Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/07/21
Area Forecast Discussion
National Weather Service La Crosse WI
400 PM CST Sat Mar 6 2021
.SHORT TERM...(This evening through Sunday)
Issued at 140 PM CST Sat Mar 6 2021
Warmer temperatures are on the way for Sunday along with stronger
winds. The area of high pressure currently extending from western
Ontario into the mid-Mississippi River Valley will work slowly off
to the east tonight and Sunday. This will allow a cold front to
emerge from the Rockies and tighten up the pressure gradient over
the region for Sunday. The winds will respond to this with gusts of
20 to 30 mph out of the south/southeast expected for a good share of
the day. These winds will bring in warmer air with highs expected to
top out from the middle/upper 40s to the upper 50s. A chance that
some locations of northeast Iowa that are snow free could briefly
touch 60.
.LONG TERM...(Sunday night through Saturday)
Issued at 140 PM CST Sat Mar 6 2021
Warm and dry conditions continue through the early part of the work
week. Wide and expansive ridging aloft is contributing to these
above normal temperatures. The ridge slightly dampens Sunday night
into Monday as a shortwave extending southward from northcentral
Canada progresses eastward through the northern Great Lakes Region.
Surface high pressure follows in its wake, which will relax surface
winds Monday to briefly flow from the west.
High pressure slides off to the east and the pressure gradient
tightens increasing winds from the south on the back side of the
high with possible wind gusts up to 25 knots by Tuesday
afternoon. Decent warm air advection and a warm front passing
through the region also aids in the warmer conditions. NAEFS and
ECMWF ensemble standardized anomalies are near 2 standard
deviations above the climatological mean for 850 and 700 mb
temperatures by Tuesday afternoon. With all the supporting
factors, Tuesday is still on target to be the warmest of the days
with potentially breaking records as afternoon temperatures climb
into the 60s. Under these favorable conditions, it is likely for
temperatures to overachieve compared to the regular blended model
guidance. Have decided to increase temperatures closer to the 75th
percentile.
Will have to watch out for cloud cover and any remaining snowpack
that would limit the increase in temperatures. However, with
temperatures remaining above freezing through the overnight hours
for much of the area, the snow coverage will greatly diminish over
these unseasonably warm days and nights.
Widespread precipitation chances return Tuesday night, continuing
through Wednesday, with chances lingering for some into Thursday.
Afternoon temperatures are still expected to be above normal, but
how high is still uncertain. Cloud coverage, precipitation, and cold
frontal passage timing would all influence the temperatures. As near
surface lapse rates steepen into the afternoon, there is a chance
for isolated thunderstorms. GEFS plumes have mean CAPE values
peaking in the afternoon around 50 to 200 J/kg across the region.
However, no severe weather is expected. As for precipitation totals,
ensemble guidance has mean QPF values around 0.25" across the
region.
After the cold front pushes through, temperatures should return
closer to seasonable normals through the end of the week. Exact
temperatures are uncertain as there is some decent spread between
the model guidance.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 400 PM CST Sat Mar 6 2021
Cigs/wx/vsby: mostly some sct-bkn upper level clouds through the
period, ahead of an approaching shortwave trough Sun. No pcpn
expected with this feature. One thing to keep an eye on is the
potential for pooling low level saturation Sun morning, ahead of the
shortwave. The NAM (per usual) is aggressive here, suggesting mvfr
cigs would develop. The RAP is fairly dry, as it most other models.
In addition, source region of said low saturation not producing much
cloud at this time - if at all (obs/satellite imagery). Will hold
with VFR for now.
Winds: winds will be on the increase by mid morning Sunday as
pressure gradient tightens. Some gusts, but those will be limited by
relatively shallow mixing due to strong warming a loft. Could see a
few hours of LLWS concerns near 00z Mon.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...04
LONG TERM...Peters
AVIATION....Rieck
Area Forecast Discussion
National Weather Service Grand Forks ND
652 PM CST Sat Mar 6 2021
.UPDATE...
Issued at 652 PM CST Sat Mar 6 2021
Strongest gusts have diminished with at least some decoupling of
the BL, however as LLJ develops and pressure gradient increases
it appears likely that gusts will increase once again tonight.
Depending on how deep we mix potential is there for some gusts
around 40 mph (though this shouldn`t be too common). I made some
adjustment to increase overnight winds to better reflect this.
There is still a signal for stratus development (which could
complicate mixing as well) and while some guidance indicates
possible fog along and west of the RRV escarpment this is much
less certain due to the winds/potential mixing. Will monitor
evening trends.
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 252 PM CST Sat Mar 6 2021
Main focus during the tonight through tomorrow night period will be
gusty winds overnight tonight as well as the potential for patchy
fog. Both are a result of the passage of a dry front late tonight
into Sunday morning.
South-southeasterly winds will remain elevated as a result of a
tightening pressure gradient and mixing ahead of a shortwave trough
and attendant dry cold front expected to pass through the Dakotas
Sunday morning. Ahead of the trough develops a 50-60 kt LLJ
overnight tonight into Sunday morning. The tightened pressure
gradient will allow some of this jet to penetrate the nocturnal
inversion, esp with the help of some terrain influences. Some CAMS
and MOS guidance suggest gusts higher than 35 mph between midnight
and 9 AM, although the nighttime lends to the thought of highest
gusty winds to remain sporadic.
There is also the potential for fog despite these gusty winds,
especially near the western Valley. Guidance like HREF and HRRR
have continued to highlight this area for fog potential.
Confidence is increased in this potential through persistence
forecasting within western and central ND where fog has been a
persistent feature in a synoptically similar set up over the last
couple of nights/mornings. Wind direction and increase in
elevation also favors area. This will be a target of opportunity
overnight tonight.
Despite the shortwave passage, temps will remain unseasonably mild
with lows staying above freezing (due to mixing and clouds) and
Sunday highs remaining in the 50s, possibly 60s in southeast ND.
Elevated westerly winds and later day WAA will aid in these temps as
well.
.LONG TERM...(Monday through Saturday)
Issued at 252 PM CST Sat Mar 6 2021
Impacts in the extended period will come from a pattern change with
southwest flow aloft developing then precip chances during the mid
week as a couple shortwaves move through with more zonal flow
expected for the end of the week. Ensembles are in good agreement
with this overall evolution this week with details of timing and
placement of smaller features yet to be determined. As a result the
upper ridge will persist over the area to start the week and his will
allow a continuation of well above normal high temps Monday and
Tuesday with 50s and 60s expected. Will need to continue to watch
for strength and placement of lead short wave possibly bringing
scattered showers into NE ND Tuesday afternoon and evening along a
cold front. By Wednesday temps will be much lower with rain/snow
chances overspreading all but the Devils Lake region. The best
chances in the forecast area of seeing a tenth of an inch or more of
precip remain across the southern valley and into the lakes and
trees area of MN where blended guidance suggests its only around 20
percent. Much of the guidance takes the majority of precip southeast
of the area. The trend of any site within the CWA of seeing more
than a tenth of an inch of QPF continues its downward direction.
Temperatures Wed through Friday will range in the 30s and low 40s
for highs. Still above the 30 year normals but much cooler than
recent temps.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 540 PM CST Sat Mar 6 2021
Gusty southeast winds eventually turn to the southwest late
tonight and then to the west-northwest as a front moves into the
region Sunday. A strong 40-50kt low level jet tonight may result
in low level wind shear, but could also result in a stronger
period of winds with gusts 30-35kt overnight. VFR conditions
across eastern ND and northwest MN eventually transitions to MVFR
as stratus develops later this evening/overnight northwest to
southeast. Eventually as the winds shift west stratus should start
to improve/lift Sunday, but this might not be until the afternoon
(west to east). There is some indication that fog may develop
near central ND, but due to winds this is much less certain
(stratus is favored).
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
$$
UPDATE...DJR
SHORT TERM...CJ
LONG TERM...JK
AVIATION...DJR
Area Forecast Discussion
National Weather Service Louisville KY
934 PM EST Sat Mar 6 2021
.Forecast Update...
Issued at 934 PM EST Sat Mar 6 2021
It will be a quiet, chilly night with high pressure in control. A
weak upper wave will bring a few clouds.
&&
.Short Term...(This evening through Sunday)
Issued at 200 PM EST Sat Mar 6 2021
Sfc analysis shows broad sfc high pressure across the region today,
leading to sunny skies, light winds, and temps in the mid-upper 40s
with a few spots around 50F. There is an upper level trough
currently swinging through the Ohio Valley region, but quiet weather
will continue tonight. With a dry air profile overhead, we will
remain dry, but could see some clouds develop around 5,000 ft this
evening and tonight as a result. RAP soundings show a ~75% saturated
850mb layer at LEX and SDF during the overnight hours, so still
expect to see scattered clouds for at least our north and northeast
CWA. Temps will drop to the upper 20s and near 30F.
For tomorrow, sfc high pressure will continue to be situated
overhead. With the upper trough off to our east by then, cloud cover
should be minimal or non-existent with NW flow aloft. Temps will
spread from the upper 40s in the Bluegrass, to upper 50s/near 60F
along our western CWA.
.Long Term...(Sunday night through Saturday)
Issued at 256 PM EST Sat Mar 6 2021
...MILDER TEMPERATURES EXPECTED NEXT WEEK...
========================================
Synoptic Overview
========================================
Overall, we`re not seeing much change in the expected hemispheric
pattern aloft for late this weekend and into next week. Upper
trough axis over the eastern US is forecast to move off to the east
while broad upper level ridging builds across the eastern two-thirds
of the country. Ridge axis looks to be centered along the
Mississippi River by early Tuesday with the axis of the ridge
shifting towards the Appalachians by mid-late week. By mid-week,
large closed low is forecast to drop into the southwestern US
resulting in a split flow pattern across North America. The Ohio
Valley will be under the broad west-southwest flow of the southern
jet. This pattern will feature a warmer period of temperatures with
increasing moisture by mid-late week. A frontal boundary is
forecast to drop into the region by late week bringing periods of
rainfall to the region from about Thursday through Saturday.
========================================
Model Discussion and Sensible Weather
========================================
Much of the early-mid part of the extended period will feature dry
and increasingly mild weather. The overall trend in the guidance
continues to edge slightly warmer as the models sense out the
developing ridge. Highs Monday should warm into the upper 50s and
lower 60s with mainly 60s across the region on Tuesday. Overnight
lows should feature readings in the 30s. The milder surge of
weather should be seen by Wed/Thu as temperatures warm into the mid-
upper 60s with a few spots hitting 70+.
Still seeing a spread within the model guidance with regards to
precipitation chances in the late week period. The Euro continues
to be most aggressive with bringing scattered showers into the
region as early as Wednesday night, while the GFS v12 and v16 runs
keep things dry through Thursday. In general, it appears that the
best chances of precip would be mainly confined to areas north of
the Ohio River in the Thursday to Friday time frame. Have gone
ahead and used a blended approach here that keeps low chance PoPs in
the forecast here. While details are still lacking, it appears that
a better chance of rainfall exists in the Friday to Saturday time
frame. The split flow pattern aloft will give the models fits and I
expect continued oscillations within the guidance until upper
pattern becomes more defined. The threat for moderate to heavy
rainfall looks a bit less as the QPF fields from the models have
decreased somewhat. However, given the wet grounds due to recent
flooding, it would not take much rainfall to generate more hydro
issues toward the end of the period.
With the expected front slicing into the region on Friday, we do
believe that we`ll see slightly cooler temperatures here. So plan on
going with upper 50s to the lower 60s across southern IN and
northern KY on Friday and Saturday with lower-mid 60s across
southern KY.
A look ahead shows a continued active pattern for the late weekend
and into the early part of week two. A period of colder weather
looks to arrive by mid-month. Teleconnection patterns still are not
favorable for significant/sustained cold with a +AO/-PNA/+NAO
pattern. However, the notable dip in the EPO is likely to result
in a period of colder weather here. Not exactly sure how long the
cool will last, but the MJO is progged to be in phase 1 mostly and
that would favor cooler than normal conditions. However, this will
depend mostly on the strength of the MJO and whether or not the La
Nina background state ends up driving the pattern.
========================================
Societal Impacts
========================================
No significant societal impacts are expected during the period.
Ongoing river flooding will continue across portions of the
Kentucky, Ohio and Green river basins. Cresting in certain basins
are expected this weekend and into early next week.
Milder conditions are expected next week, but record highs do not
look to be tied or broken. There is a slight risk that some warm
overnight minimum records could be tied/broken.
There remains a risk of moderate to occasionally heavy rainfall in
the late week and weekend period. Given antecedent soil conditions,
any rainfall would likely result in runoff and quick rises on creeks
and streams will be possible Residents in low-lying and flood prone
areas should keep an eye on forecasts next week.
A return to colder conditions is still possible around mid-month
(3/15 and beyond) and some wintry weather may be seen in some areas.
========================================
Forecast Confidence
========================================
Confidence of milder pattern next week : Moderate-High
Confidence of late week hydro issues : Low
Colder temperatures by mid-March : Low-Moderate
&&
.Aviation...(00Z TAF Issuance)
Issued at 541 PM EST Sat Mar 6 2021
No changes from previous Aviation Discussion...
VFR conditions will remain over area TAF sites with high pressure in
place, but expect some variability in wind direction. Tonight, a
shortwave will likely carry a 4k to 5k foot scattered cloud deck
from north to south through the area.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update...13
Short Term...CJP
Long Term...MJ
Aviation...13
Area Forecast Discussion
National Weather Service Marquette MI
636 PM EST Sat Mar 6 2021
.SHORT TERM...(This evening through Sunday)
Issued at 254 PM EST SAT MAR 6 2021
Current RAP analysis and GOES WV imagery continues to show an upper
level low that is still over the Canadian Maritimes, allowing for a
sfc high pressure to hold over the Upper Great Lakes. Position
hasn`t really changed from yesterday but that will slowly change
throughout the day. Northerly flow is still occurring which has been
bringing in lake-effect clouds mainly from Marquette eastward, along
Lake Superior. Drier air will filter into the area again, like
yesterday, and will see clouds start to dissipate through the
afternoon and evening. Winds will be relatively light tonight as the
upper level low slides further east as ridging from over the
northern plains will move closer to Upper Michigan, bringing in
warmer air thanks to southerly flow. Winds could be a little breezy
for Sunday with tightening of pressure gradient aloft. Not expecting
any pcpn for this period but may have just a slim chance of some
light pcpn over the Keweenaw late Sunday into Monday.
Temperature will be similar again as to what they where yesterday,
even with a few places overachieving by reaching the mid 40s. That
may happen again today depending on the cloud cover since there is
more of it today than yesterday. Given that, expect upper 20s to
near 30 along the Lake Superior Shoreline and east where clouds hang
on longer while mid to upper 30s and a few low 40s south and west.
With clouds clearing and fairly light winds tonight, could get quite
chilly especially over the interior west and east with good
potential of seeing lows below zero in those areas tonight. Highs
Sunday will be warmer with upper 30s to mid 40s over the central and
west with good mixing and southerly flow, allowing for a good
diurnal swing to occur in those areas with warming quickly through
the morning. Wouldn`t surprise me if a couple spots did reach 50
degrees for a brief period. East will remain in the low 30s with
southerly winds off Lake Michigan keeping it cooler out there.
.LONG TERM...(Sunday night through Saturday)
Issued at 304 PM EST SAT MAR 6 2021
Beginning Sunday night, mid-upper level ridge over the region will
give way to more zonal flow as a weak shortwave moves in from the
west. As with yesterday`s guidance, there still continues to be a
weak precip signal due to increasing low level moisture. However,
without deep moisture within the column, any precip would likely be
light and be more of a drizzly-type precip. Soundings suggest some
freezing rain could mix in, mainly in the central and east. These
areas could see a light glaze develop overnight, especially if
daytime temps don`t warm much. Overnight lows are generally expected
to dip into the 20s.
Following the shortwave`s passage, near zonal mid-upper level flow
on Monday with a surface ridge gradually shifting east through the
region is expected. With 850mb temps holding around +2C through the
day within this dry airmass supporting mostly clear skies, I expect
temps to soar. NBM 50th percentile has much of the west and southern
UP near 50 degrees, with mid-upper 40s elsewhere. I suspect this may
be under doing the daytime highs some given the model tendency to
underachieve this time of year. Ended up trending daytime highs
toward the 75th percentile. Monday night, the ridge will be to the
east which will result in southerly flow eventually developing. This
will lead stabilize temps and prevent them from falling too much.
Generally lows dipping into the 20s is expected. Tuesday, with the
southerly flow and WAA added into the mix, daytime highs should
climb even higher. Again went higher on the highs, trending toward
the NBM 75th percentile temps, which puts the west half of Upper
Michigan above 50F. I woudln`t be surprised if some places got close
to 60F. The east will stay a little cooler due to the moderating
effects of the cooler Lake Michigan waters. Still though, I`m
expecting mid 40s to near 50F daytime highs. With the day`s cloud
cover lingering into the overnight period, lows in the mid-upper 30s
is expected, with some low 40s in the south half along the WI/MI
border.
Overnight Tuesday, a low will eject out of the Plains and track
northeast toward the Upper Great Lakes through the day on Wednesday.
Precip is expected to overspread much of the area by afternoon and
evening. The exact track of the low is still unknown, but GEFS
solutions cluster the low by 0z Thursday primarily in northwestern
Wisconsin or eastern Minnesota. This track would favor precip
falling as rain, as the UP would still be under the influence of the
WAA ahead of the system`s cold front. It should be noted though that
if the low tracks further east, a rain/snow mix or perhaps all snow
could be favored in the western UP. With PWATS increasing to 0.75-
1.15" over the region by afternoon, along with strong fgen and theta
e advection, some moderate to heavy rainfall is possible. Following
the low lifting northeast, CAA on the backside of the system`s cold
front could result in precip transitioning over to freezing rain or
snow. Given that this is still 4-5 days out, as we better identify
the trends of this system, the sockdolager will come with subsequent
forecasts.
For folks looking for that spring xenium, dewpoints are expected to
climb above freezing beginning Monday and linger through Wednesday.
They should fall below freezing Monday night, but otherwise a few
days of above freezing dewpoints are expected. With the warmer and
more moist airmass, moisture from the air is expected to deposit
onto the snowpack due to saturation vapor pressure differences. As
this happens, latent heat release of the vapor phasing to liquid
will lead to quick melting of the snowpack this week. On Wednesday,
with the added moisture from the rainfall, this will likely result
in patchy to widespread fog. Together these will likely result in
some river rises and ponding on roads and low lying areas.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 636 PM EST SAT MAR 6 2021
VFR conditions at KIWD should continue for the TAF period, whereas
KCMX and KSAW could see some MVFR cigs tonight as we could see a
repeat of what happened last tonight at these TAF sites via lake-
effect clouds. Expecting conditions to return to VFR by morning and
continue for the rest of the day at KCMX and KSAW. Some LLWS should
move through KIWD and KCMX Sunday afternoon as WAA moves through the
area; KSAW may see some LLWS late in the TAF period as well, and
should see some more after the end of this TAF period.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 254 PM EST SAT MAR 6 2021
North winds around 20 kts will slowly diminish across the east half
of the lake through tonight and remaining below 20 knots through
early Sunday morning. Winds will turn more out of the south Sunday
mid morning and increase to 15-25 knots across most of the lake,
except for the far western end. Could have some areas over the
central and east get to 30 knots late Sunday afternoon and evening.
There may be a few gale force gusts to 35 knots as well. Winds will
fall below 20 knots for Monday and Tuesday before increasing to 20-
30 knots with some gale force gusts possible out of the south by
late Wednesday ahead of next system moving towards the lake.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JH
LONG TERM...JP
AVIATION...TAP
MARINE...JH
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
737 PM EST Sat Mar 6 2021
.UPDATE...
The majority of the showers continues to push southeast as the area
of low pressure moves over southern Florida. Some stray showers will
be possible over the next few hours, but most of the area will
remain rain-free overnight. Mostly cloudy skies will stick around
tonight until strong high pressure moves in from the northwest
allowing for drier and cooler air to filter into the region on
Sunday. Temperatures tonight and on Sunday will come in a few
degrees below average before the next warm up begins on Tuesday.
Have tweaked the POPs over the next 6 hours to better reflect
current radar coverage and HRRR guidance, otherwise forecast is
tracking fine.
&&
.AVIATION...
Some MVFR conditions expected with BKN/OVC CU/SC through early
Sunday morning, gradually clearing and becoming VFR on Sunday. Gusty
north-northeast winds around 10-15 knots with higher gusts expected
through the period.
&&
.MARINE...
Some stray showers will linger for the next few hours, clearing out
by Sunday morning. A tightening pressure gradient between the area
of low pressure over southern Florida and strong high pressure
building in from the northwest will produce gusty northeast winds
for the next 36 hours. This has warranted the issuance of a Small
Craft Advisory for the eastern gulf waters including Tampa Bay and
Charlotte Harbor through Monday morning. Conditions slightly improve
by Monday afternoon, but boaters should still use caution through
the week as some gusty easterly winds will be possible.
&&
.Preliminary Point Temps/PoPs...
TPA 55 71 48 72 / 30 0 0 0
FMY 58 76 51 75 / 30 0 0 0
GIF 54 70 48 71 / 30 0 0 0
SRQ 56 73 49 73 / 30 0 0 0
BKV 48 70 40 72 / 30 0 0 0
SPG 57 70 53 71 / 30 0 0 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...Small Craft Advisory until 1 PM EST Sunday for Coastal waters
from Tarpon Springs to Suwannee River FL out 20 NM-Waters
from Tarpon Springs to Suwannee River FL out 20 to 60 NM.
Small Craft Advisory until 8 AM EST Monday for Coastal waters
from Englewood to Tarpon Springs FL out 20 NM-Waters from
Englewood to Tarpon Springs FL out 20 to 60 NM.
Small Craft Advisory from 1 AM Sunday to 8 AM EST Monday for
Coastal waters from Bonita Beach to Englewood FL out 20 NM-
Waters from Bonita Beach to Englewood FL out 20 to 60 NM.
Small Craft Advisory from 1 AM to 1 PM EST Sunday for Charlotte
Harbor and Pine Island Sound-Tampa Bay waters.
&&
$$
UPDATE/AVIATION/MARINE...74/Wynn
UPPER AIR/DECISION SUPPORT...25/Davis