Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/21/24
Area Forecast Discussion
National Weather Service Charleston SC
907 PM EST Wed Nov 20 2024
.SYNOPSIS...
A strong cold front will push farther offshore tonight.
Canadian high pressure will build across the area Thursday and
will remain the primary feature through early next week.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
No major changes were made for the late evening update.
Tonight: Satellite and 21/02z mesoanalysis showed the cold
front extended from the far eastern Midlands to just west of
Lake Moultrie and extending south along the Georgia coast into
Northeast Florida. The front is marked by a strong stability
gradient and will continue to move rapidly east and offshore.
Strong post-frontal cold air advection will follow the front by
several hours, but will usher in a slightly modified cP airmass
as the night progresses. Lows look to bottom out in the lower
40s well inland to the upper 40s/near 50 at the beaches. Gusty
northwest winds will make it feel even cooler by daybreak
Thursday with wind chills dropping into the upper 30s/lower 40s.
Lake Winds: Impressive and deep mixing profiles will develop on
Lake Moultrie overnight as strong post-frontal cold air
advection ensues with the passage of the cold front. RAP
soundings support as much as 35-40 kt of wind at the top of the
mixed layer by midnight supporting winds 20-25 kt with gusts at
least to 30 kt, if not a tad higher at times. Winds were
slightly with waves over the open lake waters building to 2-3
ft. The combination of increasing winds and building waves will
make for dangerous wave action on the lake tonight with the
worst conditions occurring over the central and eastern portions
of the lake. Boaters are encouraged to remain off the lake.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
A powerful closed upper low will swing through the Great Lakes
on Thursday then stall near New England Friday into Saturday.
Meanwhile, strong high pressure will expand across the Southeast
at the surface. Dry weather and below normal temps expected.
Highs will top out in the upper 50s to lower 60s on Thursday,
then only reach the mid/upper 50s on Friday. Saturday should be
a tad warmer with highs in the lower 60s. Lows both nights could
dip into the mid to upper 30s inland, though we expect enough
overnight wind to prevent widespread frost development.
Lake Winds: Gusty west winds are expected to persist over Lake
Moultrie Thursday into Thursday evening during which we have a
Lake Wind Advisory in effect.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Surface high pressure will maintain influence over the local
weather Sunday through Tuesday. Not much going on upstairs with
relatively zonal flow. Rain-free forecast in place with warming
temperatures through the period. Main forecast concern remains
the potential for frost late Saturday night/early Sunday morning
as ideal radiational cooling conditions allow temperatures to
fall to the mid/upper 30s inland of the coast. Frost is
possible, mainly over far interior locations.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
21/00z TAF Discussion:
KCHS/KJZI/KSAV: The approaching cold front will clear all
terminals by 02z with gusty northwest winds developing with its
passage. These gusty winds will persist into the day Thursday.
Any lingering low clouds should scour out with FROPA. VFR will
prevail for the entire 00Z TAF period.
Extended Aviation Outlook: VFR. Gusty west winds are expected
Thursday and Friday.
&&
.MARINE...
Tonight: Strong post-frontal cold air advection will overspread
the waters overnight with the passage of a cold front.
Northwest winds will increase to 25 kt with gusts to 30 kt for
the waters within 20 NM and 25-30 kt with gusts 35 kt over
Georgia offshore waters out 20-60 NM. A Gale Warning remains in
effect for the Georgia offshore waters beyond 20 NM with high-
end Small Craft Advisories for all nearshore legs, including
Charleston Harbor. Gusts could get close to Gale Warning
criteria across the nearshore waters, mainly within 10-20 NM,
but these conditions look infrequent enough to not to justify an
upgrade to a Gale Warning at this time. This will be closely
watched this evening and overnight, however. For Charleston
Habor, northwest winds will increase to 20-25 kt with gusts to
30 kt and waves building 2-3 ft.
Thursday through Monday: Gusty west winds will persist over the
coastal waters Thursday through Friday night, maintaining the
ongoing Small Craft Advisories. For the Charleston Harbor, gusts
to 25 knots are expected Thursday through Friday. Improvement
is expected Saturday with winds and seas remaining below
advisory levels through Monday.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Lake Wind Advisory until 11 PM EST Thursday for SCZ045.
MARINE...Small Craft Advisory until 6 PM EST Friday for AMZ330.
Small Craft Advisory until 7 AM EST Saturday for AMZ350-352-
354.
Gale Warning until 7 AM EST Thursday for AMZ374.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
743 PM EST Wed Nov 20 2024
.KEY MESSAGES...
- Colder temperatures arrive tonight, with snow expected to be
seen in the air in most places at times from Thursday into
Friday.
- Locations most likely to receive impactful snow accumulations
are those elevations above 1500 feet, mainly Thursday night.
&&
.UPDATE...
Issued at 742 PM EST WED NOV 20 2024
Sfc high pressure nosing into the region in between systems has
led to a slackening pressure gradient and some of the deeper
valleys decoupling. This has resulted in some of these valley
areas to cool off faster than the previous forecast. Following
recent rainfall and with the clearing skies and slackening winds,
the potential for at least a period of patchy fog later this
evening or in the overnight has increased before clouds increase
again. Adjustments to hourly visibility, weather, temperature,
and dewpoint grids have been made accordingly.
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 329 PM EST WED NOV 20 2024
We have a very active short term period with multiple rounds of
precipitation and gusty winds at times. We begin the period with a
strong cold front crossing the area this afternoon. This has nearly
eclipsed most of the region now with just parts of far eastern
Kentucky still in the upper 50s to 60s at 2 PM. This front has
packed quite a punch this afternoon, with winds gusting up to 42 mph
here at JKL and many more open and high elevation locations seeing
35 to 40 mph. Given this did increase through winds closer to the
HRRR this afternoon along and ahead of this boundary. However, they
will relent through the afternoon. The latest trends in the
satellite show that there is decent clearing behind the front across
parts of central Kentucky and this will slide into the eastern
Kentucky later this afternoon and into the evening. This will lead
to mostly clear skies tonight before the next wave of energy
approaches by from the northwest bring in low and mid level clouds
by early Friday. Overnight lows will fall into the low to mid 30s.
Thursday, another lob of energy drops southward with a another cold
front. This cold air advection pattern will steepen the low level
lapse rates tomorrow afternoon. This will aid in enhancing the snow
shower potential tomorrow. These rounds of snow showers will be
accompanied by gusty winds at times in the 20 to 25 mph range at
times. Also, heavier snow showers could lead to brief reductions
in visibilities. There is good agreement in the models for this to
be all snow given the wet bulb potential with dewpoints in the
mid to upper 20s through the day. The good news is highs in the
afternoon will be in the upper 30s for most and therefore should
be less impactful for travel given the warm temperatures we have
seen of late. Therefore perhaps some grassy and elevated surfaces
see a dusting to perhaps a quick half an inch. However, fairly low
confidence on seeing much out of this initial round.
Thursday night, Another strong undulation in the mid-level slides
southward Thursday evening. There will also be some support from a
upper level jet streak left exit region giving way to some decent
divergence aloft. The surface reflection in the form of a low
pressure does ramp down as it heads into the Ohio Valley, but
there will still be ample energy for another round of snow to
slide into the area. Overall the profiles will support snow
through the evening and into the night. However, as we move into
the night and overnight the sounding show a warming trend as you
advect some warmer air into the area. You also start to loose the
better ice in the DGZ based on some of the HREF forecast sounding
data toward Friday morning. This will lead to some of this
activity starting to mix to more of the rain/snow late Thursday
night into early Friday morning for most areas outside of the
higher terrain where temperatures will be slower to climb. Right
now, based on temperatures at the surface most locations will
only see snow accumulations on grassy and elevated surfaces.
However, it still looks like locations above 1500 feet would have
a decent shot of snow accumulations on more surfaces with highest
amounts still mainly above 3000 feet. That said, given this no
plans to change or modify the current Winter Weather Advisory.
.LONG TERM...(Thursday night through Tuesday)
Issued at 328 PM EST WED NOV 20 2024
Active weather expected to continue in the extended portion of
the forecast, as a series of low pressure systems move through the
region. The latest runs of the GFS, ECMWF, WPC guidance, and GFS
Ensembles all have similar solutions, with large and well
developed low pressure centered over southwestern New England.
This system will be quite large, and will be impacting an area
that includes New England, the western Great Lakes, the Ohio
Valley, the Mid-Atlantic region, and the central Appalachians.
Rain and showers are expected across eastern Kentucky Friday
through Saturday, as moisture wrapping around the back side of the
eastern low pressure interacts with the terrain of the forecast
area. Light snow accumulations will be possible with this
activity, especially in the higher terrain along the Virginia
border on Friday. Temperatures should warm up enough Friday into
Saturday, to allow snow to change over the rain for all but the
highest ridges along the Virginia border. The precipitation will
linger across far eastern Kentucky through the end of the day on
Saturday, before the upper low moves far enough to our east to
allow the precip to finally come to and end.
A ridge of high pressure will settle over the region over the
weekend, and will bring dry and warmer weather back to the area
Sunday and Sunday night. After this brief respite, another area of
low pressure will barrel through the region late Sunday night and
Monday, and will bring multiple rounds of rain to eastern Kentucky
the first half of the week. This system will develop over the
central Mississippi valley and east central Plains, and will move
quickly into the Great Lakes by Monday night. A surface cold front
extending southward from this system will be our weather maker
through the middle of the week. The latest NBM data suggests that
this boundary might get hung up over our area, and will allow precip
to linger for a couple of days while the front is in place.
Temperatures will be well below normal overall, with several days
expected to max out in the 40s and low to mid 50s. Sunday and Monday
look to be much warmer, with highs in the upper 50s to lower 60s
both days. This will be in response to the persistent southerly flow
that is expected to set up across the region to begin the new work.
As far as weather hazards go, the only thing we`ll really be
watching is whether or not enough snow will fall, and if its will be
cold enough, to lead to slick roads on Friday, especially early in
the day in our eastern higher terrain counties along the Virginia
border.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 725 PM EST WED NOV 20 2024
High pressure nosing into the region has led to a decrease in
winds and gusts this evening with some deeper valleys having
decoupled near and after sunset. Skies have also cleared with VFR
observed across the region. In this area of clearing, some valley
locations could experience some MVFR to IFR reductions in valley
fog, but TAF sites are not expected to be affected. Winds will
then ramp up again between 12Z and 15Z from the west in advance of
the next round of weather, with gusts of 20-25 KT possible during
the last 12 hours of the period. At this time, have some VCSH for
KSYM, KSJS, and KJKL after 12Z with even prevailing light rain
and light snow toward the end of the period at these 3 sites. MVFR
ceilings and/or vis especially within heavier rain and snow
showers will affect northern and eastern sections of the area
starting after 13Z with KSYM, KSJS, and KJKL most likely to
experience these reductions later in the period. At the very end
of the period, these may spread to near or west of I-75 and KLOZ
and KSME could be affected as well.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 7 PM Thursday to 10 AM EST Friday
for KYZ087-113-115-117-120.
Winter Weather Advisory from 4 PM Thursday to 10 AM EST Friday
for KYZ088-118.
&&
$$
UPDATE...JP
SHORT TERM...DJ
LONG TERM...AR
AVIATION...JP
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1002 PM EST Wed Nov 20 2024
.SYNOPSIS...
A strong cold front will move across the area tonight. Another
reinforcing cold front moves through on Thursday, followed by
yet another front on Friday. High pressure then builds in over
the weekend and into next week.
&&
.NEAR TERM /OVERNIGHT/...
As of 10 PM Wed...Cold front is now racing towards ENC this
evening with this front currently stretching from NE to SW
across the Triad vicinity and currently moving through Raleigh
as of this update. Have several gusts in the 30-40 mph range as
this front continues to make its way across NC. Given the
fronts current speed, can expect these gusts to reach the
western Coastal Plain within the next hour or so and then
nearing the coast closer to the midnight to 1AM timeframe before
pushing offshore. Expecting a brief period of widespread 30-40
mph NW`rly wind gusts behind this front across the Coastal Plain
with slightly higher gusts possible near the coast and OBX.
Once the front quickly moves through the area, winds will ease
rather quickly as well with gusts falling closer to 15-20 mph
about an hour after the front passes through. Otherwise outside
of this, current forecast trends hold with scattered showers
and maybe a rumble of thunder or two possible through about 1-2
AM across ENC out ahead of the front before it pushes offshore.
Prev Disc...Attention turns to strong arctic front which will
blast through loudly tonight, as it will be accompanied by a
short but strong burst of gusty winds. The front is currently
moving through the TN Valley, and will be moving through the NC
mtns early this evening, and then quickly across the state
through ENC through the late evening hours. There will be sct to
numerous showers along and just ahead of the front, but the big
story will be the very gusty winds, and have inc winds as a
result. Think that most places even inland will gust to 30-40
mph, and on the coast 35-45 mph as it passes through. Have
relied heavily on the hourly HRRR for the fropa and associated
winds and temps. These winds will be short lived and last a half
hour or so at most but the temps will drop sharply in its wake,
going from the 60s, then quickly into the 50s and 40s for their
eventual lows by morning.
&&
.SHORT TERM /THURSDAY/...
As of 3 PM Wed...High temps return to closer to normal and even
slightly lower than climo, with readings in the upper 50s to
around 60 for most. Blustery conditions with wrly winds of 10-15
gusting to around 20 mph.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
As of 3:20 AM Wednesday...
Thursday night - Saturday night...The next front will move
through late Thursday afternoon and its CAA will send lows into
the low to mid 30s across the coastal plain. Winds will remain
strong enough to help minimize the threat for widespread
frost/freeze impacts, but it`s not out of the question for some
sheltered areas to drop below freezing. Saturday will feel very
similar to Thursday with highs struggling to exceed the 50s and
breezy winds westerly winds.
Sunday - Tuesday...High pressure will develop over the
southeastern US and extend up the mid-Atlantic coast. This will
support a dry forecast and warming trend with high temperatures
climbing from the upper 50s/low 60s on Sunday to the upper
60s/low 70s on Tuesday.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
SHORT TERM /through Thursday/...
As of 7 PM Wednesday...
- Strong cold front to bring gusty winds, SHRA, and sub-VFR
conditions to ENC this evening
A wide range of VFR to LIFR conditions are currently over ENC
this evening out ahead of a rapidly approaching front. Currently
OAJ/EWN are VFR with ISO at LIFR conditions and PGV at MVFR
conditions. General trend remains the same with any leftover
VFR conditions quickly becoming MVFR and IFR across the region
just out ahead of the approaching front with PGV/ISO maintaining
MVFR/IFR ceilings/vis over the next few hours. The cold frontal
passage will then be the main challenge tonight. Front is
forecast to enter into the Coastal Plain around 02-04Z tonight
and first impact PGV/ISO between 03-04Z followed by EWN/OAJ
between 04-05Z before finally pushing offshore by 06Z. As the
front tracks across the area winds will quickly shift from SW to
NW and gust to as high as 25 to 30 kt for a brief period of
time before gradually easing over the following several hours.
In addition to this some cross wind issues mainly at ISO/EWN
will be possible as the front tracks across these TAF sites with
a strong NW`rly wind. Guidance suggests some heavier showers
immediately with the front, and have opted to bring in temporary
IFR conditions this evening. A few TSRA cannot be ruled out,
but this risk appears low (<20% chance), and we`ll continue to
keep TSRA out of the TAFs for now due to the low risk. Behind
the front, conditions should quickly become VFR while winds
should decrease to around 10 kt by 12z. Some increase in W`rly
wind gusts Thursday to 20kt.
LONG TERM /Thursday night through Monday/...
As of 4 AM Wednesday...Gusty winds will be the main aviation
concern through the long term. With multiple fronts forecast to
move across the area, westerly winds around 10-15 kt with gusts
to 20 kt will persist through Saturday. Winds will weaken to
5-10 kt on Sunday as high pressure begins to extend into the
area.
&&
.MARINE...
SHORT TERM /through Thu/...
As of 3 PM Wed...S to SW winds of 10-15kt expected through
early evening. Big story will be strong arctic front that will
blast through the waters later this evening through early
morning hours. The wind switch will be very dramatic, and
increase out of the NW with a 35-40 kt gust(s) as the front
passes through. Because the gusts are expected to be tied to the
fropa, will not issue a gale warning because of the very brief
nature of the winds lasting less than an hour, but instead
handle with MWS`s as the front nears the waters, which will be
around midnight. SCA`s remain in place for all coastal waters
and inland rivers. Have ended the Neuse/Pamlico/Bay rivers a bit
earlier, but later shifts will likely have to reissue these as
winds come back up late afternoon or early eve Thu with
reinforcing fropa.
LONG TERM /Thursday night through Monday/...
As of 4 AM Wednesday...Additional cold fronts on Thursday and
Friday will generate unfavorable marine conditions that will
persist through early Sunday morning.
Seas will be the highest early Thursday morning (6-7 ft) and
late Friday night (6-7 ft) with a slight lull between these
times.
A slight lull is expected during the afternoon, after which
winds will become westerly and return to the same strength.
Winds will peak on Friday at 25-30 kt with a few gusts to 35 kt.
We continue to carry a strongly worded Small Craft Advisory for
the central waters at this time, but a Gale Watch will be kept
in mind.
Winds and seas will decrease through the day Saturday with all
zones expected to be below SCA criteria by early Sunday.
&&
.FIRE WEATHER...
As of 3 PM Wednesday...Elevated fire weather conditions are
possible Thursday, with min RH values falling to 30-35% inland
combined with westerly wind gusts 20 to 25 mph.
&&
.TIDES/COASTAL FLOODING...
As of 3 PM Wednesday...An extended period of 20-25kt Werly
winds behind a cold front tonight into Saturday may lead to
minor soundside flooding concerns for the Outer Banks. Current
thinking is these persistent Werly winds should remain just weak
enough to limit impacts, but minor water level rises will be
possible for soundside NOBX, Hatteras and Ocracoke Islands, and
Roanoke Island.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...None.
MARINE...Small Craft Advisory until midnight EST Saturday night for
AMZ131-135-158-230-231.
Small Craft Advisory until 8 AM EST Thursday for AMZ136-137.
Small Craft Advisory until 3 AM EST Sunday for AMZ150-152-154-
156.
&&
$$
SYNOPSIS...MHX
NEAR TERM...TL/RCF
SHORT TERM...TL
LONG TERM...CQD/OJC
AVIATION...RCF/OJC
MARINE...TL/OJC
FIRE WEATHER...MHX
TIDES/COASTAL FLOODING...MHX
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
844 PM CST Wed Nov 20 2024
.KEY MESSAGES...
- Light snow continues through this evening. Slick travel is
possible, especially with gusty winds.
- Strongest winds in western MN, gusts as high as 35mph.
- Dry weather returns tomorrow, with strongest winds shifting
east into western WI.
&&
.UPDATE...
Issued at 835 PM CST Wed Nov 20 2024
After a few hours of moderate snow this evening, reports of
1-1.5" of accumulation are common from the Twin Cities metro
southward. Any heavier/accumulating snow will continue to wind
down across the region, but occasional flurries/freezing
drizzle will continue overnight. Travel remains treacherous
with very slick roads following this evening`s snow, which seems
to have largely melted before refreezing on roadways.
Temperatures will remain below freezing tonight, so expect
difficult travel to persist into tomorrow morning. Gusty
northwest winds continue across western Minnesota with gusts
near 40 MPH at times, further complicating travel in this area.
&&
.DISCUSSION...
Issued at 254 PM CST Wed Nov 20 2024
Snow totals have generally remained at or below an inch through our
first round of snow this morning, with the highest totals further
north and west where the Winter Weather Advisory is still in place.
It currently is in effect until 6PM, but that may need to be
extended depending on how quickly the second round of snow moves
southeast. Latest hi-res guidance keeps additional totals right
at or below 2 inches for those northwestern counties, and at or
below 1 inch for elsewhere. It is expected that well-traveled
roadways will largely avoid any accumulations (similar to this
morning), but slick conditions may still develop with
temperatures dipping below freezing for much of the region
already. The main driver of forcing associated with this second
push of snow is positive (cyclonic) vorticity advection as the
low moves east. These setups can result in sporadic bursts of
heavier rates, which is highlighted by the latest suite of
models, favoring portions of east-central and southern
Minnesota. These high rates combined with strong, gusty winds
could lead to reduced visibilities at times. This is important
to be aware of given the timing taking place during the evening
rush hour. Snow should begin to taper off from north to south
around 7 to 8 PM, completely moving out of the area overnight.
As the surface low and occlusion aloft weaken, the strongest forcing
and winds will move east. As a result, most locations will be
entirely dry tomorrow, outside of a few light rain/snow showers
across west-central Wisconsin. The main concern will be a return of
strong, gusty winds, primarily over western Wisconsin and eastern
Minnesota. The latest RAP and HRRR show potential for 35 to 40 mph
wind gusts to mix down from 925 hPa. These locations have seen the
lowest totals for snowfall so far, and are expected to have little
to no blowing snow concerns with these winds.
An area of ridging upstream of the upper low will help lead to
drier, and consistent conditions through the weekend. Long
range ensembles continue to highlight potential for multiple
systems moving across the central CONUS next week, however there
is quite a bit of spread in timing and location. Members of the
GFS ensemble have higher agreement of a low impact snow-maker
moving through as early Sunday night, while the EPS favor a more
impactful storm moving through towards the end of the week
without as much of a sign for an early week system. All that to
say, there is still a lot to decipher after our current system
departs east, but there is at least a notion that an active
pattern is likely across the region.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 518 PM CST Wed Nov 20 2024
We have a few more hours of snow to go with IFR cigs/vis before
conditions improve back to MVFR through the overnight. A few
sites may briefly pop up into VFR territory overnight, but a
return to MVFR is expected by tomorrow morning.
Wind wise, a more north-northwesterly direction is expected to
take hold overnight with speeds diminishing to around 20kts.
Gusts of 25-30kts will return by late morning and last through
the end of the period.
KMSP...One more heavier band of snow is approaching the
northwest metro as of 23z. This should be done by 02z with high
end MVFR overnight. As mentioned above, winds will be gusty
again tomorrow.
/OUTLOOK FOR KMSP/
FRI...Chc MVFR cigs. Wind NW 10-15kts.
SAT...Chc MVFR cigs. Wind NW 5-10 kts.
SUN...VFR. Wind SE 5-10 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
UPDATE...Dye
DISCUSSION...BED
AVIATION...Dye
Area Forecast Discussion
National Weather Service Marquette MI
852 PM EST Wed Nov 20 2024
.KEY MESSAGES...
- Light wet snow accumulations possible tonight, mainly in the
higher terrain west of US-41 and south of the Keweenaw.
- Northerly gales 35 to 40 knots with a few gusts to 45 knots
possible across Lake Superior.
- Widespread 25 to 35 mph northerly winds will be possible
across Upper Michigan Thursday. Higher winds to 45 mph will
be possible in the Keweenaw Peninsula and near the immediate
lakeshores of Marquette and Alger counties.
&&
.UPDATE...
Issued at 852 PM EST Wed Nov 20 2024
The forecast remains on track tonight. Light rain showers are
spreading westward through the UP tonight, with periods of bright-
banding unsurprising given freezing levels only at around 1000ft. Some
spots, particularly in the higher terrain, are already seeing snow
mix in. Minor adjustments with this forecast update have been to
bump up winds slightly over the western half of the UP into early
Thursday. We may flirt with Wind Advisory criteria across the
Keweenaw and closer to Superior in Marquette county, but with some
lingering uncertainty as the highest model guidance closer to 45mph
remains an outlier, will hold off on headlines.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 407 PM EST Wed Nov 20 2024
Current RAP analysis shows an elongated mid level closed low over MN
and WI with a ridge over the Rockies. As a shortwave rotates around
the mid level closed low this evening through tonight over MI, a sfc
low deepens over the lower Great Lakes. The weakening sfc low phases
with the deepening low as it rotates from Lake Huron to eastern
Upper MI. Strong q-vector convergence over the east has allowed for
showers to expand over the eastern UP as visible on radar imagery
and available webcams. Reflectivity returns have periodically lifted
over portions of the central Upper MI and the Keweenaw already
today, but an antecedent dry airmass highlighted by dewpoint
depressions of up to 10-15F has really worked against precip
expanding westward. While some isolated rain and snow showers are
possible in the west half ahead of 7 PM EST, better chances hold off
until later this evening through tonight. At that point, a colder
airmass will have moved over the west, aiding in a transition over
to snow showers. Minimum temps in the low 30s to low 40s are
expected early on tonight as WAA strengthens after midnight. That
said, some light wet snow accumulations are possible tonight, mainly
west of US-41 and south of the Keweenaw. Highest snow totals up to
1-3 inches are possible in the high terrain of Baraga County. Opted
to cover potential hazardous travel conditions overnight with a SPS
as a transition over to rain showers by Thursday morning will
likely work against any snow accumulations.
Otherwise, the strengthening low approaching from the east will
result in increasing northwest winds tonight. Gusts are expected to
approach 20-30 mph (up to 35 mph in the Keweenaw) by Thursday
morning.
&&
.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
Issued at 429 PM EST Wed Nov 20 2024
Heading into the late week, a closed 500mb low over the Upper
Midwest descends southeast across the Great Lakes into the Eastern
Seaboard. By Thursday morning, the attendant surface pressure
reflection will have rounded counterclockwise above the Mitten of
Michigan and deepened to near 993mb just west of the Straits of
Mackinac. Guidance is in good agreement on a period of enhanced
northerly flow across Lake Superior following strong pressure rises
where gusts 35-40 knots are likely (80-100% chance) Thursday morning
into the evening. At the same time, ongoing rain/snow mix will be
transitioning to all rain as the low pressure rotates down Lake
Michigan Thursday. While northeast flow over Lake Superior typically
results in cold air advection and lake effect snow, the wound-up
TROWAL sends in low-level temps just above freezing. Rain amounts
Thursday will be maximized in the east and central UP where
northerly upslope could aid in some locals accumulating over an
inch. As the surface low pressure and upper low continue into the
eastern seaboard, ridging nudges in from the west into the Upper
Great Lakes Friday, filtering in drier air aloft. Some light precip
and drizzle will linger Friday with northerly upslope flow.
A shortwave dives southeast over Northern Ontario Saturday, sending
a shot of colder 850mb temps around -8 to -10C across Lake Superior.
Sufficient lake induced instability will be present for lake effect
clouds and maybe some light rain/snow showers over the east UP,
however, any showers will be fighting a dry surface layer, so little
to no accumulation is expected.
Active weather continues beyond the weekend with a deepening trough
over the central US late Monday into Tuesday, however, the current
deterministic model suite is still figuring out the general
timing/location of a surface low traversing eastward across the Ohio
River Valley and depth of cold air descending from Ontario. This
will be a target of opportunity for future forecast packages as lake
effect snow and colder temps could impact Thanksgiving holiday
travel.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 706 PM EST Wed Nov 20 2024
Conditions will continue to deteriorate this evening as an area of
low pressure pushes from east to west over the UP. Showers over the
Eastern and Central UP will expand westward this evening as a mix of
rain and snow. The rain snow mix transitions over to snow tonight,
with IFR conditions developing at all sites after 06z. By 12Z, snow
will transition back to rain, with IFR conditions persisting through
the day on Thursday. Otherwise, northwest winds increase tonight,
gusting up to 25-30 kts at IWD and SAW with up to ~35 kt at CMX for
Thursday morning and early afternoon.
&&
.MARINE...
Issued at 429 PM EST Wed Nov 20 2024
Deepening surface low pressure rounding Lower Michigan and
descending down the axis of Lake Michigan late tonight through
Thursday will bring marine hazards to Lake Superior through Thursday
evening. Northerly winds over central and east Lake Superior pick
up late tonight, increasing above 25 knots around 7pm EST, and 35
knots just after midnight. By Thursday morning, the pressure
gradient be comes maximized across the lake and gusts 35-40 knots
expand across much of the lake, especially closest to the Keweenaw.
A few stray gusts to 45 knots are possible (30%), particularly
between 5-10am EST. As the surface low continues south and east
Thursday evening, winds begin to slacken below gale criteria by at
least 7pm EST while remaining out of the north. Into the weekend,
northeast winds remain elevated on Friday around 25 knots with a few
gusts to 30 knots, further lessening below 20 knots Saturday. Winds
remain light through the early portions of next week, but could gust
to 25 knots on Tuesday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Warning from 5 AM EST /4 AM CST/ to 2 PM EST /1 PM CST/
Thursday for LSZ162-263.
Gale Warning from 6 AM EST /5 AM CST/ to 3 PM EST /2 PM CST/
Thursday for LSZ241>243-246-247.
Gale Warning from 2 AM to 1 PM EST Thursday for LSZ244-245.
Gale Warning from 1 AM to 1 PM EST Thursday for LSZ248>250-265-
266.
Gale Warning from 2 AM to 3 PM EST Thursday for LSZ264.
Gale Warning from 5 AM to 10 AM EST Thursday for LSZ267.
Lake Michigan...
Gale Warning from 3 AM to 1 PM EST Thursday for LMZ221-248-250.
&&
$$
UPDATE...LC
SHORT TERM...Jablonski
LONG TERM...BW
AVIATION...RM
MARINE...BW
Area Forecast Discussion
National Weather Service Springfield MO
547 PM CST Wed Nov 20 2024
.KEY MESSAGES...
- Below normal temperatures and dry conditions will occur across
the area through the end of the week.
- Temperatures increase to near normal/slightly above normal
over the weekend into early next week.
- Rain chances increase in the early to middle part of next
week.
&&
.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 245 PM CST Wed Nov 20 2024
Current water vapor imagery depicts a deep and north-south
elongated mid- and upper-level low protruding into the Ozarks
from the northern Midwest states. RAP analysis has a roaring
100-120 kt jet streak placed right over the Ozarks. Visible
satellite shows a near-textbook comma head mid-latitude cyclone
over the northern Midwest states with a cloud shield ahead of a
cold/occluded front stretching all the way from the Great Lakes
down to the Florida panhandle. WPC places a tertiary cold front
associated with this dynamic system over central IA into central
NE. Strong flow aloft overtop a tight backside pressure gradient
is forcing gusty northwesterly winds with Springfield and Joplin
briefly reaching above 40 mph gusts, but mainly our area is
experiencing gusts of 30-35 mph. Cooler high temperatures in the
middle 50s are also being experienced as cold air filtered in
behind the secondary cold frontal passage last night.
Near Red Flag fire weather conditions this afternoon:
Paired with the observed gusty winds, dewpoints are also much
drier than anticipated, with some areas such as Fort Leonard
Wood, West Plains, and Springfield dropping below NBM 10th
percentile. This is bringing widespread 20-30% observed
relative humidity values to the region. Some localized areas may
see relative humidity drop below 20% this afternoon as diurnal
and mechanical mixing continue. This has resulted in widespread
Elevated (2 of 4) to Significant (3 of 4) fire weather
conditions. Some localized areas are flirting with Red Flag
Warning criteria (<25% RH; >20 mph 20 ft winds, or >30 mph 20 ft
wind gusts). Notably, Springfield, Roby, and Fort Leonard Wood
have all briefly breached Red Flag, but only for short periods.
Fuel moistures have also been drying out throughout the day and
are hovering around 10% as of now (<9% is generally Red Flag).
With all that being said, Red Flag is not being met in widespread
areas and for long durations. Additionally, as the afternoon
progresses past 3 PM, winds are expected to decrease and RHs
will increase as temperatures cool with the setting sun.
Therefore, a Red Flag Warning will not be issued at this time,
but will continue to be closely scrutinized for any impactful
dip well below criteria for a good portion of time.
Nevertheless, it is important to continue to practice fire
safety with conditions being borderline Red Flag.
Below normal temperatures Thursday and Friday:
The tertiary cold front will drop through the area late tonight
as the upper-level low pivots to over the Great Lakes,
positioning us below a tight NW`ly flow height gradient. This
will allow even colder air to filter into the region. Lows
tonight will be in the middle 30s and highs Thursday will be
chillier in the middle 40s. Continued breezy 15-20 mph NW`ly
winds (with gusts up to 25-30 mph) will create max "feels like"
temperatures in the middle to upper 30s. Lows will be colder in
the upper 20s which will be our second hard freeze since
October 17th. The same pattern will remain fairly static into
Friday night, withs highs in the middle to upper 40s and lows in
the upper 20s again.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Issued at 245 PM CST Wed Nov 20 2024
The weekend pattern remains relatively benign, with near-normal
temperatures Saturday and above-average temperatures in the
mid- to upper 60s on Sunday thanks to a ridging pattern early
in the weekend. General ensemble consensus is that the ridge
will weaken into more of a zonal flow aloft, with the low-level
flow breaking its omega block in the second half of the
weekend. The "second half of the weekend" is intentionally
vague- the timing window is wide, with cold frontal influence
reaching us potentially as early as Sunday afternoon or as late
as Monday morning. This is when our next precipitation chances
are- though only 10-20% chances, with the highest chances in the
eastern Ozarks where higher PW values will be.
Temperatures will get colder again post-FROPA, with highs on
Tuesday and Wednesday likely returning to the 40s and lows in
the upper 20s-low 30s. Dry conditions will accompany the cooler
temperatures.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 523 PM CST Wed Nov 20 2024
Skies will be clear through the next 24 hours despite a strong
upper level are of low pressure over the Great Lake region. With
this system over the Great Lakes, surface pressure gradients
will remain tight allowing for gusty surface winds through the
forecast.
Winds will be the primary concern for aviators across the
Ozarks. This will include low level wind shear late tonight and
into Thursday morning. Wind shear will be prevalent near the
boundary layer, around 2kft AGL from the northwest.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
KS...None.
MO...None.
&&
$$
SHORT TERM...Price
LONG TERM...Camden
AVIATION...Hatch