WINDS BUT GIVEN THE MAGNITUDE OF THE
COLD AIR ADVECTION DEVELOPING EARLY MONDAY WILL LEAN TOWARDS THE
STRONGER NAM WINDS AT THIS TIME.
BY MONDAY NIGHT THE UPPER LEVEL TROUGH WILL MOVE EAST OF THE AREA AS
AN AREA OF HIGH PRESSURE AT THE SURFACE BEGINS TO SETTLE INTO
KANSAS. SKIES MAY BE CLEAR EARLY BUT BASED ON THE GFS AND ECMWF SOME
700MB MOISTURE AND WARM AIR ADVECTION IMPROVES DURING THE OVERNIGHT
HOURS ACROSS WESTERN KANSAS. GIVEN LIGHT WINDS AND DEWPOINT IN THE
UPPER 30S TO LOWER 40S WILL FAVOR THE COOLER GUIDANCE FOR OVERNIGHT
TEMPERATURES BUT AM RELUCTANT TO GO MUCH LOWER THAN THE MID 40S
GIVEN THE POTENTIAL FOR SOME CLOUD COVER TOWARDS DAYBREAK.
ON TUESDAY A TROUGH OF LOW PRESSURE A THE SURFACE WILL DEVELOP ALONG
THE LEE OF THE ROCKIES AS A NORTHWEST FLOW PERSISTS. 850MB
TEMPERATURE TRENDS TUESDAY AND WEDNESDAY CONTINUES TO SUPPORT HIGHS
REBOUNDING BACK INTO THE 80S. THIS WARM UP HOWEVER WILL BE SHORT
LIVED AS ANOTHER COLD FRONT IS FORECAST TO MOVE SOUTH ACROSS THE
CENTRAL PLAINS WEDNESDAY NIGHT OR EARLY THURSDAY. NOT ONLY WILL THIS
FRONT BRING COOLER TEMPERATURES BACK TO WESTERN KANSAS BUT THERE MAY
ALSO BE A SLIGHT CHANCE FOR THUNDERSTORMS AS WELL AS ANOTHER UPPER
LEVEL TROUGH CROSSES THE NORTHERN PLAINS. AT THIS TIME MODELS APPEAR
TO BE STRUGGLING WITH THE TRACK AND STRENGTH OF THIS NEXT UPPER
LEVEL SYSTEM. CONFIDENCE IS NOT HIGH ON WHICH MAY BE MORE CORRECT SO
WILL STAY CLOSE TO CONSENSUS FROM THE CREXTENDFCST_INT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1230 AM CDT SUN SEP 16 2012
LIGHT MOIST UPSLOPE FLOW CONTINUES AHEAD OF A LEE SIDE TROUGH INTO
THIS MORNING. NEW HRRR MODEL UPDATE CONTINUES TO SHOW AREAS OF SHALLOW
ADVECTION/RADIATION FOG DEVELOPING AFTER 09Z TILL AROUND 15Z AT
THE TAF SITES THIS MORNING. HOWEVER NEW NAM SHOWING LIGHT UPSLOPE
BECOMING LIGHT SOUTH BY 09-12Z FROM KGCK TO KDDC WITH NOT AS MUCH
FOG. NEW RAP SHOWING POSSIBLE STRATUS AND DENSE FOG EAST OF A LINE
FROM WAKEENEY TO DODGE CITY AND ASHLAND. WILL KEEP A TEMPO GROUP
GOING FOR SOME IFR VSBYS BETWEEN 09-15Z FOR THE TAF SITES WITH RAPID
CLEARING AFTER THAT. LIGHT SSE WINDS CONTINUE AHEAD OF A COLD
FRONT FORECAST TO BE NEAR KGLD BY 06Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 51 67 42 79 / 10 10 10 0
GCK 51 67 42 79 / 10 10 0 0
EHA 53 67 47 80 / 10 20 10 0
LBL 54 68 44 80 / 0 20 10 0
HYS 50 68 42 76 / 10 20 10 0
P28 57 76 46 78 / 10 20 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURKE
LONG TERM...BURGERT
AVIATION...KRUSE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1111 PM MDT SAT SEP 15 2012
.UPDATE...
ISSUED AT 1047 PM MDT SAT SEP 15 2012
INCREASED CLOUD COVER...EXTENDED AREA OF PATCHY FOG FURTHER
WEST...AND BUMPED UP LOW TEMPS ACROSS EASTERN AREAS WHERE TD
VALUES IN THE MID 50S ARE CURRENTLY REPORTED. WITH SE FLOW ALREADY
ADVECTING GOOD BL MOISTURE INTO EASTERN PARTS OF THE CWA...THINK
FOG/STRATUS POTENTIAL IS INCREASED OVER OUR CWA. IM STILL NOT SURE
ABOUT THE COVERAGE/VISIBILITY AT THIS POINT...AND HOW FAR WEST
TO GO WITH FOG. HRRR IS MOST BULLISH ON BRINGING DENSE FOG INTO OUR
CWA BY 12Z. LATEST RUC SHOWS BETTER VSBY VALUES...HOWEVER STILL
SHOWS TO THE GOOD BL MOISTURE IN PLACE AROUND THE SAME TIME AS
HRRR. NEITHER MODEL WOULD SUPPORT FOG MUCH FURTHER WEST THAN A
TRENTON TO LEOTI LINE AT THIS POINT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 1233 PM MDT SAT SEP 15 2012
MAIN CONCERN FOR THE SHORT TERM FORECAST WILL CENTER AROUND TEMPS
AND FIRE WX CONCERNS PRIOR TO PASSAGE OF COLD FRONT SUNDAY NIGHT.
ALTHOUGH MID LEVEL LAPSE RATES STEEPEN THROUGH THE NIGHT AND
THROUGH THE MORNING HOURS...BUT WITH VERY DRY AIR MASS BUILDING
INTO THE AREA...APPEARS UNLIKELY THAT ANY ASCENT WITH APPROACHING
TROUGH AND COLD FRONT WOULD BE ENOUGH TO SATURATE PARCELS AND
REALIZE ANY OF THE INSTABILITY.
MIXED LAYER PROFILES SUPPORT DEWPOINTS FALLING TO LOWER VALUES
THAN TODAY...WITH FULLY MIXED PROFILES INDICATING SOME DEWPOINTS
IN THE TEENS POSSIBLE. WITH TEMPERATURES IN THE UPPER 80S TO LOW
90S AND DEWPOINTS LIKELY BEING IN THE LOWER 20S THINK WIDESPREAD
HUMIDITIES IN THE 5-15 PERCENT RANGE IS LIKELY ACROSS THE AREA.
MIXED LAYER WINDS OFF OF NAM AND GFS DO NOT SUPPORT MUCH IN THE
WAY OF WIND SPEEDS SO DO NOT ANTICIPATE THE NEED FOR FIRE WX WATCH
OR WARNING. HOWEVER...SHOULD COLD FRONT SPEED UP AND ENTER THE
AREA AROUND THE 00Z TIME FRAME THAT COULD INCREASE FIRE DANGER
QUITE A BIT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 1244 PM MDT SAT SEP 15 2012
PATTERN WILL REMAIN VIRTUALLY UNCHANGED THROUGH THE LONG TERM
PERIOD WITH A TROUGH NEAR THE GREAT LAKES AND RIDGE NEAR THE FOUR
CORNERS RESULTING IN NORTHWEST FLOW OVER THE CENTRAL PLAINS. A
SHORTWAVE TROUGH EMBEDDED IN THE FLOW WILL BRING A COLD FRONT
THROUGH THE FORECAST AREA SUNDAY NIGHT. LOW LEVELS ARE VERY
DRY...BUT CANNOT RULE OUT AN ISOLATED LIGHT RAIN SHOWER SUNDAY
NIGHT OR MONDAY. GUSTY NORTH WINDS CAN BE EXPECTED WITH THE FRONT
LATE SUNDAY NIGHT AND MONDAY MORNING. TEMPERATURES WILL BE BELOW
NORMAL ON MONDAY WITH LIMITED SUN. THE REST OF THE WEEK WILL SEE
A COUPLE OF DRY FRONTAL PASSAGES AND TEMPERATURES NEAR TO SLIGHTLY
ABOVE NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1111 PM MDT SAT SEP 15 2012
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT KGLD THROUGH THE TAF
PERIOD. MVFR CONDITIONS ARE POSSIBLE OVER KMCK AROUND 12Z AS
FOG/STRATUS DEVELOP EAST OF THE TERMINAL IN RESPONSE TO GOOD BL
MOISTURE ADVECTING IN FROM THE SE. CANT RULE OUT CONDITIONS LOWER
THAN MVFR...HOWEVER AT THIS POINT LATEST SHORT RANGE GUIDANCE
WOULD KEEP IFR/LIFR JUST EAST OF MCK. LIGHT SOUTHERLY WINDS WILL
INCREASE SOME DURING THE DAY SUNDAY WITH AFTERNOON GUSTS AROUND
15KT. WINDS WILL SHIFT TO THE NORTH/NORTHWEST LATE SUNDAY EVENING
AS A FRONT DROPS SOUTH OVER BOTH TERMINALS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...DR
SHORT TERM...JRM
LONG TERM...024
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1054 PM MDT SAT SEP 15 2012
.UPDATE...
ISSUED AT 1047 PM MDT SAT SEP 15 2012
INCREASED CLOUD COVER...EXTENDED AREA OF PATCHY FOG FURTHER
WEST...AND BUMPED UP LOW TEMPS ACROSS EASTERN AREAS WHERE TD
VALUES IN THE MID 50S ARE CURRENTLY REPORTED. WITH SE FLOW ALREADY
ADVECTING GOOD BL MOISTURE INTO EASTERN PARTS OF THE CWA...THINK
FOG/STRATUS POTENTIAL IS INCREASED OVER OUR CWA. IM STILL NOT SURE
ABOUT THE COVERAGE/VISIBILITY AT THIS POINT...AND HOW FAR WEST
TO GO WITH FOG. HRRR IS MOST BULLISH ON BRINGING DENSE FOG INTO OUR
CWA BY 12Z. LATEST RUC SHOWS BETTER VSBY VALUES...HOWEVER STILL
SHOWS TO THE GOOD BL MOISTURE IN PLACE AROUND THE SAME TIME AS
HRRR. NEITHER MODEL WOULD SUPPORT FOG MUCH FURTHER WEST THAN A
TRENTON TO LEOTI LINE AT THIS POINT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 1233 PM MDT SAT SEP 15 2012
MAIN CONCERN FOR THE SHORT TERM FORECAST WILL CENTER AROUND TEMPS
AND FIRE WX CONCERNS PRIOR TO PASSAGE OF COLD FRONT SUNDAY NIGHT.
ALTHOUGH MID LEVEL LAPSE RATES STEEPEN THROUGH THE NIGHT AND
THROUGH THE MORNING HOURS...BUT WITH VERY DRY AIR MASS BUILDING
INTO THE AREA...APPEARS UNLIKELY THAT ANY ASCENT WITH APPROACHING
TROUGH AND COLD FRONT WOULD BE ENOUGH TO SATURATE PARCELS AND
REALIZE ANY OF THE INSTABILITY.
MIXED LAYER PROFILES SUPPORT DEWPOINTS FALLING TO LOWER VALUES
THAN TODAY...WITH FULLY MIXED PROFILES INDICATING SOME DEWPOINTS
IN THE TEENS POSSIBLE. WITH TEMPERATURES IN THE UPPER 80S TO LOW
90S AND DEWPOINTS LIKELY BEING IN THE LOWER 20S THINK WIDESPREAD
HUMIDITIES IN THE 5-15 PERCENT RANGE IS LIKELY ACROSS THE AREA.
MIXED LAYER WINDS OFF OF NAM AND GFS DO NOT SUPPORT MUCH IN THE
WAY OF WIND SPEEDS SO DO NOT ANTICIPATE THE NEED FOR FIRE WX WATCH
OR WARNING. HOWEVER...SHOULD COLD FRONT SPEED UP AND ENTER THE
AREA AROUND THE 00Z TIME FRAME THAT COULD INCREASE FIRE DANGER
QUITE A BIT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 1244 PM MDT SAT SEP 15 2012
PATTERN WILL REMAIN VIRTUALLY UNCHANGED THROUGH THE LONG TERM
PERIOD WITH A TROUGH NEAR THE GREAT LAKES AND RIDGE NEAR THE FOUR
CORNERS RESULTING IN NORTHWEST FLOW OVER THE CENTRAL PLAINS. A
SHORTWAVE TROUGH EMBEDDED IN THE FLOW WILL BRING A COLD FRONT
THROUGH THE FORECAST AREA SUNDAY NIGHT. LOW LEVELS ARE VERY
DRY...BUT CANNOT RULE OUT AN ISOLATED LIGHT RAIN SHOWER SUNDAY
NIGHT OR MONDAY. GUSTY NORTH WINDS CAN BE EXPECTED WITH THE FRONT
LATE SUNDAY NIGHT AND MONDAY MORNING. TEMPERATURES WILL BE BELOW
NORMAL ON MONDAY WITH LIMITED SUN. THE REST OF THE WEEK WILL SEE
A COUPLE OF DRY FRONTAL PASSAGES AND TEMPERATURES NEAR TO SLIGHTLY
ABOVE NORMAL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 506 PM MDT SAT SEP 15 2012
VFR CONDITIONS ARE EXPECTED AT BOTH KGLD AND KMCK THROUGH THE TAF
PERIOD. THERE IS A SMALL CHANCE FOR FOG DEVELOPMENT IN PROXIMITY
TO KMCK...HOWEVER CONFIDENCE IS MUCH HIGHER THAN ANY FOG/LOW
STRATUS WILL REMAIN EAST. WINDS WILL GENERALLY REMAIN OUT OF THE
SOUTH AND SOUTHWEST BELOW 12KT AT KGLD. AT KMCK WINDS OVERNIGHT
WILL BE LIGHT AND VARIABLE...WITH SOUTH WINDS SUNDAY AFTERNOON
GUSTING AROUND 15KT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...DR
SHORT TERM...JRM
LONG TERM...024
AVIATION...DR
AREA FORECAST DISCUSSION
NWS PADUCAH KY
308 PM CDT SUN SEP 16 2012
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
ISSUED 308 PM CDT SUN SEP 16 2012
THE WEAK SYSTEM RESPONSIBLE FOR THE SHOWERS LAST NIGHT AND EARLY
THIS MORNING DISSIPATED AS IT MOVED EAST TODAY. IN ITS WAKE...SOME
PARTIAL CLEARING DEVELOPED ACROSS THE LOWER OHIO VALLEY. WITH THE
SOLAR HEATING...A FEW ISOLATED SHOWERS POPPED UP NEAR KPOF THIS
AFTERNOON.
OF MORE SIGNIFICANCE IS A LARGER AREA OF SHOWERS AND EVEN A FEW
THUNDERSTORMS ALONG AND SOUTH OF INTERSTATE 40 AS OF 19Z. THE
MAJORITY OF THE MODELS BRING THIS AREA NORTHWARD INTO SE MISSOURI
AND SW KENTUCKY TONIGHT...AND EVENTUALLY UP INTO THE EVV AREA
SOMETIME LATE TONIGHT OR MONDAY MORNING. THE PRIMARY EXCEPTION IS
THE SREF...WHICH TENDS TO SUPPRESS THE SOUTHERN STREAM SHORTWAVE
AND ITS ASSOCIATED QPF TO OUR SOUTH. THE 15Z RUC MODEL WAS RATHER
AGGRESSIVE BRINGING MOISTURE NORTH FROM ARKANSAS...AND THIS WILL
BE THE BASIS FOR THROWING OUT THE SREF.
THE RATHER STRONG 500 MB SHORTWAVE OVER TEXAS WILL MOVE EAST
NORTHEAST TONIGHT...BACKING OUR MID LEVEL WINDS INTO THE
SOUTHWEST. THIS WILL OPEN THE DOOR FOR A SERIES OF VORT CENTERS
THAT WILL MOVE NORTHEAST INTO THE OHIO VALLEY OVERNIGHT AND
MONDAY. DEEP LAYER SOUTHERLY FLOW WILL BRING A SURGE OF HIGHER PW
AIR NORTHWARD...WITH PW VALUES CLIMBING ABOVE 1.5 INCHES BY
MONDAY. POPS WILL RISE INTO THE LIKELY CATEGORY OVERNIGHT ACROSS
FAR SOUTHERN PORTIONS OF THE FA...WITH CHANCE POPS ELSEWHERE.
LIKELY POPS WILL SPREAD NORTH AND EAST MONDAY ACROSS MOST OF
WESTERN KY AND SW INDIANA.
A STRONG COLD FRONT WILL SWING SOUTHEAST ACROSS THE LOWER OHIO
VALLEY ON MONDAY NIGHT. AS THIS COLD FRONT ENCOUNTERS MOISTURE
ASSOCIATED WITH THE SOUTHERN STREAM SHORTWAVE...NUMEROUS SHOWERS
AND SOME ISOLATED THUNDER WILL PERSIST ACROSS MUCH OF OUR REGION.
WHILE STORM TOTAL QPF IS GENERALLY UNDER AN INCH...THERE COULD BE
SOME ISOLATED HEAVIER AMOUNTS. HEAVIEST TOTALS WILL BE IN KHOP
AREA. DUE TO WIDESPREAD CLOUDS AND WEAK WIND FIELDS...CONVECTIVE
DEVELOPMENT SHOULD BE LIMITED IN COVERAGE AND INTENSITY.
ONCE THE COLD FRONT PASSES MONDAY NIGHT...WINDS WILL INCREASE FROM
THE NORTHWEST. 850 MB WINDS WILL BE AVERAGING 25 TO 30 KNOTS TUESDAY.
SURFACE WIND GUSTS MAY REACH 30 MPH WITH STRONG MIXING ON TUESDAY.
STRONG DRYING BEHIND THE FRONT WILL RESULT IN RAPID CLEARING ON
TUESDAY MORNING...BUT 850 MB TEMPS WILL BE FALLING QUICKLY INTO
THE SINGLE DIGITS. THEREFORE...HIGHS WILL NOT GET OUT OF THE 60S
DESPITE A FAIRLY MILD START TO THE DAY IN THE 50S.
TUESDAY NIGHT WILL BE CHILLY AS A SURFACE RIDGE PASSES OVER THE
OHIO VALLEY. CLEAR SKIES AND NEARLY CALM WINDS WILL BE FAVORABLE
FOR STRONG RADIATIONAL COOLING. MOS GUIDANCE IS OFTEN TOO HIGH IN
SUCH CASES...AND FORECAST WILL BE WEIGHTED TOWARD THE COOLER 2M
NAM TEMPS. THIS YIELDS UPPER 30S IN MANY PLACES...WHICH SUGGESTS
THE POSSIBILITY OF SOME PATCHY FROST.
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED 308 PM CDT SUN SEP 16 2012
TROUGHING ALOFT OVER THE WESTERN GREAT LAKES TO BEGIN THE PERIOD
IS EXPECTED TO AMPLIFY AND DEVELOP SOUTHWARD TOWARD THE LOWER OHIO
VALLEY/MID MISSISSIPPI VALLEY FRIDAY INTO SATURDAY. CONFIDENCE HAS
IMPROVED IN KEEPING THE FORECAST DRY WEDNESDAY THROUGH THURSDAY
NIGHT...AS NO RECENT MODELS HAVE ROTATED A SIGNIFICANT ENOUGH
DISTURBANCE THROUGH THE BASE OF THE TROUGH TO DRAG PRECIPITATION
INTO THE FOUR STATE REGION.
CONFIDENCE IS ALSO INCREASING IN TIMING OF THE PRIMARY COLD FRONT
THROUGH THE REGION FRIDAY AND FRIDAY NIGHT...AS THE 12Z GFS AND
ECMWF BOTH HAVE THIS GENERAL TIMING. POPS ARE STILL RATHER LOW THESE
PERIODS...AS THE MODELS NEED TO SHOW SOME STABILITY FIRST.
ALSO...SURFACE RIDGING IS EXPECTED TO PERSIST BETWEEN HERE AND THE
GULF COAST...SO THERE WILL BE LITTLE IN THE WAY OF RETURN FLOW OF
MOISTURE INTO THE FRONT. THAT SAID...THE MID AND UPPER LEVEL FORCING
MAY BE STRONG ENOUGH TO GENERATE SOME ELEVATED INSTABILITY...SO KEPT
THUNDER MENTION AREAWIDE FRIDAY AND FRIDAY NIGHT.
SLIGHT POPS ARE FORECAST FOR SATURDAY AND SATURDAY NIGHT TO ACCOUNT
FOR THE 00Z ECMWF TIMING OF THE FRONT. THE 00Z ECMWF ENSEMBLES DID
SHOW SOME SUPPORT FOR THE OLD OPERATIONAL RUN...SO CANNOT RULE IT
OUT JUST YET.
AS FOR TEMPERATURES...IT WILL FEEL RATHER COOLISH WITH HIGHS NEAR 70
AND PLENTY OF SUNSHINE WEDNESDAY. A NICE WARMING TREND IS EXPECTED
THURSDAY AND FRIDAY WITH A FEW 80S POSSIBLE ON FRIDAY. LOOKS LIKE
PLEASANT EARLY FALL CONDITIONS FOR NEXT WEEKEND...ESPECIALLY IF THE
OLD ECMWF IS NOT RIGHT. TEMPERATURES WILL BE A COUPLE OF CATEGORIES
BELOW NORMAL...BUT STILL IN THE 70S FOR HIGHS.
&&
.AVIATION...
ISSUED AT 1230 PM CDT SUN SEP 16 2012
AREAS OF RAIN/SHOWERS DIMINISHED THIS MORNING...AND THE ACCOMPANYING
IFR CONDITIONS AT KPAH/KCGI WERE IMPROVING. SOME BREAKS IN THE
CLOUDS THIS AFTERNOON WILL BURN OFF THE REMAINDER OF THE IFR LOW
CLOUDS AND FOG. VFR CONDITIONS ARE EXPECTED THIS EVENING...FOLLOWED
BY A NORTHWARD RETURN OF SHOWERS AND LOCAL IFR CONDITIONS OVERNIGHT.
THE IFR CIGS AND VSBYS WILL BE MAINLY AT THE KCGI/KPAH SITES MONDAY
MORNING...BUT DETERIORATING CONDITIONS ARE EXPECTED AT ALL SITES.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
MO...NONE.
IL...NONE.
IN...NONE.
&&
$$
SHORT TERM...MY
LONG TERM....DRS
AVIATION...MY
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
742 PM EDT MON SEP 17 2012
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 423 PM EDT MON SEP 17 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH AXIS
FROM HUDSON BAY INTO NW MN AND SE SOUTH DAKOTAS. A SHORTWAVE OVER NE
SD WAS MOVING INTO THE BASE OF THE TROUGH. AT THE SFC...A COLD FRONT
EXTENDED FROM NRN LOWER MI INTO SE WI. A LARGE POST-FRONTAL RAINBAND
FROM CNTRL WI INTO CNTRL UPPER MI WAS SUPPORTED BY MODERATE TO
STRONG MID LEVEL FGEN AND UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF
THE 250-300 MB JET. NRLY WINDS AND 850 MB TEMPS FALLING TO AROUND 3C
SUPPORTED HEAVIER LAKE ENHANCED RAIN SHOWERS INTO N CNTRL UPPER MI.
WITH DRIER AIR UPSTREAM OVER NE MN THE WRN CWA...OVER THE FAR WRN
CWA VCNTY IWD...HAS DIMINISHED OR ENDED.
TONIGHT...MDLS SUGGEST THAT THE STRONGER FGEN DYNAMICS WILL LIFT OFF
TO THE NE LATE THIS AFTERNOON AND EVENING. HOWEVER...WITH CAA
DROPPING 850 MB TEMPS TO NEAR -3C OVER LAKE SUPERIOR TONIGHT LEADING
TO LK-H8 DELTA/T TO AROUND 20C AND THE 700-500 MB TROUGH MOVING
IN...LAKE EFFECT RAIN SHOWERS WILL DEVELOP AND INTENSIFY OVERNIGHT
FOR LOCATIONS FAVORED BY N WINDS. WITH THE LOW FREEZING LEVEL...SOME
GRAUPEL WILL BE POSSIBLE WITH THE HEAVIER SHOWERS. LAKE INDUCED
TROUGHING WITH MORE OF AN NNE FLOW OVER THE ERN LAKE SHOULD MINIMIZE
PCPN INTO THE FAR ERN CWA. UPSLOPE FLOW WILL LEAD TO THE HIGHEST
PCPN AMOUNTS OVER THE HIGHER TERRAIN OVER MARQUETTE AND BARAGA
COUNTIES.
TUESDAY...LAKE EFFECT PCPN WILL CONTINUE WITH THE 850 MB THERMAL
TROF STILL OVER THE AREA. AS WINDS BACK AND BECOME MORE ANTICYCLONIC
AND SOME LOW LEVEL DRYING MOVES IN FROM THE WEST...THE PCPN SHOULD
DIMINISH SHOULD DIMINISH FROM WEST TO EAST. SHOWERS DOWNWIND OF LAKE
SUPERIOR BECOMING MORE SCATTERED THROUGH THE DAY FROM WEST TO EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 423 PM EDT MON SEP 17 2012
TUE NGT...EXPECT LINGERING LK CLDS/-SHRA OVER MAINLY THE E HALF THRU
06Z TO END WITH APRCH OF PROGRESSIVE SHRTWV RDG/DNVA/ACCOMPANYING
DRY AIRMASS AND PASSAGE OF SFC HI PRES THAT CAUSES WSHFT TO THE SW
AND EXIT OF H85 THERMAL TROF. OTRW...LOOKS LIKE THERE SHOULD BE A
SEVERAL HOUR WINDOW OF OPTIMAL RADIATIONAL COOLING CONDITIONS ACROSS
MAINLY THE INTERIOR W AND CNTRL ACCOMPANYING THE PASSAGE OF THE RDG
AXIS/DRY AIR/LIGHT WINDS. OVER THE W...QUICKER WSHFT TO THE SW AFT
06Z WITH SHARPENING PRES GRADIENT AND SOME INCRSG HI/MID CLDS IN
ADVANCE OF NEXT SHRTWV DROPPING INTO MN WL END THE FAVORABLE COOLING
CONDITIONS WELL BEFORE SUNRISE...BUT NOT BEFORE TEMPS HAVE A CHANCE
TO CRASH BEFORE 06Z FM BLO NORMAL MAX READINGS ON TUE AFTN. OPTED TO
ISSUE FREEZE WATCH FOR THE INTERIOR W HALF...WHERE MOST GUIDANCE
SHOWS WDSPRD MIN TEMPS FALLING BLO 32.
WED...NEXT FAIRLY IMPRESSIVE SHRTWV DIVING SEWD THRU NW FLOW ALF
INTO MEAN TROF OVER ERN NAMERICA IS FCST TO MOVE NEAR UPR MI BY 00Z
THU. ALTHOUGH THE MSTR RETURN AHEAD OF THIS DISTURBANCE WL BE
ANEMIC DESPITE STRENGTHENING LLVL SLY FLOW...VIGOROUS DPVA/DEEP LYR
QVECTOR CNVGC SUPPORTS LIKELY POPS OVER THE N HALF OF THE CWA ON THE
CYC SIDE OF VORT MAX TRACK AND WHERE MOISTENING OFF LK SUP MIGHT
PLAY A ROLE.
WED NGT...DNVA/LARGER SCALE QVECTOR DVGC/HIER LVL DRYING IN THE WAKE
OF SHRTWV WL END LARGER SCALE PCPN CHCS W-E. BUT INCOMING AIRMASS WL
BE COLD ENUF WITH H85 TEMPS FCST AS LO AS 1-3C TO SUPPORT LK EFFECT
-SHRA IN AREAS IMPACTED BY FCST WNW FLOW...ESPECIALLY IF THE MORE
CYC FLOW SHOWN BY THE 12Z NAM/CNDN MODELS VERIFIES.
THU...THE ARRIVAL OF ANOTHER SHRTWV/SFC LO PRES TROF WL BRING MORE
SHRA CHCS DESPITE AN ABSENCE OF SGNFT DEEP LYR MOISTENING. QUESTIONS
ON TIMING/INTENSITY OF THIS DISTURBANCE INDICATE NO MORE THAN CHC
POPS ARE APPROPRIATE.
IN THE MEDIUM/EXTENDED RANGE...WITH MEAN TROF LINGERING OVER ERN
NAMERICA...EXPECT BLO NORMAL TEMPS TO PERSIST INTO EARLY NEXT WEEK.
MODELS SHOW A SERIES OF DISTURBANCES MOVING THRU THE MEAN TROF...SO
EXPECT SHOWERS TO PERSIST ESPECIALLY THRU SAT AND NEAR THE GREAT
LAKES. BEST CHC FOR A MORE WDSPRD RAINFALL APPEARS ON FRI WHEN
MODELS SHOW A PARTICULARLY STRONG DISTURBANCE IMPACTING THE AREA.
RECENT GFS RUNS SHOW THE MOST VIGOROUS SFC CYCLOGENESIS...AND WARM
LK WATERS MIGHT SUPPORT THAT SCENARIO. VARIOUS MODELS HINT THE UPR
TROF AXIS WL SHIFT A BIT FARTHER TO THE E NEXT SUN/MON WITH EPISODES
OF MORE ACYC FLOW/DRIER WX...BUT TIMING OF THESE FEATURES IS NOT
POSSIBLE ATTM. WL FOLLOW MODEL OF CONSENSUS LOWER POPS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 741 PM EDT MON SEP 17 2012
A LAKE EFFECT SHRA REGIME IS SETTING UP FOR MUCH OF THIS FCST PERIOD
AS CHILLY AIR MASS SETTLES OVER THE UPPER LAKES UNDERNEATH DEEPENING
MID/UPPER LEVEL TROF. AS A RESULT...CONDITIONS WILL BE QUITE
VARIABLE AS LAKE EFFECT SHRA OF VARYING INTENSITY AFFECT
KIWD/KCMX/KSAW. MORE DIRECT UPSLOPING NORTHERLY WINDS SHOULD FAVOR
KIWD/KSAW FOR MORE FREQUENT SHRA AND MVFR CONDITIONS THOUGH LAKE
AIDED TROFFING SHOULD ESPECIALLY FAVOR KSAW FOR PCPN. AT KCMX...
NORTHERLY WIND IS NOT AS FAVORABLE FOR LAKE EFFECT -SHRA/LWR CIGS.
STILL...WOULD NOT BE SURPRISED TO SEE SOME BRIEF PERIODS OF MVFR
CONDITIONS EVEN THOUGH VFR SHOULD PREVAIL. IMPROVEMENT WILL BEGIN
TUE AFTN AS TROF BEGINS TO SHIFT E AND DAYTIME HEATING DISRUPTS LAKE
EFFECT PROCESSES. IT MAY BE TOWARD THE END OF THE FCST PERIOD THAT
IMPROVEMENT BEGINS AT KSAW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 423 PM EDT MON SEP 17 2012
20 TO 30 KT NORTH WINDS WILL CONTINUE IN THE SHORT TERM BUT DIMINISH
LATER TUESDAY AS HIGH PRESSURE BUILDS INTO THE REGION FROM THE WEST.
WINDS WILL GRADUALLY SHIFTING TO THE NW THEN W BY TUESDAY EVENING.
WINDS WILL BECOME LIGHT FOR AWHILE ON TUE NIGHT WITH THE PASSAGE OF
A HI PRES RIDGE ACROSS THE LAKE. BUT S WINDS WILL INCREASE QUICKLY
LATER AT NIGHT OVER THE W UNDER THE SHARPENING PRES GRADIENT BETWEEN
THE QUICKLY DEPARTING RIDGE AND AN INCOMING LO PRES TROUGH. AS THIS
DEEP TROF MOVES TO THE E...S WINDS ON WED MAY REACH GALE FORCE WHERE
THIS FLOW IS TYPICALLY ENHANCED OVER THE NCENTRAL AND E. ISSUED A
GALE WATCH WED AFTERNOON/EVENING IN THIS AREA TO ACCOUNT FOR THIS
STRONG FLOW AND FAIRLY UNSTABLE CONDITIONS OVER THE WARM LAKE WATER
THAT WILL ENHANCE MIXING. FOLLOWING THE PASSAGE OF THE TROF...LOOK
FOR A WIND SHIFT TO THE WNW WITH WINDS UP TO 25 TO 30 KTS INTO THU.
DEPENDING ON THE INTENSITY OF ANOTHER DISTURBANCE MOVING THRU THE
GREAT LAKES ON FRI/SAT...A STRONGER NNW FLOW IS POSSIBLE THEN. BUT
NO GALES ARE EXPECTED AT THIS TIME.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FREEZE WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING
FOR MIZ002-004-005-009>013-084.
LAKE SUPERIOR...
GALE WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY EVENING
FOR LSZ267.
GALE WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY EVENING
FOR LSZ266.
GALE WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY EVENING
FOR LSZ264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KC
AVIATION...ROLFSON
MARINE...JLB/KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
358 PM EDT SUN SEP 16 2012
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 356 PM EDT SUN SEP 16 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A W FLOW ALF OVER
THE GRT LKS BTWN DEEPENING TROF IN SCNTRL CAN AND PROGRESSIVE SHRTWV
RDG MOVING THRU THE GRT LKS. THERE IS A WEAK SHRTWV EMBEDDED IN THIS
FLOW MOVING THRU WRN LK SUP EARLY THIS AFTN...BUT DRY AIRMASS
DOMINATING THE AREA AND SHOWN ON THE 12Z RAOBS IS LIMITING ANY
ACCOMPANYING WX TO JUST SOME PATCHY MID/HI CLDS. A STEADY WSW LLVL
FLOW BTWN SFC HI PRES MOVING INTO THE MID ATLANTIC STATES AND A LO
PRES TROF OVER THE KEWEENAW/WRN LK SUP ASSOCIATED WITH THE SHRTWV IS
BEGINNING TO DRAW MORE SFC-H9 MSTR SHOWN ON THE 12Z MPX RAOB TOWARD
THE AREA...BUT SFC DEWPTS HAVE MIXED OUT TO AS LO AS THE MID 40S AS
OF EARLY THIS AFTN OVER THE CWA IN ADVANCE OF THIS LLVL MOISTENING.
FARTHER TO THE NW...A SHARP COLD FNT STRETCHES FM NW ONTARIO ACRS MN
INTO SDAKOTA. DUE TO THE DRYNESS OF AIRMASS AHEAD OF THIS FNT...
THERE IS CURRENTLY NO SHRA AHEAD OF THIS BNDRY. BUT MORE CLDS/SOME
-SHRA ARE EVIDENT OVER NDAKOTA IN THE COLD AIR TRAILING THE FNT WITH
APRCH OF SHRTWVS EMBEDDED IN THE DEEPENING TROF OVER SCNTRL CAN AND
ACCOMPANYING DPVA/H7-3 QVECTOR CNVGC AS WELL AS UPR DVGC IN RRQ OF
ASSOCIATED H3 JET MAX NEAR LK WINNIPEG.
LATE THIS AFTN/EARLY EVNG...ISSUED WILDFIRE POTENTIAL STATEMENT
EARLIER IN THE SHIFT TO ACCOUNT FOR COMBINATION OF WELL ABV NORMAL
TEMPS...MIN RH FALLING TO 30-35 PCT...GUSTY WSW WINDS ENHANCED BY
DEEP MIXING...AND RECENT DRYNESS. THE MOST CRITICAL CONDITIONS ARE
OVER THE SCNTRL...WHERE SHARPER PRES GRADIENT/HIER WINDS ARE
EVIDENT. QUESTION IS WHETHER RETURNING LLVL MSTR SHOWN ON THE 12Z
MPX RAOB MIGHT CAUSE SOME CONVECTION ON INCOMING LO PRES TROF UNDER
SOME DPVA/H85-5 QVECTOR CNVGC ASSOCIATED WITH APRCHG SHRTWV. RECENT
GFS RUNS HAVE BEEN QUITE CONSISTENT SHOWING SOME CONVECTION. SINCE
THE 12Z RAPID REFRESH RUC MODEL...THE FINER RES CNDN MODEL...AND THE
NAM HINT SOME CONVECTION WL IMPACT MAINLY THE CNTRL ZNS WHERE LLVL
MOISTENING AND DYNAMICS COME INTO PHASE NEAR PEAK HEATING TIME...
MAINTAINED SCHC POPS OVER THE CNTRL DESPITE MID LVL DRYNESS THAT WL
LIMIT COVERAGE OF ANY ASSOCIATED SHRA/TS TO ISOLD.
TNGT...ANY INSTABILITY SHRA/TS WL DISSIPATE WITH LOSS OF DAYTIME
HEATING/ARRIVAL OF SOME DNVA/H85-5 QVECTOR DVGC IN THE WAKE OF
INITIAL SHRTWV PASSAGE. THEN COLD FNT ASSOCIATED WITH DEEPENING TROF
IN CANADA IS PROGGED TO PUSH ACRS THE W HALF OF UPR MI BY 12Z MON.
SINCE THE SHARPEST H7-3 QVECTOR CNVGC ASSOCIATED WITH SHRTWVS MOVING
THRU THE AMPLIFYING UPR TROF/UPR DVGC IN RRQ OF H3 JET MAX MOVING
INTO NW ONTARIO IS FCST TO FOLLOW THE FROPA...EXPECT THE BULK OF ANY
PCPN TO FALL ON THE COLD SIDE OF THE BNDRY...AS IS OBSVD TODAY IN
THE NRN PLAINS. GOING POPS INCRSG TOWARD CATEGORICAL OVER THE W
APPEAR PRETTY MUCH ON TRACK...BUT DID CUT POPS OVER THE E HALF WITH
AN ABSENCE OF UPR FORCING IN THAT AREA WITHIN DRIER AIRMASS AHEAD OF
THE FROPA.
MON...AREA OF SHRA/CATEGORICAL POPS OVER THE W HALF IN THE MRNG
SHOULD SPREAD INTO THE E AS UPR TROF AXIS SHIFTS SLOWLY TO THE E AND
AREA OF IMPRESSIVE H7-3 QVECTOR CNVGC/UPR DVGC IN RRQ OF UPR JET TO
THE N SHIFTS TO THE E FOLLOWING SFC COLD FROPA. ALTHOUGH MODELS
INDICATE SOME MID LVL DRYING MIGHT IMPACT THE W IN THE AFTN...
ARRIVAL OF COLDER H85 AIR...WITH TEMPS AT THAT LVL FCST NEAR 0C OVER
THE W LATER IN THE DAY...IN CYC NLY FLOW TO W OF SFC LO THAT DVLPS
ON THE COLD FNT TO THE E SHOULD MAINTAIN LK ENHANCED SHOWERS IN THAT
AREA THRU 00Z TUE. ALTHOUGH TEMPS MIGHT WARM A BIT OVER THE E BEFORE
COLD FROPA/THICKER CLDS ARRIVE...READINGS ARE LIKELY TO FALL
FOLLOWING THE FROPA. SO NON-DIURNAL TEMP CURVE WITH STEADY/SLOWLY
FALLING TEMPS AT MOST PLACES IN THE AFTN APPEARS IN ORDER. DID
RETAIN A MENTION OF TS OVER THE E NEAR AND JUST BEHIND FROPA TIME AS
NAM FCST SDNGS HINT AT MUCAPE UP TO 500 J/KG. WITH A GUSTY N WIND...
SHRA... AND FALLING TEMPS THRU THE 50S...MON WL HAVE A DISTINCT
AUTUMNAL FEEL.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 356 PM EDT SUN SEP 16 2012
MAIN CONCERN IN THE MON NIGHT-WED TIME PERIOD CONTINUES TO BE
POPS...AND ALSO THE POSSIBILITY OF A HARD FREEZE TUESDAY NIGHT
ACROSS THE INTERIOR.
NO MAJOR CHANGES OF FORECAST THINKING FOR MONDAY NIGHT. THE UPPER
TROUGH GRADUALLY SETTLES ACROSS THE UPPER LAKES MONDAY
NIGHT...CENTERED OVER LAKE SUPERIOR BY TUESDAY MORNING. DESPITE THE
SURFACE LOW MOVING NE AND AWAY FROM THE REGION...A LAKE AGGREGATE
TROUGH WILL PERSIST ACROSS THE LAKE AS THE UPPER TROUGH MOVES
OVERHEAD. THIS WILL KEEP PBL WINDS PEGGED TO A NORTHERLY DIRECTION
ACROSS THE LAKE WHICH COMBINED WITH STEEPENING LOW LEVEL LAPSE RATES
AS THE 850MB TEMPS DROP TO -3C SHOULD FAVOR A FAIRLY PERSISTANT RAIN
ACROSS NORTH CENTRAL UPPER MICHIGAN MONDAY NIGHT. THERE ARE SOME
DIFFERENCES BETWEEN THE GFS AND NAM REGARDING THE EVOLUTION OF LOW
LEVEL WIND FLOW. THE GFS SUGGESTS THE WIND WILL BACK SLIGHTLY MONDAY
NIGHT OVER UPPER MI WHICH WOULD KEEP THE HEAVIEST PCPN JUST TO THE
EAST OF MARQUETTE. MEANWHILE...THE NAM WANTS TO KEEP THE WINDS A
LITTLE EAST OF NORTH...WHICH WOULD BE HIGHLY FAVORABLE FOR THE
HIGHER ELEVATIONS WEST OF MARQUETTE. WOULD NOT BE SURPRISED IF THE
GFS WIND VERIFIES...BUT IT MAY NOT MAKE A DIFFERENCE IN PCPN CHANCES
GIVEN THE LAKE ENHANCED NATURE OF THE PCPN VS. LAKE EFFECT. THE NAM
AND GFS ALSO SUGGEST THAT THE RAIN WILL DIMINISH MON NIGHT SOME OF
THE MID LEVEL MOISTURE BRIEFLY SCOURS OUT BEFORE A REINFORCING SHOT
OF MOISTURE MOVES IN BY TUE MORNING. ALTHOUGH THIS MAY HAPPEN...THE
FACT THAT THE LAKE INDUCED EQULIBRIUM LEVEL RISES TO OVER 20 KFT
OVERNIGHT MONDAY AND LARGE SCALE FORCING PERSISTS AS THE UPPER
TROUGH MOVES OVERHEAD SHOULD HELP TO OFFSET ANY MID LEVEL DRYING.
THE 4KM NAM NEST AND THE LOCAL WRF-ARW SUGGEST THE LAKE ENHANCED
PCPN WILL DEVELOP IN EARNEST AS SOON AS THE 850MB TEMPS DROP...SOON
AFTER 00Z. IN ADDITION...THE MORE LAKE ENHANCED NATURE OF THE PCPN
/VS LAKE EFFECT/ WOULD SUGGEST A MORE EVENLY DISTRUBUTED AREA OF
PCPN ACROSS ALL OF NORTH CENTRAL UPPER MI. WITH ALL OF THIS BEING
SAID...WILL KEEP CATEGORICAL POPS FOR MUCH OF NORTH CENTRAL UPPER
MICHIGAN CLOSER TO LAKE SUPERIOR...SIMILAR TO PREVIOUS FORECASTS. AS
FOR THE FAR EAST...PCPN MAY LIGHTEN UP MON NIGHT AS NORTHERLY PBL
FLOW NOT TERRRIBLY FAVORABLE FOR PCPN IN THAT AREA.
WITH THE UPPER TROUGH OVERHEAD ON TUESDAY...AND NEUTRAL TO SLIGHTLY
CYCLONIC PBL FLOW...WILL OPT TO MAINTAIN POPS AND RAISE THEM
SLIGHTLY TUESDAY NEAR LAKE SUPERIOR. AS THE TROUGH EXITS DURING THE
DAY...THE ASSOCIATED MID LVL FORCING WILL EXIT. THIS WILL ALLOW FOR
THE SURFACE RIDGING TO BUILD IN DURING THE DAY AND AS SUCH SHOULD
ALLOW FOR LAKE EFFECT PCPN TO GRADUALLY DIMINISH BY EVENING. AM NOT
IN TOO MUCH OF A HURRY TO END PCPN ON TUESDAY THOUGH...AS THE RIDGE
AXIS REALLY DOES NOT BUILD IN UNTIL AFTER 00Z WED. TEMPS WILL
STRUGGLE TO REACH 50 ACROSS THE INTERIOR DUE TO CLOUDS AND SHOWERS.
IN FACT...ALL NWP WANTS TO KEEP THE INTERIOR IN THE MID-UPPER 40S ON
TUESDAY. THIS SEEMS REASONABLE ESPECIALLY IF CLOUDS PERSIST...AND
HAVE THEREFORE LOWERED TEMPS ACROSS THE ENTIRE AREA ON
TUESDAY...WITH MOST INTERIOR SECTIONS STAYING IN THE 40S.
ANY REMAINING SHOWERS SHOULD END EARLY TUE EVENING...THEN THE RIDGE
BUILDS IN. THIS RIDGING COMBINED WITH PRECIPITABLE WATER VALUES AS
LOW AS 0.45 INCH SHOULD ALLOW FOR SKIES TO CLEAR OUT ACROSS THE
WEST. LAKE CLOUDS SHOULD HANG ON EAST...BUT EVEN THERE IT MAY CLEAR
OUT BY MORNING. REGARDLESS...WITH CLEAR SKIES AND LIGHT WINDS...IT
SHOULD GET COLD ACROSS THE INTERIOR. AM NOW THINKING A HARD FREEZE
IS IN STORE BY WED MORNING FOR THE INTERIOR WEST. EVEN THE RAW NAM
WHICH USUALLY HAS A WARM BIAS DURING RADIATIONAL COOLING HAS TEMPS
ACROSS IRON COUNTY IN THE 20S...AND THE GFS HAS 2M TEMPS IN THE
LOWER 30S. NAM MOS GUIDANCE SUGGEST SIMILAR TO COLDER TEMPS FOR TUE
NIGHT. WILL THEREFORE LOWER TEMPS ACROSS THE ENTIRE AREA TUE NIGHT.
SOME MODEL DIFFERENCES REGARDING THE NEXT SYSTEM. THE GFS IS MUCH
FASTER...UP TO 12 HRS...BRINIGING PCPN IN BY LUNCHTIME WED.
MEANWHILE...THE NAM AND GEM ARE MUCH SLOWER...NOT BRINGING IN PCPN
UNTIL WED EVENING. THE COMBINATION OF THE INCREASING WARM
ADVECTION/ISENTROPIC LIFT AND INCREASING MID LVL MOISTURE ACROSS THE
WEST WED AFTN IN THE NAM WOULD IMPLY AT LEAST A CHANCE FOR RAIN WED
AFTN DESPITE THE MODEL NOT PRINTING OUT MUCH QPF. WILL THEREFORE GO
WITH 30 PCPN CHANCE FOR SHOWERS WED AFTN FOR WESTERN UPPER MI. WILL
KEEP A DRY FCST FOR THE REMAINDER OF THE AREA.
IN THE EXTENDED /WED NIGHT-NEXT SUNDAY/...THE FULL AMPLITUDE LONG
WAVE TROUGH WILL PERSIST FROM HUDSON BAY THROUGH THE GREAT LAKES
REGION THROUGH THE PERIOD. THIS WILL KEEP THE WEATHER FAIRLY
UNSETTLED THROUGH SATURDAY. THE NUMERICAL GUIDANCE IS IN GOOD
AGREEMENT REGARDING THE LONG WAVE...BUT DIFFER SOMEWHAT ON SPECIFIC
DETAILS REGARDING INDIVIDUAL SHORT WAVES AND AS SUCH THEY DIFFER ON
EXACT POSITION OF THE LONG WAVE TROUGH. THE MAIN OUTLIER WITH THE
00Z RUN IS THE OPERATIONAL ECMWF WHICH KEEPS THE MAIN TROUGH
POSITIVLY TILTED WITH THE TROUGH AXIS FURTHER WEST. THIS IS LIKELY
DUE TO THAT MODEL ALLOWING STRONGER SHORT WAVE ENERGY TO DIVE DOWN
THE BACK SIDE OF THE UPPER TROUGH THURSDAY INTO FRIDAY. AT THIS
TIME...THIS IS NOT SUPPORTED BY THE GFS...NOR THE MAJORITY OF THE
ENSEMBLE MEMBERS FROM THE GFS AND ECMWF. WILL THEREFORE TREND THE
FORECAST TOWARD THE GFS/GEM COMPROMISE...BUT THE REALITY OF THE
MATTER IS THAT EITHER SOLUTION WOULD MAINTAIN UNSETTLED WEATHER FOR
THE AREA FOR MUCH OF THE EXTENDED. THERE WILL BE PERIODS OF DRY
WEATHER...BUT GIVEN THE UNCERTAINTY OF EXACT SHORT WAVE POSITIONS
ESPECIALLY FOR LATE INTO THE WEEK...IT WILL BE TOUGH TO PIN DOWN
SPECIFICS. WITH THAT BEING SAID...WILL NEED TO GO WITH CHANCE POPS
EACH DAY OF THE EXTENDED THROUGH SATURDAY. THE BEST CHANCE FOR RAIN
MAY BE FRIDAY INTO FRIDAY NIGHT WHERE THE GFS AND GEM BOTH AGREE ON
A WAVE MOVING ACROSS THE UPPER LAKES WITH LOW PRESSURE ACROSS THE
AREA. IN FACT...EVEN THE ECMWF SHOWS PCPN FRIDAY. BY SUNDAY...THE
GFS SUGGESTS THAT THE TROUGH WILL SLOWLY EXIT EAST OF THE
AREA...ALLOWING SOME DRYING TO MOVE IN. WILL THEREFORE GO WITH A DRY
FORECAST FOR NOW ON SUNDAY...BUT THAT IS SUBJECT TO CHANGE IF THE
TROUGH IS A LITTLE SLOWER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 120 PM EDT SUN SEP 16 2012
VFR CONDITIONS WILL PREVAIL THROUGH THE REST OF THIS AFTERNOON AND
INTO THE LATE HOURS TONIGHT. WINDS WILL GRADUALLY SWITCH FROM A MORE
SOUTHWEST-WESTERLY DIRECTION TO NORTHWEST AS THE FRONT PASSES LATER
ON THIS EVENING. A LOW PRESSURE TROUGH CROSSING UPPER MICHIGAN WILL
DEVELOP INTO A MORE ORGANIZED LOW PRESSURE SYSTEM...BRINGING A WAVE
OF PRECIPITATION INTO UPPER MICHIGAN DURING THE TOMORROW
MORNING-LATE AFTERNOON TIME PERIOD. EXPECT WITH MORE MODERATE RAIN
DEVELOPING THAT CEILINGS AND VISIBILITY WILL DROP FROM VFR
CONDITIONS INTO A MORE IFR REGIME. KIWD/KCMX WILL SEE RAIN STARTING
AROUND THE 10-11Z TIME...WHEREAS KSAW WILL START TO SEE LIGHT RAIN
AROUND 15Z. GUIDANCE SUGGESTS THAT CEILINGS/VIS COULD DROP TO
LIFR-VLIFR IN THE EARLY MORNING/EARLY AFTERNOON...BUT CONFIDENCE WAS
NOT HIGH ENOUGH TO INCLUDE IN THE TAF.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 356 PM EDT SUN SEP 16 2012
EXPECT RELATIVELY LIGHT WINDS UNDER 20 KTS FOR MOST OF THIS EVENING
OVER THE LAKE WITH FAIRLY HI STABILITY/A WEAK LO PRES TROF CROSSING
THE AREA. THEN EXPECT A WIND SHIFT TO THE NNW WITH THE PASSAGE OF A
STRONG COLD FRONT BY LATE EVENING OVER THE W AND THEN ON MON MORNING
OVER THE E HALF. AS COLDER AIR FOLLOWS THE FRONT OVER THE RELATIVELY
WARM WATERS OF LAKE SUPERIOR AND STABILITY DECREASES...EXPECT
STRONGER N WINDS TO 25 TO 30 KTS TO DEVELOP W TO E. BUT SINCE LATEST
GUIDANCE INDICATES THE PRES GRADIENT WILL BE WEAKER THAN EXPECTED ON
PREVIOUS SHIFTS...GALES NOW APPEAR UNLIKELY. SO THE GOING GALE WATCH
THAT WAS IN EFFECT ON MON OVER PORTIONS OF THE W HALF WAS DROPPED.
NORTH WINDS WILL PERSIST MONDAY NIGHT INTO TUESDAY BEFORE GRADUALLY
SHIFTING TO THE NW THEN W BY TUESDAY EVENING. ANOTHER LOW PRESSURE
TROUGH WILL APPROACH WED THEN PASS ACROSS THE LAKE WED NIGHT. AHEAD
OF THE TROUGH...WINDS WILL TURN SOUTHERLY AT 15-25 KT...THEN WILL
TURN W-NW BY THU MORNING. OTHER THAN SOME GUSTS CLOSE TO GALE FORCE
MONDAY EVENING...GALES ARE NOT EXPECTED AT THIS TIME THROUGH FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...MRD
AVIATION...MCD
MARINE...KC/MRD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
136 AM EDT SUN SEP 16 2012
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 339 PM EDT SAT SEP 15 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A WNW FLOW ALF
OVER THE UPR GRT LKS TO THE W OF SLOWLY DEPARTING TROF IN QUEBEC AND
E OF MORE ZONAL FLOW OVER THE NRN ROCKIES. SFC HI PRES UNDER THE
CONFLUENT UPR FLOW IN THE GRT LKS IS CENTERED OVER SE ONTARIO JUST E
OF THE SAULT. SOME SC LINGERS OVER THE ERN CWA EARLY THIS AFTN IN
ASSOCIATION WITH DEPARTING H85 THERMAL TROF/LINGERING LLVL MSTR
SHOWN ON THE 12Z APX RAOB. BUT AS THE HI IS SHIFTING TO THE E...THE
SSW RETURN FLOW ON ITS WESTERN FLANK IS DRAWING WARMER/DRIER AIR
NOTED TO THE W BACK INTO THE UPR LKS. 12Z H85 TEMPS ARE AS HI AS 20C
AT BISMARCK. 12Z H85-7 DEWPT DEPRESSIONS ARE 20 TO 25C IN THE NRN
PLAINS...WHERE PWAT IS GENERALLY 0.25 TO 0.50 INCH...AS LITTLE AS 50
PCT OF NORMAL. MOISTER AIR AT H925-85 LURKS TO THE S IN KANSAS/
MISSOURI.
TONIGHT...AS THE HI TO THE E DRIFTS FARTHER AWAY UNDER WNW FLOW
ALF...THE LLVL WIND IS FCST TO SHIFT TO THE WSW IN ADVANCE OF LO
PRES TROF APRCHG FM THE W AHEAD OF SHRTWV EMBEDDED IN THE ZONAL FLOW
ALONG THE NDAKOTA/CNDN BORDER THIS MRNG. THIS FLOW IS PROGGED TO
ADVECT THE MUCH WARMER H85 AIR TO THE W THIS MRNG INTO THE UPR
LKS...WITH H85 TEMPS FCST TO RISE AS HI AS 16-18C AT IWD BY 12Z SUN.
ANY LINGERING LO CLDS OVER THE E SHOULD DISSIPATE EARLY WITH THE
ARRIVAL OF THIS WARMER AND DRIER AIR. ALTHOUGH THE AIRMASS IS
PROGGED TO REMAIN DRY THRU THE NGT...INCRSG H925 WINDS UP TO
30-35KTS LATE AS WELL AS THE ARRIVAL OF SOME PATCHY HI CLDS INDICATE
TNGT WL BE MUCH WARMER THAN THIS MRNG. EXPECT THE HIEST MIN TEMPS
OVER THE W AND NCNTRL NEAR LK SUP.
SUN...INCOMING LO PRES TROF IS PROGGED TO DRIFT INTO THE WRN CWA IN
THE AFTN AND INTERACT WITH H85 THERMAL RDG/AXIS OF H85 TEMPS IN THE
14-15C RANGE IN PLACE. ALTHOUGH MODELS INDICATE SW FLOW IN ADVANCE
OF THE TROF WL ADVECT MOISTER LLVL AIR IN KS/MO THIS MRNG INTO THE
UPR LKS...VERY DRY H85-7 AIR IN THE NRN PLAINS/ADJOINING SRN CAN AND
LACK OF SGNFT DYNAMIC FORCING TO ERODE MID LVL CAPPING/CAUSE H5
FALLS WL BE LIMITING FACTORS FOR PCPN. EVEN WITH THESE NEGATIVES...
SOME MODELS...ESPECIALLY THE CONSISTENT 12Z GFS...DO GENERATE SOME
PCPN OVER MAINLY THE NRN TIER COUNTIES ALONG AND AHEAD OF THE
INCOMING TROF. CONSIDERING THE NEGATIVES...OPTED TO FOLLOW THE DRIER
12Z NAM/LOCAL WRF-ARW MODELS AND MAINTAIN A PCPN-FREE FCST FOR MOST
OF THE CWA. DID RETAIN GOING SCHC POPS OVER WRN AND NCNTRL LK SUP
CLOSER TO MORE SUBSTANTIAL H5 FALLS ASSOCIATED WITH DEEPENING TROF
IN SCNTRL CAN. FCST STEEP H7-5 LAPSE RATES IN EXCESS OF 7C/KM
WARRANTS A MENTION OF TS IN THIS AREA DESPITE LIMITED MSTR.
MIXING TO H8 ON NAM/GFS FCST SDNGS YIELDS HI TEMPS NEAR 80 OVER THE
INTERIOR SCNTRL AWAY FM MODERATION OFF LK MI. WITH MORE MID/HI CLDS
AND/OR THE ARRIVAL OF THE TROF/WSHFT TO THE W...TEMPS OVER THE W AND
NRN TIER WL BE LOWER. THE COMBINATION OF THE UNSEASONABLE WARMTH
OVER MAINLY THE SCNTRL...GUSTY WSW WINDS TO 25-30 MPH ENHANCED BY
THE DEEPER MIXING...AND MIN RH DIPPING TO ARND 30 PCT AS DEWPTS MIX
OUT INTO THE 45-50 RANGE DESPITE SLOW ARRIVAL OF MORE LLVL MSTR
LATER IN THE DAY WL LEAD TO AN ELEVATED RISK OF WILDFIRES...
ESPECIALLY OVER THE CNTRL AND E WHERE THE PRES GRADIENT WL REMAIN
SHARPEST THRU THE DAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 339 PM EDT SAT SEP 15 2012
THE MAIN FORECAST CONCERN FOR SUNDAY NIGHT AND MONDAY ARE POPS
ASSOCIATED WITH THE UPPER TROUGH AND COLD FRONT MOVING INTO THE
UPPER LAKES. SUNDAY NIGHT SHOULD START OUT QUIET DESPITE THE COLD
FRONT BEING OVER WESTERN LAKE SUPERIOR. MOISTURE IS VERY LIMITED
ALONG THE FRONT SUNDAY EVENING...AND DYNAMICS ARE LACKING DUE TO THE
UPPER JET STILL BEING WELL WEST OVER THE UPPER MIDWEST.
HOWEVER...THIS IS EXPECTED TO CHANGE LATER SUNDAY NIGHT INTO MONDAY
AS THE UPPER TROUGH SHARPENS AS A RESULT OF THE 110 KT UPPER JET
DIVING SOUTH FROM THE YUKON SUNDAY NIGHT. THIS WILL ALLOW THE
UPSTREAM THERMAL GRADIENT TO TIGHTEN AND ASSOCIATED FRONTOGENETIC
CIRCULATION TO STRENGTHEN LATE SUNDAY AND INTO MONDAY AS IT MOVES
INTO UPPER MICHIGAN. MEANWHILE...DEEPER PACIFIC ORIGIN MOISTURE WILL
MOVE ACROSS THE REGION /WITH PRECIPITABLE WATER VALUES GREATER THAN
1 INCH/ AS SURFACE LOW PRESSURE DEVELOPS ALONG THE FRONT IN RESPONSE
TO THE RIGHT ENTRANCE REGION OF THE JET MOVING OVERHEAD. THERE ARE
SOME DIFFERENCES BETWEEN THE GFS AND NAM WITH REGARDS TO THE
PLACEMENT OF THE LOW AND THE MOVEMENT OF THE COLD FRONT...WITH THE
GFS BEING SLOWER AND AS SUCH FURTHER WEST WITH THE LOW PRES
DEVELOPMENT COMPARED TO THE NAM. THE NAM TENDS TO AGREE MORE WITH
THE 00Z ECMWF AND ALSO HAS SOME SUPPORT FROM SREF MEMBERS.
INCREASING 850MB COLD ADVECTION WILL ALLOW FOR INCREASING LAKE
INDUCED INSTABILITY LATE MONDAY INTO MONDAY NIGHT ON N-NW PBL WINDS
ON THE NW SIDE OF THE LOW. ALL OF THIS SHOULD COMBINE TO GIVE A
PERIOD OF STEADY RAIN STARTING LATE SUNDAY NIGHT AND CONTINUING
THROUGH MONDAY...AND IN FACT CONTINUING INTO MONDAY NIGHT INTO
TUESDAY FOR AREAS NEAR LAKE SUPERIOR. WITH THE LAKE AND TERRAIN
ENHANCEMENT DUE TO NORTHERLY FLOW OFF THE LAKE...SOME AREAS CLOSE TO
LAKE SUPERIOR COULD SEE 1-1.5 INCHES OF RAIN LATE SUNDAY
NIGHT-TUESDAY MORNING.
AS SUCH...HAVE OPTED TO MAKE ONLY MINOR TWEAKS TO THE GOING
FORECAST FOR SUNDAY NIGHT INTO TUESDAY. DUE TO THE EXTREMELY DRY
AIRMASS ALONG AND AHEAD OF THE FRONT...HAVE OPTED TO BACK OFF POPS
ESPECIALLY SUNDAY EVENING. ALTHOUGH IT MAY TAKE A LITTLE TIME FOR
THE FAR EAST TO SEE STEADY RAIN ON MONDAY DUE TO THE LOW PRESSURE
DEVELOPMENT ALONG THE FRONT KEEPING THAT AREA IN THE WARM SECTOR A
LITTLE LONGER...THE EXPECTATION IS THAT THE ENTIRE AREA WILL
EVENTUALLY SEE RAIN MONDAY. WILL THEREFORE GO WITH CATEGORICAL POPS
FOR THE ENTIRE FORECAST AREA ON MONDAY BUT WILL GO WITH THE HIGHEST
POPS ACROSS NORTH CENTRAL AND WESTERN UPPER MICHIGAN DUE TO THE
EVENTUAL LAKE/TERRAIN ENHANCEMENT DURING THE AFTERNOON. WILL
CONTINUE WITH CATEGORICAL POPS NEAR LAKE SUPERIOR ON MONDAY NIGHT
WITH NORTHERLY FLOW AND 850MB TEMPS DROPPING TO -3C...ALLOWING FOR
LAKE INDUCED EQUILIBRIUM LEVELS ABOVE 20KFT. WOULD NOT BE SHOCKED IF
THERE ARE SOME LIGHTNING STRIKES MONDAY NIGHT ESPECIALLY WITH THE
UPPER TROUGH OVERHEAD.
ALTHOUGH N-NW FLOW CONTINUES INTO TUESDAY...THE PBL FLOW BECOMES
NEUTRAL OR EVEN ANTI-CYCLONIC AS THE DAY GOES ON. IN ADDITION...THE
DEEP MOISTURE SHOULD BE SCOURED OUT AND THE BEST Q-VECT CONVERGENCE
MOVES EAST. DUE TO THE MODERATE LAKE INSTABILITY FROM 850MB TEMPS
AROUND -3C COMBINED WITH ONSHORE FLOW...CANNOT REMOVE POPS NEAR THE
LAKE...BUT WILL CONTINUE WITH SCATTERED POPS. BY TUESDAY
EVENING...IT SHOULD START TO CLEAR OUT AS THE UPR TROUGH MOVES EAST
AND THE SFC HIGH MOVES OVERHEAD. ALTHOUGH THE 12Z GFS IS QUITE
PROGRESSIVE IN MOVING THE HIGH TO THE EAST TUE NIGHT...THE GEM AND
ECMWF ARE CONSISTENT IN SHOWING A SLOWER AND LESS PROGRESSIVE SOLN.
WITH THE HIGH BEING OVERHEAD...IT LOOKS LIKE A GOOD RADIATIONAL
COOLING NIGHT ESPECIALLY ACROSS THE INTERIOR WEST AWAY FROM ANY
REMAINING LAKE CLOUDS...SO AREAS OF FROST ARE EXPECTED...IF NOT A
HARD FREEZE.
TEMPS FOR MONDAY/TUESDAY WILL REMAIN BELOW NORMAL...ALTHOUGH MONDAY
WILL BE WARMER THAN TUESDAY...ESPECIALLY ACROSS THE EAST. WITH 850MB
TEMPS AROUND -3C ON TUESDAY AND BLUSTERY N-NW FLOW...EXPECT TEMPS TO
STRUGGLE TO REACH 50...ESPECIALLY WHERE IT STAYS CLOUDY FOR MUCH OF
THE DAY NEAR LAKE SUPERIOR.
IN THE EXTENDED /WED-NEXT SATURDAY/...IT CERTAINLY LOOKS LIKE A
AUTUMN PATTERN ACROSS THE GREAT LAKES AS THE PATTERN WILL BE
DOMINATED BY AN INTENSIFYING LONGITUDINAL TROUGH ACROSS CENTRAL
CANADA AND EXTENDING SOUTHWARD INTO THE GREAT LAKES REGION BY THE
END OF THE WEEK. THIS WILL ALLOW FOR THE UNSETTLED AND COOL
WEATHER TO CONTINUE. AS FOR THE SPECIFICS...THE FIRST UPPER LOW THAT
WILL PLAGUE THE AREA EARLY IN THE WEEK WILL EJECT OUT TUE NIGHT/WED
IN RESPONSE TO ANOTHER SHORTWAVE DIVING DOWN THE BACK SIDE OF THE
LONG WAVE TROUGH. THIS SHOULD ALLOW FOR BRIEF RIDGING TO BUILD
ACROSS THE UPPER GREAT LAKES WED BEFORE THE NEXT SYSTEM MOVES IN AND
CLOSES OFF OVER THE GREAT LAKES BY FRI. AS SUCH...WILL CONTINUE WITH
CHANCE POPS FOR THE ENTIRE AREA THURSDAY. AS THE EVENT BECOMES A
LITTLE CLEARER IN THE NEXT FEW DAYS...POPS WILL LIKELY NEED TO BE
INCREASED IN THE FRIDAY/SATURDAY TIME PERIOD AS IT WILL BE COLD
ENOUGH ALOFT FOR LAKE ENHANCEMENT AND MOST OF THE NAEFS MEMBERS ALL
HAVE RAIN ON FRIDAY INTO SATURDAY. THE UPPER LOW SETTLES OVER THE
GREAT LAKES ON SATURDAY...ALTHOUGH THE ECMWF POSITION IS SOUTH OF
THE GFS POSITION. REGARDLESS...SATURDAY LOOKS UNSETTLED AND RATHER
WET. TEMPS THROUGH THE EXTENDED PERIOD WILL BE BELOW NORMAL. FRIDAY
AND ESPECIALLY SATURDAY COULD STRUGGLE TO GET OUT OF THE UPPER 40S
IF IT STAYS CLOUDY AND RAINY FOR THE ENTIRE DAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 134 AM EDT SUN SEP 16 2012
VFR CONDITIONS WILL CONTINUE AT KIWD/KCMX/KSAW THRU THIS FCST PERIOD
AS LOW-LEVELS REMAIN DRY DESPITE A COLD FRONT PASSING ACROSS THE
AREA THIS AFTN/EVENING. TIGHTENING PRES GRADIENT BTWN HIGH PRES TO
THE E AND APPROACHING COLD FRONT ACROSS THE NRN PLAINS WILL LEAD TO
LLWS OVERNIGHT. LATEST KMQT VAD WIND PROFILE SHOWS SSW WINDS OF 30KT
AT 500FT AGL. OTHER THAN WIND SHIFT...COLD FRONT WILL PASS KIWD/KCMX
UNEVENTFULLY THIS AFTN AND KSAW IN THE EVENING. IT WILL BE BEYOND
THIS FCST PERIOD THAT RAIN DEVELOPS AS DYNAMICS STRENGTHEN WITH TROF
DEEPENING INTO THE UPPER MISSISSIPPI VALLEY. IFR CONDITIONS PROBABLE
MON.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 339 PM EDT SAT SEP 15 2012
EXPECT ESE WINDS UP TO 20 KTS THIS AFTERNOON TO VEER TO THE WSW
TONIGHT INTO SUN AS HI PRES IN SE ONTARIO RETREATS TO THE E AND A LO
PRES TROF APPROACHES FROM THE NW.
LOW PRESSURE WILL DEVELOP ALONG A COLD FRONT MOVING ACROSS THE UPPER
LAKES ON MONDAY. IT WILL DEEPEN AT IT MOVES JUST EAST OF LAKE
SUPERIOR ON MONDAY. THE TIGHTENING PRESSURE GRADIENT COMBINED WITH
INCREASING LAKE INSTABILITY WILL ALLOW FOR GALE FORCE NORTHERLY
WINDS ACROSS CENTRAL LAKE SUPERIOR MONDAY AND THEN ACROSS THE EAST
HALF OF LAKE SUPERIOR MONDAY NIGHT. HIGH PRESSURE BUILDS IN TUESDAY
NIGHT BEFORE A BROAD AREA OF LOW PRESSURE MOVES SOUTH THU AND
FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING FOR
LSZ267.
GALE WATCH FROM MONDAY EVENING THROUGH LATE MONDAY NIGHT FOR
LSZ266.
GALE WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR LSZ264.
GALE WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...MRD
AVIATION...ROLFSON
MARINE...KC/MRD
AREA FORECAST DISCUSSION
NWS GLASGOW MT
852 AM MDT SUN SEP 16 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH TUESDAY...
MORNING UPDATE...
UPDATES THIS MORNING WERE LIGHT. BLENDED IN HRRR AND NAM5 FOR
SLIGHTLY BETTER RESOLUTION ON WIND FIELDS. AFTER LOOKING OVER
HEAVY CLOUD COVER AND VERY LIGHT RAIN ACROSS THE REGION DECREASED
TEMPERATURES ACROSS THE FAR NORTHEAST A BIT. THERE ARE AN
ABUNDANCE OF ECHOS SHOWING UP ON RADAR BUT RAIN GAGE SITES ARE
NOT RECORDING MUCH AT THE MOMENT. CURRENTLY WAITING FOR THE
BOUNDARY LAYER TO MOISTEN UP ENOUGH TO PRODUCE MORE THAN SPRINKLES.
BUT THIS MAY TAKE A AWHILE TODAY AND THE LIFT MECHANISM MAY LEAVE
THE AREA BY THE TIME RAIN CAN FINALLY HIT THE GROUND PREVENTING
ANY SIZABLE QPF FROM ACTUALLY FORMING. GAH
PREVIOUS SHORT TERM DISCUSSION...
COLD FRONT CURRENTLY MOVING SOUTH ACROSS EASTERN MONTANA. THIS
FRONT WILL CONTINUE TO MOVE SOUTH THIS MORNING BRINGING COLDER AIR
INTO THE FORECAST AREA. SHORTWAVE TROUGH CURRENTLY MOVING THROUGH
ALBERTA AND SASKATCHEWAN WILL SLIDE THROUGH NORTHEAST MONTANA THIS
AFTERNOON AND EVENING. A FEW SHOWERS HAVE DEVELOPED OVERNIGHT
ACROSS SOUTHERN SASKATCHEWAN AHEAD OF THIS TROUGH AND WILL AFFECT
NORTHEAST MONTANA TODAY. WITH VERY DRY LOW LEVEL AIRMASS AT THE
MOMENT...SOME OF THESE SHOWERS WILL EVAPORATE BEFORE REACHING THE
GROUND RESULTING IN VIRGA. WILL GO WITH A MIX OF SLIGHT CHANCE AND
LOW CHANCE POPS FOR TODAY. TEMPERATURES WILL BE NOTICEABLY COOLER
WITH HIGHS IN THE 60S IN MOST AREAS AND UPPER 50S NORTH WITH NORTH
TO NORTHEAST WINDS 10 TO 20 MPH.
THE SHORTWAVE MOVES TO THE EAST TONIGHT ENDING THE CHANCE OF
SHOWERS. NORTHWEST FLOW ALOFT WILL PREVAIL FOR MONDAY AND TUESDAY.
A STRONG UPPER RIDGE WILL BUILD ON THE WEST COAST WHILE A LONGWAVE
TROUGH DEVELOPS TO THE EAST. HIGH PRESSURE BUILDING INTO EASTERN
MONTANA WILL DIMINISH THE WINDS AND CLEARING SKIES WILL ALLOW FOR
A COOL NIGHT WITH SOME LOW LYING AREAS SEEING BELOW FREEZING
TEMPERATURES.
SURFACE HIGH ON MONDAY WILL BRING A MOSTLY SUNNY DAY WITH LIGHT
WINDS AND SLIGHTLY WARMER TEMPERATURES. SHORTWAVE RIDGE IN
NORTHWEST FLOW ALOFT WILL BRING WARMER TEMPERATURES ON TUESDAY.
WEST TO NORTHWEST WINDS WILL INCREASE TUESDAY AFTERNOON AHEAD OF
THE NEXT COLD FRONT TUESDAY NIGHT. WITH LOW RELATIVE
HUMIDITY...CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE. WILL
HIGHLIGHT IN HAZARDOUS WEATHER OUTLOOK. FORRESTER
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...
THE EXTENDED PERIOD BEGINNING TUESDAY NIGHT WILL BRING IN SEASONAL
TEMPERATURES AND FEW CHANCES FOR RAIN. INITIALLY THERE WILL BE A
RIDGE IN THE WEST AND NORTHWESTERLY FLOW ALOFT OVER NORTHEAST
MONTANA. AN EMBEDDED SHORT WAVE TROUGH IN THE UPPER FLOW RIDING
DOWN FROM CANADA TUESDAY NIGHT WILL SEND A DRY COLD FRONT OVER
NEMONT. THIS WILL COOL TEMPERATURES FROM THE PREVIOUS DAY BY
AROUND 10F DEGREES.
THE COLD FRONT BECOMES STATIONARY...ORIENTATED NORTHWEST TO
SOUTHEAST THROUGH NEMONT. THE SLIGHTLY FLUCTUATING BOUNDARY WILL
STRADDLE NEMONT. BY THURSDAY THE RIDGE PEAK AMPLIFIES WELL INTO
BRITISH COLUMBIA...CONTINUING THE NORTHWEST FLOW OVER MONTANA.
BOTH THE GFS AND ECMWF BRING ANOTHER SHORT WAVE DISTURBANCE IN THE
UPPER FLOW AROUND THURSDAY NIGHT. THERE IS A DIFFERENCE IN THE
LONGITUDINAL POSITION OF THE COLD BOUNDARY DEPENDING ON MODEL. SO
THERE IS SOME UNCERTAINTY. THE EAST-WEST ORIENTATION OF THE
STATIONARY BOUNDARY WILL DETERMINE WHETHER TEMPERATURES REMAIN
SEASONAL OR BECOME COOLER. THERE IS ALSO THE SLIGHT POSSIBILITY
OF A LIMITED AMOUNT OF OVERRUNNING MOISTURE THAT COULD BRING SOME
LIGHT RAIN INTO FRIDAY. SCT
&&
.AVIATION...
SKIES WILL BECOME INCREASINGLY CLOUDY AS A COLD FRONT PUSHES
SOUTH FROM CANADA. ISOLATED TO SCATTERED RAIN SHOWERS CAN BE
EXPECTED TODAY. SHOWERS COULD LINGER NEAR THE NORTH DAKOTA STATE
BORDER INTO THIS EVENING BEFORE MOVING EAST.
NORTHEAST WINDS TONIGHT OF AROUND 5 TO 15 KNOTS WILL BACK TO THE
NORTH BEHIND THE COLD FRONT LATER THIS MORNING. SCT
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
426 PM EDT SUN SEP 16 2012
.SYNOPSIS...
HIGH PRESSURE WILL SHIFT OFFSHORE TONIGHT AND MONDAY. A STRONG
COLD FRONT WILL APPROACH THE AREA TUESDAY AND MOVE OFFSHORE
WEDNESDAY...FOLLOWED BY HIGH PRESSURE FOR LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 315 PM SUNDAY...ISENTROPIC LIFT AND A WEAK MID-LEVEL
SHORTWAVE HAS CONSPIRED TO BRING PATCHY LIGHT RAIN OVER MAINLY THE
WEST AND NORTHWEST PORTIONS OF THE CWA TODAY. ANOTHER WEAK
SHORTWAVE EMBEDDED IN THE ZONAL MID-LEVEL FLOW WILL CROSS THE
REGION OVER THE NEXT FEW HOURS AND WILL KEEP CHANCE POPS TO THE
WEST OF HIGHWAY 17 THROUGH THE EVENING HOURS. BOTH THE RAP AND
NAM12 SHOW PRECIPITATION DISSIPATING AROUND DARK WITH MINIMAL
CHANCES OVERNIGHT. SKIES SHOULD BE MOSTLY CLOUDY OVERNIGHT AND
HAVE GONE A LITTLE ABOVE GUIDANCE TEMPS TONIGHT WITH MINS IN THE
LOWER TO MIDDLE 70S WITH UPPER 60S OVER THE OUTER BANKS.
&&
.SHORT TERM /MONDAY/...
AS OF 315 PM SUNDAY...WITH THE LOW-LEVEL FLOW VEERING TO MORE
SOUTHEASTERLY ON MONDAY...EXPECT CLOUDY SKIES ACROSS THE REGION.
PER LATEST NAM12/GFS...THINK BULK OF THE PRECIPITATION CHANCES
WILL BE OVER THE FAR WESTERN COUNTIES ONCE AGAIN WITH MOST
ACTIVITY HOLDING OFF UNTIL LATER IN THE DAY. WITH THE CLOUD
COVER...MAXIMUM TEMPERATURES WILL BE FAIRLY UNIFORM ACROSS THE
REGION WITHIN A DEGREE OR TWO OF 80.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
AS OF 400 PM SUNDAY...A ROBUST NRN STREAM UPPER LEVEL TROUGH WILL
BE DIGGING SEWD ACROSS THE MID WEST TO START THE LONG TERM. THE
TROUGH WILL ABSORB A WEAK SRN STREAM TROUGH PRESENTLY OVER EASTERN
TX AS WELL AS TAP INTO ABUNDANT GOM MOISTURE AS IT PROGRESSES INTO
THE MID ATLANTIC TUE AND TUE NIGHT. WILL SEE H85 MOISTURE TRANSPORT
AND BULK SHEAR GRADUALLY INCREASE MON NIGHT HOWEVER DEEPEST
MOISTURE AND UPPER LEVEL SUPPORT EXPECTED TO REMAIN WEST OVER THE
APPALACHIANS/WESTERN PIEDMONT THROUGH THE OVERNIGHT PERIOD AND
HAVE BACKED POPS OFF TO SLIGHT CHANCE. UPPER LEVEL DYNAMICS
IMPROVE TUE/TUE NIGHT AS THE RIGHT ENTRANCE OF THE UPPER JET MOVES
OVER THE REGION ALONG WITH DEEPEST MOISTURE TRANSPORT ACROSS ERN
NC BRINGING THE BEST CHANCE OF SHOWERS/STORMS ACROSS THE REGION.
MODERATE SHEAR AND INSTABILITY WILL BE PRESENT AND COULD SEE
STRONG TO SEVERE STORMS DEVELOP TUE AFTERNOON/EVENING...AND SPC
HAS THE REGION IN A SLIGHT RISK FOR SEVERE ON DAY3. WHILE
INSTABILITY WILL WANE TUE NIGHT...FRONTAL FORCING MAY BRING
ADDITIONAL STRONG STORMS ACROSS THE REGION. THE FRONT PUSHES TO
THE COAST WED MORNING THEN STALLS NEAR THE GULF STREAM INTO THU.
MODELS DIFFER SOME ON AMOUNT OF MOISTURE THAT REMAINS INVOF THE
FRONT BUT COULD SEE LIGHT SHOWERS LINGERING INTO THU...ESPECIALLY
COASTAL SECTIONS AND HAVE KEPT SLT CHC POPS THROUGH THE PERIOD.
SUBSTANTIAL MID LEVEL DRYING PROGGED TO OCCUR THU THROUGH SAT
BRINGING MAINLY DRY CONDITIONS BUT COULD SEE ISOLATED SHOWERS
DEVELOP THROUGH PEAK HEATING FRI AS MODELS INDICATING A WEAK
SHORTWAVE MOVING THROUGH THE CYCLONIC FLOW ALOFT WITH THE UPPER
TROUGH PERSISTING ACROSS THE ERN CONUS. ANOTHER ROBUST NRN STREAM
SYSTEM PROGGED TO DIVE INTO THE GREAT LAKES REGION NEXT WEEKEND
POTENTIALLY BRINGING A ROUND OF SHOWERS ACROSS THE REGION
SUNDAY...HOWEVER THIS SYSTEM LOOKS DRIER AND WEAKER WITH A LIMITED
GULF MOISTURE FEED.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
SHORT TERM /TONIGHT AND MONDAY/...
AS OF 315 PM SUNDAY...ANOTHER TRICKY AVIATION FORECAST OVERNIGHT
TONIGHT. BEST GUESS HERE IS THAT EXTENSIVE CLOUD COVER SHOULD
LIMIT THE FORMATION OF DENSE FOG. NUMERICAL GUIDANCE DOES SHOW
SOME PERIODS OF MVFR STRATUS AND HAVE INCLUDED IN THE TAF BETWEEN
ROUGHLY 08Z AND 13Z. REMAINDER OF TAF CYCLE SHOULD BE IN THE VFR
RANGE.
LONG TERM /MONDAY EVENING THROUGH THURSDAY/...
AS OF 420 PM SUN...MAINLY VFR THROUGH MON NIGHT AS DEEPER
MOISTURE AND BETTER CVRG OF PRECIP STAYS TO THE W. NUMEROUS SHRA
AND A FEW TSRA WILL DEVELOP TUE/TUE NIGHT WITH PDS OF REDUCED CIGS
AND VSBYS LIKELY. PRECIP WILL GRADUALLY END FROM W TO E WED WITH
CIGS IMPROVING THROUGH THE DAY...HOWEVER A DEVELOPING LOW LEVEL
INVERSION BEHIND THE FRONT MAY MAINTAIN MVFR CIGS INTO WED NIGHT.
VFR CONDITIONS EXPECTED TO DOMINATE THU.
&&
.MARINE...
SHORT TERM /TONIGHT AND MONDAY/...
AS OF 320 PM MONDAY...WILL EXTEND THE SMALL CRAFT ADVISORY FOR
THE CENTRAL WATERS UNTIL 01Z TONIGHT AS SEEING OCCASIONAL 5 TO 6
FOOT SEAS OVER AT THE BUOY 13 MILES EAST OF OREGON INLET.
REMAINDER OF COASTAL WATERS ARE IN THE 3 TO 5 FOOT RANGE...BUT
STILL WITH 12 TO 13 SECOND SWELL PERIODS. LATEST WAVEWATCH SHOWS
COMBINED SEAS SHOULD DROP TO 5 FEET OR LESS LATER TONIGHT THROUGH
MONDAY. WINDS SHOULD CONTINUE FROM THE NE AT 15 KNOTS OR LESS.
LONG TERM /MONDAY EVENING THROUGH THURSDAY/...
AS OF 420 PM SUN...LITTLE CHANGE IN FORECAST REASONING THROUGH THE
LONG TERM. SRLY WINDS GRAD INCREASE MON NIGHT AND ESPCLY TUE AS
COLD FRONT APPROACHES....SPEEDS OF 20 TO 25 KTS LIKELY MOST WTRS
LATER TUE. GUSTY S/SW WINDS WILL CONT TUE NIGHT THEN AS FRONT
CROSSES WILL SEE NRLY WINDS DEVELOP BY LATER WED...POSS GUSTING TO
AROUND 20 KTS. N TO NE WINDS AROUND 15 KTS WED NIGHT WILL SLOWLY
DIMINISH THU. SEAS WILL BE 2 TO 4 FEET MON THEN BUILD TO 5 TO 7
FEET TUE AS WINDS RAMP UP. THE SEAS WILL REMAIN ELEVATED TUE NIGHT
THEN GRAD SUBSIDE WED IN WAKE OF FRONT WITH SEAS DROPPING BELOW 6
FT ALL WTRS BY LATE IN THE DAY. SEAS WILL SUBSIDE TO 2 TO 3 FEET
MOST WTRS THU WITH POSS STILL SOME 4 FOOTERS OUTER CNTRL AND NRN
WTRS.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR NCZ095-
103-104.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR AMZ152-
154.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...SK
AVIATION...CTC/RF/SK
MARINE...CTC/RF/SK
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
324 PM EDT SUN SEP 16 2012
.SYNOPSIS...
HIGH PRESSURE WILL SHIFT OFFSHORE TONIGHT AND MONDAY. A STRONG
COLD FRONT WILL APPROACH THE AREA TUESDAY AND MOVE OFFSHORE
WEDNESDAY...FOLLOWED BY HIGH PRESSURE FOR LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 315 PM SUNDAY...ISENTROPIC LIFT AND A WEAK MID-LEVEL
SHORTWAVE HAS CONSPIRED TO BRING PATCHY LIGHT RAIN OVER MAINLY THE
WEST AND NORTHWEST PORTIONS OF THE CWA TODAY. ANOTHER WEAK
SHORTWAVE EMBEDDED IN THE ZONAL MID-LEVEL FLOW WILL CROSS THE
REGION OVER THE NEXT FEW HOURS AND WILL KEEP CHANCE POPS TO THE
WEST OF HIGHWAY 17 THROUGH THE EVENING HOURS. BOTH THE RAP AND
NAM12 SHOW PRECIPITATION DISSIPATING AROUND DARK WITH MINIMAL
CHANCES OVERNIGHT. SKIES SHOULD BE MOSTLY CLOUDY OVERNIGHT AND
HAVE GONE A LITTLE ABOVE GUIDANCE TEMPS TONIGHT WITH MINS IN THE
LOWER TO MIDDLE 70S WITH UPPER 60S OVER THE OUTER BANKS.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
AS OF 315 PM SUNDAY...WITH THE LOW-LEVEL FLOW VEERING TO MORE
SOUTHEASTERLY ON MONDAY...EXPECT CLOUDY SKIES ACROSS THE REGION.
PER LATEST NAM12/GFS...THINK BULK OF THE PRECIPITATION CHANCES
WILL BE OVER THE FAR WESTERN COUNTIES ONCE AGAIN WITH MOST
ACTIVITY HOLDING OFF UNTIL LATER IN THE DAY. WITH THE CLOUD
COVER...MAXIMUM TEMPERATURES WILL BE FAIRLY UNIFORM ACROSS THE
REGION WITHIN A DEGREE OR TWO OF 80.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
AS OF 220 AM SUNDAY...MADE VERY LITTLE CHANGE TO PREV FCST. HIGH
PRES WILL SLIDE OFFSHORE MON WITH UPR TRF AND ASSOC COLD FRONT
WILL APPROACH FROM THE W TUE. THE FRONT IS EXPECTED TO CROSS THE
REGION WED. STILL LOOKS LIKE BULK OF THE DEEPER MOISTURE WILL
REMAIN TO THE W OF AREA THRU MON NIGHT WITH LITTLE TO NO POP CST
AND CHC DEEP INLAND. AXIS OF DEEPEST MOISTURE WILL CROSS LATER TUE
AND TUE NIGHT JUST AHEAD OF FRONT AND CONT LIKELY POPS THIS TIME.
WL BE WARM AND MODERATELY UNSTABLE TUE INTO TUE NIGHT AND A FEW
STRONG STORMS WILL BE POSS. DRIER AIR WILL SPREAD IN BEHIND THE
FRONT WED WITH PRECIP GRAD ENDING FROM W TO E DURING THE DAY.
MAINLY DRY WEATHER THU AND FRI AS FRONT DRIFTS OFFSHORE AND WEAK
HIGH PRES BUILDS IN FROM THE W. ANOTHER FRONT WILL CROSS LATE SAT
BUT LIMITED MOISTURE AND LOWERED POPS TO SLIGHT CHC FOR SAT. HIGHS
80 TO 85 MON AND TUE THEN UPR 70S TO LOWER 80S REST OF THE PERIOD.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
SHORT TERM /TONIGHT AND MONDAY/...
AS OF 315 PM SUNDAY...ANOTHER TRICKY AVIATION FORECAST OVERNIGHT
TONIGHT. BEST GUESS HERE IS THAT EXTENSIVE CLOUD COVER SHOULD
LIMIT THE FORMATION OF DENSE FOG. NUMERICAL GUIDANCE DOES SHOW
SOME PERIODS OF MVFR STRATUS AND HAVE INCLUDED IN THE TAF BETWEEN
ROUGHLY 08Z AND 13Z. REMAINDER OF TAF CYCLE SHOULD BE IN THE VFR
RANGE.
LONG TERM /MONDAY EVENING THROUGH THURSDAY/...
AS OF 220 AM SUN...MAINLY VFR THROUGH MON NIGHT AS DEEPER MOISTURE
AND BETTER CVRG OF PRECIP STAYS TO THE W. NUMEROUS SHRA AND A FEW
TSRA WILL DEVELOP TUE AND CONT INTO TUE NIGHT WITH PDS OF REDUCED
CIGS AND VSBYS LIKELY. PRECIP WILL END FROM W TO E WED WITH VFR
BECOMING DOMINANT AND THAT SHLD CONT INTO THU AS HIGH PRES BUILDS
IN FROM THE W.
&&
.MARINE...
SHORT TERM /TONIGHT AND MONDAY/...
AS OF 320 PM MONDAY...WILL EXTEND THE SMALL CRAFT ADVISORY FOR
THE CENTRAL WATERS UNTIL 01Z TONIGHT AS SEEING OCCASIONAL 5 TO 6
FOOT SEAS OVER AT THE BUOY 13 MILES EAST OF OREGON INLET.
REMAINDER OF COASTAL WATERS ARE IN THE 3 TO 5 FOOT RANGE...BUT
STILL WITH 12 TO 13 SECOND SWELL PERIODS. LATEST WAVEWATCH SHOWS
COMBINED SEAS SHOULD DROP TO 5 FEET OR LESS LATER TONIGHT THROUGH
MONDAY. WINDS SHOULD CONTINUE FROM THE NE AT 15 KNOTS OR LESS.
LONG TERM /MONDAY EVENING THROUGH THURSDAY/...
AS OF 220 AM SUN...HIGH PRES WILL DRIFT OFFSHORE MON WITH LIGHT E
WINDS BECOME SE 10 TO 15 KTS LATE. SRLY WINDS GRAD INCREASE LATER
MON NIGHT AND ESPCLY TUE AS COLD FRONT APPROACHES....SPEEDS OF 20
TO 25 KTS LIKELY MOST WTRS LATER TUE. GUSTY S/SW WINDS WILL CONT
TUE NIGHT THEN AS FRONT CROSSES WILL SEE NRLY WINDS DEVELOP BY
LATER WED...POSS GUSTING TO AROUND 20 KTS. N TO NE WINDS AROUND 15
KTS WED NIGHT WILL SLOWLY DIMINISH THU. SEAS WILL BE 2 TO 4 FEET
MON THEN BUILD TO 5 TO 7 FEET TUE AS WINDS RAMP UP. THE SEAS WILL
REMAIN ELEVATED TUE NIGHT THEN GRAD SUBSIDE WED IN WAKE OF FRONT
WITH SEAS DROPPING BELOW 6 FT ALL WTRS BY LATE IN THE DAY. SEAS
WILL SUBSIDE TO 2 TO 3 FEET MOST WTRS THU WITH POSS STILL SOME 4
FOOTERS OUTER CNTRL AND NRN WTRS.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR NCZ095-
103-104.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR AMZ152-
154.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...SK
AVIATION...CTC/SK
MARINE...CTC/SK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
100 PM EDT SUN SEP 16 2012
.SYNOPSIS...
A WEAK FRONT STALLED ACROSS THE CAROLINAS WILL WEAKEN TODAY AS IT
LIFTS BACK TO THE NORTH. LOW PRESSURE...DEVELOPING ALONG THE GULF
COAST MONDAY...WILL MOVE THROUGH THE WESTERN CAROLINAS
TUESDAY...BRINGING PERIODS OF SHOWERS AND THUNDERSTORMS TO THE
AREA...WITH LOCALLY HEAVY RAIN POSSIBLE. A COLD FRONT WILL CROSS THE
AREA EARLY WEDNESDAY...WITH HIGH PRESSURE BUILDING IN BEHIND IT
CREATING COOLER AND DRIER WEATHER FOR THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 100 PM SUNDAY...FIRST SHOWERS OF THE DAY HAVE DEVELOPED ACROSS
INLAND HORRY COUNTY AND SHOULD SPREAD NORTH AND WEST AS THE
AFTERNOON WEARS ON. LATEST FEW HRRR RUNS SHOW THE AREA FROM
WHITEVILLE TO THE GREEN SWAMP MAY HAVE AN INCREASING COVERAGE OF
SHOWERS AND POSSIBLE STORMS OVER THE NEXT 4-5 HOURS. PREVIOUS
DISCUSSION FROM 1000 AM FOLLOWS...
THIS IS NOT AN EASY FORECAST FOR THE EASTERN CAROLINAS TODAY. A
DISSIPATING STATIONARY FRONT EXTENDS FROM ABOUT 20 MILES SOUTH OF
BALD HEAD ISLAND...ONSHORE NEAR MYRTLE BEACH...AND THEN NORTHWEST
ACROSS THE EASTERN CAROLINAS IN A VERY NEBULOUS FASHION. BROAD AND
WEAK LOW-LEVEL CONVERGENCE ALONG THIS FEATURE IS PROBABLY NOT ENOUGH
BY ITSELF TO PRODUCE ANY CONVECTION LATER TODAY.
WHAT MAY HELP PRODUCE CONVECTION HOWEVER IS THE PASSAGE OF SEVERAL
WEAK UPPER LEVEL DISTURBANCES ACROSS CENTRAL AND EASTERN NORTH
CAROLINA THROUGHOUT THE DAY. THE FIRST OF THESE IS CURRENTLY
CREATING A LARGE AREA OF MODERATE RAIN AND SHOWERS JUST NORTH AND
EAST OF RALEIGH. A SECOND IS CURRENTLY PRODUCING SHOWER ACTIVITY
JUST NORTH OF CHARLOTTE. WHILE THE LARGEST IMPACT FROM THESE
DISTURBANCES SHOULD REMAIN NORTH OF OUR FORECAST AREA...THE
ASSOCIATED ACCELERATION OF THE 300 MB WIND IN A WEST-TO-EAST
ORIENTED JET STREAK WILL OPEN UP A REGION OF UPPER-LEVEL DIVERGENCE
OVER SOUTHEASTERN NORTH CAROLINA LATER TODAY. THIS IN COMBINATION
WITH LOW-LEVEL CONVERGENCE ALONG SEABREEZE BOUNDARIES AND BUOYANCY
FROM 500-800 J/KG OF SURFACE-BASED CAPE SHOULD PRODUCE SCATTERED
SHOWERS AND PERHAPS ISOLATED T-STORMS THIS AFTERNOON. THE BEST
CHANCES WILL PROBABLY EXTEND FROM THE BENNETTSVILLE-LUMBERTON AREA
SOUTHEAST TOWARD THE POINT OF CAPE FEAR WHERE CONVERGING SEABREEZE
BOUNDARIES OFTEN PRODUCE A LOCAL MAXIMUM IN LOW-LEVEL CONVERGENCE.
IN TERMS OF MODEL PERFORMANCE...THE 06Z NAM CERTAINLY IS
OUTPERFORMING THE 06Z GFS WITH MOISTURE DISTRIBUTION AND THE
POSITION OF THE FRONT. THE NAM`S FORECAST CONCENTRATION OF SHOWERS
MAY BE OVERDONE THIS AFTERNOON ACROSS OUR AREA GIVEN THE GLANCING
BLOW FROM THE TRAIN OF UPPER DISTURBANCES AND OVERALL WEAK
INSTABILITY.
VIRTUALLY NO CHANGES TO HIGH TEMPERATURE FORECASTS HAVE BEEN
MADE...STILL EXPECTING MID 80S IN THE SC PEE DEE REGION WITH LOWER
80S MOST OTHER PLACES.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...STILL A WET PERIOD EXPECTED AS SPLIT FLOW 5H
PHASING OCCURS AND A STORM SYSTEM RIDES UP THE APPALACHIANS.
MONDAY...SOUTHERN STREAM VORT SPINS OUT OF TEXAS AND A SURFACE LOW
DEVELOPS ACROSS THE GULF COAST. AT THE SAME TIME...HIGH PRESSURE
DRIFTS OFF THE MID-ATLANTIC COAST AS A WARM FRONT PUSHES UP THROUGH
THE CAROLINAS. DECENT THETA-E ADVECTION OCCURS BEHIND THE FRONT AS
SOUTHERLY FLOW DEVELOPS THROUGH MUCH OF THE COLUMN. THIS WILL
PROVIDE INCREASING CHANCES FOR SHOWERS ON MONDAY...BUT OTHER THAN
THE FRONT ITSELF...OVERALL FORCING REMAINS DISPLACED WEST OF THE CWA
SO ONLY CHC POP IS WARRANTED THROUGH MUCH OF THE DAY.
MONDAY NIGHT INTO TUESDAY...850MB TRANSPORT WINDS RISE TO NEARLY 50
KTS AS THETA-E RIDGE AXIS MOVES DIRECTLY OVERHEAD. VORT IMPULSES AND
ASSOCIATED PVA STAY JUST WEST OF THE CWA...BUT WE DO ENTER THE
DIFFLUENT REGION OF A 300MB JET...WHICH SHOULD AID LIFT DURING
TUESDAY. ADDITIONALLY...STRONG COLD FRONT WILL RAPIDLY PUSH EAST
TOWARDS THE COAST DURING THE DAY...PROVIDING AN ADDITIONAL FOCUS FOR
SHOWERS/TSTMS. AS NOTED BY PREVIOUS FORECASTER...THIS WILL BE A
RAPIDLY EVOLVING AND MOVING SYSTEM...AND HPC HAS CUT BACK ON OVERALL
QPF NUMBERS FOR THE EVENT...BUT AN AREAL AVERAGE OF AROUND ONE INCH
SEEMS PLAUSIBLE AS ROUNDS OF SHOWERS/TSTMS WILL BE ACCOMPANIED BY
PERIODS OF HEAVY RAINFALL. EVEN WITH VERY STRONG LOW LEVEL WIND
FIELDS...AM NOT ANTICIPATING SEVERE WIND DUE TO LIMITED
INSOLATION/INSTABILITY KEEPING LAPSE RATES QUITE WEAK.
COLD FRONT CROSSES THE AREA AT THE VERY END OF THE PERIOD FROM WEST
TO EAST...CAUSING RAPID DRYING THROUGH THE COLUMN...AND BY WEDNESDAY
MORNING ALL BUT THE IMMEDIATE COAST SHOULD BE DONE WITH THE SHOWERS.
MAX TEMPS THROUGH THE PERIOD WILL BE AROUND CLIMO...WARMER ON MONDAY
SINCE TUESDAY WILL FEATURE WIDESPREAD CLOUD COVER AND SHOWERS. MINS
MONDAY NIGHT WILL REMAIN WELL ABOVE CLIMO...FALLING ONLY TO AROUND
70 MOST SPOTS. TUESDAY NIGHT WILL FEATURE A DECENT TEMP GRADIENT
FROM WEST TO EAST AS COLD FRONT CROSSES THE AREA...LOW 60S WELL NW
TO AROUND 70 NEAR THE COAST.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 3 AM SUNDAY...COLD FRONT WILL BE CROSSING THE AREA AT THE
VERY START OF THE PERIOD...AND BE OFFSHORE NO LATER THAN WEDNESDAY
AFTN. DRY AND COLD ADVECTION OCCUR BEHIND THIS FRONT...AND WEDNESDAY
WILL BE COOL DUE TO NE FLOW DEVELOPING AHEAD OF HIGH PRESSURE
RIDGING DOWN THE COAST...BUT WITH CLEARING SKY CONDITIONS.
THU-SAT LOOK TO BE DRY AS WELL EVEN AS UPPER TROUGHING PERSISTS
ACROSS THE EAST THANKS TO A RELOADING VORT ACROSS THE GREAT LAKES
REGION. SURFACE HIGH PRESSURE WILL RIDGE DOWN THE COAST AND REMAIN
INTO THE WKND...WHILE FORECAST PROFILES SUGGEST A VERY DRY COLUMN
ABOVE 900MB. THIS WILL KEEP SHOWERS TO A MINIMUM...AND WILL CARRY
ONLY SILENT POP EACH DAY. A COLD FRONT WILL APPROACH AT THE VERY END
OF THE PERIOD...BUT APPEARS TO BE MOISTURE STARVED AND MAY JUST
SERVE AS A REINFORCING SHOT OF COOL/DRY AIR SATURDAY NIGHT.
EXPECT TEMPS WEDNESDAY TO BE QUITE COOL...A FEW DEGREES BELOW CLIMO.
OTHERWISE...SEASONABLE TEMPS THROUGH THE EXTENDED.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 18Z...WEAK FRONTAL BOUNDARY DRAPED FROM NEAR MYRTLE BEACH NW
THROUGH LUMBERTON. THE FRONT WILL REFORM ACROSS SOUTH-CENTRAL NORTH
CAROLINA IN THE OVERNIGHT HOURS. MODELS ARE NOT IN GOOD AGREEMENT
WITH RESPECT TO DISTRIBUTION OF SHOWER ACTIVITY OVER THE NEXT 12
HRS...WITH THE NAM MUCH MORE WIDESPREAD WITH PRECIPITATION. THINK
THERE WILL BE ENOUGH LIFT TO SUSTAINED CONVECTION ALONG AND NORTH OF
THE FRONT THIS AFTERNOON. A MID CLOUD CEILING WILL LOWER TO NEAR
MVFR BY EARLY EVENING...WITH PRECIPITATION INDUCED CEILINGS LOWERING
TO AT LEAST 2K FEET THIS EVENING WITH MORE OF A STRATIFORM PRECIP
REGIME. LBT STANDS THE BEST CHANCE FOR IFR CONDITIONS...PERHAPS
SOMETIME AFTER MIDNIGHT. SURFACE WINDS WILL HAVE REMAIN EASTERLY
THROUGH THE FORECAST PERIOD...MORE SOUTHERLY AT THE MYRTLE BEACH
AIRPORTS MONDAY AS THE FRONT WAVES NORTH.
THE EXTENDED OUTLOOK...MOISTURE WILL CONTINUE TO BE ON THE INCREASE
WITH SCATTERED CONVECTION CONTINUING MONDAY NIGHT... BECOMING
NUMEROUS ON TUESDAY WITH MODERATE CONFIDENCE FOR INTERMITTENT IFR
CONDITIONS. CONVECTION WILL CONTINUE INTO WEDNESDAY WITH IMPROVING
CONDITIONS THURSDAY INTO FRIDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 100 PM SUNDAY...NO SIGNIFICANT CHANGES WITH THE EARLY
AFTERNOON UPDATE. PREVIOUS DISCUSSION FROM 1000 AM FOLLOWS...
A DISSIPATING FRONT EXTENDS ACROSS FRYING PAN SHOALS AND ONSHORE
NEAR MYRTLE BEACH. NORTH OF THIS BOUNDARY THERE HAS BEEN A STRONGER
THAN EXPECTED PUSH ON ONSHORE WINDS WITH GUSTS ALONG THE NEW HANOVER
COUNTY BEACHES REGISTERING 15 KNOTS THIS MORNING. AS THIS BOUNDARY
WEAKENS FURTHER TODAY AND AS THE SEABREEZE CIRCULATION DEVELOPS WE
EXPECT WINDS ALL ALONG THE COASTLINE DOWN THROUGH GEORGETOWN TO TURN
EAST-SOUTHEASTERLY AT 10-15 KNOTS.
CONSIDERABLE SWELL ENERGY FROM DISTANT HURRICANE NADINE HAS ARRIVED.
THE FRYING PAN SHOALS BUOY IS REPORTING 5 FOOT SEAS EVERY 14
SECONDS...WITH 3-4 FT SEAS EVERY 15 SECONDS BEING REPORTED FROM THE
NEARSHORE WRIGHTSVILLE BEACH CORMP BUOY. THESE VERY LONG PERIOD
SWELLS OFTEN LOSE A GOOD DEAL OF AMPLITUDE AS THEY APPROACH THE
SHALLOW WATERS WITHIN A FEW MILES OF THE BEACHES...BUT AREA SURF
CAMS ARE STILL SHOWING SOLID 4 FOOT BREAKERS NORTH OF CAPE FEAR.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...SEAS 2-4 FT MONDAY WILL BE MOSTLY SWELL
DOMINATED THANKS TO A GROWING AMPLITUDE 11-13 SEC SE SWELL FROM
DISTANT HURRICANE NADINE AND A WEAK GRADIENT PRODUCING ONLY LIGHT
E/SE WINDS. AS A COLD FRONT APPROACHES FROM THE WEST...WINDS WILL
VEER TO THE SOUTH AND INCREASE QUICKLY MONDAY NIGHT TO 10-15 KTS.
THIS WILL HELP DRIVE WAVE HEIGHTS TO 3-5 FT EVEN AS NADINE`S SWELL
BEGINS TO DECAY. THE HIGHER WAVES AND SHORTER PERIODS MEANS THAT
SEAS MONDAY NIGHT WILL BE SIGNIFICANTLY STEEPER THAN THEY WILL BE
DURING MUCH OF THE DAYLIGHT PERIOD. GRADIENT TIGHTENS EVEN FURTHER
TUESDAY AND WINDS INCREASE TO 15-20 KTS...POSSIBLY 25 KTS NEAR THE
20NM BOUNDARY. THIS FORCES WAVES TO BUILD EVEN HIGHER...BECOMING 4-6
FT...AND AN SCA SEEMS LIKELY MUCH OF TUESDAY FOR AT LEAST THE
NORTHERN COASTAL WATERS. COLD FRONT APPROACHES THE COAST AT THE VERY
END OF THE PERIOD...CAUSING THE WINDS TO VEER TO THE SW AND TO EASE
AGAIN TO 10-15 KTS. SEAS FALL IN TANDEM...BECOMING 2-4 FT.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM SUNDAY...COLD FRONT CROSSES THE WATERS EARLY WEDNESDAY
AND WINDS BECOME N/NW AROUND 10 KTS THROUGH THE DAY. WEAKENING
GRADIENT AND DECAYING SWELL WILL ALLOW SEAS TO FALL TO 2-3 FT...BUT
A CONFUSED SPECTRUM IS LIKELY AS WINDS ROTATE FROM WEST...TO
NORTH...TO NORTHEAST BY THURSDAY MORNING. NE WINDS THURSDAY WILL
INCREASE TO 10-15 KTS AS A WEAK SURGE OCCURS BEHIND THE DEPARTING
COLD FRONT...BUT LITTLE CHANGE IN WAVE HEIGHTS ARE ANTICIPATED SINCE
THE SURGE WILL BE SHORT LIVED.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...43/TRA
AREA FORECAST DISCUSSION
NWS RALEIGH NC
745 AM EDT SUN SEP 16 2012
.SYNOPSIS...
A WEAK FRONT WILL HOLD NEAR THE NORTH CAROLINA AND SOUTH CAROLINA
STATE LINE THROUGH TODAY... AS HIGH PRESSURE NOSES IN FROM THE
NORTH. THE FRONT WILL RETURN AS A WARM FRONT LATE MONDAY INTO
TUESDAY... WITH THE APPROACH OF A STRONG STORM SYSTEM FROM THE
SOUTHWEST.
&&
.NEAR TERM /TODAY THROUGH MONDAY NIGHT/...
AS OF 745 AM SUNDAY...
THROUGH THE MORNING: UPDATE ISSUED EARLIER TO ACCOUNT FOR A FAIRLY
WIDE EXPANSE OF RAIN COVERING MUCH OF THE NORTHERN PIEDMONT. THIS
APPEARS TO BE ASSOCIATED IN PART WITH A SMALL MID LEVEL WAVE
EMBEDDED WITHIN THE BAND OF VORTICITY SHEARING ACROSS WRN AND NRN
NC... CONCURRENT WITH WEAK LOW LEVEL MASS CONVERGENCE AND
CONCENTRATED MOIST UPGLIDE. THE RISK OF SHALLOW BUT SLOW-MOVING AND
POTENTIALLY HEAVY SHOWERS SHOULD PERSIST INTO THE MORNING WITH
LITTLE CHANGE IN THE OVERALL REGIME... AS NOTED BY THE MOST RECENT
SPC WRF-NMM AND SREF RAIN PROBABILITIES. THE EXISTING RAIN AREA WILL
CONTINUE A SLOW DRIFT TO THE ENE... DEPARTING THE AREA BY LATE
MORNING WHICH IS SUPPORTED BY THE HRRR OUTPUT... FOLLOWED BY A BRIEF
LULL IN PRECIP CHANCES. WIDESPREAD CLOUDS ESPECIALLY IN THE NORTH
WILL TEMPER HEATING... SO THE MORNING SHOULD BE COOLER THAN USUAL
WITH ONLY A MINOR RISE THROUGH THE 60S IN MOST AREAS.
EARLIER DISCUSSION FROM 210 AM...
FOR THE REST OF TODAY AND TONIGHT: THE STRONG MID LEVEL LOW NOW OVER
WEST TX AND ASSOCIATED POSITIVELY TILTED TROUGH THROUGH THE MID MISS
VALLEY WILL EASE EASTWARD OVER THE NEXT COUPLE OF DAYS... AS
NORTHERN STREAM TROUGHING DIGS STRONGLY INTO THE UPPER MIDWEST. A
DIFFUSE SURFACE FRONTAL ZONE CURRENTLY SITS ALONG THE NC/SC STATE
LINE EXTENDING BACK THROUGH WRN NC... BENEATH A BAND OF SHEARED
VORTICITY IN THE MID LEVELS... WHILE THE SURFACE HIGH CENTERED NEAR
THE OH/PA BORDER NOSES SOUTHWARD INTO NC. AS THE SURFACE HIGH SHIFTS
OFF THE VA COAST THIS AFTERNOON... THE COMBINATION OF LOW LEVEL
RETURN FLOW FROM THE SE... THE NORTHEAST-RETREATING FRONTAL ZONE...
THE STEADILY RISING PRECIP WATER TO 150-175% OF NORMAL... INCREASING
LOW LEVEL MOISTURE TRANSPORT... AND THE NNE-MOVING BAND OF MID LEVEL
VORTICITY SHOULD ALL SUPPORT INCREASING CHANCES FOR SHOWERS AND
STORMS MAINLY IN THE WRN HALF AND SRN PORTIONS OF THE CWA TODAY...
DECREASING A BIT IN COVERAGE BUT SPREADING EASTWARD TONIGHT.
INSTABILITY SHOULD REMAIN MARGINAL WITH 400-800 J/KG OF MLCAPE IN
THE SRN/WRN PART OF THE FORECAST AREA THIS AFTERNOON... BUT DEEP
LAYER SHEAR OF 30-35 KTS SHOULD ALLOW FOR SUSTAINED CONVECTION
FOCUSED ALONG THE FRONTAL ZONE. THE PRIMARY THREAT WILL BE FROM
LOCALLY HEAVY RAINFALL TOTALS GIVEN THE WEAK WINDS THROUGH THE
LOWEST 3 KM. MAX TEMPS TODAY ARE TRICKY DUE TO THE WIDE VARIATION
THIS MORNING... RANGING FROM MID 50S IN THE NORTHWEST BENEATH THE
COOLER SURFACE RIDGE WITH VERY FEW CLOUDS... TO AROUND 70 IN PARTS
OF THE SANDHILLS AND TRIAD AREA BENEATH THICK CLOUDS. THE COOLEST
MAXES TODAY SHOULD OCCUR FROM THE TRIAD TO THE NORTHEAST WHERE THE
MOIST UPGLIDE UP AND OVER THE FRONTAL ZONE SHOULD INDUCE THICK CLOUD
COVER AND A FEW SHOWERS FALLING INTO THE RETREATING COOLER AIR MASS.
HIGHS 72-74 NW TO 83 IN THE SE. THE MOIST UPGLIDE DEEPENS TO
290K-310K AND EXPANDS EASTWARD TONIGHT ACROSS THE REMAINDER OF
CENTRAL NC... PARTICULARLY THE NORTH. WE RETAIN A FEW HUNDRED J/KG
OF MLCAPE OVERNIGHT ACCORDING TO THE NAM/ECMWF... AND WITH DEEP
LAYER SHEAR HOLDING AT 30-35 KTS... ISOLATED STORMS REMAIN POSSIBLE
OVERNIGHT. WILL HOLD ONTO SCATTERED SHOWERS AND A FEW STORMS THROUGH
THE NIGHT... WITH THE BEST COVERAGE ACROSS THE NORTH AND WEST.
MODELS DO INDICATE A VORTICITY MAXIMUM EXITING INTO SE VA LATE AT
NIGHT... AND WITH THE LACK OF OTHER UPPER FORCING INCLUDING AN
IDEALLY-LOCATED JETLET TO OUR NORTH OR NE... WE MAY SEE A LULL IN
ACTIVITY OVERNIGHT WITH JUST PATCHY SHOWERS. LOWS 60-66.
FOR MONDAY/MONDAY NIGHT: RAIN CHANCES OVER THE WRN CWA SHOULD RAMP
UPWARD QUICKLY HEADING INTO MONDAY NIGHT. THE SURFACE HIGH SHIFTS
FURTHER OFFSHORE LEADING TO A RAPIDLY STRENGTHENING SOUTHERLY LOW
LEVEL FLOW OF MOIST GULF AND ATLANTIC AIR INTO NC. THE SOUTHERN
STREAM WAVE OVER EAST TN EARLY MONDAY DAMPENS AS IT HEADS EAST
THROUGH THE LOWER MISS VALLEY... OVERTAKEN BY THE STRENGTHENING
NORTHERN STREAM LONGWAVE TROUGH DIGGING THROUGH THE UPPER MIDWEST
AND WRN GREAT LAKES. FORCING FOR ASCENT AT ALL LEVELS BEGINS TO
INTENSIFY ESPECIALLY OVER WRN NC. THE STRENGTHENING SWRLY UPPER JET
CORE OVER MI/ONTARIO WILL INDUCE BROAD STRONG UPPER DIVERGENCE FROM
THE OHIO VALLEY THROUGH THE MID SOUTH TO THE GULF COAST INCLUDING
WRN NC... AND AS THE 40-50 KT LOW LEVEL JET BECOMES MORE DEFINED
OVER WRN NC... LOW LEVEL MASS CONVERGENCE ACTING ON PRECIP WATER
VALUES APPROACHING 2.0 INCHES SHOULD SUPPORT NUMEROUS TO WIDESPREAD
SHOWERS AND STORMS. INSTABILITY WANES A BIT WITH LOSS OF DAYTIME
HEATING MONDAY EVENING BUT IS EXPECTED TO RISE ANEW IN THE WRN/SW
CWA TO NEAR 500 J/KG (MLCAPE) MONDAY NIGHT WITH ABUNDANT LOWER
TROPOSPHERIC WARM AIR ADVECTION. MAIN CHANGE TO EARLIER FORECAST
PRECIP CHANCES WILL BE TO REDUCE OVERALL PRECIP CHANCES IN THE EAST
AS THE BULK OF THE FORCING AND MOISTURE TRANSPORT WILL BE FOCUSED
OVER WRN NC. WILL INDICATE A SLOW INCREASE IN POPS FROM CHANCE WEST
/ SLIGHT CHANCE OR NO POP EAST MONDAY MORNING... TRENDING UPWARD TO
LIKELY THEN CATEGORICAL POPS IN THE FAR WRN CWA MONDAY AFTERNOON
THROUGH NIGHT... WHILE KEEPING JUST A LOW CHANCE IN THE FAR EAST
AWAY FROM THE LIFT SOURCES. TRAINING STORMS WILL YIELD A FLOODING
THREAT IN THE FAR WRN PIEDMONT BACK TOWARD THE MOUNTAINS...
INCLUDING THE TRIAD AND ALBEMARLE/WADESBORO REGIONS... LATE MONDAY
THROUGH MONDAY NIGHT. HIGHS 76-83... WARMEST EAST. VERY MILD LOWS OF
65-70. -GIH
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS OF 315 AM SUNDAY...
A SHORTWAVE TROUGH IS EXPECTED TO DEAMPLIFY AND LIFT NORTHEAST ALONG
THE APPALACHIANS MONDAY NIGHT THROUGH TUESDAY NIGHT AHEAD OF A
NORTHERN STREAM SYSTEM FORECAST TO DIG INTO THE MIDWEST STATES. DUE
TO CONVECTIVE FEEDBACK ISSUES...THE GFS IS MOSTLY DISCOUNTED AT THIS
TIME AND THE CURRENT FORECAST WILL RELY ON THE SLOWER ECMWF AND NAM
SOLUTIONS.
THE SURFACE COLD FRONT ASSOCIATED WITH THE NORTHERN
STREAM TROUGH IS FORECAST TO STRETCH FROM NEAR TOLEDO TO NASHVILLE
AT 12Z TUESDAY MORNING. THE STRONGEST SYNOPTIC SCALE LIFT WILL BE
OVER WESTERN NC EARLY TUESDAY MORNING...WHERE BACK LOW LEVEL UPSLOPE
FLOW AND A 40KT LOW LEVEL JET WILL BE COUPLED WITH STRENGTHENING
UPPER LEVEL DIVERGENCE IN THE RIGHT ENTRANCE REGION OF AN JET OVER
THE GREAT LAKES. THUS..WIDESPREAD SHOWERS ARE EXPECTED OVER THE
FOOTHILLS AND WESTERN PIEDMONT...WITH ONLY ISOLATED TO SCATTERED
SHOWERS FURTHER EAST OVER CENTRAL NC. PRECIP IS EXPECTED TO SPREAD
EAST DURING THE DAY AS THE LOW LEVEL JET SHIFTS EASTWARD AND STRONG
WARM SECTOR THETA E ADVECTION SURGES ACROSS THE CWA. THE CURRENT
POP FORECAST OF 80-80 PERCENT IN THE WEST EARLY AND 70-80 PERCENT
OVER THE EAST DURING THE AFTERNOON LOOKS GOOD AND NO SIGNIFICANT
CHANGES WILL BE MADE. HIGHS TUESDAY SHOULD RANGE FROM THE MID 70S
WEST TO LOWER 80S IN THE EAST....THOUGH CONFIDENCE SOMEWHAT LOW DUE
TO THE POTENTIAL DIABATIC IMPACTS FROM CLOUD COVER AND PRECIP
WHILE UNCERTAINTY REMAINS REGARDING THE SEVERE THREAT TUESDAY...THE
SLOWING TREND IN THE MODELS SUPPORTS A MORE FAVORABLE DIURNAL
TIMING...ESPECIALLY FOR PREFRONTAL CONVECTION. STRENGTHENING DEEP
LAYER SHEAR ASSOCIATED WITH 60-90M HEIGHT FALLS OVER THE OHIO VALLEY
REGION AND A 40-50KT LOW LEVEL JET WILL SUPPORT SUPERCELLAR ACTIVITY
WHERE SUFFICIENT INSTABILITY CAN DEVELOP. LOW LEVEL SHEAR WILL
STRONG...WITH MODELS SHOWING LONG AND CURVED HODOGRAPHS AND 0-1KM
BULK SHEAR IN EXCESS OF 20-25KT. WHILE INSTABILITY REMAINS
QUESTIONABLE...NEARLY ALL MODELS SHOW DEWPOINTS CLIMBING INTO
THE UPPER 60S TO AROUND 70S IN THE SOUTHEAST...AND WARM/THETA E
ADVECTION WILL HELP TO OVERCOME WIDESPREAD CLOUD COVER AND WEAK MID
LEVEL LAPSE RATES. SREF PLUMES POINT TOWARD 500-1000 J/KG OF SBCAPE
ACROSS CENTRAL NC....WHICH COULD BE GREATER IF BREAKS IN CLOUD COVER
DEVELOP. OUTSIDE OF WARM ADVECTION AND/OR A WEAK DISTURBANCE IN THE
SOUTHWESTERLY FLOW ALOFT...THERE IS ALSO SOME UNCERTAINTY REGARDING
THE EXTENT OF PREFRONTAL FORCING...AND THUS THE COVERAGE AND TIMING
OF PREFRONTAL CONVECTION. HOWEVER...SEVERE WIND/TORNADO THREAT
STILL REMAINS A CONCERN MAY DEVELOP BASED ON THE ABOVE KINEMATICS
AND INSTABILITY.
STRONGER DEEP LAYER FORCING IS EXPECTED TO REACH THE WESTERN CWA BY
00Z TUESDAY AFTERNOON/EVENING AS THE THE COLD FRONT AND MID LEVEL
TROUGH AXIS CROSS THE MOUNTAINS. THIS WILL PUSH THE REMAINING
SHOWERS/STORMS EASTWARD ACROSS THE AREA...WITH MODELS SHOWING PRECIP
EXITING THE EASTERN CWA BY 09-12Z. WHILE MODELS HAVE SHOWN SIGNS OF
A WEAK LOW DEVELOPING ALONG THE FRONT...THE THREAT OF SEVERE WEATHER
SHOULD BECOME MORE OF A STRAIGHT LINE WIND THREAT AS WIND PROFILES
BECOME INCREASINGLY UNIDIRECTIONAL TUESDAY EVENING. LOWS
TUESDAY NIGHT WILL DEPEND ON THE TIMING OF THE FRONT AND QUICKLY
PRECIP COMES TO AN END...BUT GUIDANCE MOSTLY AGREES ON MID 50S WEST
TO MID 60S EAST.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 315 AM SUNDAY...
QUIETER WEATHER IS EXPECTED WEDNESDAY THROUGH THE END OF THE WEEK.
THE MEAN UPPER LEVEL TROUGH AXIS IS FORECAST TO LAG BACK TO THE WEST
FROM THE MIDWEST TO THE DEEP SOUTH...BUT MORE STABLE AIR AND HIGH
PRESSURE WILL BUILD ACROSS TN VALLEY AND INTO CENTRAL NC IN THE WAKE
OF THE STORM SYSTEM DEPARTING THE REGION WEDNESDAY MORNING. MODELS
HAVE BEEN SHOWING A SLOWING TREND WITH THE FRONTAL PASSAGE TUESDAY
NIGHT INTO WEDNESDAY...SO IT IS POSSIBLE THAT FRONT MAY STALL NEAR
OR JUST OFFSHORE. LOW LEVEL THICKNESSES ARE FORECAST TO DIP INTO
THE 1360S...KEEPING HIGHS WEDNESDAY AND THURSDAY ABOUT A CATEGORY
BELOW NORMAL...73-78. A SLOW MODERATION IS THEN EXPECTED FOR THE
REMAINDER OF THE WEEK HIGHS CLIMBING BACK TOWARD THE UPPER 70S AND
LOWER 80S. A SHORTWAVE IS FORECAST TO SWING ACROSS THE NORTHERN US
AND GREAT LAKES REGION OVER THE WEEKEND...WHICH MAY SEND ANOTHER
COLD FRONT ACROSS THE MIDWEST STATES AND TOWARD THE APPALACHIANS.
HOWEVER.. THERE IS ENOUGH DISAGREEMENT IN THE MEDIUM RANGE MODELS TO
NOT SHOW ANY SENSIBLE IMPACTS IN THE FORECAST.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 745 AM SUNDAY...
VFR CIGS/VSBYS WILL DOMINATE OVER MUCH OF CENTRAL NC THROUGH THE
DAYLIGHT HOURS... BUT A MAJOR EXCEPTION TO THIS IS THE MVFR FOG AND
MVFR-IFR CIGS AT KINT/KGSO THIS MORNING. A WEAK FRONTAL ZONE
EXTENDING ACROSS WRN AND SRN NC EARLY THIS MORNING WILL SLOWLY SHIFT
TO THE NNE TODAY INTO TONIGHT... AS INCREASING SOUTHWESTERLY FLOW
JUST ABOVE THE GROUND PUMPS INCREASING MOISTURE INTO THE REGION.
CLOUDS WILL CONTINUE TO SLOWLY THICKEN WITH LOWERING BASES AT
KRDU/KFAY/KRWI THROUGH THIS AFTERNOON AND NIGHT. AT KINT/KGSO...
AFFECTED THROUGH MUCH OF THE PREDAWN HOURS BY RAIN... WILL SEE THE
MVFR TO IFR CIGS HOLD FOR MUCH OF THE MORNING BEFORE LIFTING TO VFR
BY EARLY AFTERNOON... BY 17-19Z. CIGS ARE LIKELY TO GRADUALLY DROP
TO MVFR LATE THIS AFTERNOON THROUGH THE EVENING... AS PATCHY RAIN
MOVES INTO THE REGION. EXPECT CIGS/VSBYS TO DROP TO MVFR AND
POTENTIALLY IFR AFTER 06Z TONIGHT.
LOOKING BEYOND 12Z MONDAY MORNING... MVFR CIGS NEAR DAYBREAK SHOULD
LIFT TO VFR BY MIDDAY MONDAY. CIGS WILL ONCE AGAIN SLOWLY LOWER TO
MVFR FROM WEST TO EAST LATE MONDAY ONWARD AS A POWERFUL STORM SYSTEM
-- A DEEPENING MID LEVEL TROUGH OVER THE MISS VALLEY AND
ACCOMPANYING STRONG COLD FRONT -- APPROACHES NC FROM THE WEST. THE
RISK OF ADVERSE AVIATION CONDITIONS WILL BE GREATEST STARTING MONDAY
EVENING WITH LOWERING CIGS/VSBYS AND WIDESPREAD SHOWERS AND STORMS
OVERSPREADING THE AREA. LOW LEVEL WIND SHEAR IS POSSIBLE ESPECIALLY
MONDAY NIGHT INTO TUESDAY WHEN WINDS WILL INCREASE TO 35-50 KTS FROM
THE SSW THROUGH THE LOWEST 10 THOUSAND FT AGL. AVIATION CONDITIONS
WILL IMPROVE WEDNESDAY AS THE COLD FRONT SWEEPS THROUGH. GENERALLY
VFR CONDITIONS ARE EXPECTED LATE WEDNESDAY TO THURSDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS GRAY ME
355 AM EDT TUE SEP 18 2012
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO MOVE EAST INTO THE ATLANTIC TODAY.
MEANWHILE LOW PRESSURE WILL TRACK NORTHWARD THROUGH UPSTATE NEW
YORK TODAY WITH A STRONG COLD FRONT PUSHING ACROSS NEW HAMPSHIRE
AND MAINE TONIGHT. HEAVY RAIN AND GUSTY WINDS ARE EXPECTED AS IT
MOVES THROUGH. HIGH PRESSURE WILL BUILD IN WEDNESDAY THROUGH
FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AFTER SOME FILTERED SUNSHINE EARLY THIS MORNING...WINDS WILL GRADUALLY
INCREASE TODAY WELL AHEAD OF FAST MOVING SYSTEM THAT HAS EXITED
THE GULF OF MEXICO DURING THE OVERNIGHT HOURS. MOST OF THE
RAINFALL WILL BE CONFINED TO NH...WITH POPS INCREASING LATER IN
THE DAY. THE LATEST HRRR MODEL RUN DOES HAVE SHOWER ACTIVITY
REACHING WRN ME SHORTLY AFTER 18Z.
USED A BLEND OF MAV/MET MOS FOR DAYTIME MAXES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
VERY LITTLE IN THE WAY TO THE FCST PHILOSOPHY FOR TONIGHTS FCST.
THE 00Z MODEL SUITE CONTINUES TO DEPICT LOW PRESSURE DEEPENING
THIS AFTERNOON AND EVENING...AND PASSING WELL WEST OF OUR REGION.
A STRONG SOUTHERLY GRADIENT WILL CROSS THE REGION AHEAD OF THIS
SYSTEM WITH WINDS 50-60 KT AT 925 MB. PREFFERRED THE STRONG GFS
WIND FIELDS FOR THIS RUN. THIS MODEL ALLOWS FOR THE MIXING OF WIND
GUSTS LOCALLY OVER 45 MPH ALONG THE SHORELINE AND ACROSS THE SOUTH
FACING HILLTOPS. WITH LEAVES STILL ON THE TREES...THIS WILL ALLOW
FOR DOWNED TREE LIMBS AND SOME POWER OUTAGES.
QPF IS EXPECTED TO BE IN THE 1 TO 3 INCH RAIN...WHICH OUR RIVERS
SHOULD BE ABLE TO EASILY HANDLE. DRY ANTECEDENT CONDS HAVE BEEN IN
PLACE OVER THE REGION. THE HIGHEST RAINFALL TOTALS WILL BE IN
UPSLOPE LOCATIONS OVER THE MTNS IN NRN NH. HAVE KEPT THE SLGT CHC
FOR A TSTM TO CROSS THE REGION OVERNIGHT AS WELL.
WINDS WILL DIMINISH TOWARDS MORNING FROM WEST TO EAST AS THE FRONT
CROSSES THE REGION. SLIGHTLY DRIER AIR WILL ENTER THE REGION DURG
THE DAY WEDNESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
HIGH PRES WILL BE CENTERED OVER NORTHERN NEW ENGLAND WEDNESDAY
NIGHT THROUGH THURSDAY AND THEN WILL BEGIN MOVING NORTHEAST INTO
THE MARITIMES ON FRIDAY. THIS WILL ALLOW VERY COOL TEMPERATURES
WEDNESDAY AND THURSDAY NIGHTS DUE TO RADIATIONAL COOLING WITH THE
CLEAR SKIES AND CALM WINDS. TEMPERATURES WILL DROP INTO THE UPPER 20S
AND LOWER 30S ACROSS THE MOUNTAINS AND FOOTHILLS...WHERE SOME
SITES WILL DROP BELOW FREEZING FOR THE SECOND TIME AFTER LAST
NIGHT. FOR SOME AREAS THIS WILL BE THE FIRST FREEZE. AREAS OF
FROST AND FOG ARE LIKELY ACROSS THE FOOTHILLS AS WELL. MOST OTHER
INLAND AREAS WILL DROP INTO THE MID TO UPPER 30S. A COOL SUNNY DAY
WILL BE EXPECTED THURSDAY WITH MORE CLOUDS AND MAYBE EVEN A FEW
SHWRS PSBL FRIDAY AS WE REMAIN WEDGED BETWEEN THE OFFSHORE SYSTEM
AND THE ONE DEVELOPING TO OUR W. ON SATURDAY A TROF WITH AN
ASSOCIATED COLD FRONT APPROACHES THE REGION AND MOVES THROUGH THE
REGION BY LATE SUNDAY WITH SCT SHWRS. DRY CONDITIONS AND HIGH
PRESSURE RETURN FOR THE EARLY PART OF NEXT WEEK.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
SHORT TERM...VFR THIS MORNING...EXCEPT FOR FOG IN THE CONNECTICUT
RIVER VALLEY AT LEBANON AND WHITEFIELD TONIGHT. EXPECT
DETERIORATING CONDITIONS BEGINNING LATE THIS MORNING OVER NEW
HAMPSHIRE WITH CONDITIONS BECOMING MVFR THROUGH THE DAY IN
SHOWERS. IFR AND LIFR CONDS EXPECTED TONIGHT...BEFORE A GRADUAL
IMPROVEMENT IN CIGS/VSBYS FROM WEST TO EAST WED MRNG.
LONG TERM...PREVAILING VFR CONDITIONS THRU EARLY FRI WITH CONDS
BECOMING MVFR IN ANY SCT SHWRS OVER THE WEEKEND.
&&
.MARINE...
SHORT TERM...A STRONG SOUTHERLY FLOW WILL DEVELOP AHEAD OF A COLD
FRONT TONIGHT. A LOW LEVEL JET JUST ABOVE THE SURFACE WILL ALLOW
FOR STRONG WIND GUSTS OVER THE WATERS OVERNIGHT AND EARLY WEDNESDAY MORNING.
A GALE WARNING HAS BEEN ISSUED FOR WINDS UP TO 45 KT.
LONG TERM...WINDS AND WAVES WILL DIMINISH QUICKLY BY WEDNESDAY
NIGHT BUT WILL REQUIRE A SMALL CRAFT ADVISORY FOR A FEW HOURS ONCE
THE ABOVE WARNINGS HAVE EXPIRED. WINDS AND SEAS WILL REMAIN BLO
SCA CRIT FOR THURS AND INTO THE WEEKEND.
&&
.SPLASH-OVER AND SOME BEACH EROSION...MAY NEED TO ISSUE A
STATEMENT FOR LCL SPLASH-OVER AND BEACH EROSION FOR THE TIME OF
HIGH TIDE TONIGHT. ESTOFS EXPERIMENTAL RUNS CONT TO SHOW A 2+ FOOT
STORM SURGE OVER MUCH OF THE PENOBSCOT BAY REGION. THE HIGH
ASTRONOMICAL TIDES...STORM SURGE AND BUILDING SEAS MAY LEAD TO THE
SPLASH-OVER SHORTLY AFTER MIDNIGHT TONIGHT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WIND ADVISORY FROM 6 PM THIS EVENING TO 6 AM EDT WEDNESDAY FOR
MEZ007>009-012>014-018>028.
NH...WIND ADVISORY FROM 6 PM THIS EVENING TO 6 AM EDT WEDNESDAY FOR
NHZ001>010-013-014.
MARINE...GALE WARNING FROM 6 PM THIS EVENING TO 9 AM EDT WEDNESDAY FOR
ANZ150>154.
&&
$$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
341 AM EDT TUE SEP 18 2012
.SHORT TERM...TODAY AND TONIGHT
A COLD FRONT CONTINUES TO MAKE STEADY PROGRESS EASTWARD THROUGH THE
CENTRAL GREAT LAKES REGION. SURFACE OBSERVATIONS SHOW THIS COLD
FRONT EXTENDING FROM THE SAGINAW VALLEY SOUTHWARD TO JACKSON
MICHIGAN AS OF 07Z. THE 3KM HRRR MODEL SHOWS THIS FRONT CLEARING THE
CWA AROUND 10Z WITH COOLER DRIER AIR FILTERING IN FROM THE NORTHWEST
BEHIND THE FRONT. THE LATE PUSH OF COLD AIR WILL MEAN HIGH
TEMPERATURES WILL LIKELY OCCUR EARLY THIS MORNING...WITH FALLING
MORNING TEMPERATURES AND A MODEST REBOUND DURING THE AFTERNOON
HOURS. MOST LOCATIONS WILL SEE TEMPERATURES STAYING WITHIN A NARROW
RANGE DURING THE DAYTIME HOURS AS COLD AIR ADVECTION FIGHTS THE
NORMAL BOUNCE AFFORDED BY DIURNAL HEATING. UPSTREAM OBSERVATIONS
SHOW THE LIGHTNING ACTIVITY PREVIOUSLY ASSOCIATED WITH THE SHOWERS
BEHIND THE FRONT HAS DISAPPEARED...WITH NOT MUCH IN THE WAY OF
ELEVATED CAPE OVER SOUTHEAST MICHIGAN WILL REMOVE THE REMAINING
THUNDER PREVIOUSLY ASSOCIATED WITH THIS ACTIVITY.
WINDS WILL TURN NORTHWESTERLY AND BE QUITE GUSTY BEHIND THE FRONT
WITH GUSTS TO 30 MPH. TOOK DOWN PRECIPITATION CHANCES ACROSS THE
EASTERN CWA DURING THE MORNING HOURS AS HIGH QPF AMOUNTS SHOWN BY
THE NWP MODELS IS NOT SUPPORTED BY UPSTREAM OBSERVATIONS WITH
RAPIDLY FALLING DEW POINTS INTO THE 40S BEHIND THE FRONT AND
REGIONAL RADAR REFLECTIVITY SEVERELY LACKING IN COVERAGE ACROSS THE
CENTRAL GREAT LAKES. THE BEST MOISTURE AND RAIN COVERAGE IS
CURRENTLY OVER THE OHIO VALLEY SHOULD STAY THERE DESPITE THE HEALTHY
VORT MAX OVER THE UPPER MISSISSIPPI VALLEY FORECAST TO TRACK THROUGH
THE CENTRAL GREAT LAKES DURING THE DAYTIME HOURS. WATER VAPOR
IMAGERY SHOWS A LOT OF DRY AIR EMBEDDED WITH THIS SHORTWAVE WITH THE
BEST MOISTURE BEING SCOURED OUT BY THE COLD FRONT CURRENTLY TRACKING
THROUGH THE CENTRAL GREAT LAKES. WHILE THE SHORTWAVE WILL PRODUCE
SOME SHOWER ACTIVITY...IT IS WORTHY OF A CHANCY MENTION INSTEAD OF
LIKELY POPS GIVEN THE LACK OF MOISTURE AND FAILURE OF THE SHORTWAVE
TO TRACK THROUGH WHEN WE STILL HAVE DECENT MOISTURE ACROSS THE
REGION.
SKIES WILL CLEAR OUT TONIGHT AS THIS SHORTWAVE TRACKS EAST AND
RIDGING MAKES ITS WAY THROUGH THE CENTRAL GREAT LAKES. THE ABUNDANT
RADIATIONAL COOLING AND VERY COLD TEMPERATURES IN PLACE OVER THE
CENTRAL GREAT LAKES WILL ALLOW OVERNIGHT TEMPERATURES TO TUMBLE INTO
THE UPPER 30S AND LOWER 40S. WHILE SOME LOCATIONS WILL FALL INTO THE
MIDDLE 30S...WINDS SHOULD STAY UP ENOUGH WITH THE PRESSURE GRADIENT
TO PREVENT MUCH IN THE WAY OF FROST FROM FORMING.
&&
.LONG TERM...WEDNESDAY THROUGH MONDAY
THE STRENGTH OF THE UPPER LEVEL LOW HEIGHT/POTENTIAL VORTICITY
ANOMALIES...BOTH TO THE EAST AND WEST OF LOWER MICHIGAN...MEANS THE
AREA WILL BE POSITIONED WITHIN A WEAKNESS OR COL OF THE MEAN UPPER
LEVEL TROUGH ON WEDNESDAY. WITH NO ALTERNATIVE...SOUTHEASTERN
MICHIGAN WILL FEEL THE EFFECTS OF A COLUMN THAT HAD BEEN HEAVILY
MODULATED BY SUBSIDENCE. ORIENTATION OF THE UPSTREAM UPPER LEVEL JET
AXIS ALONG WITH STRONG UPPER LEVEL WIND MAGNITUDES SUGGESTS THE NEXT
UPPER LEVEL SYSTEM WILL BE AT THE DOORSTEP OF THE AREA AT 00Z
THURSDAY. MODEL SOUNDINGS DO SHOW SOME FAIRLY STEEP 700-500MB LAPSE
RATES ARRIVING OVER THE TRI CITIES IN THE 22-01Z TIMEFRAME.
HOWEVER...LACK OF MODELED UVV IN THAT SLAB ALONG WITH UNSATURATED
CONDITIONS IN THE LOWEST 7500 FT PRECLUDES ANY INTRODUCTION OF POPS.
CLOUDS WILL BE ABSENT A BETTER PART OF THE DAY BEFORE INCREASING
VERY LATE. HIGHS WEDNESDAY ARE EXPECTED TO RISE COMFORTABLY IN THE
MIDDLE 60S.
THE AFOREMENTIONED ORIENTATION OF THE UPPER LEVEL JET AXIS ALONG
WITH THE VERY FAVORABLE BULLWHIP PATTERN(18Z WED-00Z THUR) ARE BIG
INDICATORS THE WEDNESDAY NIGHT/THURSDAY SYSTEM WILL HAVE A GREAT DEAL
OF DYNAMICS. THE LEFT EXIT CURL ALONG WITH SHARP NOSE OF THE LOW TO
MIDLEVEL THETA E RIDGE SUGGESTS THE BEST FORCING/SURFACE LOW WILL
LIFT NORTHEASTWARD FROM WESTERN WISCONSIN 00Z-THURSDAY TO A HUNDRED
MILES OR SO NORTH OF LAKE HURON BY 12Z-THURSDAY. PLAN VIEW
DEPICTIONS OF A NUMBER OF PARAMETERS ALL POINT TO A RATHER SHARP
LOWER TROPOSPHERIC FRONT WHISTLING THROUGH. SYSTEM RELATIVE
ISENTROPIC ASCENT AND FRONTOGENESIS ARE NOT AS STRONG AS ONE WOULD
LIKE TO SEE...BUT DEPTH OF DEFORMATION AND CONVERGENCE ARE GOOD FOR
MID TO HIGH CHANCE POPS IN MANY AREAS. THE FRONT BECOMES RATHER
SLUGGISH AND LINGERS THROUGHOUT THE MORNING ON THURSDAY. WILL CARRY
A LOW BLANKET POP WEDNESDAY NIGHT FOR THE DETROIT AREAS...BUT ONE
CAN GET THE SENSE THAT DETROIT MAY BE PRECIPITATION FREE UNTIL THE
14-18Z TIMEFRAME AS THINNING 700MB THETA E AXIS EVENTUALLY SLIDES IN
OVERHEAD. FELT COMFORTABLE GOING WITH A WARMER END BLEND FOR HIGHS
ON THURSDAY...UPPER 60S TO AROUND 70 DEGREES. ANOTHER ROUND OF
REMNANT SUBSIDENCE IS SHOWN TO SPREAD ACROSS THE AREA THURSDAY
AFTERNOON...KEEPING CONDITIONS DRY FOR THURSDAY NIGHT.
&&
.MARINE...
A STRONG COLD FRONT WILL SHIFT WINDS TO THE NORTHWEST AS WIND SPEEDS
INCREASE TO 25 TO 30 KNOTS ACROSS MUCH OF LAKE HURON AND 20 TO 25
KNOTS ELSEWHERE. SIGNIFICANT WAVE HEIGHTS WILL INCREASE ACCORDINGLY
TODAY FEATURING SEVERAL HOURS OF 6 TO 9 FOOT WAVES OVER THE OPEN
WATERS OF SOUTHERN LAKE HURON AND 5 TO 7 FEET FROM OUTER SAGINAW BAY
TO PORT HURON. SMALL CRAFT ADVISORIES HAVE THEREFORE BEEN ISSUED FOR
ALL OF THE NEARSHORE ZONES. WINDS COULD BRIEFLY APPROACH GALE
CONDITIONS TODAY ACROSS SOUTHERN LAKE HURON...HOWEVER THE TIME
WINDOW APPEARS TOO BRIEF AND MARGINAL TO ISSUE GALE WARNINGS AT THIS
TIME. WINDS WILL SLOWLY SUBSIDE TONIGHT AND WEDNESDAY...WITH SMALL
CRAFT ADVISORIES BEING DROPPED TONIGHT THROUGH WEDNESDAY MORNING AS
WINDS AND WAVES SLOWLY SUBSIDE. THE PATTERN WILL REMAIN ACTIVE WITH
SEVERAL EPISODES OF GUSTY NORTHWEST FLOW AND ELEVATED WAVE
CONDITIONS LIKELY THROUGH THE FORECAST PERIOD.
&&
.AVIATION...ISSUED 1153 PM EDT MON SEP 17 2012
//DISCUSSION...
THE COLD FRONT NOW OVER THE SAGINAW AREA WILL PUSH EAST OF METRO
DETROIT BY 12Z. WHILE LINGERING INSTABILITY COULD CERTAINLY TOUCH
OFF SOME ADDITIONAL THUNDERSTORMS ALONG THE FRONT EARLY THIS
MORNING...CONFIDENCE REMAINS TOO LOW TO INCLUDE IN THE TERMINAL
FCSTS ATTM. SFC DEWPOINTS HAVE BEEN SLOWLY INCHING UPWARDS THIS
EVENING. THE ADVECTION OF THIS HIGHER MOISTURE COMBINED WITH SHALLOW
POST FRONTAL COLD AIR ADVECTION WILL SET THE STAGE FOR STRATUS
DEVELOPMENT EARLY THIS MORNING...BASES OF WHICH MAY FALL TO IFR. AS
THE DEPTH OF COLD AIR INCREASES ON TUESDAY...THERE WILL BE A SLOW
YET STEADY RISE IN CEILING HEIGHTS DURING THE COURSE OF THE DAY.
FOR DTW...A LITTLE BETTER INFLUX OF MOISTURE ALLOWED SCATTERED
SHOWERS AND FEW THUNDERSTORMS TO MOVE INTO THE METRO AREA FROM
TOLEDO THIS EVENING. THESE SHOWERS MAY LINGER OVER THE NEXT COUPLE
OF HOURS. THE NEXT CHANCE OF RAIN WILL ARRIVE AROUND 10 OR 11Z WITH
THE PASSAGE OF THE COLD FRONT. THIS FRONT WILL BE MARKED BY A WIND
SHIFT TO THE NW. RECENT MODEL SOUNDINGS AND OBSERVATIONS SUGGEST
THAT CEILINGS WILL RAPIDLY DROP TO MVFR AROUND 08Z...THEN POSSIBLY
DROP INTO THE IFR CATEGORY TOWARD DAYBREAK.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILINGS WILL BE BELOW 5000 FT THIS MORNING
INTO EARLY AFTERNOON.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS
FROM PORT AUSTIN TO HARBOR BEACH...FROM 8 AM TUESDAY TO NOON
WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT
SANILAC...FROM 8 AM TUESDAY TO 8 AM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT SANILAC TO PORT
HURON...FROM 11 AM TUESDAY TO 8 AM WEDNESDAY.
SMALL CRAFT ADVISORY...INNER SAGINAW BAY...FROM 11 AM TUESDAY TO
MIDNIGHT WEDNESDAY.
LAKE ST CLAIR...
SMALL CRAFT ADVISORY...FROM 11 AM TUESDAY TO 10 PM TUESDAY.
MI WATERS OF LAKE ERIE...
SMALL CRAFT ADVISORY...FROM 11 AM TUESDAY TO 10 PM TUESDAY.
&&
$$
SHORT TERM...KURIMSKI
LONG TERM....CB
MARINE.......KURIMSKI
AVIATION.....SC
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
118 AM EDT TUE SEP 18 2012
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 423 PM EDT MON SEP 17 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH AXIS
FROM HUDSON BAY INTO NW MN AND SE SOUTH DAKOTAS. A SHORTWAVE OVER NE
SD WAS MOVING INTO THE BASE OF THE TROUGH. AT THE SFC...A COLD FRONT
EXTENDED FROM NRN LOWER MI INTO SE WI. A LARGE POST-FRONTAL RAINBAND
FROM CNTRL WI INTO CNTRL UPPER MI WAS SUPPORTED BY MODERATE TO
STRONG MID LEVEL FGEN AND UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF
THE 250-300 MB JET. NRLY WINDS AND 850 MB TEMPS FALLING TO AROUND 3C
SUPPORTED HEAVIER LAKE ENHANCED RAIN SHOWERS INTO N CNTRL UPPER MI.
WITH DRIER AIR UPSTREAM OVER NE MN THE WRN CWA...OVER THE FAR WRN
CWA VCNTY IWD...HAS DIMINISHED OR ENDED.
TONIGHT...MDLS SUGGEST THAT THE STRONGER FGEN DYNAMICS WILL LIFT OFF
TO THE NE LATE THIS AFTERNOON AND EVENING. HOWEVER...WITH CAA
DROPPING 850 MB TEMPS TO NEAR -3C OVER LAKE SUPERIOR TONIGHT LEADING
TO LK-H8 DELTA/T TO AROUND 20C AND THE 700-500 MB TROUGH MOVING
IN...LAKE EFFECT RAIN SHOWERS WILL DEVELOP AND INTENSIFY OVERNIGHT
FOR LOCATIONS FAVORED BY N WINDS. WITH THE LOW FREEZING LEVEL...SOME
GRAUPEL WILL BE POSSIBLE WITH THE HEAVIER SHOWERS. LAKE INDUCED
TROUGHING WITH MORE OF AN NNE FLOW OVER THE ERN LAKE SHOULD MINIMIZE
PCPN INTO THE FAR ERN CWA. UPSLOPE FLOW WILL LEAD TO THE HIGHEST
PCPN AMOUNTS OVER THE HIGHER TERRAIN OVER MARQUETTE AND BARAGA
COUNTIES.
TUESDAY...LAKE EFFECT PCPN WILL CONTINUE WITH THE 850 MB THERMAL
TROF STILL OVER THE AREA. AS WINDS BACK AND BECOME MORE ANTICYCLONIC
AND SOME LOW LEVEL DRYING MOVES IN FROM THE WEST...THE PCPN SHOULD
DIMINISH SHOULD DIMINISH FROM WEST TO EAST. SHOWERS DOWNWIND OF LAKE
SUPERIOR BECOMING MORE SCATTERED THROUGH THE DAY FROM WEST TO EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 423 PM EDT MON SEP 17 2012
TUE NGT...EXPECT LINGERING LK CLDS/-SHRA OVER MAINLY THE E HALF THRU
06Z TO END WITH APRCH OF PROGRESSIVE SHRTWV RDG/DNVA/ACCOMPANYING
DRY AIRMASS AND PASSAGE OF SFC HI PRES THAT CAUSES WSHFT TO THE SW
AND EXIT OF H85 THERMAL TROF. OTRW...LOOKS LIKE THERE SHOULD BE A
SEVERAL HOUR WINDOW OF OPTIMAL RADIATIONAL COOLING CONDITIONS ACROSS
MAINLY THE INTERIOR W AND CNTRL ACCOMPANYING THE PASSAGE OF THE RDG
AXIS/DRY AIR/LIGHT WINDS. OVER THE W...QUICKER WSHFT TO THE SW AFT
06Z WITH SHARPENING PRES GRADIENT AND SOME INCRSG HI/MID CLDS IN
ADVANCE OF NEXT SHRTWV DROPPING INTO MN WL END THE FAVORABLE COOLING
CONDITIONS WELL BEFORE SUNRISE...BUT NOT BEFORE TEMPS HAVE A CHANCE
TO CRASH BEFORE 06Z FM BLO NORMAL MAX READINGS ON TUE AFTN. OPTED TO
ISSUE FREEZE WATCH FOR THE INTERIOR W HALF...WHERE MOST GUIDANCE
SHOWS WDSPRD MIN TEMPS FALLING BLO 32.
WED...NEXT FAIRLY IMPRESSIVE SHRTWV DIVING SEWD THRU NW FLOW ALF
INTO MEAN TROF OVER ERN NAMERICA IS FCST TO MOVE NEAR UPR MI BY 00Z
THU. ALTHOUGH THE MSTR RETURN AHEAD OF THIS DISTURBANCE WL BE
ANEMIC DESPITE STRENGTHENING LLVL SLY FLOW...VIGOROUS DPVA/DEEP LYR
QVECTOR CNVGC SUPPORTS LIKELY POPS OVER THE N HALF OF THE CWA ON THE
CYC SIDE OF VORT MAX TRACK AND WHERE MOISTENING OFF LK SUP MIGHT
PLAY A ROLE.
WED NGT...DNVA/LARGER SCALE QVECTOR DVGC/HIER LVL DRYING IN THE WAKE
OF SHRTWV WL END LARGER SCALE PCPN CHCS W-E. BUT INCOMING AIRMASS WL
BE COLD ENUF WITH H85 TEMPS FCST AS LO AS 1-3C TO SUPPORT LK EFFECT
-SHRA IN AREAS IMPACTED BY FCST WNW FLOW...ESPECIALLY IF THE MORE
CYC FLOW SHOWN BY THE 12Z NAM/CNDN MODELS VERIFIES.
THU...THE ARRIVAL OF ANOTHER SHRTWV/SFC LO PRES TROF WL BRING MORE
SHRA CHCS DESPITE AN ABSENCE OF SGNFT DEEP LYR MOISTENING. QUESTIONS
ON TIMING/INTENSITY OF THIS DISTURBANCE INDICATE NO MORE THAN CHC
POPS ARE APPROPRIATE.
IN THE MEDIUM/EXTENDED RANGE...WITH MEAN TROF LINGERING OVER ERN
NAMERICA...EXPECT BLO NORMAL TEMPS TO PERSIST INTO EARLY NEXT WEEK.
MODELS SHOW A SERIES OF DISTURBANCES MOVING THRU THE MEAN TROF...SO
EXPECT SHOWERS TO PERSIST ESPECIALLY THRU SAT AND NEAR THE GREAT
LAKES. BEST CHC FOR A MORE WDSPRD RAINFALL APPEARS ON FRI WHEN
MODELS SHOW A PARTICULARLY STRONG DISTURBANCE IMPACTING THE AREA.
RECENT GFS RUNS SHOW THE MOST VIGOROUS SFC CYCLOGENESIS...AND WARM
LK WATERS MIGHT SUPPORT THAT SCENARIO. VARIOUS MODELS HINT THE UPR
TROF AXIS WL SHIFT A BIT FARTHER TO THE E NEXT SUN/MON WITH EPISODES
OF MORE ACYC FLOW/DRIER WX...BUT TIMING OF THESE FEATURES IS NOT
POSSIBLE ATTM. WL FOLLOW MODEL OF CONSENSUS LOWER POPS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 118 AM EDT TUE SEP 18 2012
A LAKE EFFECT SHRA REGIME WILL BE THE RULE FOR THE FIRST HALF OR SO
OF THIS FCST PERIOD AS CHILLY AIR MASS SETTLES OVER THE UPPER LAKES
UNDERNEATH DEEPENING MID/UPPER LEVEL TROF. AS A RESULT...CONDITIONS
WILL BE QUITE VARIABLE AS LAKE EFFECT SHRA OF VARYING INTENSITY
AFFECT KIWD/KCMX/KSAW. MORE DIRECT UPSLOPING NORTHERLY WINDS SHOULD
FAVOR KIWD/KSAW FOR MORE FREQUENT SHRA AND MVFR CONDITIONS THOUGH
LAKE AIDED TROFFING SHOULD ESPECIALLY FAVOR KSAW FOR PCPN. AT
KCMX...NORTHERLY WIND IS NOT AS FAVORABLE FOR LAKE EFFECT -SHRA/LWR
CIGS. STILL...WOULD NOT BE SURPRISED TO SEE SOME BRIEF PERIODS OF
MVFR CONDITIONS EVEN THOUGH VFR SHOULD PREVAIL. IMPROVEMENT WILL
BEGIN THIS AFTN FROM W TO E AS TROF BEGINS TO SHIFT E AND DAYTIME
HEATING DISRUPTS LAKE EFFECT PROCESSES. VFR CONDITIONS WILL BE THE
RULE BY EVENING...IF NOT SOONER.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 423 PM EDT MON SEP 17 2012
20 TO 30 KT NORTH WINDS WILL CONTINUE IN THE SHORT TERM BUT DIMINISH
LATER TUESDAY AS HIGH PRESSURE BUILDS INTO THE REGION FROM THE WEST.
WINDS WILL GRADUALLY SHIFTING TO THE NW THEN W BY TUESDAY EVENING.
WINDS WILL BECOME LIGHT FOR AWHILE ON TUE NIGHT WITH THE PASSAGE OF
A HI PRES RIDGE ACROSS THE LAKE. BUT S WINDS WILL INCREASE QUICKLY
LATER AT NIGHT OVER THE W UNDER THE SHARPENING PRES GRADIENT BETWEEN
THE QUICKLY DEPARTING RIDGE AND AN INCOMING LO PRES TROUGH. AS THIS
DEEP TROF MOVES TO THE E...S WINDS ON WED MAY REACH GALE FORCE WHERE
THIS FLOW IS TYPICALLY ENHANCED OVER THE NCENTRAL AND E. ISSUED A
GALE WATCH WED AFTERNOON/EVENING IN THIS AREA TO ACCOUNT FOR THIS
STRONG FLOW AND FAIRLY UNSTABLE CONDITIONS OVER THE WARM LAKE WATER
THAT WILL ENHANCE MIXING. FOLLOWING THE PASSAGE OF THE TROF...LOOK
FOR A WIND SHIFT TO THE WNW WITH WINDS UP TO 25 TO 30 KTS INTO THU.
DEPENDING ON THE INTENSITY OF ANOTHER DISTURBANCE MOVING THRU THE
GREAT LAKES ON FRI/SAT...A STRONGER NNW FLOW IS POSSIBLE THEN. BUT
NO GALES ARE EXPECTED AT THIS TIME.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FREEZE WATCH FROM LATE TONIGHT THROUGH WEDNESDAY MORNING FOR
MIZ002-004-005-009>013-084.
LAKE SUPERIOR...
GALE WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY EVENING
FOR LSZ267.
GALE WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY EVENING
FOR LSZ266.
GALE WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY EVENING
FOR LSZ264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KC
AVIATION...ROLFSON
MARINE...JLB/KC
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
404 AM CDT TUE SEP 18 2012
.SHORT TERM...
CONVECTIVE COMPLEX IN ASSOCIATION WITH AN UPPER SHORTWAVE AND COLD
FRONT WAS MOVING INTO THE BIG COUNTRY AT 3 AM. THERE WERE SOME
STRONG STORMS ASSOCIATED WITH IT...WHICH MAY BE PRODUCING SOME SMALL
HAIL.
COLD FRONT AND UPPER SHORTWAVE MOVE SE ACROSS THE BIG COUNTRY AND
HEARTLAND THIS MORNING. THIS AREA WILL ALSO BE IN AN AREA OF UPPER
LEVEL DIVERGENCE ASSOCIATED WITH THE LEFT EXIT REGION OF A 100 KT
JET AT 200 MB...WITH THE AXIS OF THE JET ALONG I-10. MORNING STORM
ACTIVITY WAS MORE WIDESPREAD THAN THE NAM OR GFS MODELS THIS
MORNING. RUC MODEL HOWEVER DOES HAVE A BETTER HANDLE ON STORM
PLACEMENT AND AREAL EXTENT...THOUGH EVEN THE RUC RAPIDLY WEAKENS
CONVECTIVE ACTIVITY BY 9 AM AND CONFINES RAINFALL TO THE BIG COUNTRY.
DID KEEP A SLIGHT CHANCE OF STORMS IN FARTHER WEST IN THE CONCHO
VALLEY HOWEVER...WITH A VORT MAX INDICATED IN WATER VAPOR
LOOP...EMBEDDED IN THE WESTERN SIDE OF THE UPPER SHORTWAVE IN NEW
MEXICO. WENT SLIGHTLY COOLER THAN GFS MOS TODAY WITH COLD ADVECTION
AND MID/UPPER LEVEL CLOUDS ASSOCIATED WITH SHORTWAVE. KEPT
THUNDERSTORM CHANCES ONLY FOR THIS MORNING...WITH SUBSIDENCE BEHIND
EXITING SHORTWAVE BY NOON.
.LONG TERM...
A DRY FORECAST IN STORE FOR WEST CENTRAL TEXAS IN THE LONG TERM.
WEDNESDAY THROUGH FRIDAY...UPPER LEVEL RIDGE WILL REMAIN CENTERED
OVER THE WESTERN US. ANOMALOUSLY DEEP UPPER TROUGH WILL BE MAINTAINED
ACROSS THE NORTHERN GREAT LAKES AND UPPER MIDWEST. FOR WEST CENTRAL
TEXAS...TEMPERATURES WILL BE WARMER ON WEDNESDAY AS LIGHT SOUTHERLY
FLOW DEVELOPS WITH AMPLE SUNSHINE. PER THE 850 MB THERMAL PATTERN...
EXPECT DAYTIME TEMPERATURES TO BE A FEW DEGREES ABOVE NORMAL WITH
AFTERNOON HIGHS IN THE UPPER 80S TO LOWER 90S THURSDAY AND FRIDAY.
SOME MODEL DISAGREEMENT IS SHOWN WITH PROGRESS AND STRENGTH OF A
COLD FRONT FOR NEXT WEEKEND. AS A STRONG UPPER LOW DEVELOPS SOUTH
TOWARD THE NORTHERN GREAT LAKES...A DISTURBANCE IS PROGGED TO
PINWHEEL AROUND ITS SOUTHWESTERN PERIPHERY ON SATURDAY. THE 00Z
ECMWF HAS A STRONGER ASSOCIATED COLD FRONT DROPPING SOUTH ACROSS
WEST CENTRAL TEXAS LATE SATURDAY NIGHT AND SUNDAY MORNING...WITH A
1030 MB SURFACE HIGH DROPPING SOUTH ACROSS THE NORTHERN AND CENTRAL
PLAINS BEHIND THE FRONT. THE 00Z GFS HAS A CONSIDERABLY WEAKER
COLD FRONT MOVING SOUTH INTO THE BIG COUNTRY ON SATURDAY AFTERNOON...
AND BRINGS ONLY A GLANCING SHOT OF SLIGHTLY COOLER AIR INTO WEST
CENTRAL TEXAS. THE GFS ENSEMBLE SHOWS CONSIDERABLE SPREAD IN
SURFACE WINDS FOR NEXT WEEKEND. TIMING AND STRENGTH OF COLD FRONT
WILL LIKELY DEPEND ON EVOLUTION OF THE UPPER LEVEL FLOW PATTERN
ACROSS THE GREAT LAKES AND MIDWEST. GIVEN THE UNCERTAINTY...LITTLE
CHANGE WAS MADE TO THE WIND FIELD FOR NEXT WEEKEND. EITHER WAY
WITH THE MODELS...MOISTURE LOOKS TOO LIMITED IN OUR AREA TO
SUPPORT RAIN CHANCES WITH THE COLD FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 79 56 86 63 89 / 30 0 0 5 5
SAN ANGELO 82 57 88 62 90 / 20 0 0 5 5
JUNCTION 84 55 87 57 89 / 10 0 0 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
04/19
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
241 AM CDT TUE SEP 18 2012
.DISCUSSION...
UPPER LOW THAT AFFECTED NORTH TEXAS THIS PAST WEEKEND WAS MOVING
INTO THE LOWER MISSISSIPPI VALLEY THIS MORNING. ANOTHER VIGOROUS
SHORTWAVE CAN BE SEEN WITHIN NORTHWEST FLOW ALOFT MOVING OVER THE
TEXAS PANHANDLE EARLY THIS MORNING. MEANWHILE...A COLD FRONT WAS
MOVING ACROSS THE RED RIVER AND AS OF 2 AM WAS ALONG A LAKE TEXOMA...
BOWIE...SEYMOUR LINE. THE FRONT WAS EXPECTED TO REACH THE I-20
BETWEEN 4 AND 5 AM...OR BEFORE SUNRISE...THEN MOVE THROUGH CENTRAL
TEXAS BY MID-LATE MORNING. BRISK AND COOLER CONDITIONS ARE
EXPECTED BEHIND THE FRONT TODAY WITH NORTH WINDS 10 TO 20 MPH
EXPECTED BEHIND THE FRONT. CAA IS IMPRESSIVE AS WELL... THOUGH
LAGGING ABOUT 100 MILES BEHIND THE FRONT. THE CAA COMBINED WITH
WITH MID AND HIGH CLOUDINESS THE FIRST HALF OF THE DAY WILL KEEP
HIGH TEMPERATURES THIS AFTERNOON DOWN IN THE MID AND UPPER 70S
NORTH WITH LOWER 80S SOUTH OF I-20.
IN ADDITION...MID LEVEL MOISTURE WILL BE SUBSTANTIAL ENOUGH FOR A
FEW THUNDERSTORMS ACROSS OUR WESTERN CWA LATER THIS MORNING PER
WRF AND HRRR MODELS. THE BEST STRONGEST FORCING WILL TRACK ACROSS
THE SOUTHWEST COUNTIES LATER THIS MORNING. ELSEWHERE...FORCING IS
NOT EXPECTED TO BE AS STRONG WITH ISOLATED SHOWERS EXPECTED. THE
ELEVATED AND HIGH-BASED NATURE OF CONVECTION WILL RESULT IN ONLY
LIGHT RAINFALL AMOUNTS...LIKELY LESS THAN QUARTER OF AN INCH.
HOWEVER...STEEP MID LEVEL LAPSE RATES AT/ABOVE 7 DEG C/KM AND
STRONG FORCING ALOFT MAY RESULT IN A STRONG STORM OR TWO CONTAINING
FREQUENT LIGHTNING AND POSSIBLY SMALL HAIL ACROSS THE WESTERN
COUNTIES LATER THIS MORNING. BEST LIFT SHIFTS SOUTH OF I-20 WITH
THE FRONT PUSHING TO THE TEXAS COAST THIS AFTERNOON...AS THIS
SYSTEM WILL BE MUCH MORE PROGRESSIVE THAN THE PREVIOUS WEEKEND
SYSTEM WAS. WILL CONTINUE A SLIGHT CHANCE ACROSS THE CENTRAL TEXAS
COUNTIES THIS AFTERNOON...BEFORE BOTH THE SHORTWAVE AND FRONT MOVE
AWAY FROM THE AREA BY EVENING.
HIGH PRESSURE WILL SETTLE IN TONIGHT WITH LIGHT WINDS AND MOSTLY
CLEAR SKIES. EXPECT A GOOD RADIATIONAL COOLING SET UP WITH LOWS
FALLING FALLING INTO THE 50S...THOUGH SOME ISOLATED READINGS IN
THE UPPER 40S CANNOT BE RULED OUT ACROSS PROTECTED RURAL AREAS.
HIGHS WILL REBOUND INTO THE UPPER 70S ACROSS THE EAST TO THE MID
80S IN THE WEST WEDNESDAY. THE UPPER RIDGE WILL CONTINUE EXPANDING
OVERHEAD THURSDAY AND FRIDAY WITH A MODERATION OF TEMPERATURES.
HIGHS BY FRIDAY WILL SOAR TO NEAR 90 DEGREES...BUT THE HUMIDITY
SHOULD BE RELATIVELY LOW. THE GREAT LAKES VORTEX WILL DEEPEN BY
LATE FRIDAY INTO THE WEEKEND AND WILL DRAG ANOTHER COLD FRONT INTO
NORTH TEXAS SATURDAY OR POSSIBLY SATURDAY NIGHT DEPENDING ON
WHETHER YOU BUY THE SLOWER ECMWF OR FASTER GEM/GFS MODELS. HAVE
TAKEN A MEAN ON THE TIMING AND WARMED HIGHS BACK UP SLIGHTLY ON
SATURDAY. WITH MOISTURE AVAILABILITY NOT LOOKING VERY GOOD WITH
THIS FRONT...HAVE DECIDED TO LEAVE THE FORECAST NEXT WEEKEND DRY.
05/
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 78 57 81 62 85 / 10 0 0 5 5
WACO, TX 80 56 83 59 85 / 20 0 0 0 5
PARIS, TX 75 52 78 55 84 / 10 0 0 5 5
DENTON, TX 78 53 82 60 87 / 10 0 0 5 5
MCKINNEY, TX 77 53 80 57 87 / 10 0 0 5 5
DALLAS, TX 79 59 81 64 86 / 10 0 0 5 5
TERRELL, TX 78 54 80 57 85 / 10 0 0 5 5
CORSICANA, TX 80 55 81 57 85 / 10 5 0 0 5
TEMPLE, TX 81 56 82 58 85 / 20 5 0 0 5
MINERAL WELLS, TX 76 55 84 60 87 / 20 0 0 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/
AREA FORECAST DISCUSSION...UPDATED
NWS TAMPA BAY RUSKIN FL
950 AM EDT TUE SEP 18 2012
.UPDATE (REST OF TODAY)...
13Z WATER VAPOR AND H4 RUC ANALYSIS SHOWS A NOW HIGHLY AMPLIFIED
UPPER LEVEL PATTERN ACROSS NORTH AMERICA. NORTHERN STREAM FLOW
ARRIVES ATOP RIDGING ALONG THE BRITISH COLUMBIA COASTLINE BEFORE
RAPIDLY DIVING SOUTHWARD INTO A DOMINANT LONG WAVE TROUGH IN CONTROL
OF THE EASTERN HALF OF THE CONTINENT. THIS TROUGH AXIS EXTENDS FROM
ONTARIO THROUGH THE GREAT LAKES AND DOWN ALL THE WAY TO THE NORTHERN
GULF COAST. SHORTWAVE ENERGY ROUNDING THE BASE OF THIS TROUGH HAS
BEEN PIVOTING EASTWARD AND NORTHEASTWARD THIS MORNING FROM NEAR THE
MS DELTA REGION TO SOUTHERN AL/GA. DEEP LAYER QG FORCING IN ADVANCE
OF THIS ENERGY ALONG WITH SOME WEAK UPPER LEVEL DIFFLUENCE AND
ABUNDANT DEEP LAYER MOISTURE HAS BEEN SUFFICIENT TO FORCE SEVERAL
LINES OF CONVECTION ACROSS NORTH FLORIDA AND THE NE GULF OF MEXICO
THIS MORNING. THESE BANDS OF CONVECTION HAVE BEEN CONSOLIDATING OVER
THE PAST FEW HOURS AND WILL KEEP RAIN CHANCES LIKELY TO CATEGORICAL
FROM TAMPA BAY NORTHWARD ALONG THE NATURE COAST ZONES INTO AT LEAST
THE EARLY AFTERNOON. SOUTH OF TAMPA BAY RAIN CHANCES (SCATTERED
SHOWERS/STORMS) WILL SLOWLY INCREASE INTO THE AFTERNOON DUE MORE TO
TYPICAL DIURNAL HEATING PROCESSES.
AT THE SURFACE...FORECAST AREA RESIDES BETWEEN THE SUBTROPICAL RIDGE
AXIS ALONG THE FLORIDA STRAITS AND A COLD FRONT EXTENDING FROM NEAR
ATLANTA GA SOUTHWARD TO THE FLORIDA PANHANDLE. THIS FRONT WILL
SLOWLY PROCEED EASTWARD...BUT WILL NOT BE REACHING OUR ZONES THROUGH
TONIGHT.
IN THE NEXT SEVERAL HOURS...AS THE MAIN AREA OF CONVECTION CROSSES
THE NATURE COAST...A FEW STRONGER STORMS ARE NOT OUT OF THE
QUESTION. LOW LEVEL JET OF 30-40 KNOTS EXTENDS DOWN INTO
LEVY/CITRUS/SUMTER COUNTIES...AND SOME OF THIS MOMENTUM WILL LIKELY
BE TRANSPORTED TO THE SURFACE BY THE CONVECTION. WILL CONTINUE TO
MONITOR RADAR TRENDS CLOSELY...BUT CURRENTLY NOT ANTICIPATING ANY
WIDESPREAD SEVERE WEATHER POTENTIAL. AFTER THE EARLY AFTERNOON
HOURS...ALTHOUGH THE FORECAST WILL REMAIN WET...THE PASSAGE AND
WEAKENING OF THE SHORTWAVE TO OUR NORTH WILL PIVOT THE LOW LEVEL JET
EASTWARD AS WELL AND DIMINISH THE OVERALL THREAT FOR STRONGER WIND
GUSTS.
&&
.PREVIOUS DISCUSSION (TONIGHT THROUGH THURSDAY)...
THE LARGE SCALE TROUGH CONTINUES ACROSS THE EASTERN U.S. THROUGH THE
PERIOD. THE SHORT WAVE TROUGH ROTATES THROUGH THE LARGE SCALE TROUGH
TODAY AND THEN TRACKS NE AS IT DAMPENS OUT TONIGHT. THE GULF COAST
COMPLEX WILL MOVE NE ACROSS THE SE U.S. AND MERGE WITH THE PLAINS
FRONT AS THAT FEATURE SHIFTS TO THE EAST AND SE. THIS FRONT SAGS IN
ACROSS CENTRAL FL BY WED AND THEN WEAKENS THERE THROUGH THU.
WITH THE AREA UNDER DEEP AND MOIST SW FLOW THE FORECAST WILL
CONTINUE WITH SHOWERS AND THUNDERSTORMS. THESE WILL BE SCATTERED TO
NUMEROUS TODAY WITH THE HIGHEST COVERAGE IN THE NORTH AS UPPER LEVEL
ENERGY MOVES BY TO THE NORTH. THIS MAY ALSO RESULT IN SOME OF THE
STORMS BECOMING STRONG. SHOWERS AND STORMS WILL TAPER OFF WED AND
THU...BUT STILL STAY IN THE SCATTERED RANGE...AS THE FRONT BEGINS TO
DECAY AND SLIGHTLY DRIER AIR WORKS IN FROM THE NW. HIGH TEMPERATURES
WILL RUN NEAR NORMAL ALTHOUGH THEY MAY WARM A DEGREE OR TWO BY
THU...THE LOWS WILL BE JUST ABOVE NORMAL. ROBUST SOUTHWEST WINDS
TODAY RESULT IN THE THREAT OF RIPS CURRENTS AT AREA BEACHES AND A
BEACH HAZARD STATEMENT WILL IN IN PLACE THROUGH THIS EVENING. AFTER
TODAY WINDS CONTINUE SW OR WEST AND GRADUALLY DIMINISH.
&&
.AVIATION...
VFR WITH TEMPO MVFR/IFR AS SHOWERS MOVE IN OFF THE GULF THIS
MORNING. MAIN IMPACTS WILL BE BEFORE 14Z AT PIE...TPA AND SRQ. VFR
WITH VCTS AFTER 14Z.
&&
.MARINE...
WINDS WILL BE AT ADVISORY LEVELS IN THE NORTH AND CAUTION CRITERIA
ACROSS THE CENTRAL TODAY. THE NEXT FORECAST WILL HEADLINE THOSE
AREAS. AS THE FRONT SAGS IN ACROSS THE WATERS BY WED AND BEGINS TO
DECAY THE GRADIENT WILL RELAX WITH DIMINISHING WINDS AND SEAS.
ALTHOUGH SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH THE PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 89 75 86 75 / 60 30 50 30
FMY 90 75 89 74 / 50 30 50 20
GIF 89 73 90 74 / 60 30 50 20
SRQ 90 76 86 77 / 60 30 50 30
BKV 89 72 88 70 / 60 30 40 20
SPG 89 77 86 78 / 60 30 50 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...BEACH HAZARDS STATEMENT FROM 10 AM EDT THIS MORNING
THROUGH THIS EVENING FOR CHARLOTTE-HILLSBOROUGH-LEE-
MANATEE-PINELLAS-SARASOTA.
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR
TARPON SPRINGS TO SUWANNEE RIVER OUT 20 NM-TARPON
SPRINGS TO SUWANNEE RIVER OUT 20 TO 60 NM.
&&
$$
UPDATE...MROCZKA
AVIATION...JILLSON
PREVIOUS DISCUSSION...RUDE
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
714 AM EDT TUE SEP 18 2012
.AVIATION...
//DISCUSSION...
A COLD FRONT HAS PASSED THROUGH ALL OF THE TAF SITES THIS
MORNING...WITH LINGERING SHOWERS AND STRATUS BEHIND THE
FRONT...OCCASIONALLY FALLING TO IFR. SEVERAL HOURS AFTER THE FRONT
PASSES CONDITIONS ARE EXPECTED TO BRIEFLY IMPROVE TO VFR...BEFORE
FALLING BACK TO MVFR WITH ADDITIONAL SHOWERS THROUGH THE EARLY
AFTERNOON. VERY GUSTY NORTHWEST WINDS WILL DEVELOP LATER THIS
MORNING ONCE THE INVERSION BREAKS...WITH GUSTS TO 20 TO 25 KNOTS.
RIDGING WILL CLEAR SKIES OUT THIS EVENING...AS A LOOSER PRESSURE
GRADIENT BRINGS WINDS DOWN BELOW 10 KNOTS THROUGH THE OVERNIGHT
HOURS.
FOR DTW...SCATTERED SHOWERS AND IFR STRATUS WILL LINGER BEHIND THE
COLD FRONT DURING THE MORNING HOURS...AS NORTHWEST WINDS INCREASE TO
10 TO 20 KNOTS BY 13Z. CONDITIONS WILL IMPROVE TO MVFR THROUGH THE
MORNING...EVENTUALLY INCREASING TO VFR LATE THIS AFTERNOON AS COOL
DRY AIR SCOURS OUT THE LOW LEVEL MOISTURE.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FT THIS MORNING INTO EARLY
AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 341 AM EDT TUE SEP 18 2012
SHORT TERM...TODAY AND TONIGHT
A COLD FRONT CONTINUES TO MAKE STEADY PROGRESS EASTWARD THROUGH THE
CENTRAL GREAT LAKES REGION. SURFACE OBSERVATIONS SHOW THIS COLD
FRONT EXTENDING FROM THE SAGINAW VALLEY SOUTHWARD TO JACKSON
MICHIGAN AS OF 07Z. THE 3KM HRRR MODEL SHOWS THIS FRONT CLEARING THE
CWA AROUND 10Z WITH COOLER DRIER AIR FILTERING IN FROM THE NORTHWEST
BEHIND THE FRONT. THE LATE PUSH OF COLD AIR WILL MEAN HIGH
TEMPERATURES WILL LIKELY OCCUR EARLY THIS MORNING...WITH FALLING
MORNING TEMPERATURES AND A MODEST REBOUND DURING THE AFTERNOON
HOURS. MOST LOCATIONS WILL SEE TEMPERATURES STAYING WITHIN A NARROW
RANGE DURING THE DAYTIME HOURS AS COLD AIR ADVECTION FIGHTS THE
NORMAL BOUNCE AFFORDED BY DIURNAL HEATING. UPSTREAM OBSERVATIONS
SHOW THE LIGHTNING ACTIVITY PREVIOUSLY ASSOCIATED WITH THE SHOWERS
BEHIND THE FRONT HAS DISAPPEARED...WITH NOT MUCH IN THE WAY OF
ELEVATED CAPE OVER SOUTHEAST MICHIGAN WILL REMOVE THE REMAINING
THUNDER PREVIOUSLY ASSOCIATED WITH THIS ACTIVITY.
WINDS WILL TURN NORTHWESTERLY AND BE QUITE GUSTY BEHIND THE FRONT
WITH GUSTS TO 30 MPH. TOOK DOWN PRECIPITATION CHANCES ACROSS THE
EASTERN CWA DURING THE MORNING HOURS AS HIGH QPF AMOUNTS SHOWN BY
THE NWP MODELS IS NOT SUPPORTED BY UPSTREAM OBSERVATIONS WITH
RAPIDLY FALLING DEW POINTS INTO THE 40S BEHIND THE FRONT AND
REGIONAL RADAR REFLECTIVITY SEVERELY LACKING IN COVERAGE ACROSS THE
CENTRAL GREAT LAKES. THE BEST MOISTURE AND RAIN COVERAGE IS
CURRENTLY OVER THE OHIO VALLEY SHOULD STAY THERE DESPITE THE HEALTHY
VORT MAX OVER THE UPPER MISSISSIPPI VALLEY FORECAST TO TRACK THROUGH
THE CENTRAL GREAT LAKES DURING THE DAYTIME HOURS. WATER VAPOR
IMAGERY SHOWS A LOT OF DRY AIR EMBEDDED WITH THIS SHORTWAVE WITH THE
BEST MOISTURE BEING SCOURED OUT BY THE COLD FRONT CURRENTLY TRACKING
THROUGH THE CENTRAL GREAT LAKES. WHILE THE SHORTWAVE WILL PRODUCE
SOME SHOWER ACTIVITY...IT IS WORTHY OF A CHANCY MENTION INSTEAD OF
LIKELY POPS GIVEN THE LACK OF MOISTURE AND FAILURE OF THE SHORTWAVE
TO TRACK THROUGH WHEN WE STILL HAVE DECENT MOISTURE ACROSS THE
REGION.
SKIES WILL CLEAR OUT TONIGHT AS THIS SHORTWAVE TRACKS EAST AND
RIDGING MAKES ITS WAY THROUGH THE CENTRAL GREAT LAKES. THE ABUNDANT
RADIATIONAL COOLING AND VERY COLD TEMPERATURES IN PLACE OVER THE
CENTRAL GREAT LAKES WILL ALLOW OVERNIGHT TEMPERATURES TO TUMBLE INTO
THE UPPER 30S AND LOWER 40S. WHILE SOME LOCATIONS WILL FALL INTO THE
MIDDLE 30S...WINDS SHOULD STAY UP ENOUGH WITH THE PRESSURE GRADIENT
TO PREVENT MUCH IN THE WAY OF FROST FROM FORMING.
LONG TERM...WEDNESDAY THROUGH MONDAY
THE STRENGTH OF THE UPPER LEVEL LOW HEIGHT/POTENTIAL VORTICITY
ANOMALIES...BOTH TO THE EAST AND WEST OF LOWER MICHIGAN...MEANS THE
AREA WILL BE POSITIONED WITHIN A WEAKNESS OR COL OF THE MEAN UPPER
LEVEL TROUGH ON WEDNESDAY. WITH NO ALTERNATIVE...SOUTHEASTERN
MICHIGAN WILL FEEL THE EFFECTS OF A COLUMN THAT HAD BEEN HEAVILY
MODULATED BY SUBSIDENCE. ORIENTATION OF THE UPSTREAM UPPER LEVEL JET
AXIS ALONG WITH STRONG UPPER LEVEL WIND MAGNITUDES SUGGESTS THE NEXT
UPPER LEVEL SYSTEM WILL BE AT THE DOORSTEP OF THE AREA AT 00Z
THURSDAY. MODEL SOUNDINGS DO SHOW SOME FAIRLY STEEP 700-500MB LAPSE
RATES ARRIVING OVER THE TRI CITIES IN THE 22-01Z TIMEFRAME.
HOWEVER...LACK OF MODELED UVV IN THAT SLAB ALONG WITH UNSATURATED
CONDITIONS IN THE LOWEST 7500 FT PRECLUDES ANY INTRODUCTION OF POPS.
CLOUDS WILL BE ABSENT A BETTER PART OF THE DAY BEFORE INCREASING
VERY LATE. HIGHS WEDNESDAY ARE EXPECTED TO RISE COMFORTABLY IN THE
MIDDLE 60S.
THE AFOREMENTIONED ORIENTATION OF THE UPPER LEVEL JET AXIS ALONG
WITH THE VERY FAVORABLE BULLWHIP PATTERN(18Z WED-00Z THUR) ARE BIG
INDICATORS THE WEDNESDAY NIGHT/THURSDAY SYSTEM WILL HAVE A GREAT DEAL
OF DYNAMICS. THE LEFT EXIT CURL ALONG WITH SHARP NOSE OF THE LOW TO
MIDLEVEL THETA E RIDGE SUGGESTS THE BEST FORCING/SURFACE LOW WILL
LIFT NORTHEASTWARD FROM WESTERN WISCONSIN 00Z-THURSDAY TO A HUNDRED
MILES OR SO NORTH OF LAKE HURON BY 12Z-THURSDAY. PLAN VIEW
DEPICTIONS OF A NUMBER OF PARAMETERS ALL POINT TO A RATHER SHARP
LOWER TROPOSPHERIC FRONT WHISTLING THROUGH. SYSTEM RELATIVE
ISENTROPIC ASCENT AND FRONTOGENESIS ARE NOT AS STRONG AS ONE WOULD
LIKE TO SEE...BUT DEPTH OF DEFORMATION AND CONVERGENCE ARE GOOD FOR
MID TO HIGH CHANCE POPS IN MANY AREAS. THE FRONT BECOMES RATHER
SLUGGISH AND LINGERS THROUGHOUT THE MORNING ON THURSDAY. WILL CARRY
A LOW BLANKET POP WEDNESDAY NIGHT FOR THE DETROIT AREAS...BUT ONE
CAN GET THE SENSE THAT DETROIT MAY BE PRECIPITATION FREE UNTIL THE
14-18Z TIMEFRAME AS THINNING 700MB THETA E AXIS EVENTUALLY SLIDES IN
OVERHEAD. FELT COMFORTABLE GOING WITH A WARMER END BLEND FOR HIGHS
ON THURSDAY...UPPER 60S TO AROUND 70 DEGREES. ANOTHER ROUND OF
REMNANT SUBSIDENCE IS SHOWN TO SPREAD ACROSS THE AREA THURSDAY
AFTERNOON...KEEPING CONDITIONS DRY FOR THURSDAY NIGHT.
MARINE...
A STRONG COLD FRONT WILL SHIFT WINDS TO THE NORTHWEST AS WIND SPEEDS
INCREASE TO 25 TO 30 KNOTS ACROSS MUCH OF LAKE HURON AND 20 TO 25
KNOTS ELSEWHERE. SIGNIFICANT WAVE HEIGHTS WILL INCREASE ACCORDINGLY
TODAY FEATURING SEVERAL HOURS OF 6 TO 9 FOOT WAVES OVER THE OPEN
WATERS OF SOUTHERN LAKE HURON AND 5 TO 7 FEET FROM OUTER SAGINAW BAY
TO PORT HURON. SMALL CRAFT ADVISORIES HAVE THEREFORE BEEN ISSUED FOR
ALL OF THE NEARSHORE ZONES. WINDS COULD BRIEFLY APPROACH GALE
CONDITIONS TODAY ACROSS SOUTHERN LAKE HURON...HOWEVER THE TIME
WINDOW APPEARS TOO BRIEF AND MARGINAL TO ISSUE GALE WARNINGS AT THIS
TIME. WINDS WILL SLOWLY SUBSIDE TONIGHT AND WEDNESDAY...WITH SMALL
CRAFT ADVISORIES BEING DROPPED TONIGHT THROUGH WEDNESDAY MORNING AS
WINDS AND WAVES SLOWLY SUBSIDE. THE PATTERN WILL REMAIN ACTIVE WITH
SEVERAL EPISODES OF GUSTY NORTHWEST FLOW AND ELEVATED WAVE
CONDITIONS LIKELY THROUGH THE FORECAST PERIOD.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS
FROM PORT AUSTIN TO HARBOR BEACH...UNTIL NOON WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT
SANILAC...UNTIL 8 AM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT SANILAC TO PORT
HURON...FROM 11 AM TUESDAY TO 8 AM WEDNESDAY.
SMALL CRAFT ADVISORY...INNER SAGINAW BAY...FROM 11 AM TUESDAY TO
MIDNIGHT WEDNESDAY.
LAKE ST CLAIR...
SMALL CRAFT ADVISORY...FROM 11 AM TUESDAY TO 10 PM TUESDAY.
MI WATERS OF LAKE ERIE...
SMALL CRAFT ADVISORY...FROM 11 AM TUESDAY TO 10 PM TUESDAY.
&&
$$
AVIATION.....KURIMSKI
SHORT TERM...KURIMSKI
LONG TERM....CB
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1033 AM EDT TUE SEP 18 2012
.SYNOPSIS...
A VIGOROUS LOW PRESSURE SYSTEM WILL BRING STRONG...GUSTY WIND TO
THE AREA LATE THIS MORNING THROUGH THIS EVENING. THIS WILL BE
AHEAD OF A STRONG COLD FRONT THAT WILL ALSO BRING RAIN TO THE
REGION TODAY. THE SYSTEM WILL QUICKLY MOVE OUT OVERNIGHT...AND HIGH
PRESSURE WILL BRING QUIETER CONDITIONS FOR THE REMAINDER OF THE
WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE... BROAD SWATH OF RA/+RA CONTS TO TRACK NEWD THROUGH
CNY/NE PA ATTM...BEING FUELED BY STG POS THETA-E ADVCTN ON THE
LEADING EDGE OF AN INCRG LOW-LVL JET. WE EXPECT STEADY RAIN TO
PERSIST TIL PERHAPS MID TO LATE AFTN...WHEN THE BACK EDGE OF THE
MAIN PCPN SHIELD...NOW ACRS WRN PA...ATTEMPTS TO MOVE INTO THE CWA
FROM SW TO NE. A BIG QUESTION IS WHAT HAPPENS AFTER THAT...JUST AHD
OF THE COLD FROPA IN THE 21Z-01Z TIME FRAME.
MOST OF THE CONVECTION ALLOWING MODELS (HRRR AND 4 KM WRF...FOR
EXAMPLE) INDICATE THAT SOME SORT OF ENHANCED/CONVECTIVE LN FORMS
ON THE BACK EDGE OF THE STEADIER PCPN AFTER 21Z...TRANSLATING
MAINLY ACRS NE PA AND PTNS OF THE SRN TIER LATE IN THE DAY.
THIS...OF COURSE...WILL DEPEND ON HOW MUCH INSTAB CAN FORM. THE
LATEST RUC SHOWS ML CAPE OF 200-400 THIS TIME FRAME IN OUR SERN
ZNS...WITH THE 12Z NAM COMING IN SHOWING MORE (500-800). GIVEN
EXTENSIVE CLOUD COVER/PCPN FOR SVRL MORE HRS AT LEAST...AND WHAT`S
BEING OBSERVED UPSTREAM ON SPC MESO`S ATTM (ML CAPE OF 100-200 IN
SE PA)...WE`RE INCLINED TO BUY THE MORE CONSERVATIVE RUC. ACRS
ROUGHLY THE SERN HALF OF THE CWA...WE`LL STILL MENTION ISOLD
TSRA...WHILE SHOWING OCNL +RA JUST ABT EVERYWHERE. THE BEST SVR
POTENTIAL APPEARS TO BE JUST SE OF THE CWA...WHERE THE PRIMARY
IMPETUS FOR ANY DISCERNIBLE LN OR DISCRETE CELL FORMATION IS.
KBGM VWP HAS 20-30 KT SRLY FLOW AT 2K FT AGL ATTM...WITH 40-50 KT
AT 3-4K FT AGL. KBGM BASE VEL PRODS ALSO SHOW THE 50-60 KT CORE
MOVG NWD THROUGH ERN PA...AND DESCENDING SOMEWHAT WITH TIME. THE
MOST FAVORABLE TIME FOR CONSISTENTLY STG GRADIENT WIND GUSTS WILL BE
FROM ABT 17-22Z. WIND ADVISORIES REMAIN IN TACT.
UNLESS TRAINING OF HEAVY RAIN BANDS FORM...WE`RE STILL NOT
EXPECTING ANY SIG HYDRO RELATED PROBLEMS...SO NO WATCHES PLANNED
FOR THE TIME BEING.
PREV DISC... THE BIG STORY OF THE DAY LOOKS TO BE THE STRONG
WINDS EXPECTED AHEAD OF A COLD FRONT. CURRENTLY, AN ELONGATED SFC
LOW IS SITUATED FROM AROUND NEW ORLEANS ALL THE WAY UP TO THE
NORTH OF THE GREAT LAKES. THIS LOW WILL TIGHTEN UP AND DEVELOP
FURTHER OVER THE EASTERN GREAT LAKES THIS MORNING. WITH A
TIGHTENING PRESSURE GRADIENT, ORIENTED EAST TO WEST, WINDS WILL
INCREASE THIS MORNING OUT OF THE SOUTH TO SOUTH EAST. GIVEN THAT A
LLJ IS ALSO EXPECTED BETWEEN 925MB AND 850MB AT AROUND 60 KTS THIS
AFTERNOON, WINDS SHOULD BE ABLE TO INCREASE TO AROUND 20 TO 25 KTS
SUSTAINED, ESPECIALLY IN HIGHER TERRAIN. SOME OF THE HIGH WINDS
ALOFT SHOULD ALSO MIX DOWN, ALLOWING FREQUENT GUSTS OF 35 TO 40
KTS. THERE IS A SMALL POTENTIAL FOR THE HIGHER ELEVATIONS OF THE
CATSKILLS TO SEE INFREQUENT GUSTS OF OVER 45 KTS. MODELS ARE
INDICATING THAT THE FRONT AND LLJ WILL QUICKLY PUSH EASTWARD LATE
THIS AFTERNOON AND MAY BE TOTALLY OUT OF THE CWA BY 00Z. IT WILL
LINGER THE LONGEST IN THE EASTERN ZONES, HENCE THE ADVISORY
LASTING A FEW HOURS LONGER.
ON TOP OF THE STRONG WINDS TODAY, RAIN WILL BE ANOTHER FACTOR.
MODELS ARE INDICATING PWATS OF NEARLY TWO INCHES TODAY. ALSO, CURRENT
HPC PREDICTIONS SHOW AROUND 2 INCHES ARE POSSIBLE ACROSS THE CWA
TODAY. CAN NOT DISAGREE WITH THIS ASSESSMENT. WITH CURRENT MONTHLY
RAINFALL TOTALS BEING BELOW NORMAL AND LOW RIVER LEVELS, NOT
EXPECTING ANY IMPACTS ON A LARGE SCALE. THERE MAY BE SOME MINOR
FLASH FLOODING AT HEADWATERS AND AREAS THAT NORMALLY REACT QUICKLY
TO ANY RAIN. ALSO, LOW LYING AREAS AND URBAN AREAS WITH POOR
DRAINAGE COULD SEE SOME PONDING OF WATER.
AS FAR AS CONVECTIVE POTENTIAL TODAY. WHILE SPC DOES HAVE MUCH OF
THE AREA IN A SLIGHT RISK, THE FEELING IS THAT IT IS UNLIKELY IN
THE BGM CWA AS THE LLJ WILL LIKELY BE TO STRONG FOR ANY
SIGNIFICANT CELLS TO DEVELOP BEFORE BEING SHEARED APART. ALSO,
CAPS VALUES LOOK TO STRUGGLE TO GET ABOVE 300 JOULES THIS
AFTERNOON AS RAIN SHOWERS AND CLOUD COVER HAVE ALREADY BEGAN TO
OVERSPREAD THE REGION, WHICH WILL LIMIT INSOLATION TODAY. LAPSE
RATES WILL ALSO GREATLY LIMIT ANY CONVECTIVE POTENTIAL AS THE
STRUGGLE TO REACH 6 TODAY. EVEN SO, HAVE KEPT A MENTION OF AN
ISOLATED, GENERAL THUNDERSTORM OVER THE SOUTHERN ZONES THIS
AFTERNOON AS AN ISOLATED CELL COULD DEVELOP A CAUSE A FEW STRIKES
BEFORE BEING TORN APART.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL BUILD OVER THE AREA. AS IT DOES, SOME COLDER
850MB TEMPS WILL MOVE ACROSS THE GREAT LAKE EARLY WEDNESDAY MORNING.
CURRENTLY THE NAM IS SHOWING TEMPS OF -1C AT 850MB. THE GFS AND
THE ECMWF ARE ONLY 1 OR 2 DEGREES WARMER. GIVEN THIS AND A WEST
NORTHWESTERLY FLOW EARLY WEDNESDAY MORNING, SOME LAKE EFFECT
SHOWERS MAY TRY TO POP UP, MAINLY ACROSS NORTHERN ONONDAGA AND
ONEIDA COUNTIES. THE CHANCE WILL DIMINISH WITH DAYTIME HEATING AND
MIXING WEDNESDAY LATE MORNING. THE REMAINDER OF THE FORECAST
PERIOD WILL BE COOL AND QUIET, WITH HIGH TEMPS IN THE UPPER 50S
AND LOW 60S WEDNESDAY AFTERNOON AND MIDDLE TO UPPER 60S ON
THURSDAY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
315 AM UPDATE...CURRENT FORECAST IN GOOD SHAPE, LATEST MODEL RUNS
REMAIN CONSISTENT WITH PREVIOUS CYCLE, NO SIGNIFICANT CHANGES.
PREVIOUS DISC...
FRIDAY THROUGH FRIDAY NIGHT...A DEEP CUT OFF LOW WILL MOVE INTO
THE UPPER MIDWEST DURING THIS TIME. MEANWHILE FARTHER TO THE EAST
IN OUR NECK OF THE WOODS...WE WILL REMAIN IN A DEEP SOUTHWESTERLY
FLOW AHEAD OF THE CUT OFF LOW. INITIALLY THIS WILL BE GREAT NEWS
WITH OUR AREA REMAINING DRY AND EXPERIENCING ABOVE NORMAL TEMPS.
HIGHS FRIDAY SHOULD BE WELL INTO THE 70S...WITH NEAR 80 DEGREE
READINGS ACROSS THE LAKE PLAIN.
SATURDAY AND BEYOND...THE DOWNSIDE TO THE SLOW MOVEMENT OF THE CUT OFF LOW
MENTIONED ABOVE WILL BE AN UNSETTLED WEEKEND. AS THE CUT OFF LOW
MOVES NORTHEAST AND WE BEGIN TO FEEL THE EFFECTS OF THE H5
TROF...RAIN WILL SPREAD OUR WAY LATER SATURDAY INTO SUNDAY. THE
GFS HINTS THAT WE MAY SEE A DRY SLOT LATER SUNDAY...BUT PLENTY OF
UNCERTAINTY EXISTS WITH THE EURO KEEPING US WET. WILL KEEP CHANCE
POPS IN ESPECIALLY ACROSS THE NORTH TO COVER THIS.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
AN INTENSIFYING LOW PRES SYSTEM IN THE OH VALLEY WITH PRODUCE
MODERATE RAIN ACROSS THE TERMINALS THROUGH TODAY. WIDESPREAD LOW
MVFR CONDITIONS ARE EXPECTED WITH IFR LIKELY FOR MUCH OF THE DAY
AT KITH/KBGM. STRONG FLOW SHOULD PREVENT WIDESPREAD IFR CIGS. A
STRONG COLD FRONT WILL CROSS THE REGION BETWEEN 23Z-02Z, WITH
PRECIP ENDING AROUND THREE HOURS AFTER FROPA BUT IN GENERAL MVFR
CIGS WILL PERSIST.
WINDS S/SE AT 10 KTS THEN INCREASING BY MID MORNING FROM THE SOUTH
AT 10-15 KNOTS WITH GUSTS 25-30 KNOTS BECOMING SOUTHWEST DURING
THE AFTERNOON THEN WESTERLY AFTER FROPA AROUND 10 KNOTS WITH GUSTS
AROUND 20 KNOTS.
AT KAVP/KELM LOW LEVEL WIND SHEAR WILL EXISTS THROUGH MID MORNING
WITH LIGHT WINDS AT THE SFC AND GUSTY SOUTHERLY WINDS AT 2K FT.
OUTLOOK...
WED...VFR.
THU/FRI...VFR EXCEPT IFR FOG AT KELM EACH MORNING FROM 8 TO 14Z.
SAT...MVFR POSSIBLE IN SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR PAZ038>040-043-
044-047-072.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ048.
NY...WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ009-025-036-
037-044-045-055-056.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ046-057-062.
&&
$$
SYNOPSIS...SLI
NEAR TERM...SLI
SHORT TERM...SLI
LONG TERM...HEDEN/RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
958 AM CDT TUE SEP 18 2012
.UPDATE...
UPDATED THE POPS AND WEATHER GRIDS.
&&
.DISCUSSION...
UPDATED TO FORECAST TO REMOVE THE POPS AND WEATHER FOR THE BIG
COUNTRY.
&&
.PREV DISCUSSION... /ISSUED 633 AM CDT TUE SEP 18 2012/
DISCUSSION...
/SEE BELOW FOR AVIATION DISCUSSION/
AVIATION...
THUNDERSTORMS WILL MOVE THROUGH KABI THROUGH 14Z. STORMS HAVE
WEAKENED...BUT MAY STILL BE CAPABLE OF WINDS OF 35 KTS AND LOWERED
VISIBILITIES OF 1 TO 3 MILES. SCATTERED LIGHT SHOWERS AND PERHAPS A
THUNDERSTORM MAY ALSO AFFECT KSJT THROUGH 14Z...BUT WILL ONLY PUT
VCTS IN THE TAF AS MOST OF THE STORMS WILL PASS NORTH. OTHERWISE
NORTH WINDS INCREASE TO 10 KT AS A COLD FRONT MOVES THROUGH THIS
MORNING.
PREV DISCUSSION... /ISSUED 404 AM CDT TUE SEP 18 2012/
SHORT TERM...
CONVECTIVE COMPLEX IN ASSOCIATION WITH AN UPPER SHORTWAVE AND COLD
FRONT WAS MOVING INTO THE BIG COUNTRY AT 3 AM. THERE WERE SOME
STRONG STORMS ASSOCIATED WITH IT...WHICH MAY BE PRODUCING SOME SMALL
HAIL.
COLD FRONT AND UPPER SHORTWAVE MOVE SE ACROSS THE BIG COUNTRY AND
HEARTLAND THIS MORNING. THIS AREA WILL ALSO BE IN AN AREA OF UPPER
LEVEL DIVERGENCE ASSOCIATED WITH THE LEFT EXIT REGION OF A 100 KT
JET AT 200 MB...WITH THE AXIS OF THE JET ALONG I-10. MORNING STORM
ACTIVITY WAS MORE WIDESPREAD THAN THE NAM OR GFS MODELS THIS
MORNING. RUC MODEL HOWEVER DOES HAVE A BETTER HANDLE ON STORM
PLACEMENT AND AREAL EXTENT...THOUGH EVEN THE RUC RAPIDLY WEAKENS
CONVECTIVE ACTIVITY BY 9 AM AND CONFINES RAINFALL TO THE BIG COUNTRY.
DID KEEP A SLIGHT CHANCE OF STORMS IN FARTHER WEST IN THE CONCHO
VALLEY HOWEVER...WITH A VORT MAX INDICATED IN WATER VAPOR
LOOP...EMBEDDED IN THE WESTERN SIDE OF THE UPPER SHORTWAVE IN NEW
MEXICO. WENT SLIGHTLY COOLER THAN GFS MOS TODAY WITH COLD ADVECTION
AND MID/UPPER LEVEL CLOUDS ASSOCIATED WITH SHORTWAVE. KEPT
THUNDERSTORM CHANCES ONLY FOR THIS MORNING...WITH SUBSIDENCE BEHIND
EXITING SHORTWAVE BY NOON.
LONG TERM...
A DRY FORECAST IN STORE FOR WEST CENTRAL TEXAS IN THE LONG TERM.
WEDNESDAY THROUGH FRIDAY...UPPER LEVEL RIDGE WILL REMAIN CENTERED
OVER THE WESTERN US. ANOMALOUSLY DEEP UPPER TROUGH WILL BE MAINTAINED
ACROSS THE NORTHERN GREAT LAKES AND UPPER MIDWEST. FOR WEST CENTRAL
TEXAS...TEMPERATURES WILL BE WARMER ON WEDNESDAY AS LIGHT SOUTHERLY
FLOW DEVELOPS WITH AMPLE SUNSHINE. PER THE 850 MB THERMAL PATTERN...
EXPECT DAYTIME TEMPERATURES TO BE A FEW DEGREES ABOVE NORMAL WITH
AFTERNOON HIGHS IN THE UPPER 80S TO LOWER 90S THURSDAY AND FRIDAY.
SOME MODEL DISAGREEMENT IS SHOWN WITH PROGRESS AND STRENGTH OF A
COLD FRONT FOR NEXT WEEKEND. AS A STRONG UPPER LOW DEVELOPS SOUTH
TOWARD THE NORTHERN GREAT LAKES...A DISTURBANCE IS PROGGED TO
PINWHEEL AROUND ITS SOUTHWESTERN PERIPHERY ON SATURDAY. THE 00Z
ECMWF HAS A STRONGER ASSOCIATED COLD FRONT DROPPING SOUTH ACROSS
WEST CENTRAL TEXAS LATE SATURDAY NIGHT AND SUNDAY MORNING...WITH A
1030 MB SURFACE HIGH DROPPING SOUTH ACROSS THE NORTHERN AND CENTRAL
PLAINS BEHIND THE FRONT. THE 00Z GFS HAS A CONSIDERABLY WEAKER
COLD FRONT MOVING SOUTH INTO THE BIG COUNTRY ON SATURDAY AFTERNOON...
AND BRINGS ONLY A GLANCING SHOT OF SLIGHTLY COOLER AIR INTO WEST
CENTRAL TEXAS. THE GFS ENSEMBLE SHOWS CONSIDERABLE SPREAD IN
SURFACE WINDS FOR NEXT WEEKEND. TIMING AND STRENGTH OF COLD FRONT
WILL LIKELY DEPEND ON EVOLUTION OF THE UPPER LEVEL FLOW PATTERN
ACROSS THE GREAT LAKES AND MIDWEST. GIVEN THE UNCERTAINTY...LITTLE
CHANGE WAS MADE TO THE WIND FIELD FOR NEXT WEEKEND. EITHER WAY
WITH THE MODELS...MOISTURE LOOKS TOO LIMITED IN OUR AREA TO
SUPPORT RAIN CHANCES WITH THE COLD FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 79 56 86 63 89 / 10 0 0 5 5
SAN ANGELO 82 57 88 62 90 / 20 0 0 5 5
JUNCTION 84 55 87 57 89 / 20 0 0 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
REIMER
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
633 AM CDT TUE SEP 18 2012
.DISCUSSION...
/SEE BELOW FOR AVIATION DISCUSSION/
&&
.AVIATION...
THUNDERSTORMS WILL MOVE THROUGH KABI THROUGH 14Z. STORMS HAVE
WEAKENED...BUT MAY STILL BE CAPABLE OF WINDS OF 35 KTS AND LOWERED
VISIBILITIES OF 1 TO 3 MILES. SCATTERED LIGHT SHOWERS AND PERHAPS A
THUNDERSTORM MAY ALSO AFFECT KSJT THROUGH 14Z...BUT WILL ONLY PUT
VCTS IN THE TAF AS MOST OF THE STORMS WILL PASS NORTH. OTHERWISE
NORTH WINDS INCREASE TO 10 KT AS A COLD FRONT MOVES THROUGH THIS
MORNING.
&&
.PREV DISCUSSION... /ISSUED 404 AM CDT TUE SEP 18 2012/
SHORT TERM...
CONVECTIVE COMPLEX IN ASSOCIATION WITH AN UPPER SHORTWAVE AND COLD
FRONT WAS MOVING INTO THE BIG COUNTRY AT 3 AM. THERE WERE SOME
STRONG STORMS ASSOCIATED WITH IT...WHICH MAY BE PRODUCING SOME SMALL
HAIL.
COLD FRONT AND UPPER SHORTWAVE MOVE SE ACROSS THE BIG COUNTRY AND
HEARTLAND THIS MORNING. THIS AREA WILL ALSO BE IN AN AREA OF UPPER
LEVEL DIVERGENCE ASSOCIATED WITH THE LEFT EXIT REGION OF A 100 KT
JET AT 200 MB...WITH THE AXIS OF THE JET ALONG I-10. MORNING STORM
ACTIVITY WAS MORE WIDESPREAD THAN THE NAM OR GFS MODELS THIS
MORNING. RUC MODEL HOWEVER DOES HAVE A BETTER HANDLE ON STORM
PLACEMENT AND AREAL EXTENT...THOUGH EVEN THE RUC RAPIDLY WEAKENS
CONVECTIVE ACTIVITY BY 9 AM AND CONFINES RAINFALL TO THE BIG COUNTRY.
DID KEEP A SLIGHT CHANCE OF STORMS IN FARTHER WEST IN THE CONCHO
VALLEY HOWEVER...WITH A VORT MAX INDICATED IN WATER VAPOR
LOOP...EMBEDDED IN THE WESTERN SIDE OF THE UPPER SHORTWAVE IN NEW
MEXICO. WENT SLIGHTLY COOLER THAN GFS MOS TODAY WITH COLD ADVECTION
AND MID/UPPER LEVEL CLOUDS ASSOCIATED WITH SHORTWAVE. KEPT
THUNDERSTORM CHANCES ONLY FOR THIS MORNING...WITH SUBSIDENCE BEHIND
EXITING SHORTWAVE BY NOON.
LONG TERM...
A DRY FORECAST IN STORE FOR WEST CENTRAL TEXAS IN THE LONG TERM.
WEDNESDAY THROUGH FRIDAY...UPPER LEVEL RIDGE WILL REMAIN CENTERED
OVER THE WESTERN US. ANOMALOUSLY DEEP UPPER TROUGH WILL BE MAINTAINED
ACROSS THE NORTHERN GREAT LAKES AND UPPER MIDWEST. FOR WEST CENTRAL
TEXAS...TEMPERATURES WILL BE WARMER ON WEDNESDAY AS LIGHT SOUTHERLY
FLOW DEVELOPS WITH AMPLE SUNSHINE. PER THE 850 MB THERMAL PATTERN...
EXPECT DAYTIME TEMPERATURES TO BE A FEW DEGREES ABOVE NORMAL WITH
AFTERNOON HIGHS IN THE UPPER 80S TO LOWER 90S THURSDAY AND FRIDAY.
SOME MODEL DISAGREEMENT IS SHOWN WITH PROGRESS AND STRENGTH OF A
COLD FRONT FOR NEXT WEEKEND. AS A STRONG UPPER LOW DEVELOPS SOUTH
TOWARD THE NORTHERN GREAT LAKES...A DISTURBANCE IS PROGGED TO
PINWHEEL AROUND ITS SOUTHWESTERN PERIPHERY ON SATURDAY. THE 00Z
ECMWF HAS A STRONGER ASSOCIATED COLD FRONT DROPPING SOUTH ACROSS
WEST CENTRAL TEXAS LATE SATURDAY NIGHT AND SUNDAY MORNING...WITH A
1030 MB SURFACE HIGH DROPPING SOUTH ACROSS THE NORTHERN AND CENTRAL
PLAINS BEHIND THE FRONT. THE 00Z GFS HAS A CONSIDERABLY WEAKER
COLD FRONT MOVING SOUTH INTO THE BIG COUNTRY ON SATURDAY AFTERNOON...
AND BRINGS ONLY A GLANCING SHOT OF SLIGHTLY COOLER AIR INTO WEST
CENTRAL TEXAS. THE GFS ENSEMBLE SHOWS CONSIDERABLE SPREAD IN
SURFACE WINDS FOR NEXT WEEKEND. TIMING AND STRENGTH OF COLD FRONT
WILL LIKELY DEPEND ON EVOLUTION OF THE UPPER LEVEL FLOW PATTERN
ACROSS THE GREAT LAKES AND MIDWEST. GIVEN THE UNCERTAINTY...LITTLE
CHANGE WAS MADE TO THE WIND FIELD FOR NEXT WEEKEND. EITHER WAY
WITH THE MODELS...MOISTURE LOOKS TOO LIMITED IN OUR AREA TO
SUPPORT RAIN CHANCES WITH THE COLD FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 79 56 86 63 89 / 30 0 0 5 5
SAN ANGELO 82 57 88 62 90 / 20 0 0 5 5
JUNCTION 84 55 87 57 89 / 10 0 0 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99/04
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
611 AM CDT TUE SEP 18 2012
.AVIATION...
EXPECT VFR WITH NORTH FLOW THRU TODAY. FRONT SHOULD BE THROUGH
METROPLEX TAF SITES NEAR 12Z...SO WILL START TAFS WITH POST
FRONTAL NORTH WINDS. MVFR STRATUS IN OKLAHOMA WELL BEHIND FRONT
WILL REACH METROPLEX AROUND 16-17Z...AND WITH MORNING WARMING
SHOULD REMAIN SCT. WILL HAVE TO KEEP AN EYE ON IT BUT SHOULD IT GO
BKN IT MAY BE ABOVE 030 BY THEN. WINDS WILL TURN BACK SOUTH LATE
IN THE EVENING. 84
&&
.PREV DISCUSSION... /ISSUED 241 AM CDT TUE SEP 18 2012/
UPPER LOW THAT AFFECTED NORTH TEXAS THIS PAST WEEKEND WAS MOVING
INTO THE LOWER MISSISSIPPI VALLEY THIS MORNING. ANOTHER VIGOROUS
SHORTWAVE CAN BE SEEN WITHIN NORTHWEST FLOW ALOFT MOVING OVER THE
TEXAS PANHANDLE EARLY THIS MORNING. MEANWHILE...A COLD FRONT WAS
MOVING ACROSS THE RED RIVER AND AS OF 2 AM WAS ALONG A LAKE TEXOMA...
BOWIE...SEYMOUR LINE. THE FRONT WAS EXPECTED TO REACH THE I-20
BETWEEN 4 AND 5 AM...OR BEFORE SUNRISE...THEN MOVE THROUGH CENTRAL
TEXAS BY MID-LATE MORNING. BRISK AND COOLER CONDITIONS ARE
EXPECTED BEHIND THE FRONT TODAY WITH NORTH WINDS 10 TO 20 MPH
EXPECTED BEHIND THE FRONT. CAA IS IMPRESSIVE AS WELL... THOUGH
LAGGING ABOUT 100 MILES BEHIND THE FRONT. THE CAA COMBINED WITH
WITH MID AND HIGH CLOUDINESS THE FIRST HALF OF THE DAY WILL KEEP
HIGH TEMPERATURES THIS AFTERNOON DOWN IN THE MID AND UPPER 70S
NORTH WITH LOWER 80S SOUTH OF I-20.
IN ADDITION...MID LEVEL MOISTURE WILL BE SUBSTANTIAL ENOUGH FOR A
FEW THUNDERSTORMS ACROSS OUR WESTERN CWA LATER THIS MORNING PER
WRF AND HRRR MODELS. THE BEST STRONGEST FORCING WILL TRACK ACROSS
THE SOUTHWEST COUNTIES LATER THIS MORNING. ELSEWHERE...FORCING IS
NOT EXPECTED TO BE AS STRONG WITH ISOLATED SHOWERS EXPECTED. THE
ELEVATED AND HIGH-BASED NATURE OF CONVECTION WILL RESULT IN ONLY
LIGHT RAINFALL AMOUNTS...LIKELY LESS THAN QUARTER OF AN INCH.
HOWEVER...STEEP MID LEVEL LAPSE RATES AT/ABOVE 7 DEG C/KM AND
STRONG FORCING ALOFT MAY RESULT IN A STRONG STORM OR TWO CONTAINING
FREQUENT LIGHTNING AND POSSIBLY SMALL HAIL ACROSS THE WESTERN
COUNTIES LATER THIS MORNING. BEST LIFT SHIFTS SOUTH OF I-20 WITH
THE FRONT PUSHING TO THE TEXAS COAST THIS AFTERNOON...AS THIS
SYSTEM WILL BE MUCH MORE PROGRESSIVE THAN THE PREVIOUS WEEKEND
SYSTEM WAS. WILL CONTINUE A SLIGHT CHANCE ACROSS THE CENTRAL TEXAS
COUNTIES THIS AFTERNOON...BEFORE BOTH THE SHORTWAVE AND FRONT MOVE
AWAY FROM THE AREA BY EVENING.
HIGH PRESSURE WILL SETTLE IN TONIGHT WITH LIGHT WINDS AND MOSTLY
CLEAR SKIES. EXPECT A GOOD RADIATIONAL COOLING SET UP WITH LOWS
FALLING FALLING INTO THE 50S...THOUGH SOME ISOLATED READINGS IN
THE UPPER 40S CANNOT BE RULED OUT ACROSS PROTECTED RURAL AREAS.
HIGHS WILL REBOUND INTO THE UPPER 70S ACROSS THE EAST TO THE MID
80S IN THE WEST WEDNESDAY. THE UPPER RIDGE WILL CONTINUE EXPANDING
OVERHEAD THURSDAY AND FRIDAY WITH A MODERATION OF TEMPERATURES.
HIGHS BY FRIDAY WILL SOAR TO NEAR 90 DEGREES...BUT THE HUMIDITY
SHOULD BE RELATIVELY LOW. THE GREAT LAKES VORTEX WILL DEEPEN BY
LATE FRIDAY INTO THE WEEKEND AND WILL DRAG ANOTHER COLD FRONT INTO
NORTH TEXAS SATURDAY OR POSSIBLY SATURDAY NIGHT DEPENDING ON
WHETHER YOU BUY THE SLOWER ECMWF OR FASTER GEM/GFS MODELS. HAVE
TAKEN A MEAN ON THE TIMING AND WARMED HIGHS BACK UP SLIGHTLY ON
SATURDAY. WITH MOISTURE AVAILABILITY NOT LOOKING VERY GOOD WITH
THIS FRONT...HAVE DECIDED TO LEAVE THE FORECAST NEXT WEEKEND DRY.
05/
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 78 57 81 62 85 / 10 0 0 5 5
WACO, TX 80 56 83 59 85 / 20 0 0 0 5
PARIS, TX 75 52 78 55 84 / 10 0 0 5 5
DENTON, TX 78 53 82 60 87 / 10 0 0 5 5
MCKINNEY, TX 77 53 80 57 87 / 10 0 0 5 5
DALLAS, TX 79 59 81 64 86 / 10 0 0 5 5
TERRELL, TX 78 54 80 57 85 / 10 0 0 5 5
CORSICANA, TX 80 55 81 57 85 / 10 5 0 0 5
TEMPLE, TX 81 56 82 58 85 / 20 5 0 0 5
MINERAL WELLS, TX 76 55 84 60 87 / 20 0 0 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
204 PM EDT TUE SEP 18 2012
.SYNOPSIS...
SLOW MOVING, BUT POTENT, COLD FRONT WILL SWEEP THROUGH THE REGION
LATER TONIGHT AS THE PARENT LOW PRESSURE SYSTEM MOVES TO OUR
NORTHEAST. HIGH PRESSURE WILL BUILD IN FROM THE NORTH LATER ON
WEDNESDAY THROUGH FRIDAY. ANOTHER COLD FRONT LOOKS TO PUSH THROUGH
OUR REGION LATE IN THE DAY ON SATURDAY WITH HIGH PRESSURE ONCE
AGAIN FILLING IN BEHIND IT LATER ON SUNDAY INTO MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOOKING AT THE 12Z SFC ANALYSIS AND UPPER AIR PATTERN. AS MY MID
SHIFT PREDECESSOR HAS BEEN SAYING FOR DAYS WE STILL HAVE AN
UNPHASED SYSTEM APPROACHING FROM THE WEST. IT LOOKS AS THOUGH MOST
OF THE ACTION WILL BE FROM THE SOUTHERN STREAM SYSTEM WITH THE
SECOND FRONT MAYBE PROLONGING LIGHTER RAIN CHANCES DEEPER INTO THE
NIGHT.
EVEN WITHOUT THE PHASING THERE IS SFC BASED INSTABILITY AND KDIX
AND KDOX VMP ARE BOTH SHOWING 50KTS OF WIND ALRDY AT 3K. THE HI
RES WRF-NMM EAST IS SHOWING THE BEST DEPICTION OF ONOGING
CONVECTION, BOTH THE HRRR AND COSPA SEEM TOO HOT TOO EAST TOO
FAST. WE HAVE CLOUDED OVER WHICH WOULD REDUCE INSTABILITY A BIT,
BUT ITS NOT ENOUGH. SO WE WILL WAIT FOR ORGANIZATION TO ENHANCE
THE POTENTIAL FOR SEVERE WEATHER AND FOLLOWING THE WRF-NMM-E FOR
NOW AS HIEST IMPACT TIME.
THE HEAVIEST RAIN HAS FALLEN SO FAR NORTH AND WEST WHERE FFG IS
HIGH, SO UNLESS THERE IS TRAINING, SO FAR SO GOOD.
IF WE DID NOT HAVE THE TOPOGRAPHY NW, WE ARE TEMPTED TO DROP THE
ADVISORY THERE, BUT WITH THE HIER TERRAIN, WE WILL KEEP IT GOING.
HIEST CONFIDENCE OUTSIDE OF CONVECTION REMAINS EAST FOR WIND ADVY
GUSTS. NO BIG CHANGES TO TEMPS AND DEW POINTS.
AS HAS BEEN NOTED IN PREVIOUS DISCUSSIONS, TODAY LOOKS TO BE AN
ACTIVE DAY. THE MODELS STILL SUPPORT THE HEAVY RAIN CONCERN
ESPECIALLY AS ONE MOVES NORTHWEST THROUGH THE FORECAST AREA. THE
ISENTROPIC LIFT RAIN OCCURRING EARLY THIS MORNING WAS MODERATE IN
NATURE, AND THE WATER VAPOR IMAGERY ALONG WITH SURFACE AND H8 DEW
POINTS AND H7 THETA E VALUES CONFIRM THAT MOISTURE IS DEEP. WE
START WITH HIGH FFG AND FFH VALUES (THE MOST VULNERABLE PLACES ARE
FAR NORTHERN NEW JERSEY AND THE AREA IN AND NEAR URBANIZED PARTS
OF THE DELAWARE VALLEY), BUT PLACES WHERE CONVECTION (ONCE IT
DEVELOPS) HITS HARDEST LIKELY WILL SEE SOME KIND OF FLOOD ADVISORY
OR WARNING. OUR QPF FOR TODAY THROUGH TONIGHT RANGES FROM A BIT
OVER AN INCH SOUTHEAST TO ALMOST 2.5 INCHES NORTHWEST, BUT LOCALES
HARD HIT BY CONVECTION COULD SEE IN EXCESS OF 4 INCHES ANYWHERE IN
THE FORECAST AREA.
REGARDING CONVECTION, THE DYNAMICS TO SUPPORT IT DEVELOP DURING THE
COURSE OF THE DAY WITH THE ADVANCING UPPER JET, A MID LEVEL IMPULSE
THAT WAS THE ROBUST TEXAS WAVE MOVING UP FROM THE SOUTHWEST, AND
GOOD MID LEVEL Q-VECTOR CONVERGENCE. LOWER LEVEL FRONTOGENESIS
INCREASES AS THE COLD FRONT APPROACHES, AND HELICITY BECOMES VERY
ROBUST AS A STRONG LOW LEVEL JET APPROACHES. THE LIMITING FACTOR
WOULD BE INSTABILITY. THERE IS ENOUGH ALOFT FOR SOME LOW TOP
CONVECTION TO DEVELOP, AND IT WOULD REQUIRE A BREAK BETWEEN THE
ISENTROPIC LIFT RAIN AND THE CONVECTIVE RAIN FOR US TO WARM
SUFFICIENTLY TO TAP THAT INSTABILITY AT THE SURFACE AND DEVELOP
STRONG TO SEVERE STORMS. THAT IS A POSSIBILITY, AND SPC MAINTAINS
OUR AREA IN A SLIGHT RISK.
REGARDING WINDS OUTSIDE OF CONVECTION, IT ALSO IS THE CASE THAT WE
WOULD HAVE TO WARM SUFFICIENTLY AT THE SURFACE TO MIX THE STRONG
WINDS AT ABOUT H950 DOWN. THE NAM SAYS WE WILL, ALTHOUGH THE GFS
DOES NOT. THE ADVISORY LIKELY STANDS A BETTER CHANCE VERIFYING
SOUTHEAST THAN NORTHWEST (EXCEPT FOR OUR HIGHER ELEVATIONS
NORTHWEST), BECAUSE THE CHANCES OF A SIGNIFICANT BREAK IN RAIN AND
CLOUDS IS HIGHER THERE. WE ARE NOT CONFIDENT ENOUGH TO TRIM THE
ADVISORY GEOGRAPHICALLY AT THIS POINT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
THE COLD FRONT AND MOST OF THE SUPPORT ALOFT MOVE THROUGH THE AREA
FROM LATE EVENING NORTHWEST TO AFTER MIDNIGHT SOUTHEAST (THE HIGHER
ONE GOES, THE MORE THE KINEMATICS AND DYNAMICS HANG BACK WITH THE
UPPER JET JUST INTO OUR WESTERN ZONES AROUND DAYBREAK). THE FRONT
SHOULD TAKE THE WINDS AND THE CONVECTION (POSSIBLY STRONG) WITH
HEAVY RAIN WITH IT, ALTHOUGH THERE MAY BE SOME REAR INFLOW RAINFALL
BEHIND THE FRONT THAT WOULD BE ENHANCED (AS THE PREVIOUS LONG TERM
FORECASTER NOTED) BY TRAILING FRONTOGENETIC FORCING AND THE UPPER
JET. SINCE WINDS ALOFT ARE STRONGEST NEAR THE COLD FRONT, WE DID NOT
CHANGE THE ADVISORY TIMING AT THIS POINT ALTHOUGH IT MAY BE MORE
DIFFICULT TO MIX WINDS DOWN OUTSIDE OF CONVECTION AFTER DUSK.
GUIDANCE AND CONTINUITY WERE RELIED ON FOR MINIMUM TEMPERATURES IN
THIS DYNAMIC PERIOD.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
5-WAVE MODEL GUIDANCE SHOWS MID-LEVEL RIDGING TO OUR EAST WITH A
LONGWAVE TROUGH TO OUR IMMEDIATE WEST WITH ANOTHER RIDGE OVER THE
WESTERN UNITED STATES. THE RIDGE TO OUR EAST WILL NOT ALLOW MUCH
WEST-EAST PROGRESSION OF THE TROUGH OVER THE MID-WEST WHICH KEEPS
OUR SENSIBLE WEATHER DRY BUT A TAD COOLER THAN NORMAL WITH AN
ONSHORE FLOW ESTABLISHING ITSELF BY THURSDAY. THE BLOCKY PATTERN
WILL ALSO KEEP THE COLD FRONT THAT MOVED THROUGH LATE TUESDAY NIGHT
CLOSER TO THE COAST WHICH COULD PLAY A FACTOR IN A BIT MORE CLOUD
COVER THAN CURRENTLY FORECASTED.
DRYING TREND WILL CONTINUE THROUGH THE EARLY PART OF WEDNESDAY AS
THE POTENT COLD FRONT PUSHES FURTHER OFFSHORE, BUT AS WAS SAID
ABOVE, GETS HUNG UP A BIT. A BRISK NORTH-NORTHWEST WIND KICKS IN AND
REALLY BEGINS TO COOL THE COLUMN. 850MB TEMPERATURES DROP TO NEAR
5-6C AND IF WE ARE ABLE TO MIX UP TO THAT LEVEL ADIABATICALLY, THAT
WOULD YIELD MAXIMUM TEMPERATURES AROUND 71F...WELL BELOW NORMAL. THE
STAT GUIDANCE SUGGESTED TEMPERATURES WOULD BE A BIT WARMER THAN THIS
WHICH SEEMS COMPLETELY PROBABLE GIVEN A MINOR DOWNSLOPING COMPONENT
TOMORROW AFTERNOON UNDER AMPLE SUNSHINE.
THE STRONGER FLOW WEAKENS AS HIGH PRESSURE TO OUR NORTHWEST SLOWLY
BUILDS IN ON THURSDAY GIVING US MORE OF AN ONSHORE WIND. OCEAN
TEMPERATURES RANGING FROM THE LOW TO MID-70S SHOULD PERMIT DAYTIME
MAXES IN THE MID TO UPPER 70S, MAINLY INTERIOR AREAS, ON BOTH
THURSDAY AND FRIDAY...PLENTY OF SUNSHINE BOTH DAYS TOO. THIS HIGH
THEN SLIDES TO OUR EAST AND SETS UP A WEAK RETURN FLOW ON SATURDAY.
ENERGY ACROSS THE UPPER MID-WEST DIVES INTO THE STUCK LONGWAVE
TROUGH TO OUR WEST AND BEGINS TO NUDGE IT TOWARDS THE EAST. THIS
MID-LEVEL WAVE THEN DROPS A COLD FRONT THROUGH OUR REGION BY LATER
ON SATURDAY INTO SUNDAY MORNING. THIS IS OUR NEXT CHANCE AT
UNSETTLED WEATHER...TIMING IS STILL IN QUESTION DUE TO HOW STRONG
THE ENERGY DIVING INTO THE BASE OF THE TROUGH ACTUALLY IS AND
THEREFORE HOW FAST IT PUSHING IT EAST. FOR THE TIME BEING MAINTAINED
CHANCE POPS ON SATURDAY AND PART OF SUNDAY AND THEN DRY OUT MONDAY
WITH HIGH PRESSURE NEARING. TEMPERATURES WILL ALSO FALL BACK BELOW
NORMAL ON SUNDAY AND MONDAY BEHIND THE SECOND COLD FRONTAL PASSAGE.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
HEAVY RAIN ASSOCIATED WITH AN APPROACHING STORM SYSTEM WILL CONTINUE
TO SPREAD EAST ACROSS THE TAF SITES THIS AFTERNOON INTO THIS
EVENING. CONDITIONS ARE MOSTLY VFR OR MVFR EARLY THIS AFTERNOON, BUT
AS THE SHOWERS SPREAD EASTWARD, CONDITIONS WILL DETERIORATE. AS THE
HEAVIEST LINE OF SHOWERS, AND POSSIBLE THUNDERSTORMS, REACHES THE
AREA LATER THIS AFTERNOON/THIS EVENING, THE TERMINALS WILL LIKELY
BECOME IFR FOR A PERIOD OF TIME. THERE ARE ACTUALLY TWO FRONTS THAT
ARE MOVING TOWARD THE AREA; THE FIRST HAS THE HEAVY RAINFALL, LOW
CIG/VSBY CONDITIONS, AND WIND A WIND SHIFT, AND WILL SLOWLY MOVE
ACROSS THE TAF SITES AROUND 22-02Z FROM WEST TO EAST. THE SECOND
FRONT WILL CROSS THE AREA OVERNIGHT, AND WILL HAVE ANOTHER WIND
SHIFT WITH NORTHWEST WINDS TO FOLLOW; ALSO, WINDS ARE EXPECTED TO
DIMINISH BEHIND THE SECOND FRONT. AHEAD AND ALONG THE INITIAL
FRONT, WINDS WILL CONTINUE TO GUST IN THE UPPER 20S TO MID 30S.
ON WEDNESDAY, WINDS MAY BE A BIT GUSTY EARLY IN THE DAY ONCE WE
BEGIN TO MIX-OUT BY MID-MORNING, BUT THE WINDS GUSTS WILL LIKELY
DIMINISH THROUGH THE AFTERNOON. VFR CONDITIONS SHOULD PREVAIL FOR
THE ENTIRE DAY.
OUTLOOK...
THURSDAY - FRIDAY...VFR CONDITIONS EXPECTED. WINDS TURN MORE NORTH-
NORTHEAST ON THURSDAY AND FRIDAY. POSSIBLE MVFR VSBYS IN THE EARLY
MORNING HOURS OUTSIDE OF THE PHL METRO AREA.
SATURDAY...STARTS OFF VFR WITH POSSIBLE MVFR CIGS AND VSBYS AS COLD
FRONT SLIDES THROUGH LATER IN THE DAY. SCATTERED SHOWERS ALSO
POSSIBLE.
&&
.MARINE...
GALES WERE STARTED AT THE PRESENT AS WE ARE STARTING TO SEE SOME
GALE FORCE GUSTS.
WE MAINTAIN THE GALE WARNING AS IT WAS. WATER TEMPERATURES NEAR 25 C
STAND A FAIR CHANCE OF TAPPING THE STRONG WINDS EXPECTED TO DEVELOP
AT AROUND 1500 FT. THE COLD FRONT WILL CROSS THE WATERS WELL AFTER
MIDNIGHT TONIGHT, AND THAT WILL END THE GALES. SEAS OF UP TO 10 OR
11 FT ARE FORECAST FOR THE OCEAN AND SEAS OF UP TO 6 FT ARE FORECAST
FOR THE BAY WHILE THE GALES OCCUR.
OUTLOOK...
NORTHWEST WINDS WILL REMAIN QUITE GUSTY ON WEDNESDAY AT AROUND 25
KNOTS, ULTIMATELY DIMINISHING BY LATE IN THE AFTERNOON. HIGH
PRESSURE BUILDS IN FROM THE NORTH-NORTHWEST AND WINDS BEGIN TO TURN
MORE TOWARDS THE NORTHEAST BY THURSDAY AND FRIDAY. SEAS WILL DROP
FROM 8 FEET EARLY WEDNESDAY TO 4 FEET BY EARLY THURSDAY MORNING AND
REMAIN THERE THROUGH AT LEAST SATURDAY. THIS IS WHEN THE NEXT
SYSTEM, A COLD FRONT, MOVES IN FROM THE NORTHWEST AND COULD AFFECT
OUR WATERS WITH SHOWERS AND POSSIBLE THUNDERSTORMS. WINDS WILL
GENERALLY BE OUT OF THE SOUTH-SOUTHEAST ON SATURDAY AND THEN TURN
TOWARDS THE WEST AFTER THE FRONT GOES THROUGH BY SUNDAY.
&&
.TIDES/COASTAL FLOODING...
CBOFS, DBOFS AND A LOCAL ALGORITHM ARE POINTING TO ADVISORY LEVEL
TIDES FROM REEDY POINT UP THE TIDAL DELAWARE RIVER THIS AFTERNOON
AND UP CHESAPEAKE BAY THIS EVENING INTO THE OVERNIGHT. WITH A STRONG
SOUTHERLY FLOW EXPECTED TO DEVELOP AND WITH THE POSSIBILITY OF HEAVY
RAINFALL NOT BEING ABLE TO DRAIN WELL IF IT OCCURS AROUND HIGH TIDE,
WE ISSUED AN ADVISORY FOR THE ABOVE LOCATIONS.
&&
.RIP CURRENTS...
WE HAVE GONE WITH A HIGH RISK OF RIP CURRENTS FOR TODAY, WITH
WAVES IN THE SURF ZONE EXPECTED TO BE MAINLY IN THE 4 TO 7 FOOT
RANGE ALONG WITH A STRONG SOUTHERLY WIND.
CONDITIONS SHOULD IMPROVE DURING THE MIDDLE AND LATTER PART OF
THE WEEK.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR PAZ054-055-
060>062-067>071.
COASTAL FLOOD ADVISORY UNTIL 6 PM EDT THIS EVENING FOR PAZ070-
071.
NJ...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR NJZ001-007>010-
012>027.
HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR NJZ014-
024>026.
COASTAL FLOOD ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
NJZ016>019.
DE...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR DEZ001>004.
HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR DEZ004.
COASTAL FLOOD ADVISORY UNTIL 6 PM EDT THIS EVENING FOR DEZ001.
MD...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR MDZ008-012-015-
019-020.
COASTAL FLOOD ADVISORY FROM 6 PM THIS EVENING TO 1 AM EDT
WEDNESDAY FOR MDZ008-012-015-019-020.
MARINE...GALE WARNING UNTIL 4 AM EDT WEDNESDAY FOR ANZ430-431-450>455.
&&
$$
SYNOPSIS...HEAVENER
NEAR TERM...GIGI
SHORT TERM...DELISI
LONG TERM...HEAVENER
AVIATION...ROBERTSON/HEAVENER
MARINE...DELISI/HEAVENER
TIDES/COASTAL FLOODING...DELISI
RIP CURRENTS...DELISI
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1202 PM EDT TUE SEP 18 2012
.SYNOPSIS...
SLOW MOVING, BUT POTENT, COLD FRONT WILL SWEEP THROUGH THE REGION
LATER TONIGHT AS THE PARENT LOW PRESSURE SYSTEM MOVES TO OUR
NORTHEAST. HIGH PRESSURE WILL BUILD IN FROM THE NORTH LATER ON
WEDNESDAY THROUGH FRIDAY. ANOTHER COLD FRONT LOOKS TO PUSH THROUGH
OUR REGION LATE IN THE DAY ON SATURDAY WITH HIGH PRESSURE ONCE
AGAIN FILLING IN BEHIND IT LATER ON SUNDAY INTO MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOOKING AT THE 12Z SFC ANALYSIS AND UPPER AIR PATTERN. AS MY MID
SHIFT PREDECESSOR HAS BEEN SAYING FOR DAYS WE STILL HAVE AN
UNPHASED SYSTEM APPROACHING FROM THE WEST. IT LOOKS AS THOUGH MOST
OF THE ACTION WILL BE FROM THE SOUTHERN STREAM SYSTEM WITH THE
SECOND FRONT MAYBE PROLONGING LIGHTER RAIN CHANCES DEEPER INTO THE
NIGHT.
EVEN WITHOUT THE PHASING THERE IS SFC BASED INSTABILITY AND KDIX
AND KDOX VMP ARE BOTH SHOWING 50KTS OF WIND ALRDY AT 3K. THE HI
RES WRF-NMM EAST IS SHOWING THE BEST DEPICTION OF ONOGING
CONVECTION, BOTH THE HRRR AND COSPA SEEM TOO HOT TOO EAST TOO
FAST. WE HAVE CLOUDED OVER WHICH WOULD REDUCE INSTABILITY A BIT,
BUT ITS NOT ENOUGH. SO WE WILL WAIT FOR ORGANIZATION TO ENHANCE
THE POTENTIAL FOR SEVERE WEATHER AND FOLLOWING THE WRF-NMM-E FOR
NOW AS HIEST IMPACT TIME.
THE HEAVIEST RAIN HAS FALLEN SO FAR NORTH AND WEST WHERE FFG IS
HIGH, SO UNLESS THERE IS TRAINING, SO FAR SO GOOD.
IF WE DID NOT HAVE THE TOPOGRAPHY NW, WE ARE TEMPTED TO DROP THE
ADVISORY THERE, BUT WITH THE HIER TERRAIN, WE WILL KEEP IT GOING.
HIEST CONFIDENCE OUTSIDE OF CONVECTION REMAINS EAST FOR WIND ADVY
GUSTS. NO BIG CHANGES TO TEMPS AND DEW POINTS.
AS HAS BEEN NOTED IN PREVIOUS DISCUSSIONS, TODAY LOOKS TO BE AN
ACTIVE DAY. THE MODELS STILL SUPPORT THE HEAVY RAIN CONCERN
ESPECIALLY AS ONE MOVES NORTHWEST THROUGH THE FORECAST AREA. THE
ISENTROPIC LIFT RAIN OCCURRING EARLY THIS MORNING WAS MODERATE IN
NATURE, AND THE WATER VAPOR IMAGERY ALONG WITH SURFACE AND H8 DEW
POINTS AND H7 THETA E VALUES CONFIRM THAT MOISTURE IS DEEP. WE
START WITH HIGH FFG AND FFH VALUES (THE MOST VULNERABLE PLACES ARE
FAR NORTHERN NEW JERSEY AND THE AREA IN AND NEAR URBANIZED PARTS
OF THE DELAWARE VALLEY), BUT PLACES WHERE CONVECTION (ONCE IT
DEVELOPS) HITS HARDEST LIKELY WILL SEE SOME KIND OF FLOOD ADVISORY
OR WARNING. OUR QPF FOR TODAY THROUGH TONIGHT RANGES FROM A BIT
OVER AN INCH SOUTHEAST TO ALMOST 2.5 INCHES NORTHWEST, BUT LOCALES
HARD HIT BY CONVECTION COULD SEE IN EXCESS OF 4 INCHES ANYWHERE IN
THE FORECAST AREA.
REGARDING CONVECTION, THE DYNAMICS TO SUPPORT IT DEVELOP DURING THE
COURSE OF THE DAY WITH THE ADVANCING UPPER JET, A MID LEVEL IMPULSE
THAT WAS THE ROBUST TEXAS WAVE MOVING UP FROM THE SOUTHWEST, AND
GOOD MID LEVEL Q-VECTOR CONVERGENCE. LOWER LEVEL FRONTOGENESIS
INCREASES AS THE COLD FRONT APPROACHES, AND HELICITY BECOMES VERY
ROBUST AS A STRONG LOW LEVEL JET APPROACHES. THE LIMITING FACTOR
WOULD BE INSTABILITY. THERE IS ENOUGH ALOFT FOR SOME LOW TOP
CONVECTION TO DEVELOP, AND IT WOULD REQUIRE A BREAK BETWEEN THE
ISENTROPIC LIFT RAIN AND THE CONVECTIVE RAIN FOR US TO WARM
SUFFICIENTLY TO TAP THAT INSTABILITY AT THE SURFACE AND DEVELOP
STRONG TO SEVERE STORMS. THAT IS A POSSIBILITY, AND SPC MAINTAINS
OUR AREA IN A SLIGHT RISK.
REGARDING WINDS OUTSIDE OF CONVECTION, IT ALSO IS THE CASE THAT WE
WOULD HAVE TO WARM SUFFICIENTLY AT THE SURFACE TO MIX THE STRONG
WINDS AT ABOUT H950 DOWN. THE NAM SAYS WE WILL, ALTHOUGH THE GFS
DOES NOT. THE ADVISORY LIKELY STANDS A BETTER CHANCE VERIFYING
SOUTHEAST THAN NORTHWEST (EXCEPT FOR OUR HIGHER ELEVATIONS
NORTHWEST), BECAUSE THE CHANCES OF A SIGNIFICANT BREAK IN RAIN AND
CLOUDS IS HIGHER THERE. WE ARE NOT CONFIDENT ENOUGH TO TRIM THE
ADVISORY GEOGRAPHICALLY AT THIS POINT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
THE COLD FRONT AND MOST OF THE SUPPORT ALOFT MOVE THROUGH THE AREA
FROM LATE EVENING NORTHWEST TO AFTER MIDNIGHT SOUTHEAST (THE HIGHER
ONE GOES, THE MORE THE KINEMATICS AND DYNAMICS HANG BACK WITH THE
UPPER JET JUST INTO OUR WESTERN ZONES AROUND DAYBREAK). THE FRONT
SHOULD TAKE THE WINDS AND THE CONVECTION (POSSIBLY STRONG) WITH
HEAVY RAIN WITH IT, ALTHOUGH THERE MAY BE SOME REAR INFLOW RAINFALL
BEHIND THE FRONT THAT WOULD BE ENHANCED (AS THE PREVIOUS LONG TERM
FORECASTER NOTED) BY TRAILING FRONTOGENETIC FORCING AND THE UPPER
JET. SINCE WINDS ALOFT ARE STRONGEST NEAR THE COLD FRONT, WE DID NOT
CHANGE THE ADVISORY TIMING AT THIS POINT ALTHOUGH IT MAY BE MORE
DIFFICULT TO MIX WINDS DOWN OUTSIDE OF CONVECTION AFTER DUSK.
GUIDANCE AND CONTINUITY WERE RELIED ON FOR MINIMUM TEMPERATURES IN
THIS DYNAMIC PERIOD.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
5-WAVE MODEL GUIDANCE SHOWS MID-LEVEL RIDGING TO OUR EAST WITH A
LONGWAVE TROUGH TO OUR IMMEDIATE WEST WITH ANOTHER RIDGE OVER THE
WESTERN UNITED STATES. THE RIDGE TO OUR EAST WILL NOT ALLOW MUCH
WEST-EAST PROGRESSION OF THE TROUGH OVER THE MID-WEST WHICH KEEPS
OUR SENSIBLE WEATHER DRY BUT A TAD COOLER THAN NORMAL WITH AN
ONSHORE FLOW ESTABLISHING ITSELF BY THURSDAY. THE BLOCKY PATTERN
WILL ALSO KEEP THE COLD FRONT THAT MOVED THROUGH LATE TUESDAY NIGHT
CLOSER TO THE COAST WHICH COULD PLAY A FACTOR IN A BIT MORE CLOUD
COVER THAN CURRENTLY FORECASTED.
DRYING TREND WILL CONTINUE THROUGH THE EARLY PART OF WEDNESDAY AS
THE POTENT COLD FRONT PUSHES FURTHER OFFSHORE, BUT AS WAS SAID
ABOVE, GETS HUNG UP A BIT. A BRISK NORTH-NORTHWEST WIND KICKS IN AND
REALLY BEGINS TO COOL THE COLUMN. 850MB TEMPERATURES DROP TO NEAR
5-6C AND IF WE ARE ABLE TO MIX UP TO THAT LEVEL ADIABATICALLY, THAT
WOULD YIELD MAXIMUM TEMPERATURES AROUND 71F...WELL BELOW NORMAL. THE
STAT GUIDANCE SUGGESTED TEMPERATURES WOULD BE A BIT WARMER THAN THIS
WHICH SEEMS COMPLETELY PROBABLE GIVEN A MINOR DOWNSLOPING COMPONENT
TOMORROW AFTERNOON UNDER AMPLE SUNSHINE.
THE STRONGER FLOW WEAKENS AS HIGH PRESSURE TO OUR NORTHWEST SLOWLY
BUILDS IN ON THURSDAY GIVING US MORE OF AN ONSHORE WIND. OCEAN
TEMPERATURES RANGING FROM THE LOW TO MID-70S SHOULD PERMIT DAYTIME
MAXES IN THE MID TO UPPER 70S, MAINLY INTERIOR AREAS, ON BOTH
THURSDAY AND FRIDAY...PLENTY OF SUNSHINE BOTH DAYS TOO. THIS HIGH
THEN SLIDES TO OUR EAST AND SETS UP A WEAK RETURN FLOW ON SATURDAY.
ENERGY ACROSS THE UPPER MID-WEST DIVES INTO THE STUCK LONGWAVE
TROUGH TO OUR WEST AND BEGINS TO NUDGE IT TOWARDS THE EAST. THIS
MID-LEVEL WAVE THEN DROPS A COLD FRONT THROUGH OUR REGION BY LATER
ON SATURDAY INTO SUNDAY MORNING. THIS IS OUR NEXT CHANCE AT
UNSETTLED WEATHER...TIMING IS STILL IN QUESTION DUE TO HOW STRONG
THE ENERGY DIVING INTO THE BASE OF THE TROUGH ACTUALLY IS AND
THEREFORE HOW FAST IT PUSHING IT EAST. FOR THE TIME BEING MAINTAINED
CHANCE POPS ON SATURDAY AND PART OF SUNDAY AND THEN DRY OUT MONDAY
WITH HIGH PRESSURE NEARING. TEMPERATURES WILL ALSO FALL BACK BELOW
NORMAL ON SUNDAY AND MONDAY BEHIND THE SECOND COLD FRONTAL PASSAGE.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY AND TONIGHT...FREQUENT MVFR CONDITIONS WITH OCCASIONAL IFR
CONDITIONS ARE FORECAST INTO THE EVENING FIRST IN SHOWERS AND THEN
IN THUNDERSTORMS. THEY SHOULD IMPROVE TO VFR BY A FEW HOURS BEFORE
DAYBREAK FROM NORTHWEST TO SOUTHEAST. THUNDERSTORMS COULD BE
ACCOMPANIED BY STRONG WIND GUSTS. SOUTHERLY SURFACE WINDS OUTSIDE OF
THUNDERSTORMS COULD INCREASE TO ABOVE 30 KNOTS DURING THE DAY (THAT
WAS IN THE TAFS AS OF EARLY THIS MORNING), BUT IF AND WHERE THAT
DOES NOT HAPPEN LOW LEVEL WIND SHEAR WOULD DEVELOP (THAT WAS NOT IN
THE TAFS AS OF THIS MORNING). THE IMPROVEMENT TO VFR WILL
COINCIDE WITH A SHIFT IN THE WINDS TO THE WEST. ANY THREAT OF
STRONG WINDS OR LLWS WILL END WITH THAT SHIFT.
OUTLOOK...
WEDNESDAY - FRIDAY...VFR CONDITIONS EXPECTED. GUSTY NORTHWEST WINDS
ON WEDNESDAY BEGIN TO DIMINISH BY LATE EVENING. WINDS TURN MORE
NORTH-NORTHEAST ON THURSDAY AND FRIDAY. POSSIBLE MVFR VSBYS IN THE
EARLY MORNING HOURS OUTSIDE OF THE PHL METRO AREA.
SATURDAY...STARTS OFF VFR WITH POSSIBLE MVFR CIGS AND VSBYS AS COLD
FRONT SLIDES THROUGH LATER IN THE DAY. SCATTERED SHOWERS ALSO
POSSIBLE.
&&
.MARINE...
GALES WERE STARTED AT THE PRESENT AS WE ARE STARTING TO SEE SOME
GALE FORCE GUSTS.
WE MAINTAIN THE GALE WARNING AS IT WAS. WATER TEMPERATURES NEAR 25 C
STAND A FAIR CHANCE OF TAPPING THE STRONG WINDS EXPECTED TO DEVELOP
AT AROUND 1500 FT. THE COLD FRONT WILL CROSS THE WATERS WELL AFTER
MIDNIGHT TONIGHT, AND THAT WILL END THE GALES. SEAS OF UP TO 10 OR
11 FT ARE FORECAST FOR THE OCEAN AND SEAS OF UP TO 6 FT ARE FORECAST
FOR THE BAY WHILE THE GALES OCCUR.
OUTLOOK...
NORTHWEST WINDS WILL REMAIN QUITE GUSTY ON WEDNESDAY AT AROUND 25
KNOTS, ULTIMATELY DIMINISHING BY LATE IN THE AFTERNOON. HIGH
PRESSURE BUILDS IN FROM THE NORTH-NORTHWEST AND WINDS BEGIN TO TURN
MORE TOWARDS THE NORTHEAST BY THURSDAY AND FRIDAY. SEAS WILL DROP
FROM 8 FEET EARLY WEDNESDAY TO 4 FEET BY EARLY THURSDAY MORNING AND
REMAIN THERE THROUGH AT LEAST SATURDAY. THIS IS WHEN THE NEXT
SYSTEM, A COLD FRONT, MOVES IN FROM THE NORTHWEST AND COULD AFFECT
OUR WATERS WITH SHOWERS AND POSSIBLE THUNDERSTORMS. WINDS WILL
GENERALLY BE OUT OF THE SOUTH-SOUTHEAST ON SATURDAY AND THEN TURN
TOWARDS THE WEST AFTER THE FRONT GOES THROUGH BY SUNDAY.
&&
.TIDES/COASTAL FLOODING...
CBOFS, DBOFS AND A LOCAL ALGORITHM ARE POINTING TO ADVISORY LEVEL
TIDES FROM REEDY POINT UP THE TIDAL DELAWARE RIVER THIS AFTERNOON
AND UP CHESAPEAKE BAY THIS EVENING INTO THE OVERNIGHT. WITH A STRONG
SOUTHERLY FLOW EXPECTED TO DEVELOP AND WITH THE POSSIBILITY OF HEAVY
RAINFALL NOT BEING ABLE TO DRAIN WELL IF IT OCCURS AROUND HIGH TIDE,
WE ISSUED AN ADVISORY FOR THE ABOVE LOCATIONS.
&&
.RIP CURRENTS...
WE HAVE GONE WITH A HIGH RISK OF RIP CURRENTS FOR TODAY, WITH
WAVES IN THE SURF ZONE EXPECTED TO BE MAINLY IN THE 4 TO 7 FOOT
RANGE ALONG WITH A STRONG SOUTHERLY WIND.
CONDITIONS SHOULD IMPROVE DURING THE MIDDLE AND LATTER PART OF
THE WEEK.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR PAZ054-055-
060>062-067>071.
COASTAL FLOOD ADVISORY UNTIL 6 PM EDT THIS EVENING FOR PAZ070-
071.
NJ...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR NJZ001-007>010-
012>027.
HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR NJZ014-
024>026.
COASTAL FLOOD ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
NJZ016>019.
DE...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR DEZ001>004.
HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR DEZ004.
COASTAL FLOOD ADVISORY UNTIL 6 PM EDT THIS EVENING FOR DEZ001.
MD...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR MDZ008-012-015-
019-020.
COASTAL FLOOD ADVISORY FROM 6 PM THIS EVENING TO 1 AM EDT
WEDNESDAY FOR MDZ008-012-015-019-020.
MARINE...GALE WARNING UNTIL 4 AM EDT WEDNESDAY FOR ANZ430-431-450>455.
&&
$$
SYNOPSIS...HEAVENER
NEAR TERM...DELISI/GIGI
SHORT TERM...DELISI
LONG TERM...HEAVENER
AVIATION...DELISI/HEAVENER
MARINE...DELISI/HEAVENER
TIDES/COASTAL FLOODING...DELISI
RIP CURRENTS...DELISI
AREA FORECAST DISCUSSION
NWS MIAMI FL
509 PM EDT TUE SEP 18 2012
.UPDATE...LINE OF SHOWERS AND THUNDERSTORMS OVER THE GULF OF
MEXICO IS MOVING TOWARDS THE GULF COAST/NAPLES AREA. THIS LINE
WILL IMPACT THIS AREA THROUGH EARLY EVENING. THE LINE IS MOVING
STEADILY EASTWARD...AND LATEST HRRR SHOWS THIS CONVECTION TRACKING
ACROSS SOUTH FLORIDA TONIGHT, REACHING THE EAST COAST METRO AREA
AT AROUND MIDNIGHT. GIVEN THE AMPLIFIED TROUGH AND INCOMING
SHORTWAVE, THIS SEEMS PLAUSIBLE. AS SUCH, HAVE UPDATED THE
FORECAST TO ACCOUNT FOR LIKELY ACTIVITY GULF COAST AND A CHANCE
OF THUNDERSTORMS EAST COAST METRO TONIGHT...AS THERE IS THE
POTENTIAL FOR THIS LINE OF STORMS TO MOVE INTO THE AREA TONIGHT.
IN OTHER WORDS, NOT OUR TYPICAL DIURNAL CYCLE. LIGHTNING/HEAVY
RAINS MAIN IMPACTS, BUT LOCALIZED WIND GUSTS OF 40-50 MPH
POSSIBLE. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 210 PM EDT TUE SEP 18 2012/
DISCUSSION...AN EXTREMELY COMPLEX WEATHER PATTERN IS DEVELOPING
ACROSS THE U.S. WHICH WILL HAVE ITS AFFECTS ON SOUTH FLORIDA. A MID
LEVEL TROUGH OVER THE GULF COAST NEAR THE LOWER MISSISSIPPI VALLEY
THIS MORNING IS BECOMING ABSORBED INTO LARGER SCALE TROUGH DEEPENING
INTO THE SOUTHEAST STATES WITH ITS ASSOCIATED COLD FRONT MOVING INTO
THE FL PANHANDLE. THIS SYSTEM WILL RAPIDLY LIFT TO THE NORTHEAST
TONIGHT AND WEDNESDAY AS ANOTHER TROUGH ROTATES THROUGH THE BASE OF
THE MAIN TROUGH AXIS AND MASSIVE RIDGES BUILD OVER THE WESTERN U.S.
AND THE WESTERN ATLANTIC. THIS IN TURN WILL ALLOW THE COLD FRONT TO
MOVE INTO NORTH CENTRAL FLORIDA AND STALL AS THE PENINSULA SOMEWHAT
BECOMES SANDWICHED IN BETWEEN ALL OF THESE SYSTEMS. THIS EVOLVING
SITUATION WILL ALSO RESULT IN ANOTHER DAY ON WEDNESDAY OF DEEP
SOUTHWESTERLY FLOW AND KEEP THE HIGHEST POPS OVER THE INTERIOR AND
EAST COAST METRO REGIONS.
ON THURSDAY, THE RIDGE OUT WEST WILL CONTINUE TO AMPLIFY WITH THE
MAIN ENERGY OF THE EASTERN TROUGH CONTINUING TO LIFT TO THE
NORTHEAST. THIS HAPPENS DUE TO THE ATLANTIC RIDGE SHIFTING WEST AS A
LARGE MID LEVEL TROUGH MOVES INTO THE CENTRAL ATLANTIC. REACTING TO
THIS WILL BE THE SFC RIDGE SHIFTING BACK NORTH PLACING SOUTH FLORIDA
IN A LOW LEVEL SOUTHEAST FLOW WITH WEAKER STEERING ALOFT. THE END
RESULT WILL BE SEA BREEZE DRIVEN ACTIVITY MOVING VERY LITTLE BUT
TENDING TO FAVOR THE INTERIOR SECTIONS. ALL IN ALL IN THE SHORT
TERM, MAJOR WEATHER SYSTEMS WILL BE FAR REMOVED FROM SOUTH FLORIDA
BUT PLACING US IN A FAVORABLE LOCATION FOR DAILY AFTERNOON/EVENING
SHOWERS AND THUNDERSTORMS.
IN THE EXTENDED PERIOD INTO THE WEEKEND AND EARLY NEXT WEEK, THE
WEATHER PATTERN WILL CHANGE VERY SLOWLY AND IT APPEARS THAT SOUTH
FLORIDA WILL BE UNDER THE INFLUENCE OF SEVERAL DAYS WITH SEA BREEZE
INTERACTION VARIETY THUNDERSTORM ACTIVITY. SO THE MAIN AREA OF
CONCERN FOR RAINFALL FROM THURSDAY INTO EARLY NEXT WEEK WILL BE THE
FAR WESTERN SUBURBS OF BOTH COASTS AND ANY LOCATION OVER THE
INTERIOR.
AVIATION...A RIDGE OF HIGH PRESSURE AT THE SURFACE AND ALOFT
SOUTHEAST OF THE AREA AND OVER THE FLA STRAITS WILL PERSIST THROUGH
THE PERIOD. WINDS WILL BE SOUTHERLY < 10 KTS THEN BECOME SSW TO SW
AND INCREASE 10 TO 15 KNOTS AS THE DAY PROGRESSES. NO E COAST SEA
BREEZE EXPECTED. WITH THE SSW-SW WIND FLOW...SOME VCSH AT KAPF WITH
VCTS EXPECTED AT ALL TERMINALS AFT 17Z. POSSIBLE THAT SOME MVFR
VSBY/CIG AT ANY ONE TERMINAL IF A TSRA MOVES OVER LATER TODAY.
MARINE...OUTSIDE OF SHOWERS AND THUNDERSTORMS, BOATING CONDITIONS
WILL BE TRANQUIL WITH A SOUTH TO SOUTHWEST WIND LESS THAN 15 KNOTS
THROUGH WEDNESDAY BECOMING SOUTHEASTERLY AT LESS THAN 15 KNOTS
THURSDAY INTO THE WEEKEND. THIS WILL RESULT IN SEAS OF LESS THAN 4 FEET.
FIRE WEATHER...NO PROBLEMS OR CONCERNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 76 89 75 87 / 40 50 30 40
FORT LAUDERDALE 77 90 76 87 / 40 40 20 40
MIAMI 77 90 78 88 / 40 40 20 40
NAPLES 76 89 74 89 / 60 30 20 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS TAMPA BAY RUSKIN FL
200 PM EDT TUE SEP 18 2012
.SYNOPSIS...
18Z WATER VAPOR AND H4 RUC ANALYSIS SHOWS A HIGHLY AMPLIFIED UPPER
LEVEL PATTERN ACROSS NORTH AMERICA. NORTHERN STREAM FLOW ARRIVES
ATOP RIDGING ALONG THE BRITISH COLUMBIA COASTLINE BEFORE RAPIDLY
DIVING SOUTHWARD INTO A DOMINANT LONG WAVE TROUGH IN CONTROL OF THE
EASTERN HALF OF THE CONTINENT. THIS TROUGH AXIS EXTENDS FROM ONTARIO
THROUGH THE GREAT LAKES AND DOWN ALL THE WAY TO THE NORTHERN GULF
COAST. SHORTWAVE ENERGY ROUNDING THE BASE OF THIS TROUGH HAS BEEN
PIVOTING EASTWARD AND NORTHEASTWARD TODAY FROM NEAR THE MS DELTA
REGION TO SOUTHERN AL/GA. DEEP LAYER QG FORCING IN ADVANCE OF THIS
ENERGY ALONG WITH SOME WEAK UPPER LEVEL DIFFLUENCE AND ABUNDANT DEEP
LAYER MOISTURE HAS BEEN SUFFICIENT TO FORCE SEVERAL BANDS OF
CONVECTION ACROSS NORTH/CENTRAL FLORIDA AND THE EASTERN GULF OF
MEXICO. THE MOST ORGANIZED CONVECTION AND HIGHEST RAIN CHANCES
(CATEGORICAL) WILL REMAIN FROM THE TAMPA BAY AREA NORTHWARD THE REST
OF THE AFTERNOON. SOUTH OF TAMPA BAY RAIN CHANCES (SCATTERED
SHOWERS/STORMS) WILL CONTINUE TO INCREASE IN COVERAGE...BUT BE A
RESULT OF MORE TYPICAL DIURNAL HEATING PROCESSES.
AT THE SURFACE...FORECAST AREA RESIDES BETWEEN THE SUBTROPICAL RIDGE
AXIS ALONG THE FLORIDA STRAITS AND A COLD FRONT EXTENDING FROM NEAR
ATLANTA GA SOUTHWARD TO THE FLORIDA PANHANDLE. THIS FRONT WILL
SLOWLY PROCEED EASTWARD...BUT WILL NOT BE REACHING OUR ZONES THROUGH
TONIGHT.
&&
.SHORT TERM (TONIGHT THROUGH THURSDAY)...
TONIGHT...THE SHORTWAVE ENERGY THAT HAS BEEN FORCING MUCH OF THE
ORGANIZED CONVECTION TODAY WILL BE SHEARING OUT TO THE NORTHEAST
THIS EVENING WITH A WEAKENING OF THE OVERALL SYNOPTIC FORCING.
HOWEVER...WITH THE MAIN UPPER LEVEL TROUGH AXIS STILL TO OUR
WEST...THE WEAK DIFFLUENCE ALOFT...ALONG WITH ANY SMALLER IMPULSE
MOVING THROUGH THE FLOW WILL KEEP PERIODS OF SHOWERS AND STORMS
MOVING ASHORE. FORECAST WILL SHOW POPS IN THE LIKELY RANGE MOST
PLACES THROUGH THE EVENING HOURS...AND THEN TAPER BACK TO CHANCE
POPS AFTER MIDNIGHT.
WEDNESDAY...COLD FRONT WILL SETTLE OVER THE NATURE COAST ZONES IN A
POSITION FAR ENOUGH NORTH TO PREVENT ANY SIGNIFICANT INTRUSION OF
DRIER AIR. WHILE NO POTENT IMPULSES ARE EXPECTED TO ORGANIZE
CONVECTION...THE GENERAL CYCLONIC FLOW...DEEP MOISTURE AND
DIFFLUENCE ALOFT SHOULD RESULT IN DECENT COVERAGES OF SHOWERS AND
STORMS THROUGH THE DAY. THESE STORMS MAY BE MOSTLY CONFINED CLOSE TO
THE COAST IN THE MORNING...BUT SHOULD EXPAND INLAND WITH TIME AS
DIURNAL HEATING AIDS THE OVERALL LIFT. HAVE GONE WITH CHANCE 30-50%
POPS NORTH AND LIKELY 60% POPS ALONG AND SOUTH OF THE I-4 CORRIDOR.
THURSDAY...
UPPER TROUGH WILL BEGIN TO SHOW SIGNS OF WEAKENING WHILE THE SURFACE
FRONT DISSIPATES OVER THE NORTHERN/CENTRAL PENINSULA. WITH LESS IN
THE WAY OF FOCUS FOR LIFT...WILL KEEP LIKELY POPS OUT OF THE
FORECAST FOR THE TIME BEING. HOWEVER...DEEP LAYER MOISTURE WILL
STILL BE IN PLACE...AND THIS SHOULD BE ENOUGH TO SUPPORT AT LEAST OF
CHANCE POP FOR SCATTERED MAINLY DIURNALLY FORCED CONVECTION.
&&
LONG TERM (FRIDAY THROUGH MONDAY)...
LITTLE CHANGE IN THE U/L PATTERN THROUGH THE PERIOD AS AN EXTENSIVE
L/W TROUGH EXTENDING FROM THE GREAT LAKES THROUGH THE NORTHERN GULF
OF MEXICO FRIDAY WILL ONLY PUSH TO THE EASTERN SEABOARD BY MONDAY AS
STRONG U/L DISTURBANCES ROTATE THROUGH THE BASE OF THE TROUGH...WITH
THE TROUGH AMPLIFYING AND DIGGING OVER THE SOUTHEAST U.S. SUNDAY.
WEAK SURFACE HIGH ALONG THE EAST COAST FRIDAY AND SATURDAY WITH WEAK
EASTERLY GRADIENT ACROSS WEST CENTRAL AND SOUTHWEST FLORIDA. DEEP
LAYER MOISTURE WILL BE SUFFICIENT FOR SCATTERED AFTERNOON SHOWERS
AND THUNDERSTORMS TO DEVELOP WHICH WILL BE ENHANCED ALONG THE WEST
COAST SEA BREEZE BOUNDARY. HIGHEST POPS FROM TAMPA SOUTH TO FORT
MYERS IN REGION OF BEST MOISTURE AVAILABILITY AND INSTABILITY. A
COLD FRONT WILL MOVE ACROSS THE SOUTHEAST U.S. SATURDAY NIGHT INTO
SUNDAY AND STALL OVER NORTH FLORIDA. SURFACE HIGH PRESSURE BUILDING
OVER THE MIDWEST WILL ADVECT SLIGHTLY DRIER AIR OVER PORTIONS OF THE
FORECAST AREA SUNDAY AND MONDAY WITH DEW POINTS DROPPING INTO THE
MID 60S IN PORTIONS OF THE NORTHERN CWA AND INTERIOR. THE DRIER AIR
WILL ALSO SIGNIFICANTLY DECREASE THE CHANCE OF SHOWERS AND
THUNDERSTORMS BOTH SUNDAY AND MONDAY. TEMPERATURES WILL RUN NEAR
CLIMATIC NORMALS THROUGH THE PERIOD.
&&
.AVIATION...
CONTINUED MVFR/IFR WITH GUSTY WINDS IN TSRA FOR PIE AND TPA THROUGH
20Z. OTHERWISE PRIMARILY VFR.
&&
.MARINE...
A COLD FRONT WILL CONTINUE TO SLOWLY CROSS THE NORTHEAST GULF OF
MEXICO TONIGHT AND WEDNESDAY. ADVISORY AND CAUTIONARY LEVEL WINDS
ONGOING ACROSS THE NORTHERN AND CENTRAL WATERS WILL SLOWLY DECREASE
AS THE FRONT APPROACHES TONIGHT. THE FRONT WILL THEN SLOWLY DECAY
INTO THE LATER PORTION OF THE WEEK ALLOWING WINDS AND SEAS TO
FURTHER DIMINISH.
&&
.FIRE WEATHER...
A WEAK COLD FRONT WILL SLOWLY SAG INTO THE REGION FROM THE NORTHWEST
LATER TONIGHT AND WEDNESDAY...AND THEN DECAY INTO THE LATER PORTION
OF THE WEEK. THERE WILL NOT BE MUCH IN THE WAY OF DRIER AIR ARRIVING
WITH THIS FRONT...EVEN FOR THE NORTHERN NATURE COAST ZONES.
THEREFORE...DO NOT ANTICIPATE ANY CRITICAL FIRE WEATHER CONDITIONS
THROUGH THE REMAINDER OF THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 75 85 74 87 / 60 50 30 50
FMY 75 90 73 89 / 60 60 30 50
GIF 74 89 71 91 / 60 60 20 50
SRQ 76 85 73 87 / 60 50 30 50
BKV 72 87 67 88 / 60 50 20 50
SPG 77 84 75 86 / 60 50 30 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...BEACH HAZARDS STATEMENT UNTIL 10 PM EDT THIS EVENING FOR
CHARLOTTE-HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA.
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR
TARPON SPRINGS TO SUWANNEE RIVER OUT 20 NM-TARPON
SPRINGS TO SUWANNEE RIVER OUT 20 TO 60 NM.
&&
$$
UPDATE...MROCZKA
AVIATION...JILLSON
PREVIOUS DISCUSSION...RUDE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1126 AM MDT TUE SEP 18 2012
.UPDATE...
ISSUED AT 1058 AM MDT TUE SEP 18 2012
LATEST SURFACE ANALYSIS SHOWS A SURFACE TROUGH JUST EAST OF AN
IMPERIAL TO GOODLAND LINE...EXTENDING SOUTH BETWEEN LAMAR AND
TRIBUNE. UPSTREAM WINDS IN THE NEBRASKA PANHANDLE REPORT WIND
GUSTS OF 25 MPH...WITH GUSTS NEAR 20 MPH OVER EASTERN COLORADO.
AM THINKING THE STRONGER WIND GUSTS OVER 25 MPH SHOULD REMAIN
NORTH OF THE AREA.
IN ADDITION LATEST HRRR MODEL RUNS/MOS AGREE WITH PLACING THE
CORRIDOR OF STRONGEST WINDS FROM ROUGHLY YUMA SOUTHEAST TO
ST.FRANCIS FOR THE AFTERNOON. THE HRRR HAS REDUCED THE WIND GUSTS
FOR THE AFTERNOON SO AM MORE CONFIDENT THAT A FIRE WEATHER
HIGHLIGHT WILL NOT BE NEEDED. HOWEVER CONDITIONS OVER THE
OUTLINED AREA MAY REACH CRITICAL FIRE WEATHER CONDITIONS FOR AN
HOUR OR TWO DURING THE MID AFTERNOON...WHICH IS TOO BRIEF A WINDOW
FOR A HIGHLITE TO BE ISSUED.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 200 AM MDT TUE SEP 18 2012
SFC HIGH JUST EAST OF THE AREA WILL CONTINUE TO MOVE AWAY FROM THE
AREA AS A SFC TROUGH MOVES IN. BREEZY NORTHWEST WINDS TO 25 MPH
EXPECTED WITH THIS TROUGH AS WELL AS SOME MID AND HIGH LEVEL
CLOUDS. HIGH TEMPERATURES TODAY REBOUND BACK INTO THE MID 70S TO
AROUND 80 IN EASTERN COLORADO...LOW TO MID 80S ELSEWHERE. LOWS
TONIGHT IN THE 40S TO AROUND 50.
COLD FRONT MOVES THROUGH WEDNESDAY...HOWEVER ITS IMPACT REGARDING
TEMPERATURE WONT BE FELT TIL THURSDAY. WEDNESDAY HIGHS 75 TO 80 IN
EASTERN COLORADO...MID 80S TO AROUND 90 ELSEWHERE WITH GUSTY NORTH
WINDS TO 25 OR 30 MPH. FOR WEDNESDAY NIGHT LOWS IN THE UPPER 30S TO
UPPER 40S.
SLIGHTLY COOLER TEMPERATURES IN THE LOW TO MID 80S EXPECTED THURSDAY
UNDER SOME MID AND UPPER LEVEL CLOUDS. LOWS THURSDAY NIGHT IN THE
UPPER 40S TO MID 50S.
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 200 AM MDT TUE SEP 18 2012
AN UPPER-LEVEL RIDGE WILL DEVELOP OVER THE GREAT BASIN REGION AND
MOVE EASTWARD OVER THE ROCKIES DURING THE EXTENDED PERIOD.
MEANWHILE SURFACE HIGH PRESSURE WILL BUILD IN OVER THE NORTHERN
PLAINS AS A STRONG TROUGH OVER THE MIDWEST AT THE BEGINNING OF THE
PERIOD MOVES EAST. OVERALL THE FLOW FOR THE TRI-STATE REGION WILL
BE OUT OF THE NORTHWEST DUE TO THIS PATTERN. WITH NO SIGNIFICANT
FORCING NOR MOISTURE SOURCE AVAILABLE...NO PRECIPITATION IS
EXPECTED THRU MONDAY. ADJUSTED TEMPERATURES DOWN SLIGHTLY EARLY IN
THE WEEKEND TO BETTER MATCH BIAS CORRECTED GUIDANCE AND MODEL
TREND OVER THE PAST FEW DAYS. THE PERIOD WILL BEGIN COOLER THAN
NORMAL AND BECOME WARMER THAN NORMAL BY MONDAY AS THE RIDGE MOVES
OVER THE HIGH PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1058 AM MDT TUE SEP 18 2012
VFR CONDITIONS FORECAST FOR THE 18Z TAFS. LATEST SURFACE ANALYSIS
PLACES A TROUGH JUST EAST OF KGLD. AM EXPECTING THE TROUGH TO MOVE
THROUGH KMCK AROUND 20Z...OR POSSIBLY AN HOUR SOONER. WINDS MAYBE
GUSTY BEHIND THE TROUGH...BUT THE MAIN AREA OF GUSTS IS WELL
BEHIND THE TROUGH OVER THE SOUTHERN NEBRASKA PANHANDLE. THE WINDS
WILL DECLINE DURING THE LATE AFTERNOON...BECOMING VARIABLE
OVERNIGHT.
WEDNESDAY ANOTHER SURFACE TROUGH/COLD FRONT WILL MOVE THROUGH
DURING THE MORNING/EARLY AFTERNOON...WITH WINDS INCREASING BEHIND
THE TROUGH/FRONT DURING THE LATE MORNING AND AFTERNOON.
&&
.FIRE WEATHER...
ISSUED AT 200 AM MDT TUE SEP 18 2012
CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE WEDNESDAY AFTERNOON
BEHIND A COLD FRONTAL PASSAGE. RELATIVE HUMIDITY VALUES AS LOW AS
15 PERCENT AND NORTH WINDS GUSTING TO 25 MPH ARE EXPECTED. A FIRE
WEATHER HIGHLITE MAY BE NEEDED FOR LOCATIONS GENERALLY ALONG AND
EAST OF THE COLORADO/KANSAS BORDER.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...99
LONG TERM...JJM
AVIATION...JTL
FIRE WEATHER...99
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
505 PM EDT TUE SEP 18 2012
.SYNOPSIS...
SHOWERS WILL END BY THIS EVENING AS A COLD FRONT CROSSES THE
REGION. HIGH PRESSURE WILL THEN MAINTAIN DRY WEATHER UNTIL THE
APPROACH OF ANOTHER FRONT THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE COLD FRONT NOW EXTENDS FROM JUST EAST OF DUBOIS TO ROUGHLY
MORGANTOWN AS OF 5 PM...AND CONTINUES TO TRUCK EASTWARD. WITH THE
FRONTAL PASSAGE...GOOD MIXING IS BRINGING DOWN SOME HIGHER
MOMENTUM AIR FROM THE LOWEST FEW KILOMETERS OF THE ATMOSPHERE TO
THE SURFACE. BUFKIT SOUNDINGS SUGGEST UP TO 30 KTS ARE AVAILABLE
BEHIND THE FRONT...AND SURFACE OBSERVATIONS HAVE GENERALLY
REFLECTED 20-30 KT GUSTS FAIRLY UNIFORMLY ACROSS UPSTREAM METARS
TO BELIEVE THIS SHOULD CONTINUE TO BE THE CASE AS THE FRONT
CRUISES EASTWARD OUT OF THE CWA THIS EVENING.
WHILE POPS WERE TAPERED DOWN WITH THE FRONTAL PASSAGE...THEY WERE
NOT REMOVED ALTOGETHER OVERNIGHT. LOW LEVEL LAPSE RATES AND
RESIDUAL MOISTURE IN THE LOWEST 8-10 KM COUPLED WITH NORTHWESTERLY
SURFACE FLOW WOULD INDICATE A FEW ISOLATED SHOWERS MAY BE
POSSIBLE. EVEN WITH SOME LARGE SCALE SUBSIDENCE TOWARD THE MORNING
HOURS STARTING TO ERODE THE MOIST LAYER FROM THE SOUTHWEST...POPS
WILL TAKE A WHILE TO BE REMOVED FARTHER NORTHEAST ALONG THE I-80
CORRIDOR. REGARDLESS...ALL MEANINGFUL QPF WILL BE EXHAUSTED AS THE
FRONT EXITS THIS EVENING...WITH ONLY TRIVIAL AMOUNTS BEHIND THE
FRONT. FRIES
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
THE PROGNOSIS OF A BUILDING SFC HIGH UNDER A BROAD TROF ALOFT
SUPPORTS A DRY...BUT COOL FORECAST FOR WEDNESDAY. A STRONG SHRTWV
THAT IS FORECAST TO DIG ACRS THE WRN LAKES WL AMPLIFY THE PARENT
TROF...BUT INITIATE A PD OF WARM ADVCTN THAT WL WARM THURSDAY AND
FRIDAY TEMPS BACK TOWARD NORMAL.
HOWEVER...THE NEXT IN SERIES OF REINFORCING DISTURBANCES IS
PROJECTED TO SEND A CDFNT TWD THE UPR OHIO ON FRIDAY. SLIGHT RAIN
CHANCES WERE CONTINUED FOR THE NWRN TIER OF COUNTIES FOR THE LATE
AFTN...BUT A BTR CHC OF PCPN CURRENTLY IS TIMED FOR AFTER
DARK...AND INTO SATURDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
CONSENSUS OF RECENT NAEFS AND ECMWF ENSEMBLE MODEL OUTPUT SHOW A
COLD FRONT OF MODERATE STRENGTH MOVING EASTWARD THROUGH THE UPPER
OHIO VALLEY DAYTIME SATURDAY...FOLLOWED BY A COLD UPPER LEVEL
TROUGH. CONCUR WITH HPC THINKING THAT THIS SCENARIO SHOULD LIKELY
PROVIDE A FRONTAL BAND OF SHOWERS SATURDAY...AND LINGERING
SCATTERED COLD POOL INSTABILITY SHOWERS SUNDAY.
TEMPERATURES CAN BE AS MUCH AS 5 TO 10 DEGREES COOLER THAN NORMAL
FOR THIS FIRST WEEKEND OF AUTUMN.
ENSUING HIGH PRESSURE WILL PROVIDE DRY CONDITIONS MONDAY AND TUESDAY
BUT TEMPERATURES SHOULD REMAIN COOLER THAN NORMAL.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
RECENT RADAR AND SURFACE DATA...COUPLED WITH RECENT HRRR AND NAM
MODEL OUTPUT SHOWS A COLD FRONTAL BAND OF MAINLY MVFR SHOWERS WILL
PASS EASTWARD THROUGH THE UPPER OHIO VALLEY THROUGH 22Z.
SURFACE WINDS WILL BECOME WEST TO NORTHWEST WITH THE COLD FRONTAL
PASSAGE WITH GUSTS UP TO 25 KTS POSSIBLE.
CONCUR WITH NAM MODEL PROFILES AND GFS LAMP THAT POST SYSTEM COLD
POOL STRATOCUMULUS CEILINGS WILL BE MAINLY AT VFR LEVELS TONIGHT AND
DAYTIME WEDNESDAY.
SURFACE WINDS TONIGHT AND WEDNESDAY WILL BE MAINLY NORTHWEST AT NO
MORE THAN 12 KTS.
.OUTLOOK /WEDNESDAY NIGHT THROUGH SUNDAY/...
EXPECT PREVALENT VFR DUE TO HIGH PRESSURE SUBSIDENCE AND DRYING INTO
FRIDAY...ALTHOUGH A BRIEF PERIOD OF RESTRICTIONS DUE TO EARLY
MORNING FOG CANNOT BE RULED OUT. RESTRICTIONS WILL BECOME COMMON
FRIDAY NIGHT INTO SUNDAY DUE TO SHOWERS ASSOCIATED WITH THE PASSAGE
OF A COLD FRONT SATURDAY AND ENSUING COLD POOL INSTABILITY SUNDAY.
ANY REMAINING MVFR POST SYSTEM COLD POOL STRATOCUMULUS SHOULD LIFT
TO VFR LEVELS BY LATE WEDNESDAY MORNING. THEREAFTER...HIGH PRESSURE
WILL SUSTAIN DRY VFR INTO FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
245 PM EDT TUE SEP 18 2012
.SYNOPSIS...
SHOWERS WILL END BY THIS EVENING AS A COLD FRONT CROSSES THE
REGION. HIGH PRESSURE WILL THEN MAINTAIN DRY WEATHER UNTIL THE
APPROACH OF ANOTHER FRONT THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
MID AFTN UPDATE INCLUDED ADJUSTMENTS DUE TO RADAR AND HRRR MODEL
DEPICTIONS OF A COLD FRONTAL BAND OF SHOWERS PASSING EASTWARD
THROUGH THE UPPER OHIO VALLEY. CONTINUE TO EXPECT SHOWERS TO EXIT
EAST BY EVENING.
WITH THE ADVENT OF SUBSIDENCE AND COLD ADVCTN TNGT...EXPECT
DIMINISHED...BUT NOT ELIMINATED CLOUD COVER TO ACCOMPANY OVRNGT
LOWS APPROX 5 TO 10 DEGREES UNDER THE SEASONAL AVERAGES.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
THE PROGNOSIS OF A BUILDING SFC HIGH UNDER A BROAD TROF ALOFT
SUPPORTS A DRY...BUT COOL FORECAST FOR WEDNESDAY. A STRONG SHRTWV
THAT IS FORECAST TO DIG ACRS THE WRN LAKES WL AMPLIFY THE PARENT
TROF...BUT INITIATE A PD OF WARM ADVCTN THAT WL WARM THURSDAY AND
FRIDAY TEMPS BACK TOWARD NORMAL.
HOWEVER...THE NEXT IN SERIES OF REINFORCING DISTURBANCES IS
PROJECTED TO SEND A CDFNT TWD THE UPR OHIO ON FRIDAY. SLIGHT RAIN
CHANCES WERE CONTINUED FOR THE NWRN TIER OF COUNTIES FOR THE LATE
AFTN...BUT A BTR CHC OF PCPN CURRENTLY IS TIMED FOR AFTER
DARK...AND INTO SATURDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
CONSENSUS OF RECENT NAEFS AND ECMWF ENSEMBLE MODEL OUTPUT SHOW A
COLD FRONT OF MODERATE STRENGTH MOVING EASTWARD THROUGH THE UPPER
OHIO VALLEY DAYTIME SATURDAY...FOLLOWED BY A COLD UPPER LEVEL
TROUGH. CONCUR WITH HPC THINKING THAT THIS SCENARIO SHOULD LIKELY
PROVIDE A FRONTAL BAND OF SHOWERS SATURDAY...AND LINGERING
SCATTERED COLD POOL INSTABILITY SHOWERS SUNDAY.
TEMPERATURES CAN BE AS MUCH AS 5 TO 10 DEGREES COOLER THAN NORMAL
FOR THIS FIRST WEEKEND OF AUTUMN.
ENSUING HIGH PRESSURE WILL PROVIDE DRY CONDITIONS MONDAY AND TUESDAY
BUT TEMPERATURES SHOULD REMAIN COOLER THAN NORMAL.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
RECENT RADAR AND SURFACE DATA...COUPLED WITH RECENT HRRR AND NAM
MODEL OUTPUT SHOWS A COLD FRONTAL BAND OF MAINLY MVFR SHOWERS WILL
PASS EASTWARD THROUGH THE UPPER OHIO VALLEY THROUGH 22Z.
SURFACE WINDS WILL BECOME WEST TO NORTHWEST WITH THE COLD FRONTAL
PASSAGE WITH GUSTS UP TO 25 KTS POSSIBLE.
CONCUR WITH NAM MODEL PROFILES AND GFS LAMP THAT POST SYSTEM COLD
POOL STRATOCUMULUS CEILINGS WILL BE MAINLY AT VFR LEVELS TONIGHT AND
DAYTIME WEDNESDAY.
SURFACE WINDS TONIGHT AND WEDNESDAY WILL BE MAINLY NORTHWEST AT NO
MORE THAN 12 KTS.
.OUTLOOK /WEDNESDAY NIGHT THROUGH SUNDAY/...
EXPECT PREVALENT VFR DUE TO HIGH PRESSURE SUBSIDENCE AND DRYING INTO
FRIDAY...ALTHOUGH A BRIEF PERIOD OF RESTRICTIONS DUE TO EARLY
MORNING FOG CANNOT BE RULED OUT. RESTRICTIONS WILL BECOME COMMON
FRIDAY NIGHT INTO SUNDAY DUE TO SHOWERS ASSOCIATED WITH THE PASSAGE
OF A COLD FRONT SATURDAY AND ENSUING COLD POOL INSTABILITY SUNDAY.
ANY REMAINING MVFR POST SYSTEM COLD POOL STRATOCUMULUS SHOULD LIFT
TO VFR LEVELS BY LATE WEDNESDAY MORNING. THEREAFTER...HIGH PRESSURE
WILL SUSTAIN DRY VFR INTO FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
15/11
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1258 PM EDT TUE SEP 18 2012
.AVIATION...
//DISCUSSION...
VISIBLE SATELLITE IMAGERY SHOWS MICHIGAN`S LOWER PENINSULA SHROUDED
IN MVFR STRATOCU THIS AFTERNOON AS LAKE INSTABILITY HAS DEVELOPED IN
THE WAKE OF LAST NIGHT`S COLD FRONT. DIURNAL HEATING HAS ALLOWED FOR
AN ACCELERATED EXPANSION TO THE SOUTHEAST WHICH SUGGESTS A HIGH
PROBABILITY THAT THESE CLOUDS WILL WORK INTO THE DETROIT AREA
INCLUDING DTW. BRISK NORTHWEST FLOW WITHIN THE CONVECTIVE BOUNDARY
LAYER SHOULD MAINTAIN MVFR CEILINGS INTO THE EVENING BEFORE SURFACE
HIGH PRESSURE BUILDS INTO THE AREA FROM THE WEST. THE EXPECTATION IS
THAT STRATOCU WILL BEGIN TO DISSIPATE AFTER 21Z FROM PTK SOUTHWARD
AS THIS OCCURS. FOR AREAS TO THE NORTH, IT MAY TAKE UNTIL DRY AIR
WORKS OVER LAKE MICHIGAN AND THE LOW LEVEL FLOW WEAKENS LATE TONIGHT
AROUND 06Z. THE TAFS WILL REFLECT THIS EXPECTATION. NORTHWEST WINDS
WILL GUST TO AROUND 20 KNOTS UNTIL THE ONSET OF NOCTURNAL COOLING.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET BEFORE 21Z. LOW
CONFIDENCE BETWEEN 21Z AND 03Z.
&&
.PREV DISCUSSION...ISSUED 341 AM EDT TUE SEP 18 2012
SHORT TERM...TODAY AND TONIGHT
A COLD FRONT CONTINUES TO MAKE STEADY PROGRESS EASTWARD THROUGH THE
CENTRAL GREAT LAKES REGION. SURFACE OBSERVATIONS SHOW THIS COLD
FRONT EXTENDING FROM THE SAGINAW VALLEY SOUTHWARD TO JACKSON
MICHIGAN AS OF 07Z. THE 3KM HRRR MODEL SHOWS THIS FRONT CLEARING THE
CWA AROUND 10Z WITH COOLER DRIER AIR FILTERING IN FROM THE NORTHWEST
BEHIND THE FRONT. THE LATE PUSH OF COLD AIR WILL MEAN HIGH
TEMPERATURES WILL LIKELY OCCUR EARLY THIS MORNING...WITH FALLING
MORNING TEMPERATURES AND A MODEST REBOUND DURING THE AFTERNOON
HOURS. MOST LOCATIONS WILL SEE TEMPERATURES STAYING WITHIN A NARROW
RANGE DURING THE DAYTIME HOURS AS COLD AIR ADVECTION FIGHTS THE
NORMAL BOUNCE AFFORDED BY DIURNAL HEATING. UPSTREAM OBSERVATIONS
SHOW THE LIGHTNING ACTIVITY PREVIOUSLY ASSOCIATED WITH THE SHOWERS
BEHIND THE FRONT HAS DISAPPEARED...WITH NOT MUCH IN THE WAY OF
ELEVATED CAPE OVER SOUTHEAST MICHIGAN WILL REMOVE THE REMAINING
THUNDER PREVIOUSLY ASSOCIATED WITH THIS ACTIVITY.
WINDS WILL TURN NORTHWESTERLY AND BE QUITE GUSTY BEHIND THE FRONT
WITH GUSTS TO 30 MPH. TOOK DOWN PRECIPITATION CHANCES ACROSS THE
EASTERN CWA DURING THE MORNING HOURS AS HIGH QPF AMOUNTS SHOWN BY
THE NWP MODELS IS NOT SUPPORTED BY UPSTREAM OBSERVATIONS WITH
RAPIDLY FALLING DEW POINTS INTO THE 40S BEHIND THE FRONT AND
REGIONAL RADAR REFLECTIVITY SEVERELY LACKING IN COVERAGE ACROSS THE
CENTRAL GREAT LAKES. THE BEST MOISTURE AND RAIN COVERAGE IS
CURRENTLY OVER THE OHIO VALLEY SHOULD STAY THERE DESPITE THE HEALTHY
VORT MAX OVER THE UPPER MISSISSIPPI VALLEY FORECAST TO TRACK THROUGH
THE CENTRAL GREAT LAKES DURING THE DAYTIME HOURS. WATER VAPOR
IMAGERY SHOWS A LOT OF DRY AIR EMBEDDED WITH THIS SHORTWAVE WITH THE
BEST MOISTURE BEING SCOURED OUT BY THE COLD FRONT CURRENTLY TRACKING
THROUGH THE CENTRAL GREAT LAKES. WHILE THE SHORTWAVE WILL PRODUCE
SOME SHOWER ACTIVITY...IT IS WORTHY OF A CHANCY MENTION INSTEAD OF
LIKELY POPS GIVEN THE LACK OF MOISTURE AND FAILURE OF THE SHORTWAVE
TO TRACK THROUGH WHEN WE STILL HAVE DECENT MOISTURE ACROSS THE
REGION.
SKIES WILL CLEAR OUT TONIGHT AS THIS SHORTWAVE TRACKS EAST AND
RIDGING MAKES ITS WAY THROUGH THE CENTRAL GREAT LAKES. THE ABUNDANT
RADIATIONAL COOLING AND VERY COLD TEMPERATURES IN PLACE OVER THE
CENTRAL GREAT LAKES WILL ALLOW OVERNIGHT TEMPERATURES TO TUMBLE INTO
THE UPPER 30S AND LOWER 40S. WHILE SOME LOCATIONS WILL FALL INTO THE
MIDDLE 30S...WINDS SHOULD STAY UP ENOUGH WITH THE PRESSURE GRADIENT
TO PREVENT MUCH IN THE WAY OF FROST FROM FORMING.
LONG TERM...WEDNESDAY THROUGH MONDAY
THE STRENGTH OF THE UPPER LEVEL LOW HEIGHT/POTENTIAL VORTICITY
ANOMALIES...BOTH TO THE EAST AND WEST OF LOWER MICHIGAN...MEANS THE
AREA WILL BE POSITIONED WITHIN A WEAKNESS OR COL OF THE MEAN UPPER
LEVEL TROUGH ON WEDNESDAY. WITH NO ALTERNATIVE...SOUTHEASTERN
MICHIGAN WILL FEEL THE EFFECTS OF A COLUMN THAT HAD BEEN HEAVILY
MODULATED BY SUBSIDENCE. ORIENTATION OF THE UPSTREAM UPPER LEVEL JET
AXIS ALONG WITH STRONG UPPER LEVEL WIND MAGNITUDES SUGGESTS THE NEXT
UPPER LEVEL SYSTEM WILL BE AT THE DOORSTEP OF THE AREA AT 00Z
THURSDAY. MODEL SOUNDINGS DO SHOW SOME FAIRLY STEEP 700-500MB LAPSE
RATES ARRIVING OVER THE TRI CITIES IN THE 22-01Z TIMEFRAME.
HOWEVER...LACK OF MODELED UVV IN THAT SLAB ALONG WITH UNSATURATED
CONDITIONS IN THE LOWEST 7500 FT PRECLUDES ANY INTRODUCTION OF POPS.
CLOUDS WILL BE ABSENT A BETTER PART OF THE DAY BEFORE INCREASING
VERY LATE. HIGHS WEDNESDAY ARE EXPECTED TO RISE COMFORTABLY IN THE
MIDDLE 60S.
THE AFOREMENTIONED ORIENTATION OF THE UPPER LEVEL JET AXIS ALONG
WITH THE VERY FAVORABLE BULLWHIP PATTERN(18Z WED-00Z THUR) ARE BIG
INDICATORS THE WEDNESDAY NIGHT/THURSDAY SYSTEM WILL HAVE A GREAT DEAL
OF DYNAMICS. THE LEFT EXIT CURL ALONG WITH SHARP NOSE OF THE LOW TO
MIDLEVEL THETA E RIDGE SUGGESTS THE BEST FORCING/SURFACE LOW WILL
LIFT NORTHEASTWARD FROM WESTERN WISCONSIN 00Z-THURSDAY TO A HUNDRED
MILES OR SO NORTH OF LAKE HURON BY 12Z-THURSDAY. PLAN VIEW
DEPICTIONS OF A NUMBER OF PARAMETERS ALL POINT TO A RATHER SHARP
LOWER TROPOSPHERIC FRONT WHISTLING THROUGH. SYSTEM RELATIVE
ISENTROPIC ASCENT AND FRONTOGENESIS ARE NOT AS STRONG AS ONE WOULD
LIKE TO SEE...BUT DEPTH OF DEFORMATION AND CONVERGENCE ARE GOOD FOR
MID TO HIGH CHANCE POPS IN MANY AREAS. THE FRONT BECOMES RATHER
SLUGGISH AND LINGERS THROUGHOUT THE MORNING ON THURSDAY. WILL CARRY
A LOW BLANKET POP WEDNESDAY NIGHT FOR THE DETROIT AREAS...BUT ONE
CAN GET THE SENSE THAT DETROIT MAY BE PRECIPITATION FREE UNTIL THE
14-18Z TIMEFRAME AS THINNING 700MB THETA E AXIS EVENTUALLY SLIDES IN
OVERHEAD. FELT COMFORTABLE GOING WITH A WARMER END BLEND FOR HIGHS
ON THURSDAY...UPPER 60S TO AROUND 70 DEGREES. ANOTHER ROUND OF
REMNANT SUBSIDENCE IS SHOWN TO SPREAD ACROSS THE AREA THURSDAY
AFTERNOON...KEEPING CONDITIONS DRY FOR THURSDAY NIGHT.
MARINE...
A STRONG COLD FRONT WILL SHIFT WINDS TO THE NORTHWEST AS WIND SPEEDS
INCREASE TO 25 TO 30 KNOTS ACROSS MUCH OF LAKE HURON AND 20 TO 25
KNOTS ELSEWHERE. SIGNIFICANT WAVE HEIGHTS WILL INCREASE ACCORDINGLY
TODAY FEATURING SEVERAL HOURS OF 6 TO 9 FOOT WAVES OVER THE OPEN
WATERS OF SOUTHERN LAKE HURON AND 5 TO 7 FEET FROM OUTER SAGINAW BAY
TO PORT HURON. SMALL CRAFT ADVISORIES HAVE THEREFORE BEEN ISSUED FOR
ALL OF THE NEARSHORE ZONES. WINDS COULD BRIEFLY APPROACH GALE
CONDITIONS TODAY ACROSS SOUTHERN LAKE HURON...HOWEVER THE TIME
WINDOW APPEARS TOO BRIEF AND MARGINAL TO ISSUE GALE WARNINGS AT THIS
TIME. WINDS WILL SLOWLY SUBSIDE TONIGHT AND WEDNESDAY...WITH SMALL
CRAFT ADVISORIES BEING DROPPED TONIGHT THROUGH WEDNESDAY MORNING AS
WINDS AND WAVES SLOWLY SUBSIDE. THE PATTERN WILL REMAIN ACTIVE WITH
SEVERAL EPISODES OF GUSTY NORTHWEST FLOW AND ELEVATED WAVE
CONDITIONS LIKELY THROUGH THE FORECAST PERIOD.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS
FROM PORT AUSTIN TO HARBOR BEACH...UNTIL NOON WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT
HURON...UNTIL 8 AM WEDNESDAY.
SMALL CRAFT ADVISORY...INNER SAGINAW BAY...UNTIL MIDNIGHT WEDNESDAY.
LAKE ST CLAIR...
SMALL CRAFT ADVISORY...UNTIL 10 PM TUESDAY.
MI WATERS OF LAKE ERIE...
SMALL CRAFT ADVISORY...UNTIL 10 PM TUESDAY.
&&
$$
AVIATION.....JVC
SHORT TERM...KURIMSKI
LONG TERM....CB
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
615 PM EDT TUE SEP 18 2012
.SYNOPSIS...
A COLD FRONT WILL SLOWLY PUSH ACROSS THE REGION TONIGHT...WITH
RAIN AND GUSTY WINDS SUBSIDING BY LATER THIS EVENING. HIGH
PRESSURE WILL BUILD IN...BRINGING DRY WEATHER FROM WEDNESDAY
THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
610PM...REMOVED ENTIRE REMAINING REGION OF TORNADO WATCH.
SIGNIFICANT CONVECTION HAS MOVED EAST OF THE REGION. WHILE SRH
VALUES REMAIN EXTREME, INSTABILITY NEVER MATERIALIZED TO SUPPORT
CONVECTION.
5PM...REMOVED WESTERN PORTION OF TORNADO WATCH WHERE
RAIN COOLED AIR AS STABILIZED ATMOSPHERE QUITE A BIT, AND WIND
SHEAR HAS DECREASED. WILL CONTINUE EASTERN PORTION FOR AT LEAST
THE NEXT HOUR.
330 PM UPDATE... WE APPEAR TO BE TRANSITIONING FROM A SVR/WIND
THREAT...TO MORE OF A HVY RAIN THREAT ATTM.
THE BACK EDGE OF THE PRE-FRNTL BAND OF RAIN/EMBEDDED TSRA IS
SLOWLY PUSHING EWD FROM ABT THE I-81 CORRIDOR LATE THIS AFTN. THE
MAIN CONCERN IS TURNING TO A TRAINING SW-NE BATCH OF
+RA/TSRA...EXTENDING FROM S-CNTRL PA UP INTO OUR SERN ZNS...SO FF
WATCHES HAVE BEEN POSTED FOR LUZERNE/LACK/WAYNE/PIKE/SULL CNTYS. SINCE
THE LEADING NRN STREAM WV IS LIFTING OUT TO THE NE THROUGH
ONT...IT WILL LIKELY TAKE THE SECOND WV COMING IN BEHIND IT FROM
WI/UPR MI...TO FINALLY KICK THE HVYR RAIN BAND EWD AFTER 00Z.
AS FOR THE WIND/SVR SITN...STG SYNOPTIC-SCALE WINDS ARE PUSHING
EWD ATTM...AND THE OVERALL WIND THREAT SHOULD BE LWRG WITH TIME
TWDS 00Z. DITTO FOR THE SVR CONVECTIVE SITN.
LTR TNT...DRIER AIR WILL ULTIMATELY PUSH IN FROM THE W...WITH POPS
DIMINISHING BY/AFTER 06Z.
PREV DISC... 1230 PM UPDATE... TOR WATCH #643 ISSUED FOR NE PA
AND SULL CNTY NY...TIL 23Z. THUS...WE`VE ADDED SOME ENHANCED
WORDING FOR THE ISOLD TSRA THIS AREA.
LINEAR FEATURES ARE BCMG MORE PROMINENT ALG THE BACK EDGE OF THE
STEADIER PCPN...AS ALLUDED TO IN PREV DISC. ML CAPES REMAIN FAIRLY
LOW...ON THE ORDER OF 100-200...BUT LOW-LVL SHEAR IS EXTREMELY
IMPRESSIVE (0-1 KM SREL HEL OF 400+). UNLESS MORE DESTAB
OCCURS...DISCRETE CELL DVLPMT IS UNLIKELY...BUT LINES OF
SHRA/EMBEDDED TSRA...WITH LOCALIZED 50+ KT GUSTS ARE PLAUSIBLE.
WE`LL CONTINUE TO MONITOR CLOSELY.
PREV DISC... 10 AM UPDATE... BROAD SWATH OF RA/+RA CONTS TO TRACK
NEWD THROUGH CNY/NE PA ATTM...BEING FUELED BY STG POS THETA-E
ADVCTN ON THE LEADING EDGE OF AN INCRG LOW-LVL JET. WE EXPECT
STEADY RAIN TO PERSIST TIL PERHAPS MID TO LATE AFTN...WHEN THE
BACK EDGE OF THE MAIN PCPN SHIELD...NOW ACRS WRN PA...ATTEMPTS TO
MOVE INTO THE CWA FROM SW TO NE. A BIG QUESTION IS WHAT HAPPENS
AFTER THAT...JUST AHD OF THE COLD FROPA IN THE 21Z-01Z TIME FRAME.
MOST OF THE CONVECTION ALLOWING MODELS (HRRR AND 4 KM WRF...FOR
EXAMPLE) INDICATE THAT SOME SORT OF ENHANCED/CONVECTIVE LN FORMS
ON THE BACK EDGE OF THE STEADIER PCPN AFTER 21Z...TRANSLATING
MAINLY ACRS NE PA AND PTNS OF THE SRN TIER LATE IN THE DAY.
THIS...OF COURSE...WILL DEPEND ON HOW MUCH INSTAB CAN FORM. THE
LATEST RUC SHOWS ML CAPE OF 200-400 THIS TIME FRAME IN OUR SERN
ZNS...WITH THE 12Z NAM COMING IN SHOWING MORE (500-800). GIVEN
EXTENSIVE CLOUD COVER/PCPN FOR SVRL MORE HRS AT LEAST...AND WHAT`S
BEING OBSERVED UPSTREAM ON SPC MESO`S ATTM (ML CAPE OF 100-200 IN
SE PA)...WE`RE INCLINED TO BUY THE MORE CONSERVATIVE RUC. ACRS
ROUGHLY THE SERN HALF OF THE CWA...WE`LL STILL MENTION ISOLD
TSRA...WHILE SHOWING OCNL +RA JUST ABT EVERYWHERE. THE BEST SVR
POTENTIAL APPEARS TO BE JUST SE OF THE CWA...WHERE THE PRIMARY
IMPETUS FOR ANY DISCERNIBLE LN OR DISCRETE CELL FORMATION IS.
KBGM VWP HAS 20-30 KT SRLY FLOW AT 2K FT AGL ATTM...WITH 40-50 KT
AT 3-4K FT AGL. KBGM BASE VEL PRODS ALSO SHOW THE 50-60 KT CORE
MOVG NWD THROUGH ERN PA...AND DESCENDING SOMEWHAT WITH TIME. THE
MOST FAVORABLE TIME FOR CONSISTENTLY STG GRADIENT WIND GUSTS WILL BE
FROM ABT 17-22Z. WIND ADVISORIES REMAIN IN TACT.
UNLESS TRAINING OF HEAVY RAIN BANDS FORM...WE`RE STILL NOT
EXPECTING ANY SIG HYDRO RELATED PROBLEMS...SO NO WATCHES PLANNED
FOR THE TIME BEING.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
340 PM UPDATE... VERY BRIEF DISCN...DUE TO ONGOING SVR WX.
DRY WX STILL ANTICIPATED WED-FRI...OTHER THAN SOME ISOLD -SHRA
EARLY WED...DUE TO A WEAK LAKE RESPONSE.
TEMPS WILL BE UNCHANGED...AS CURRENT MAX/MIN TEMP GRIDS MATCH
BLENDED MOS WELL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
315 AM UPDATE...CURRENT FORECAST IN GOOD SHAPE, LATEST MODEL RUNS
REMAIN CONSISTENT WITH PREVIOUS CYCLE, NO SIGNIFICANT CHANGES.
PREVIOUS DISC...
FRIDAY THROUGH FRIDAY NIGHT...A DEEP CUT OFF LOW WILL MOVE INTO
THE UPPER MIDWEST DURING THIS TIME. MEANWHILE FARTHER TO THE EAST
IN OUR NECK OF THE WOODS...WE WILL REMAIN IN A DEEP SOUTHWESTERLY
FLOW AHEAD OF THE CUT OFF LOW. INITIALLY THIS WILL BE GREAT NEWS
WITH OUR AREA REMAINING DRY AND EXPERIENCING ABOVE NORMAL TEMPS.
HIGHS FRIDAY SHOULD BE WELL INTO THE 70S...WITH NEAR 80 DEGREE
READINGS ACROSS THE LAKE PLAIN.
SATURDAY AND BEYOND...THE DOWNSIDE TO THE SLOW MOVEMENT OF THE CUT OFF LOW
MENTIONED ABOVE WILL BE AN UNSETTLED WEEKEND. AS THE CUT OFF LOW
MOVES NORTHEAST AND WE BEGIN TO FEEL THE EFFECTS OF THE H5
TROF...RAIN WILL SPREAD OUR WAY LATER SATURDAY INTO SUNDAY. THE
GFS HINTS THAT WE MAY SEE A DRY SLOT LATER SUNDAY...BUT PLENTY OF
UNCERTAINTY EXISTS WITH THE EURO KEEPING US WET. WILL KEEP CHANCE
POPS IN ESPECIALLY ACROSS THE NORTH TO COVER THIS.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
OVERVIEW...MVFR CIGS AND VSBYS LIKELY TO PERSIST THROUGH 21Z AS A PRE-FRONTAL
TROF MOVES THROUGH THE TERMINALS AND WE HAVE WIDESPREAD RAIN.
AFTER THIS TIME VSBYS SHOULD IMPROVE AS THE RAIN ENDS...BUT MVFR
CIGS LIKELY TO PERSIST THROUGH EARLY TONIGHT WITH VFR THEREAFTER.
DETAILS...A LINE OF HEAVIER RAIN IS MOVING ACROSS THE TERMINALS NOW...WELL
AHEAD OF A COLD FRONT OVER WESTERN NY. MVFR CIGS AND VSBYS LIKELY
WITH THE RAIN THROUGH 21Z. SOME BRIEF IFR VSBYS POSSIBLE AT
KRME...KBGM...KAVP DUE TO HEAVIER RAIN DURING THIS TIME. IN
ADDITION SOME PERIODS OF VFR LIKELY AT KRME/KSYR/KAVP DUE TO
STRONG DOWNSLOPING WINDS (SOUTHEAST). ONCE THIS LINE MOVES EAST OF
THE AREA AFTER 21Z...VSBYS WILL IMPROVE TO VFR BUT MVFR CIGS WILL
LINGER THROUGH 03Z - 06Z TONIGHT. AT THE ELEVATED SITES OF KBGM
AND KITH...IFR CIGS ARE POSSIBLE DURING THIS TIME.
AFTER 06Z GENERALLY VFR IS EXPECTED. DUE TO THE RAINFALL IFR
CONDITIONS CAN`T BE RULED OUT AT KELM DUE TO FOG. CONFIDENCE TOO
LOW TO INCLUDE AT THIS TIME DUE TO BREEZY BOUNDARY LAYER WINDS. SCT
CU AROUND 5KFT WEDNESDAY AND VFR CONDITIONS.
SOUTHEAST WINDS SHIFTING TO THE SOUTHWEST BY 21Z SUSTAINED 10 TO
20 KTS...WITH GUSTS TOWARD 30 KTS. SOUTHWEST WINDS BECOMING WEST
TONIGHT WITH GUSTS TOWARD 20KTS THROUGH 03Z...THEN AROUND 10KTS
OVERNIGHT. NORTHWEST WINDS 10 TO 15 KTS WEDNESDAY.
OUTLOOK...
THU/FRI...VFR EXCEPT IFR FOG AT KELM EACH MORNING FROM 8 TO 14Z.
SAT...MVFR POSSIBLE IN SHOWERS.
SUN...GENERALLY VFR...MVFR POSSIBLE NORTH IN SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR PAZ040-044-
047-048-072.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ048.
NY...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR NYZ062.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ046-057-062.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...DJP/MLJ
SHORT TERM...MLJ
LONG TERM...HEDEN/RRM
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
502 PM EDT TUE SEP 18 2012
.SYNOPSIS...
A COLD FRONT WILL SLOWLY PUSH ACROSS THE REGION TONIGHT...WITH
RAIN AND GUSTY WINDS SUBSIDING BY LATER THIS EVENING. HIGH
PRESSURE WILL BUILD IN...BRINGING DRY WEATHER FROM WEDNESDAY
THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
5PM...REMOVED WESTERN PORTION OF TORNADO WATCH WHERE RAIN COOLED
AIR AS STABILIZED ATMOSPHERE QUITE A BIT, AND WIND SHEAR HAS
DECREASED. WILL CONTINUE EASTERN PORTION FOR AT LEAST THE NEXT
HOUR.
330 PM UPDATE... WE APPEAR TO BE TRANSITIONING FROM A SVR/WIND
THREAT...TO MORE OF A HVY RAIN THREAT ATTM.
THE BACK EDGE OF THE PRE-FRNTL BAND OF RAIN/EMBEDDED TSRA IS
SLOWLY PUSHING EWD FROM ABT THE I-81 CORRIDOR LATE THIS AFTN. THE
MAIN CONCERN IS TURNING TO A TRAINING SW-NE BATCH OF
+RA/TSRA...EXTENDING FROM S-CNTRL PA UP INTO OUR SERN ZNS...SO FF
WATCHES HAVE BEEN POSTED FOR LUZERNE/LACK/WAYNE/PIKE/SULL CNTYS. SINCE
THE LEADING NRN STREAM WV IS LIFTING OUT TO THE NE THROUGH
ONT...IT WILL LIKELY TAKE THE SECOND WV COMING IN BEHIND IT FROM
WI/UPR MI...TO FINALLY KICK THE HVYR RAIN BAND EWD AFTER 00Z.
AS FOR THE WIND/SVR SITN...STG SYNOPTIC-SCALE WINDS ARE PUSHING
EWD ATTM...AND THE OVERALL WIND THREAT SHOULD BE LWRG WITH TIME
TWDS 00Z. DITTO FOR THE SVR CONVECTIVE SITN.
LTR TNT...DRIER AIR WILL ULTIMATELY PUSH IN FROM THE W...WITH POPS
DIMINISHING BY/AFTER 06Z.
PREV DISC... 1230 PM UPDATE... TOR WATCH #643 ISSUED FOR NE PA
AND SULL CNTY NY...TIL 23Z. THUS...WE`VE ADDED SOME ENHANCED
WORDING FOR THE ISOLD TSRA THIS AREA.
LINEAR FEATURES ARE BCMG MORE PROMINENT ALG THE BACK EDGE OF THE
STEADIER PCPN...AS ALLUDED TO IN PREV DISC. ML CAPES REMAIN FAIRLY
LOW...ON THE ORDER OF 100-200...BUT LOW-LVL SHEAR IS EXTREMELY
IMPRESSIVE (0-1 KM SREL HEL OF 400+). UNLESS MORE DESTAB
OCCURS...DISCRETE CELL DVLPMT IS UNLIKELY...BUT LINES OF
SHRA/EMBEDDED TSRA...WITH LOCALIZED 50+ KT GUSTS ARE PLAUSIBLE.
WE`LL CONTINUE TO MONITOR CLOSELY.
PREV DISC... 10 AM UPDATE... BROAD SWATH OF RA/+RA CONTS TO TRACK
NEWD THROUGH CNY/NE PA ATTM...BEING FUELED BY STG POS THETA-E
ADVCTN ON THE LEADING EDGE OF AN INCRG LOW-LVL JET. WE EXPECT
STEADY RAIN TO PERSIST TIL PERHAPS MID TO LATE AFTN...WHEN THE
BACK EDGE OF THE MAIN PCPN SHIELD...NOW ACRS WRN PA...ATTEMPTS TO
MOVE INTO THE CWA FROM SW TO NE. A BIG QUESTION IS WHAT HAPPENS
AFTER THAT...JUST AHD OF THE COLD FROPA IN THE 21Z-01Z TIME FRAME.
MOST OF THE CONVECTION ALLOWING MODELS (HRRR AND 4 KM WRF...FOR
EXAMPLE) INDICATE THAT SOME SORT OF ENHANCED/CONVECTIVE LN FORMS
ON THE BACK EDGE OF THE STEADIER PCPN AFTER 21Z...TRANSLATING
MAINLY ACRS NE PA AND PTNS OF THE SRN TIER LATE IN THE DAY.
THIS...OF COURSE...WILL DEPEND ON HOW MUCH INSTAB CAN FORM. THE
LATEST RUC SHOWS ML CAPE OF 200-400 THIS TIME FRAME IN OUR SERN
ZNS...WITH THE 12Z NAM COMING IN SHOWING MORE (500-800). GIVEN
EXTENSIVE CLOUD COVER/PCPN FOR SVRL MORE HRS AT LEAST...AND WHAT`S
BEING OBSERVED UPSTREAM ON SPC MESO`S ATTM (ML CAPE OF 100-200 IN
SE PA)...WE`RE INCLINED TO BUY THE MORE CONSERVATIVE RUC. ACRS
ROUGHLY THE SERN HALF OF THE CWA...WE`LL STILL MENTION ISOLD
TSRA...WHILE SHOWING OCNL +RA JUST ABT EVERYWHERE. THE BEST SVR
POTENTIAL APPEARS TO BE JUST SE OF THE CWA...WHERE THE PRIMARY
IMPETUS FOR ANY DISCERNIBLE LN OR DISCRETE CELL FORMATION IS.
KBGM VWP HAS 20-30 KT SRLY FLOW AT 2K FT AGL ATTM...WITH 40-50 KT
AT 3-4K FT AGL. KBGM BASE VEL PRODS ALSO SHOW THE 50-60 KT CORE
MOVG NWD THROUGH ERN PA...AND DESCENDING SOMEWHAT WITH TIME. THE
MOST FAVORABLE TIME FOR CONSISTENTLY STG GRADIENT WIND GUSTS WILL BE
FROM ABT 17-22Z. WIND ADVISORIES REMAIN IN TACT.
UNLESS TRAINING OF HEAVY RAIN BANDS FORM...WE`RE STILL NOT
EXPECTING ANY SIG HYDRO RELATED PROBLEMS...SO NO WATCHES PLANNED
FOR THE TIME BEING.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
340 PM UPDATE... VERY BRIEF DISCN...DUE TO ONGOING SVR WX.
DRY WX STILL ANTICIPATED WED-FRI...OTHER THAN SOME ISOLD -SHRA
EARLY WED...DUE TO A WEAK LAKE RESPONSE.
TEMPS WILL BE UNCHANGED...AS CURRENT MAX/MIN TEMP GRIDS MATCH
BLENDED MOS WELL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
315 AM UPDATE...CURRENT FORECAST IN GOOD SHAPE, LATEST MODEL RUNS
REMAIN CONSISTENT WITH PREVIOUS CYCLE, NO SIGNIFICANT CHANGES.
PREVIOUS DISC...
FRIDAY THROUGH FRIDAY NIGHT...A DEEP CUT OFF LOW WILL MOVE INTO
THE UPPER MIDWEST DURING THIS TIME. MEANWHILE FARTHER TO THE EAST
IN OUR NECK OF THE WOODS...WE WILL REMAIN IN A DEEP SOUTHWESTERLY
FLOW AHEAD OF THE CUT OFF LOW. INITIALLY THIS WILL BE GREAT NEWS
WITH OUR AREA REMAINING DRY AND EXPERIENCING ABOVE NORMAL TEMPS.
HIGHS FRIDAY SHOULD BE WELL INTO THE 70S...WITH NEAR 80 DEGREE
READINGS ACROSS THE LAKE PLAIN.
SATURDAY AND BEYOND...THE DOWNSIDE TO THE SLOW MOVEMENT OF THE CUT OFF LOW
MENTIONED ABOVE WILL BE AN UNSETTLED WEEKEND. AS THE CUT OFF LOW
MOVES NORTHEAST AND WE BEGIN TO FEEL THE EFFECTS OF THE H5
TROF...RAIN WILL SPREAD OUR WAY LATER SATURDAY INTO SUNDAY. THE
GFS HINTS THAT WE MAY SEE A DRY SLOT LATER SUNDAY...BUT PLENTY OF
UNCERTAINTY EXISTS WITH THE EURO KEEPING US WET. WILL KEEP CHANCE
POPS IN ESPECIALLY ACROSS THE NORTH TO COVER THIS.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
OVERVIEW...MVFR CIGS AND VSBYS LIKELY TO PERSIST THROUGH 21Z AS A PRE-FRONTAL
TROF MOVES THROUGH THE TERMINALS AND WE HAVE WIDESPREAD RAIN.
AFTER THIS TIME VSBYS SHOULD IMPROVE AS THE RAIN ENDS...BUT MVFR
CIGS LIKELY TO PERSIST THROUGH EARLY TONIGHT WITH VFR THEREAFTER.
DETAILS...A LINE OF HEAVIER RAIN IS MOVING ACROSS THE TERMINALS NOW...WELL
AHEAD OF A COLD FRONT OVER WESTERN NY. MVFR CIGS AND VSBYS LIKELY
WITH THE RAIN THROUGH 21Z. SOME BRIEF IFR VSBYS POSSIBLE AT
KRME...KBGM...KAVP DUE TO HEAVIER RAIN DURING THIS TIME. IN
ADDITION SOME PERIODS OF VFR LIKELY AT KRME/KSYR/KAVP DUE TO
STRONG DOWNSLOPING WINDS (SOUTHEAST). ONCE THIS LINE MOVES EAST OF
THE AREA AFTER 21Z...VSBYS WILL IMPROVE TO VFR BUT MVFR CIGS WILL
LINGER THROUGH 03Z - 06Z TONIGHT. AT THE ELEVATED SITES OF KBGM
AND KITH...IFR CIGS ARE POSSIBLE DURING THIS TIME.
AFTER 06Z GENERALLY VFR IS EXPECTED. DUE TO THE RAINFALL IFR
CONDITIONS CAN`T BE RULED OUT AT KELM DUE TO FOG. CONFIDENCE TOO
LOW TO INCLUDE AT THIS TIME DUE TO BREEZY BOUNDARY LAYER WINDS. SCT
CU AROUND 5KFT WEDNESDAY AND VFR CONDITIONS.
SOUTHEAST WINDS SHIFTING TO THE SOUTHWEST BY 21Z SUSTAINED 10 TO
20 KTS...WITH GUSTS TOWARD 30 KTS. SOUTHWEST WINDS BECOMING WEST
TONIGHT WITH GUSTS TOWARD 20KTS THROUGH 03Z...THEN AROUND 10KTS
OVERNIGHT. NORTHWEST WINDS 10 TO 15 KTS WEDNESDAY.
OUTLOOK...
THU/FRI...VFR EXCEPT IFR FOG AT KELM EACH MORNING FROM 8 TO 14Z.
SAT...MVFR POSSIBLE IN SHOWERS.
SUN...GENERALLY VFR...MVFR POSSIBLE NORTH IN SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR PAZ040-044-
047-048-072.
WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR PAZ038>040-043-
044-047-072.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ048.
NY...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR NYZ062.
WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ009-025-036-
037-044-045-055-056.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ046-057-062.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...DJP/MLJ
SHORT TERM...MLJ
LONG TERM...HEDEN/RRM
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
341 PM EDT TUE SEP 18 2012
.SYNOPSIS...
A COLD FRONT WILL SLOWLY PUSH ACROSS THE REGION TONIGHT...WITH
RAIN AND GUSTY WINDS SUBSIDING BY LATER THIS EVENING. HIGH
PRESSURE WILL BUILD IN...BRINGING DRY WEATHER FROM WEDNESDAY
THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
330 PM UPDATE... WE APPEAR TO BE TRANSITIONING FROM A SVR/WIND
THREAT...TO MORE OF A HVY RAIN THREAT ATTM.
THE BACK EDGE OF THE PRE-FRNTL BAND OF RAIN/EMBEDDED TSRA IS
SLOWLY PUSHING EWD FROM ABT THE I-81 CORRIDOR LATE THIS AFTN. THE
MAIN CONCERN IS TURNING TO A TRAINING SW-NE BATCH OF
+RA/TSRA...EXTENDING FROM S-CNTRL PA UP INTO OUR SERN ZNS...SO FF
WATCHES HAVE BEEN POSTED FOR LUZERNE/LACK/WAYNE/PIKE/SULL CNTYS. SINCE
THE LEADING NRN STREAM WV IS LIFTING OUT TO THE NE THROUGH
ONT...IT WILL LIKELY TAKE THE SECOND WV COMING IN BEHIND IT FROM
WI/UPR MI...TO FINALLY KICK THE HVYR RAIN BAND EWD AFTER 00Z.
AS FOR THE WIND/SVR SITN...STG SYNOPTIC-SCALE WINDS ARE PUSHING
EWD ATTM...AND THE OVERALL WIND THREAT SHOULD BE LWRG WITH TIME
TWDS 00Z. DITTO FOR THE SVR CONVECTIVE SITN.
LTR TNT...DRIER AIR WILL ULTIMATELY PUSH IN FROM THE W...WITH POPS
DIMINISHING BY/AFTER 06Z.
PREV DISC... 1230 PM UPDATE... TOR WATCH #643 ISSUED FOR NE PA
AND SULL CNTY NY...TIL 23Z. THUS...WE`VE ADDED SOME ENHANCED
WORDING FOR THE ISOLD TSRA THIS AREA.
LINEAR FEATURES ARE BCMG MORE PROMINENT ALG THE BACK EDGE OF THE
STEADIER PCPN...AS ALLUDED TO IN PREV DISC. ML CAPES REMAIN FAIRLY
LOW...ON THE ORDER OF 100-200...BUT LOW-LVL SHEAR IS EXTREMELY
IMPRESSIVE (0-1 KM SREL HEL OF 400+). UNLESS MORE DESTAB
OCCURS...DISCRETE CELL DVLPMT IS UNLIKELY...BUT LINES OF
SHRA/EMBEDDED TSRA...WITH LOCALIZED 50+ KT GUSTS ARE PLAUSIBLE.
WE`LL CONTINUE TO MONITOR CLOSELY.
PREV DISC... 10 AM UPDATE... BROAD SWATH OF RA/+RA CONTS TO TRACK
NEWD THROUGH CNY/NE PA ATTM...BEING FUELED BY STG POS THETA-E
ADVCTN ON THE LEADING EDGE OF AN INCRG LOW-LVL JET. WE EXPECT
STEADY RAIN TO PERSIST TIL PERHAPS MID TO LATE AFTN...WHEN THE
BACK EDGE OF THE MAIN PCPN SHIELD...NOW ACRS WRN PA...ATTEMPTS TO
MOVE INTO THE CWA FROM SW TO NE. A BIG QUESTION IS WHAT HAPPENS
AFTER THAT...JUST AHD OF THE COLD FROPA IN THE 21Z-01Z TIME FRAME.
MOST OF THE CONVECTION ALLOWING MODELS (HRRR AND 4 KM WRF...FOR
EXAMPLE) INDICATE THAT SOME SORT OF ENHANCED/CONVECTIVE LN FORMS
ON THE BACK EDGE OF THE STEADIER PCPN AFTER 21Z...TRANSLATING
MAINLY ACRS NE PA AND PTNS OF THE SRN TIER LATE IN THE DAY.
THIS...OF COURSE...WILL DEPEND ON HOW MUCH INSTAB CAN FORM. THE
LATEST RUC SHOWS ML CAPE OF 200-400 THIS TIME FRAME IN OUR SERN
ZNS...WITH THE 12Z NAM COMING IN SHOWING MORE (500-800). GIVEN
EXTENSIVE CLOUD COVER/PCPN FOR SVRL MORE HRS AT LEAST...AND WHAT`S
BEING OBSERVED UPSTREAM ON SPC MESO`S ATTM (ML CAPE OF 100-200 IN
SE PA)...WE`RE INCLINED TO BUY THE MORE CONSERVATIVE RUC. ACRS
ROUGHLY THE SERN HALF OF THE CWA...WE`LL STILL MENTION ISOLD
TSRA...WHILE SHOWING OCNL +RA JUST ABT EVERYWHERE. THE BEST SVR
POTENTIAL APPEARS TO BE JUST SE OF THE CWA...WHERE THE PRIMARY
IMPETUS FOR ANY DISCERNIBLE LN OR DISCRETE CELL FORMATION IS.
KBGM VWP HAS 20-30 KT SRLY FLOW AT 2K FT AGL ATTM...WITH 40-50 KT
AT 3-4K FT AGL. KBGM BASE VEL PRODS ALSO SHOW THE 50-60 KT CORE
MOVG NWD THROUGH ERN PA...AND DESCENDING SOMEWHAT WITH TIME. THE
MOST FAVORABLE TIME FOR CONSISTENTLY STG GRADIENT WIND GUSTS WILL BE
FROM ABT 17-22Z. WIND ADVISORIES REMAIN IN TACT.
UNLESS TRAINING OF HEAVY RAIN BANDS FORM...WE`RE STILL NOT
EXPECTING ANY SIG HYDRO RELATED PROBLEMS...SO NO WATCHES PLANNED
FOR THE TIME BEING.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
340 PM UPDATE... VERY BRIEF DISCN...DUE TO ONGOING SVR WX.
DRY WX STILL ANTICIPATED WED-FRI...OTHER THAN SOME ISOLD -SHRA
EARLY WED...DUE TO A WEAK LAKE RESPONSE.
TEMPS WILL BE UNCHANGED...AS CURRENT MAX/MIN TEMP GRIDS MATCH
BLENDED MOS WELL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
315 AM UPDATE...CURRENT FORECAST IN GOOD SHAPE, LATEST MODEL RUNS
REMAIN CONSISTENT WITH PREVIOUS CYCLE, NO SIGNIFICANT CHANGES.
PREVIOUS DISC...
FRIDAY THROUGH FRIDAY NIGHT...A DEEP CUT OFF LOW WILL MOVE INTO
THE UPPER MIDWEST DURING THIS TIME. MEANWHILE FARTHER TO THE EAST
IN OUR NECK OF THE WOODS...WE WILL REMAIN IN A DEEP SOUTHWESTERLY
FLOW AHEAD OF THE CUT OFF LOW. INITIALLY THIS WILL BE GREAT NEWS
WITH OUR AREA REMAINING DRY AND EXPERIENCING ABOVE NORMAL TEMPS.
HIGHS FRIDAY SHOULD BE WELL INTO THE 70S...WITH NEAR 80 DEGREE
READINGS ACROSS THE LAKE PLAIN.
SATURDAY AND BEYOND...THE DOWNSIDE TO THE SLOW MOVEMENT OF THE CUT OFF LOW
MENTIONED ABOVE WILL BE AN UNSETTLED WEEKEND. AS THE CUT OFF LOW
MOVES NORTHEAST AND WE BEGIN TO FEEL THE EFFECTS OF THE H5
TROF...RAIN WILL SPREAD OUR WAY LATER SATURDAY INTO SUNDAY. THE
GFS HINTS THAT WE MAY SEE A DRY SLOT LATER SUNDAY...BUT PLENTY OF
UNCERTAINTY EXISTS WITH THE EURO KEEPING US WET. WILL KEEP CHANCE
POPS IN ESPECIALLY ACROSS THE NORTH TO COVER THIS.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
OVERVIEW...MVFR CIGS AND VSBYS LIKELY TO PERSIST THROUGH 21Z AS A PRE-FRONTAL
TROF MOVES THROUGH THE TERMINALS AND WE HAVE WIDESPREAD RAIN.
AFTER THIS TIME VSBYS SHOULD IMPROVE AS THE RAIN ENDS...BUT MVFR
CIGS LIKELY TO PERSIST THROUGH EARLY TONIGHT WITH VFR THEREAFTER.
DETAILS...A LINE OF HEAVIER RAIN IS MOVING ACROSS THE TERMINALS NOW...WELL
AHEAD OF A COLD FRONT OVER WESTERN NY. MVFR CIGS AND VSBYS LIKELY
WITH THE RAIN THROUGH 21Z. SOME BRIEF IFR VSBYS POSSIBLE AT
KRME...KBGM...KAVP DUE TO HEAVIER RAIN DURING THIS TIME. IN
ADDITION SOME PERIODS OF VFR LIKELY AT KRME/KSYR/KAVP DUE TO
STRONG DOWNSLOPING WINDS (SOUTHEAST). ONCE THIS LINE MOVES EAST OF
THE AREA AFTER 21Z...VSBYS WILL IMPROVE TO VFR BUT MVFR CIGS WILL
LINGER THROUGH 03Z - 06Z TONIGHT. AT THE ELEVATED SITES OF KBGM
AND KITH...IFR CIGS ARE POSSIBLE DURING THIS TIME.
AFTER 06Z GENERALLY VFR IS EXPECTED. DUE TO THE RAINFALL IFR
CONDITIONS CAN`T BE RULED OUT AT KELM DUE TO FOG. CONFIDENCE TOO
LOW TO INCLUDE AT THIS TIME DUE TO BREEZY BOUNDARY LAYER WINDS. SCT
CU AROUND 5KFT WEDNESDAY AND VFR CONDITIONS.
SOUTHEAST WINDS SHIFTING TO THE SOUTHWEST BY 21Z SUSTAINED 10 TO
20 KTS...WITH GUSTS TOWARD 30 KTS. SOUTHWEST WINDS BECOMING WEST
TONIGHT WITH GUSTS TOWARD 20KTS THROUGH 03Z...THEN AROUND 10KTS
OVERNIGHT. NORTHWEST WINDS 10 TO 15 KTS WEDNESDAY.
OUTLOOK...
THU/FRI...VFR EXCEPT IFR FOG AT KELM EACH MORNING FROM 8 TO 14Z.
SAT...MVFR POSSIBLE IN SHOWERS.
SUN...GENERALLY VFR...MVFR POSSIBLE NORTH IN SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR PAZ040-044-
047-048-072.
WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR PAZ038>040-043-
044-047-072.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ048.
NY...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR NYZ062.
WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ009-025-036-
037-044-045-055-056.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ046-057-062.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...MLJ
SHORT TERM...MLJ
LONG TERM...HEDEN/RRM
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
248 PM EDT TUE SEP 18 2012
.SYNOPSIS...
A VIGOROUS LOW PRESSURE SYSTEM WILL BRING STRONG...GUSTY WIND TO
THE AREA LATE THIS MORNING THROUGH THIS EVENING. THIS WILL BE
AHEAD OF A STRONG COLD FRONT THAT WILL ALSO BRING RAIN TO THE
REGION TODAY. THE SYSTEM WILL QUICKLY MOVE OUT OVERNIGHT...AND HIGH
PRESSURE WILL BRING QUIETER CONDITIONS FOR THE REMAINDER OF THE
WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1230 PM UPDATE... TOR WATCH #643 ISSUED FOR NE PA AND SULL CNTY
NY...TIL 23Z. THUS...WE`VE ADDED SOME ENHANCED WORDING FOR THE
ISOLD TSRA THIS AREA.
LINEAR FEATURES ARE BCMG MORE PROMINENT ALG THE BACK EDGE OF THE
STEADIER PCPN...AS ALLUDED TO IN PREV DISC. ML CAPES REMAIN FAIRLY
LOW...ON THE ORDER OF 100-200...BUT LOW-LVL SHEAR IS EXTREMELY
IMPRESSIVE (0-1 KM SREL HEL OF 400+). UNLESS MORE DESTAB
OCCURS...DISCRETE CELL DVLPMT IS UNLIKELY...BUT LINES OF
SHRA/EMBEDDED TSRA...WITH LOCALIZED 50+ KT GUSTS ARE PLAUSIBLE.
WE`LL CONTINUE TO MONITOR CLOSELY.
PREV DISC... 10 AM UPDATE... BROAD SWATH OF RA/+RA CONTS TO TRACK
NEWD THROUGH CNY/NE PA ATTM...BEING FUELED BY STG POS THETA-E
ADVCTN ON THE LEADING EDGE OF AN INCRG LOW-LVL JET. WE EXPECT
STEADY RAIN TO PERSIST TIL PERHAPS MID TO LATE AFTN...WHEN THE
BACK EDGE OF THE MAIN PCPN SHIELD...NOW ACRS WRN PA...ATTEMPTS TO
MOVE INTO THE CWA FROM SW TO NE. A BIG QUESTION IS WHAT HAPPENS
AFTER THAT...JUST AHD OF THE COLD FROPA IN THE 21Z-01Z TIME FRAME.
MOST OF THE CONVECTION ALLOWING MODELS (HRRR AND 4 KM WRF...FOR
EXAMPLE) INDICATE THAT SOME SORT OF ENHANCED/CONVECTIVE LN FORMS
ON THE BACK EDGE OF THE STEADIER PCPN AFTER 21Z...TRANSLATING
MAINLY ACRS NE PA AND PTNS OF THE SRN TIER LATE IN THE DAY.
THIS...OF COURSE...WILL DEPEND ON HOW MUCH INSTAB CAN FORM. THE
LATEST RUC SHOWS ML CAPE OF 200-400 THIS TIME FRAME IN OUR SERN
ZNS...WITH THE 12Z NAM COMING IN SHOWING MORE (500-800). GIVEN
EXTENSIVE CLOUD COVER/PCPN FOR SVRL MORE HRS AT LEAST...AND WHAT`S
BEING OBSERVED UPSTREAM ON SPC MESO`S ATTM (ML CAPE OF 100-200 IN
SE PA)...WE`RE INCLINED TO BUY THE MORE CONSERVATIVE RUC. ACRS
ROUGHLY THE SERN HALF OF THE CWA...WE`LL STILL MENTION ISOLD
TSRA...WHILE SHOWING OCNL +RA JUST ABT EVERYWHERE. THE BEST SVR
POTENTIAL APPEARS TO BE JUST SE OF THE CWA...WHERE THE PRIMARY
IMPETUS FOR ANY DISCERNIBLE LN OR DISCRETE CELL FORMATION IS.
KBGM VWP HAS 20-30 KT SRLY FLOW AT 2K FT AGL ATTM...WITH 40-50 KT
AT 3-4K FT AGL. KBGM BASE VEL PRODS ALSO SHOW THE 50-60 KT CORE
MOVG NWD THROUGH ERN PA...AND DESCENDING SOMEWHAT WITH TIME. THE
MOST FAVORABLE TIME FOR CONSISTENTLY STG GRADIENT WIND GUSTS WILL BE
FROM ABT 17-22Z. WIND ADVISORIES REMAIN IN TACT.
UNLESS TRAINING OF HEAVY RAIN BANDS FORM...WE`RE STILL NOT
EXPECTING ANY SIG HYDRO RELATED PROBLEMS...SO NO WATCHES PLANNED
FOR THE TIME BEING.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL BUILD OVER THE AREA. AS IT DOES, SOME COLDER
850MB TEMPS WILL MOVE ACROSS THE GREAT LAKE EARLY WEDNESDAY MORNING.
CURRENTLY THE NAM IS SHOWING TEMPS OF -1C AT 850MB. THE GFS AND
THE ECMWF ARE ONLY 1 OR 2 DEGREES WARMER. GIVEN THIS AND A WEST
NORTHWESTERLY FLOW EARLY WEDNESDAY MORNING, SOME LAKE EFFECT
SHOWERS MAY TRY TO POP UP, MAINLY ACROSS NORTHERN ONONDAGA AND
ONEIDA COUNTIES. THE CHANCE WILL DIMINISH WITH DAYTIME HEATING AND
MIXING WEDNESDAY LATE MORNING. THE REMAINDER OF THE FORECAST
PERIOD WILL BE COOL AND QUIET, WITH HIGH TEMPS IN THE UPPER 50S
AND LOW 60S WEDNESDAY AFTERNOON AND MIDDLE TO UPPER 60S ON
THURSDAY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
315 AM UPDATE...CURRENT FORECAST IN GOOD SHAPE, LATEST MODEL RUNS
REMAIN CONSISTENT WITH PREVIOUS CYCLE, NO SIGNIFICANT CHANGES.
PREVIOUS DISC...
FRIDAY THROUGH FRIDAY NIGHT...A DEEP CUT OFF LOW WILL MOVE INTO
THE UPPER MIDWEST DURING THIS TIME. MEANWHILE FARTHER TO THE EAST
IN OUR NECK OF THE WOODS...WE WILL REMAIN IN A DEEP SOUTHWESTERLY
FLOW AHEAD OF THE CUT OFF LOW. INITIALLY THIS WILL BE GREAT NEWS
WITH OUR AREA REMAINING DRY AND EXPERIENCING ABOVE NORMAL TEMPS.
HIGHS FRIDAY SHOULD BE WELL INTO THE 70S...WITH NEAR 80 DEGREE
READINGS ACROSS THE LAKE PLAIN.
SATURDAY AND BEYOND...THE DOWNSIDE TO THE SLOW MOVEMENT OF THE CUT OFF LOW
MENTIONED ABOVE WILL BE AN UNSETTLED WEEKEND. AS THE CUT OFF LOW
MOVES NORTHEAST AND WE BEGIN TO FEEL THE EFFECTS OF THE H5
TROF...RAIN WILL SPREAD OUR WAY LATER SATURDAY INTO SUNDAY. THE
GFS HINTS THAT WE MAY SEE A DRY SLOT LATER SUNDAY...BUT PLENTY OF
UNCERTAINTY EXISTS WITH THE EURO KEEPING US WET. WILL KEEP CHANCE
POPS IN ESPECIALLY ACROSS THE NORTH TO COVER THIS.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
OVERVIEW...MVFR CIGS AND VSBYS LIKELY TO PERSIST THROUGH 21Z AS A PREFRONTAL
TROF MOVES THROUGH THE TERMINALS AND WE HAVE WIDESPREAD RAIN.
AFTER THIS TIME VSBYS SHOULD IMPROVE AS THE RAIN ENDS...BUT MVFR
CIGS LIKELY TO PERSIST THROUGH EARLY TONIGHT WITH VFR THEREAFTER.
DETAILS...A LINE OF HEAVIER RAIN IS MOVING ACROSS THE TERMINALS NOW...WELL
AHEAD OF A COLD FRONT OVER WESTERN NY. MVFR CIGS AND VSBYS LIKELY
WITH THE RAIN THROUGH 21Z. SOME BRIEF IFR VSBYS POSSIBLE AT
KRME...KBGM...KAVP DUE TO HEAVIER RAIN DURING THIS TIME. IN
ADDITION SOME PERIODS OF VFR LIKELY AT KRME/KSYR/KAVP DUE TO
STRONG DOWNSLOPING WINDS (SOUTHEAST). ONCE THIS LINE MOVES EAST OF
THE AREA AFTER 21Z...VSBYS WILL IMPROVE TO VFR BUT MVFR CIGS WILL
LINGER THROUGH 03Z - 06Z TONIGHT. AT THE ELEVATED SITES OF KBGM
AND KITH...IFR CIGS ARE POSSIBLE DURING THIS TIME.
AFTER 06Z GENERALLY VFR IS EXPECTED. DUE TO THE RAINFALL IFR
CONDITIONS CAN`T BE RULED OUT AT KELM DUE TO FOG. CONFIDENCE TOO
LOW TO INCLUDE AT THIS TIME DUE TO BREEZY BOUNDARY LAYER WINDS. SCT
CU AROUND 5KFT WEDNESDAY AND VFR CONDITIONS.
SOUTHEAST WINDS SHIFTING TO THE SOUTHWEST BY 21Z SUSTAINED 10 TO
20 KTS...WITH GUSTS TOWARD 30 KTS. SOUTHWEST WINDS BECOMING WEST
TONIGHT WITH GUSTS TOWARD 20KTS THROUGH 03Z...THEN AROUND 10KTS
OVERNIGHT. NORTHWEST WINDS 10 TO 15 KTS WEDNESDAY.
OUTLOOK...
THU/FRI...VFR EXCEPT IFR FOG AT KELM EACH MORNING FROM 8 TO 14Z.
SAT...MVFR POSSIBLE IN SHOWERS.
SUN...GENERALLY VFR...MVFR POSSIBLE NORTH IN SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR PAZ038>040-043-
044-047-072.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ048.
NY...WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ009-025-036-
037-044-045-055-056.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ046-057-062.
&&
$$
SYNOPSIS...SLI
NEAR TERM...SLI
SHORT TERM...SLI
LONG TERM...HEDEN/RRM
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1239 PM EDT TUE SEP 18 2012
.SYNOPSIS...
A VIGOROUS LOW PRESSURE SYSTEM WILL BRING STRONG...GUSTY WIND TO
THE AREA LATE THIS MORNING THROUGH THIS EVENING. THIS WILL BE
AHEAD OF A STRONG COLD FRONT THAT WILL ALSO BRING RAIN TO THE
REGION TODAY. THE SYSTEM WILL QUICKLY MOVE OUT OVERNIGHT...AND HIGH
PRESSURE WILL BRING QUIETER CONDITIONS FOR THE REMAINDER OF THE
WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1230 PM UPDATE... TOR WATCH #643 ISSUED FOR NE PA AND SULL CNTY
NY...TIL 23Z. THUS...WE`VE ADDED SOME ENHANCED WORDING FOR THE
ISOLD TSRA THIS AREA.
LINEAR FEATURES ARE BCMG MORE PROMINENT ALG THE BACK EDGE OF THE
STEADIER PCPN...AS ALLUDED TO IN PREV DISC. ML CAPES REMAIN FAIRLY
LOW...ON THE ORDER OF 100-200...BUT LOW-LVL SHEAR IS EXTREMELY
IMPRESSIVE (0-1 KM SREL HEL OF 400+). UNLESS MORE DESTAB
OCCURS...DISCRETE CELL DVLPMT IS UNLIKELY...BUT LINES OF
SHRA/EMBEDDED TSRA...WITH LOCALIZED 50+ KT GUSTS ARE PLAUSIBLE.
WE`LL CONTINUE TO MONITOR CLOSELY.
PREV DISC... 10 AM UPDATE... BROAD SWATH OF RA/+RA CONTS TO TRACK
NEWD THROUGH CNY/NE PA ATTM...BEING FUELED BY STG POS THETA-E
ADVCTN ON THE LEADING EDGE OF AN INCRG LOW-LVL JET. WE EXPECT
STEADY RAIN TO PERSIST TIL PERHAPS MID TO LATE AFTN...WHEN THE
BACK EDGE OF THE MAIN PCPN SHIELD...NOW ACRS WRN PA...ATTEMPTS TO
MOVE INTO THE CWA FROM SW TO NE. A BIG QUESTION IS WHAT HAPPENS
AFTER THAT...JUST AHD OF THE COLD FROPA IN THE 21Z-01Z TIME FRAME.
MOST OF THE CONVECTION ALLOWING MODELS (HRRR AND 4 KM WRF...FOR
EXAMPLE) INDICATE THAT SOME SORT OF ENHANCED/CONVECTIVE LN FORMS
ON THE BACK EDGE OF THE STEADIER PCPN AFTER 21Z...TRANSLATING
MAINLY ACRS NE PA AND PTNS OF THE SRN TIER LATE IN THE DAY.
THIS...OF COURSE...WILL DEPEND ON HOW MUCH INSTAB CAN FORM. THE
LATEST RUC SHOWS ML CAPE OF 200-400 THIS TIME FRAME IN OUR SERN
ZNS...WITH THE 12Z NAM COMING IN SHOWING MORE (500-800). GIVEN
EXTENSIVE CLOUD COVER/PCPN FOR SVRL MORE HRS AT LEAST...AND WHAT`S
BEING OBSERVED UPSTREAM ON SPC MESO`S ATTM (ML CAPE OF 100-200 IN
SE PA)...WE`RE INCLINED TO BUY THE MORE CONSERVATIVE RUC. ACRS
ROUGHLY THE SERN HALF OF THE CWA...WE`LL STILL MENTION ISOLD
TSRA...WHILE SHOWING OCNL +RA JUST ABT EVERYWHERE. THE BEST SVR
POTENTIAL APPEARS TO BE JUST SE OF THE CWA...WHERE THE PRIMARY
IMPETUS FOR ANY DISCERNIBLE LN OR DISCRETE CELL FORMATION IS.
KBGM VWP HAS 20-30 KT SRLY FLOW AT 2K FT AGL ATTM...WITH 40-50 KT
AT 3-4K FT AGL. KBGM BASE VEL PRODS ALSO SHOW THE 50-60 KT CORE
MOVG NWD THROUGH ERN PA...AND DESCENDING SOMEWHAT WITH TIME. THE
MOST FAVORABLE TIME FOR CONSISTENTLY STG GRADIENT WIND GUSTS WILL BE
FROM ABT 17-22Z. WIND ADVISORIES REMAIN IN TACT.
UNLESS TRAINING OF HEAVY RAIN BANDS FORM...WE`RE STILL NOT
EXPECTING ANY SIG HYDRO RELATED PROBLEMS...SO NO WATCHES PLANNED
FOR THE TIME BEING.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL BUILD OVER THE AREA. AS IT DOES, SOME COLDER
850MB TEMPS WILL MOVE ACROSS THE GREAT LAKE EARLY WEDNESDAY MORNING.
CURRENTLY THE NAM IS SHOWING TEMPS OF -1C AT 850MB. THE GFS AND
THE ECMWF ARE ONLY 1 OR 2 DEGREES WARMER. GIVEN THIS AND A WEST
NORTHWESTERLY FLOW EARLY WEDNESDAY MORNING, SOME LAKE EFFECT
SHOWERS MAY TRY TO POP UP, MAINLY ACROSS NORTHERN ONONDAGA AND
ONEIDA COUNTIES. THE CHANCE WILL DIMINISH WITH DAYTIME HEATING AND
MIXING WEDNESDAY LATE MORNING. THE REMAINDER OF THE FORECAST
PERIOD WILL BE COOL AND QUIET, WITH HIGH TEMPS IN THE UPPER 50S
AND LOW 60S WEDNESDAY AFTERNOON AND MIDDLE TO UPPER 60S ON
THURSDAY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
315 AM UPDATE...CURRENT FORECAST IN GOOD SHAPE, LATEST MODEL RUNS
REMAIN CONSISTENT WITH PREVIOUS CYCLE, NO SIGNIFICANT CHANGES.
PREVIOUS DISC...
FRIDAY THROUGH FRIDAY NIGHT...A DEEP CUT OFF LOW WILL MOVE INTO
THE UPPER MIDWEST DURING THIS TIME. MEANWHILE FARTHER TO THE EAST
IN OUR NECK OF THE WOODS...WE WILL REMAIN IN A DEEP SOUTHWESTERLY
FLOW AHEAD OF THE CUT OFF LOW. INITIALLY THIS WILL BE GREAT NEWS
WITH OUR AREA REMAINING DRY AND EXPERIENCING ABOVE NORMAL TEMPS.
HIGHS FRIDAY SHOULD BE WELL INTO THE 70S...WITH NEAR 80 DEGREE
READINGS ACROSS THE LAKE PLAIN.
SATURDAY AND BEYOND...THE DOWNSIDE TO THE SLOW MOVEMENT OF THE CUT OFF LOW
MENTIONED ABOVE WILL BE AN UNSETTLED WEEKEND. AS THE CUT OFF LOW
MOVES NORTHEAST AND WE BEGIN TO FEEL THE EFFECTS OF THE H5
TROF...RAIN WILL SPREAD OUR WAY LATER SATURDAY INTO SUNDAY. THE
GFS HINTS THAT WE MAY SEE A DRY SLOT LATER SUNDAY...BUT PLENTY OF
UNCERTAINTY EXISTS WITH THE EURO KEEPING US WET. WILL KEEP CHANCE
POPS IN ESPECIALLY ACROSS THE NORTH TO COVER THIS.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AN INTENSIFYING LOW PRES SYSTEM IN THE OH VALLEY WITH PRODUCE
MODERATE RAIN ACROSS THE TERMINALS THROUGH TODAY. WIDESPREAD LOW
MVFR CONDITIONS ARE EXPECTED WITH IFR LIKELY FOR MUCH OF THE DAY
AT KITH/KBGM. STRONG FLOW SHOULD PREVENT WIDESPREAD IFR CIGS. A
STRONG COLD FRONT WILL CROSS THE REGION BETWEEN 23Z-02Z, WITH
PRECIP ENDING AROUND THREE HOURS AFTER FROPA BUT IN GENERAL MVFR
CIGS WILL PERSIST.
WINDS S/SE AT 10 KTS THEN INCREASING BY MID MORNING FROM THE SOUTH
AT 10-15 KNOTS WITH GUSTS 25-30 KNOTS BECOMING SOUTHWEST DURING
THE AFTERNOON THEN WESTERLY AFTER FROPA AROUND 10 KNOTS WITH GUSTS
AROUND 20 KNOTS.
AT KAVP/KELM LOW LEVEL WIND SHEAR WILL EXISTS THROUGH MID MORNING
WITH LIGHT WINDS AT THE SFC AND GUSTY SOUTHERLY WINDS AT 2K FT.
OUTLOOK...
WED...VFR.
THU/FRI...VFR EXCEPT IFR FOG AT KELM EACH MORNING FROM 8 TO 14Z.
SAT...MVFR POSSIBLE IN SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR PAZ038>040-043-
044-047-072.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ048.
NY...WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ009-025-036-
037-044-045-055-056.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ046-057-062.
&&
$$
SYNOPSIS...SLI/MLJ
NEAR TERM...SLI/MLJ
SHORT TERM...SLI
LONG TERM...HEDEN/RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1218 PM CDT TUE SEP 18 2012
.DISCUSSION...
SEE AVIATION DISCUSSION BELOW.
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL OVER THE NEXT 24 HOURS. THE SCATTERED
CLOUD COVER WILL MOVE OFF AND DISSIPATE BY 20Z. WINDS WILL REMAIN
GENERALLY LESS THAN 11 KTS WITH VARIABLE WINDS OVERNIGHT AT
BBD...JCT...AND SOA.
&&
.PREV DISCUSSION... /ISSUED 958 AM CDT TUE SEP 18 2012/
UPDATE...
UPDATED THE POPS AND WEATHER GRIDS.
DISCUSSION...
UPDATED TO FORECAST TO REMOVE THE POPS AND WEATHER FOR THE BIG
COUNTRY.
PREV DISCUSSION... /ISSUED 633 AM CDT TUE SEP 18 2012/
DISCUSSION...
/SEE BELOW FOR AVIATION DISCUSSION/
AVIATION...
THUNDERSTORMS WILL MOVE THROUGH KABI THROUGH 14Z. STORMS HAVE
WEAKENED...BUT MAY STILL BE CAPABLE OF WINDS OF 35 KTS AND LOWERED
VISIBILITIES OF 1 TO 3 MILES. SCATTERED LIGHT SHOWERS AND PERHAPS A
THUNDERSTORM MAY ALSO AFFECT KSJT THROUGH 14Z...BUT WILL ONLY PUT
VCTS IN THE TAF AS MOST OF THE STORMS WILL PASS NORTH. OTHERWISE
NORTH WINDS INCREASE TO 10 KT AS A COLD FRONT MOVES THROUGH THIS
MORNING.
PREV DISCUSSION... /ISSUED 404 AM CDT TUE SEP 18 2012/
SHORT TERM...
CONVECTIVE COMPLEX IN ASSOCIATION WITH AN UPPER SHORTWAVE AND COLD
FRONT WAS MOVING INTO THE BIG COUNTRY AT 3 AM. THERE WERE SOME
STRONG STORMS ASSOCIATED WITH IT...WHICH MAY BE PRODUCING SOME SMALL
HAIL.
COLD FRONT AND UPPER SHORTWAVE MOVE SE ACROSS THE BIG COUNTRY AND
HEARTLAND THIS MORNING. THIS AREA WILL ALSO BE IN AN AREA OF UPPER
LEVEL DIVERGENCE ASSOCIATED WITH THE LEFT EXIT REGION OF A 100 KT
JET AT 200 MB...WITH THE AXIS OF THE JET ALONG I-10. MORNING STORM
ACTIVITY WAS MORE WIDESPREAD THAN THE NAM OR GFS MODELS THIS
MORNING. RUC MODEL HOWEVER DOES HAVE A BETTER HANDLE ON STORM
PLACEMENT AND AREAL EXTENT...THOUGH EVEN THE RUC RAPIDLY WEAKENS
CONVECTIVE ACTIVITY BY 9 AM AND CONFINES RAINFALL TO THE BIG COUNTRY.
DID KEEP A SLIGHT CHANCE OF STORMS IN FARTHER WEST IN THE CONCHO
VALLEY HOWEVER...WITH A VORT MAX INDICATED IN WATER VAPOR
LOOP...EMBEDDED IN THE WESTERN SIDE OF THE UPPER SHORTWAVE IN NEW
MEXICO. WENT SLIGHTLY COOLER THAN GFS MOS TODAY WITH COLD ADVECTION
AND MID/UPPER LEVEL CLOUDS ASSOCIATED WITH SHORTWAVE. KEPT
THUNDERSTORM CHANCES ONLY FOR THIS MORNING...WITH SUBSIDENCE BEHIND
EXITING SHORTWAVE BY NOON.
LONG TERM...
A DRY FORECAST IN STORE FOR WEST CENTRAL TEXAS IN THE LONG TERM.
WEDNESDAY THROUGH FRIDAY...UPPER LEVEL RIDGE WILL REMAIN CENTERED
OVER THE WESTERN US. ANOMALOUSLY DEEP UPPER TROUGH WILL BE MAINTAINED
ACROSS THE NORTHERN GREAT LAKES AND UPPER MIDWEST. FOR WEST CENTRAL
TEXAS...TEMPERATURES WILL BE WARMER ON WEDNESDAY AS LIGHT SOUTHERLY
FLOW DEVELOPS WITH AMPLE SUNSHINE. PER THE 850 MB THERMAL PATTERN...
EXPECT DAYTIME TEMPERATURES TO BE A FEW DEGREES ABOVE NORMAL WITH
AFTERNOON HIGHS IN THE UPPER 80S TO LOWER 90S THURSDAY AND FRIDAY.
SOME MODEL DISAGREEMENT IS SHOWN WITH PROGRESS AND STRENGTH OF A
COLD FRONT FOR NEXT WEEKEND. AS A STRONG UPPER LOW DEVELOPS SOUTH
TOWARD THE NORTHERN GREAT LAKES...A DISTURBANCE IS PROGGED TO
PINWHEEL AROUND ITS SOUTHWESTERN PERIPHERY ON SATURDAY. THE 00Z
ECMWF HAS A STRONGER ASSOCIATED COLD FRONT DROPPING SOUTH ACROSS
WEST CENTRAL TEXAS LATE SATURDAY NIGHT AND SUNDAY MORNING...WITH A
1030 MB SURFACE HIGH DROPPING SOUTH ACROSS THE NORTHERN AND CENTRAL
PLAINS BEHIND THE FRONT. THE 00Z GFS HAS A CONSIDERABLY WEAKER
COLD FRONT MOVING SOUTH INTO THE BIG COUNTRY ON SATURDAY AFTERNOON...
AND BRINGS ONLY A GLANCING SHOT OF SLIGHTLY COOLER AIR INTO WEST
CENTRAL TEXAS. THE GFS ENSEMBLE SHOWS CONSIDERABLE SPREAD IN
SURFACE WINDS FOR NEXT WEEKEND. TIMING AND STRENGTH OF COLD FRONT
WILL LIKELY DEPEND ON EVOLUTION OF THE UPPER LEVEL FLOW PATTERN
ACROSS THE GREAT LAKES AND MIDWEST. GIVEN THE UNCERTAINTY...LITTLE
CHANGE WAS MADE TO THE WIND FIELD FOR NEXT WEEKEND. EITHER WAY
WITH THE MODELS...MOISTURE LOOKS TOO LIMITED IN OUR AREA TO
SUPPORT RAIN CHANCES WITH THE COLD FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 79 57 86 63 89 / 10 0 0 5 5
SAN ANGELO 82 58 88 62 90 / 20 0 0 0 5
JUNCTION 84 57 87 57 89 / 20 0 0 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
REIMER
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1210 PM CDT TUE SEP 18 2012
.AVIATION...
MVFR CEILINGS WILL CONTINUE TO LIFT AND SCATTER THROUGH EARLY
AFTERNOON AS DRIER AIR FILTERS IN BEHIND A COLD FRONT. EXPECT VFR
CONDITIONS AT ALL TAF SITES THIS AFTERNOON THROUGH WEDNESDAY
MORNING WITH A MOSTLY CLEAR SKY. A NORTH WIND WILL PREVAIL BETWEEN
10 AND 15 KNOTS THIS AFTERNOON AND SHOULD DECREASE BELOW 12 KNOTS
AFTER SUNSET. THE WIND WILL BECOME LIGHT AND VARIABLE OVERNIGHT
THEN TURN TO THE SOUTHEAST/SOUTH WEDNESDAY MORNING IN RESPONSE TO
DEVELOPING SURFACE LOW PRESSURE ACROSS THE CENTRAL AND SOUTHERN
HIGH PLAINS.
79
&&
.UPDATE...
FOR THE MIDDAY UPDATE...WE HAVE MOVED THE THUNDER POTENTIAL FARTHER
SOUTH TO THE FAR SOUTHERN COUNTIES WHILE ISOLATED SHOWERS REMAIN
POSSIBLE SOUTH OF I-20. THE SHORTWAVE CURRENTLY MOVING ACROSS THE
TEXAS HILL COUNTRY AS IT PREPARES TO DROP INTO THE BASE OF THE
LONG WAVE UPPER TROUGH ALIGNED NORTH-SOUTH ALONG THE MISSISSIPPI
RIVER. DRY LOW LEVEL AIR AND SURFACE DEWPOINTS IN THE MID 40S AS
CROSSED THE RED RIVER AND WILL CONTINUE TO PUSH SOUTH DURING THE
DAY. EXPECT THE CLEARING TO MOVE SOUTH OF I-20 JUST AFTER MIDDAY
THEN THROUGH THE SOUTHERN COUNTIES BY 5 OR 6 PM. LITTLE CHANGE WAS
MADE TO THE EXTEND FORECAST FOR NOW. 75
&&
.PREV DISCUSSION... /ISSUED 241 AM CDT TUE SEP 18 2012/
UPPER LOW THAT AFFECTED NORTH TEXAS THIS PAST WEEKEND WAS MOVING
INTO THE LOWER MISSISSIPPI VALLEY THIS MORNING. ANOTHER VIGOROUS
SHORTWAVE CAN BE SEEN WITHIN NORTHWEST FLOW ALOFT MOVING OVER THE
TEXAS PANHANDLE EARLY THIS MORNING. MEANWHILE...A COLD FRONT WAS
MOVING ACROSS THE RED RIVER AND AS OF 2 AM WAS ALONG A LAKE TEXOMA...
BOWIE...SEYMOUR LINE. THE FRONT WAS EXPECTED TO REACH THE I-20
BETWEEN 4 AND 5 AM...OR BEFORE SUNRISE...THEN MOVE THROUGH CENTRAL
TEXAS BY MID-LATE MORNING. BRISK AND COOLER CONDITIONS ARE
EXPECTED BEHIND THE FRONT TODAY WITH NORTH WINDS 10 TO 20 MPH
EXPECTED BEHIND THE FRONT. CAA IS IMPRESSIVE AS WELL... THOUGH
LAGGING ABOUT 100 MILES BEHIND THE FRONT. THE CAA COMBINED WITH
WITH MID AND HIGH CLOUDINESS THE FIRST HALF OF THE DAY WILL KEEP
HIGH TEMPERATURES THIS AFTERNOON DOWN IN THE MID AND UPPER 70S
NORTH WITH LOWER 80S SOUTH OF I-20.
IN ADDITION...MID LEVEL MOISTURE WILL BE SUBSTANTIAL ENOUGH FOR A
FEW THUNDERSTORMS ACROSS OUR WESTERN CWA LATER THIS MORNING PER
WRF AND HRRR MODELS. THE BEST STRONGEST FORCING WILL TRACK ACROSS
THE SOUTHWEST COUNTIES LATER THIS MORNING. ELSEWHERE...FORCING IS
NOT EXPECTED TO BE AS STRONG WITH ISOLATED SHOWERS EXPECTED. THE
ELEVATED AND HIGH-BASED NATURE OF CONVECTION WILL RESULT IN ONLY
LIGHT RAINFALL AMOUNTS...LIKELY LESS THAN QUARTER OF AN INCH.
HOWEVER...STEEP MID LEVEL LAPSE RATES AT/ABOVE 7 DEG C/KM AND
STRONG FORCING ALOFT MAY RESULT IN A STRONG STORM OR TWO CONTAINING
FREQUENT LIGHTNING AND POSSIBLY SMALL HAIL ACROSS THE WESTERN
COUNTIES LATER THIS MORNING. BEST LIFT SHIFTS SOUTH OF I-20 WITH
THE FRONT PUSHING TO THE TEXAS COAST THIS AFTERNOON...AS THIS
SYSTEM WILL BE MUCH MORE PROGRESSIVE THAN THE PREVIOUS WEEKEND
SYSTEM WAS. WILL CONTINUE A SLIGHT CHANCE ACROSS THE CENTRAL TEXAS
COUNTIES THIS AFTERNOON...BEFORE BOTH THE SHORTWAVE AND FRONT MOVE
AWAY FROM THE AREA BY EVENING.
HIGH PRESSURE WILL SETTLE IN TONIGHT WITH LIGHT WINDS AND MOSTLY
CLEAR SKIES. EXPECT A GOOD RADIATIONAL COOLING SET UP WITH LOWS
FALLING FALLING INTO THE 50S...THOUGH SOME ISOLATED READINGS IN
THE UPPER 40S CANNOT BE RULED OUT ACROSS PROTECTED RURAL AREAS.
HIGHS WILL REBOUND INTO THE UPPER 70S ACROSS THE EAST TO THE MID
80S IN THE WEST WEDNESDAY. THE UPPER RIDGE WILL CONTINUE EXPANDING
OVERHEAD THURSDAY AND FRIDAY WITH A MODERATION OF TEMPERATURES.
HIGHS BY FRIDAY WILL SOAR TO NEAR 90 DEGREES...BUT THE HUMIDITY
SHOULD BE RELATIVELY LOW. THE GREAT LAKES VORTEX WILL DEEPEN BY
LATE FRIDAY INTO THE WEEKEND AND WILL DRAG ANOTHER COLD FRONT INTO
NORTH TEXAS SATURDAY OR POSSIBLY SATURDAY NIGHT DEPENDING ON
WHETHER YOU BUY THE SLOWER ECMWF OR FASTER GEM/GFS MODELS. HAVE
TAKEN A MEAN ON THE TIMING AND WARMED HIGHS BACK UP SLIGHTLY ON
SATURDAY. WITH MOISTURE AVAILABILITY NOT LOOKING VERY GOOD WITH
THIS FRONT...HAVE DECIDED TO LEAVE THE FORECAST NEXT WEEKEND DRY.
05/
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 78 57 83 62 86 / 10 0 0 5 5
WACO, TX 80 56 85 59 86 / 20 0 0 0 5
PARIS, TX 75 52 80 55 85 / 10 0 0 5 5
DENTON, TX 78 53 84 60 88 / 10 0 0 5 5
MCKINNEY, TX 77 53 82 57 88 / 10 0 0 5 5
DALLAS, TX 79 59 83 64 87 / 10 0 0 5 5
TERRELL, TX 78 54 82 57 86 / 10 0 0 5 5
CORSICANA, TX 80 55 83 57 86 / 10 5 0 0 5
TEMPLE, TX 81 56 84 58 86 / 20 5 0 0 5
MINERAL WELLS, TX 76 55 86 60 88 / 20 0 0 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
79/75
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1129 AM CDT TUE SEP 18 2012
.UPDATE...
FOR THE MIDDAY UPDATE...WE HAVE MOVED THE THUNDER POTENTIAL FARTHER
SOUTH TO THE FAR SOUTHERN COUNTIES WHILE ISOLATED SHOWERS REMAIN
POSSIBLE SOUTH OF I-20. THE SHORTWAVE CURRENTLY MOVING ACROSS THE
TEXAS HILL COUNTRY AS IT PREPARES TO DROP INTO THE BASE OF THE
LONG WAVE UPPER TROUGH ALIGNED NORTH-SOUTH ALONG THE MISSISSIPPI
RIVER. DRY LOW LEVEL AIR AND SURFACE DEWPOINTS IN THE MID 40S AS
CROSSED THE RED RIVER AND WILL CONTINUE TO PUSH SOUTH DURING THE
DAY. EXPECT THE CLEARING TO MOVE SOUTH OF I-20 JUST AFTER MIDDAY
THEN THROUGH THE SOUTHERN COUNTIES BY 5 OR 6 PM. LITTLE CHANGE WAS
MADE TO THE EXTEND FORECAST FOR NOW. 75
&&
.AVIATION...
EXPECT VFR WITH NORTH FLOW THRU TODAY. FRONT SHOULD BE THROUGH
METROPLEX TAF SITES NEAR 12Z...SO WILL START TAFS WITH POST
FRONTAL NORTH WINDS. MVFR STRATUS IN OKLAHOMA WELL BEHIND FRONT
WILL REACH METROPLEX AROUND 16-17Z...AND WITH MORNING WARMING
SHOULD REMAIN SCT. WILL HAVE TO KEEP AN EYE ON IT BUT SHOULD IT GO
BKN IT MAY BE ABOVE 030 BY THEN. WINDS WILL TURN BACK SOUTH LATE
IN THE EVENING. 84
&&
.PREV DISCUSSION... /ISSUED 241 AM CDT TUE SEP 18 2012/
UPPER LOW THAT AFFECTED NORTH TEXAS THIS PAST WEEKEND WAS MOVING
INTO THE LOWER MISSISSIPPI VALLEY THIS MORNING. ANOTHER VIGOROUS
SHORTWAVE CAN BE SEEN WITHIN NORTHWEST FLOW ALOFT MOVING OVER THE
TEXAS PANHANDLE EARLY THIS MORNING. MEANWHILE...A COLD FRONT WAS
MOVING ACROSS THE RED RIVER AND AS OF 2 AM WAS ALONG A LAKE TEXOMA...
BOWIE...SEYMOUR LINE. THE FRONT WAS EXPECTED TO REACH THE I-20
BETWEEN 4 AND 5 AM...OR BEFORE SUNRISE...THEN MOVE THROUGH CENTRAL
TEXAS BY MID-LATE MORNING. BRISK AND COOLER CONDITIONS ARE
EXPECTED BEHIND THE FRONT TODAY WITH NORTH WINDS 10 TO 20 MPH
EXPECTED BEHIND THE FRONT. CAA IS IMPRESSIVE AS WELL... THOUGH
LAGGING ABOUT 100 MILES BEHIND THE FRONT. THE CAA COMBINED WITH
WITH MID AND HIGH CLOUDINESS THE FIRST HALF OF THE DAY WILL KEEP
HIGH TEMPERATURES THIS AFTERNOON DOWN IN THE MID AND UPPER 70S
NORTH WITH LOWER 80S SOUTH OF I-20.
IN ADDITION...MID LEVEL MOISTURE WILL BE SUBSTANTIAL ENOUGH FOR A
FEW THUNDERSTORMS ACROSS OUR WESTERN CWA LATER THIS MORNING PER
WRF AND HRRR MODELS. THE BEST STRONGEST FORCING WILL TRACK ACROSS
THE SOUTHWEST COUNTIES LATER THIS MORNING. ELSEWHERE...FORCING IS
NOT EXPECTED TO BE AS STRONG WITH ISOLATED SHOWERS EXPECTED. THE
ELEVATED AND HIGH-BASED NATURE OF CONVECTION WILL RESULT IN ONLY
LIGHT RAINFALL AMOUNTS...LIKELY LESS THAN QUARTER OF AN INCH.
HOWEVER...STEEP MID LEVEL LAPSE RATES AT/ABOVE 7 DEG C/KM AND
STRONG FORCING ALOFT MAY RESULT IN A STRONG STORM OR TWO CONTAINING
FREQUENT LIGHTNING AND POSSIBLY SMALL HAIL ACROSS THE WESTERN
COUNTIES LATER THIS MORNING. BEST LIFT SHIFTS SOUTH OF I-20 WITH
THE FRONT PUSHING TO THE TEXAS COAST THIS AFTERNOON...AS THIS
SYSTEM WILL BE MUCH MORE PROGRESSIVE THAN THE PREVIOUS WEEKEND
SYSTEM WAS. WILL CONTINUE A SLIGHT CHANCE ACROSS THE CENTRAL TEXAS
COUNTIES THIS AFTERNOON...BEFORE BOTH THE SHORTWAVE AND FRONT MOVE
AWAY FROM THE AREA BY EVENING.
HIGH PRESSURE WILL SETTLE IN TONIGHT WITH LIGHT WINDS AND MOSTLY
CLEAR SKIES. EXPECT A GOOD RADIATIONAL COOLING SET UP WITH LOWS
FALLING FALLING INTO THE 50S...THOUGH SOME ISOLATED READINGS IN
THE UPPER 40S CANNOT BE RULED OUT ACROSS PROTECTED RURAL AREAS.
HIGHS WILL REBOUND INTO THE UPPER 70S ACROSS THE EAST TO THE MID
80S IN THE WEST WEDNESDAY. THE UPPER RIDGE WILL CONTINUE EXPANDING
OVERHEAD THURSDAY AND FRIDAY WITH A MODERATION OF TEMPERATURES.
HIGHS BY FRIDAY WILL SOAR TO NEAR 90 DEGREES...BUT THE HUMIDITY
SHOULD BE RELATIVELY LOW. THE GREAT LAKES VORTEX WILL DEEPEN BY
LATE FRIDAY INTO THE WEEKEND AND WILL DRAG ANOTHER COLD FRONT INTO
NORTH TEXAS SATURDAY OR POSSIBLY SATURDAY NIGHT DEPENDING ON
WHETHER YOU BUY THE SLOWER ECMWF OR FASTER GEM/GFS MODELS. HAVE
TAKEN A MEAN ON THE TIMING AND WARMED HIGHS BACK UP SLIGHTLY ON
SATURDAY. WITH MOISTURE AVAILABILITY NOT LOOKING VERY GOOD WITH
THIS FRONT...HAVE DECIDED TO LEAVE THE FORECAST NEXT WEEKEND DRY.
05/
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 78 57 83 62 86 / 10 0 0 5 5
WACO, TX 80 56 85 59 86 / 20 0 0 0 5
PARIS, TX 75 52 80 55 85 / 10 0 0 5 5
DENTON, TX 78 53 84 60 88 / 10 0 0 5 5
MCKINNEY, TX 77 53 82 57 88 / 10 0 0 5 5
DALLAS, TX 79 59 83 64 87 / 10 0 0 5 5
TERRELL, TX 78 54 82 57 86 / 10 0 0 5 5
CORSICANA, TX 80 55 83 57 86 / 10 5 0 0 5
TEMPLE, TX 81 56 84 58 86 / 20 5 0 0 5
MINERAL WELLS, TX 76 55 86 60 88 / 20 0 0 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/75
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1155 AM CDT TUE SEP 18 2012
.UPDATE...
FORECAST TEMPS APPEAR TO BE ON TRACK SO FAR AND MATCH UP WELL WITH
925 MB TEMPS OF AROUND 8 DEGREES NORTHEAST TO 10 DEGREES
SOUTHWEST. STILL KEEPING SLIGHT CHANCE OF SHOWERS IN THE
FORECAST...AS THE LEFT EXIT REGION OF A 250 MB JET MOVES THROUGH
AND THE 500 MB TROUGH EXITS. THE HRRR AND RUC SHOW SOME SPOTTY
DEVELOPMENT THIS AFTERNOON AS WELL AND THERE IS SOME
DEVELOPMENT ALREADY OCCURRING...MAINLY IN NORTHEAST WISCONSIN.
&&
.AVIATION/18Z TAFS/...
VFR CONDITIONS ARE EXPECTED FOR THE ENTIRE PERIOD. THERE IS STILL
A SLIGHT CHANCE FOR SHOWERS THIS AFTERNOON...MAINLY EAST OF
MADISON...AS AN UPPER TROUGH AND JET SHIFT EAST. SCATTERED TO
BROKEN CLOUD COVER EXPECTED AROUND 4.5 TO 5.5 KFT THIS AFTERNOON.
THEN CLEAR SKIES TONIGHT WITH SOME MID TO HIGH CLOUDS BUILDING
IN LATE. COULD SEE SCATTERED TO BROKEN DECK AROUND 9 KFT BY EARLY
TOMORROW MORNING...AHEAD OF A COLD FRONT THAT WILL PASS THROUGH MSN
BETWEEN 21 AND 00Z TOMORROW. LOOKS LIKE PRECIPITATION WILL HOLD
OFF WITH THE FRONT UNTIL MID TO LATE AFTERNOON IN MSN AND LATER IN
THE EASTERN AREAS. ALSO...STRONG SOUTH TO SOUTHWEST WINDS ARE
EXPECTED AHEAD OF THE FRONT ON WEDNESDAY.
&&
.MARINE...
A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE NEARSHORE WATERS
INTO THIS EVENING AS A TROUGH OF LOW PRESSURE SLIDES EAST AND HIGH
PRESSURE BUILDS INTO THE REGION. STRONG SOUTH TO SOUTHWEST WINDS
ARE EXPECTED TOMORROW AS A COLD FRONT APPROACHES. A SMALL CRAFT
ADVISORY OR POSSIBLY A GALE WARNING WILL BE NEEDED.
&&
.PREV DISCUSSION... /ISSUED 333 AM CDT TUE SEP 18 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM TO HIGH
COLD ADVECTION WILL WEAKEN LATER THIS MORNING BUT A 540 DM THICKNESS
TROUGH WILL PROGRESS ACROSS WI TODAY. FCST SOUNDINGS INDICATE JUST
ENOUGH DEPTH TO SHALLOW CAPE FOR ISOLD LGT SHOWERS THIS AFTERNOON.
SCT-BKN CUMULUS THIS AFTERNOON AND 925 MB TEMPS AROUND 9C ONLY
YIELDS HIGH TEMPS AROUND 60F. A NARROW SFC RIDGE AXIS WILL THEN
SHIFT FROM WEST TO EAST ACROSS WI THIS EVENING INTO THE EARLY
OVERNIGHT WITH TEMPS COOLING QUICKLY. HOWEVER MID TO HIGH CLOUDS
INCREASE LATE DUE TO MID LEVEL WARM ADVECTION DEVELOPING AHEAD OF A
DIGGING 120 KT JET AND ASSOCIATED SHORTWAVE TROUGH/SFC LOW FROM SASK
AND MANITOBA CANADA. THUS EXPECT PATCHY/AREAS OF FROST INLAND WITH
LOW TEMPS IN THE MID TO UPPER 30S...VERSUS COLDER TEMPS AND
WIDESPREAD FROST IF MORE IDEAL RADIATIONAL COOLING CONDITIONS WERE
EXPECTED.
WEDNESDAY...FORECAST CONFIDENCE...MEDIUM
DECENT COLD FRONT AND TRAILING SHORTWAVE TO MOVE THROUGH ON
WEDNESDAY. PLENTY OF LIFT WITH FRONTOGENESIS AND Q-VECTOR
CONVERGENCE. MODELS ALSO SHOWING 40-45KT LOW LEVEL JET AHEAD OF THE
FRONT RIGHT OVER SOUTHERN WISCONSIN. MOISTURE COULD DEFINITELY BE
BETTER...BUT SEEMS TO BE VIGOROUS ENOUGH OF A SYSTEM TO RAISE POPS
TO HIGH CHANCE. BEST CHANCE SEEMS LIKE IT WILL BE LATE AFTERNOON AND
INTO THE EVENING WITH CURRENT MODEL TIMING OF THE FRONT.
OTHER STORY WEDNESDAY WILL BE THE STRONG SOUTHERLY WINDS. A TIGHT
PRESSURE GRADIENT IS EXPECTED TO SETUP OVER SOUTHERN
WISCONSIN...WITH GUSTS OF 30-40 MPH EXPECTED. THE GRADIENT IS
TIGHTER WITH THE NAM...SUGGESTING GUSTS COULD POSSIBLY APPROACH
WIND ADVISORY CRITERIA. STUCK WITH THE MIDDLE GROUND FOR NOW...BUT
EITHER WAY...WILL LIKELY BE THE WINDIEST DAY IN A WHILE.
WITH SOME SUN EXPECTED IN AT LEAST THE MORNING...SHOULD SEE HIGHS
SNEAK UP INTO THE LOW 70S...AS 925 MB TEMPS SURGE AHEAD OF THE
FRONT. COULD SEE TEMPS EVEN MILDER IF MILDER NAM 925 MB TEMPS
VERIFY.
THURSDAY AND FRIDAY...FORECAST CONFIDENCE...MEDIUM
SHOULD SEE QUIET WEATHER BRIEFLY DURING THE DAY THURSDAY AS HIGH
PRESSURE SLIDES BY TO THE SOUTH. EXPECTING SOME SUN IN AT LEAST THE
MORNING AGAIN...SO BUMPED HIGHS UP A BIT WITH 925 MB TEMPS
SUGGESTING HIGHS AROUND 70.
KEPT SOME POPS IN THERE FOR THURSDAY NIGHT AND FRIDAY AS ANOTHER
SHORTWAVE AND COLD FRONT MOVE THROUGH. MODELS CONTINUE TO BOUNCE
AROUND WITH LOCATION OF BEST FORCING AND MOISTURE...SO NOT A LOT
OF CONFIDENCE WITH THE DETAILS OF THIS ONE. DOES LOOK COOLER
FRIDAY UNDER NORTHWEST WINDS BEHIND THE FRONT.
SATURDAY THROUGH MONDAY...FORECAST CONFIDENCE...MEDIUM
YET ANOTHER SHORTWAVE EXPECTED SATURDAY...POSSIBLY BRINGING MORE
SHOWERS TO THE AREA. HIGH PRESSURE TO THEN SLIDE THROUGH THE REGION
SUNDAY AND MONDAY...BRINGING QUIETER WEATHER TO SOUTHERN WISCONSIN.
COOLER AIR EXPECTED TO CONTINUE THROUGH THE WEEKEND...WARMING BACK
TO AROUND NORMAL EARLY NEXT WEEK.
AVIATION/12Z TAFS/...
VFR CONDITIONS WILL PREVAIL TODAY AND TONIGHT. SCT STRATUS AROUND
1 KFT MAY CONTINUE THROUGH THE EARLY MORNING IN ERN WI BUT
DIMINISH BY 14-15Z. SCT-BKN CUMULUS AROUND 7 KFT IS THEN EXPECTED
BY LATE MORNING THROUGH THE AFTERNOON WITH A SLIGHT CHANCE OF
SHOWERS AS AN UPPER TROUGH AXIS SHIFTS EAST ACROSS SRN WI. HIGH
PRESSURE AND MO CLEAR SKIES FOR MOST OF TNT WITH MID TO HIGH
CLOUDS INCREASING WED AM.
MARINE...
SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE NEARSHORE WATERS INTO
THIS EVENING AS BRISK NNWLY WINDS AND HIGH WAVES CONTINUE IN THE
WAKE OF A COLD FRONT AND AIDED BY UNSTABLE CONDITIONS OVER THE LAKE.
HIGH PRESSURE WILL THEN COME ACROSS THE LAKE TONIGHT WITH MUCH
LIGHTER WINDS AND SUBSIDING WAVES. BREEZY SSWLY WINDS WILL THEN
DEVELOP WEDNESDAY AS STRONG LOW PRESSURE MOVES ACROSS SRN CANADA. A
SMALL CRAFT ADVISORY OR POSSIBLY A GALE WARNING MAY BE NEEDED.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR LMZ644>646.
SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LMZ643.
&&
$$
UPDATE...MEB
TODAY/TONIGHT AND AVIATION/MARINE...GEHRING
WEDNESDAY THROUGH MONDAY...DDV