Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/20/25
AREA FORECAST DISCUSSION
National Weather Service Albany NY
1022 PM EDT Wed Mar 19 2025
.SYNOPSIS...
Clouds continue to increase tonight with milder temperatures,
as a cold front approaches from the west. Low pressure will
move northeast into southern Quebec, as the cold front will
bring showers to the region during the mid to late afternoon. As
the front slowly moves across the region Thursday night into
Friday morning a coastal low moves along it, as the rain will
transition to snow with some accumulations especially over the
higher terrain with much cooler and blustery conditions during
the day to close the week.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
As of 10:20 PM EDT...Minor update to reflect current surface
observations for wind gusts across the Mid-Hudson Valley and
Greater Capital District regions as winds are still breezy
between 25 and 35 mph this late evening. The rest of the
forecast is doing well and on track through 3 AM this morning.
As of 8:10 PM EDT...Minor update to wind gusts through the next
two to three hours to reflect current surface observations as
winds are less than 10 mph in the Mid-Hudson Valley, Litchfield
Hills, portions of the Berkshires and eastern Windham county.
The rest of the forecast is doing well and on track through
midnight tonight.
As of 400 pm EDT...Mid and upper level ridging continues near
the East Coast ahead of the approaching closed H500 low over
central Plains MO/IA. A stretched/elongated sfc high remains
near the East Coast. The strong subsidence from the ridge
allowed temps to rise in the 60s to 70s across most of the
region with breezy southerly winds.
Some cirrus has increased due to the low to mid level warm
advection. The sfc high to the northeast and the onshore flow
is going to allow some lower stratus to form along the Long
Island and New England Coast. The lower stratus should move into
locations along and south and east of the Capital Region. Some
patchy fog may form over the Berkshires, east of the southern
greens and near NW CT. We could have a little patchy drizzle
over the Litchfield Hills with the south/southeast flow. Where
the stratus does not form and move in, some mid and high clouds
will increase. It will remain breezy over the higher terrain and
in the confluent zone of the Mohawk and Hudson Valley in the
Capital District with southerly winds 10-20 mph. Expect low
temps to be milder than last night with lower to mid 40s in the
valleys, expect some upper 30s in the CT River Valley in the
Upper Hudson Valley near Lake George. Some of the higher
terrain will be in the mid 30s to around 40F.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
Key Messages:
- Mild temps tomorrow with chances of showers increasing west of
the Hudson River Valley in the mid afternoon.
- Rain, some accumulating snow, gusty winds and cooling
temperatures with a passing system Thursday night into Friday.
Discussion:
Low pressure moves from the central and eastern Great Lakes into
southeast Ontario and southwest Quebec during the day. Low and
mid level heights begin to fall over western NY during the
afternoon. The south to southwest low-level jet at 850 hPa
increases to 35-50 KT. In fact, the latest NAEFS +V-component
anomalies are +2 to +3 STDEVs above normal /strong
southerlies/. It will take some time for the low stratus to
burn off. It will be mild and the chance for showers increasing
over the western Dack, western Mohawk Valley and the eastern
Catskills in the mid to late pm, as the low-level convergence
increases with a prefrontal trough and the cold front. The
warmest temps tomorrow will likely be over the northern areas of
the Upper Hudson River Vally towards KGFL where more sunshine
may occur. Nonetheless, max temps should run 10 to 15 degrees
above normal. We did go close to the 75% for the NBM winds as
the southerly winds will be 10-20 mph with some gusts 30-35 mph
with isolated high ones. High will be in the 50s to lower 60s
with some upper 40s to lower 50s over the higher terrain.
The rain picks up Thu night with some enhanced lift ahead of a
secondary or coastal low that forms near the Delmarva or NJ. The
mid and upper level trough shift from neutral to negatively
tilted tapping some Atlantic moisture. PWATs rise +1 to +2
STDEVs above normal. The increasing differential thickness and
cyclonic vorticity advection occurs with the wave. Colder air
advects in from the west to northwest in the wake of the front.
Dynamical cooling north/northwest of the wave with increasing
low to mid level frontogenesis will tend to have the rain
transition to snow over the higher terrain 06Z-12Z...and likely
in the valleys. The CAMS /3-km HRRR and NAMNest/ and the EC show
very little snow in the valleys including the Capital District.
The latest NBM still has 30-50% probabilities for 1" of snow in
the Capital District/Upper Hudson/Mohawk Valleys with much
higher probs of 50-80% over the higher terrain. It should be
noted 3" of snow or greater probabilities are 30-40% over the
southern Greens and northern Berkshires.
We have a slushy coating to less than a half inch of snow over
in the Capital District/Mohawk Valley/Upper Hudson Valley with
1-3" over the southern Greens (maybe slightly higher over the
high peaks), Berkshires and a few inches in the Catskills. The
snow quickly ends late Friday morning as the wave moves across
southeast New England. The mid and upper deformation zone snow
showers may persist the longest over the southern Greens. Lows
Thu night fall into the mid 20s to mid/upper 30s.
It becomes windy in the wake of the coast low with west to
northwest winds increasing to 15-25 mph with some gusts 30-45
mph. It looks like we will fall just short of Wind Advisory
Criteria with frequent gusts of 46-57 mph. It will be much
colder on Friday with highs in the 30s to around 40F over the
hills and mtns. Expect highs in the lower to mid 40s in the
valleys. The winds decrease Fri night with weak ridging building
in. The skies become partly cloudy to mostly clear with lows in
the 20s to lower 30s.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Key Messages:
- An upper level disturbance brings isolated to scattered showers to
open the weekend.
- A storm system brings widespread precipitation likely again on
Monday (60-80 percent probabilities) with some accumulating light
snow amounts possible.
Discussion:
Weak mid level ridging moves east of the forecast area Saturday
morning, as a short-wave trough approaches from the Great Lakes
Region for scattered showers in the afternoon. The short-wave
trough and a cold front should be moving through quickly early
Saturday night with a few snow showers or flurries over the western
Dacks, southern Greens and western Mohawk Valley with minor light
accums of a dusting to under an inch. Strong cold advection occurs
in the wake of the cold front and trough Saturday night. After highs
in the lower to mid 50s in the valleys and 40s to lower 50s over the
higher terrain, expect lows to fall into the 20s with teens over the
northern mtns. The second half of the weekend looks drier, but brisk
and cool. In the west/northwest flow aloft max temps will run about
5-10 degrees below normal. Deeper mixing and a sfc pressure gradient
will allow for northwest winds 10-20 mph with some gusts 25-35 mph.
Max temps will range from the upper 20s to mid 30s over the mtns and
upper 30s to lower/mid 40s in the valleys. Brief ridging builds in
early Sun night, but then clouds increase ahead of a warm front with
low pressure approaching from the Upper Midwest and western Great
Lakes Region.
The warm front helps increase isentropic lift prior to day break and
along the systems triple point a secondary low could form over
PA/Delmarva Region. This secondary wave and the strong lift may
produce a period of snow (some light accumulations) in the morning
which is supported by the GFS/CMC/EC and some of the ensembles. The
best for accumulating snow may be along or north of the I-90
corridor. The question is how far west the secondary low forms and
how much cold air remains in place. Some Gulf and Atlantic moisture
is tapped for perhaps a quarter to two thirds of an inch of QPF. We
began the morning with likely/categorical values for some snow and
then have temps warming for more rain across the entire region with
some rain/snow mix over the higher terrain. PoPs were increased to
the 70-80% range. A lull in the pcpn could occur in the afternoon
if we break into a dry slot. After lows in the 20s with some teens
over the Adirondack Park, expect highs in the 30s over the mtns and
lower to upper 40s in the valleys, Taconics, and NW CT.
Broad cyclonic flow sets over eastern Canada, the Great Lakes Region
and the Northeast Mon night into Wednesday with lingering rain and
snow showers. The mid and upper level trough persists into the mid
week. The chances begin to diminish Tue night into Wed with just
some residual lake effect/westerly upslope snow/rain showers over
the western Dacks, western Mohawk Valley, eastern Catskills, the
Taconics and western New England higher terrain. Temps will be near
to slightly below normal for late in the extended period.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Through 00z Friday...VFR conditions start the TAF period with a
few passing high clouds. Low level stratus clouds with MVFR to
IFR conditions are expected to spread northward to KPOU/KPSF
shortly after 06z as they increase into these airfields from
the Atlantic Ocean. For KPOU, did include mention of low
visibility in less than one mile due to the potential for fog
development in a TEMPO group from 09z to 12z. For KALB,
confidence has increase to include mention of MVFR/IFR
conditions in the low stratus cloud deck towards the 09z
timeframe. Low stratus clouds should prevail through 15z to 18z
for KPOU, KPSF, and KALB with latest forecast soundings
supporting moisture being trapped underneath a strong inversion.
Winds continue to be breezy through 6z and 9z for KALB and KPSF
with winds gusting between 15 and 25 knots. Winds should
decrease to less than 15 knots during this timeframe, but
increase again tomorrow afternoon with winds gusting between 15
and 25 knots. Continued mention low level wind shear as well
with 2 kft winds reaching between 35 and 45 knots.
Outlook...
Thursday Night: High Operational Impact. Breezy. Definite RA...SN.
Friday: Moderate Operational Impact. Windy With Gusts To 34 kts. Chance of RA...SN.
Friday Night: Low Operational Impact. Breezy. NO SIG WX.
Saturday: Moderate Operational Impact. Breezy. Chance of SHRA.
Saturday Night: Low Operational Impact. Breezy. NO SIG WX.
Sunday: Low Operational Impact. Breezy. NO SIG WX.
Sunday Night: Moderate Operational Impact. Chance of SN.
Monday: High Operational Impact. Definite SHRA...RA...SN.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...Wasula/Webb
NEAR TERM...Wasula/Webb
SHORT TERM...Wasula
LONG TERM...Wasula
AVIATION...Webb
Larger forecast discrepancy and concern will be an enhanced
precipitation band moving north along the Mississippi River
Valley into northeast Iowa and southwest Wisconsin at 19Z. Due
to a slew of varying parameters at play, many questions surround
the immediate impacts from this band. At the northern extremity
of this heavier precipitation, the weather office has experienced
a mix of thundersnow, hail, sleet, and graupel over the last
hour. The wide mix is partially due to a band of near freezing
surface temperatures sandwiched between the aforementioned precipitation
band to the northwest and the slightly unstable precipitation to the
south.
GOES infrared satellite imagery shows the increased moisture with
this incoming precipitation intensifying over the last couple of
hours with a dry corridor to it`s northwest, abutting the ongoing
southwest to northeast snowfall band. To the south of this
slightly unstable area of higher precipitation, a meso-beta
area of cyclonic winds has been taking shape over the last
couple of hours near Davenport, IA. Tied to RAP mesoanalysis
placing a low level baroclinic boundary extending from southwest
to northeast, could expect further cyclogenesis through the
afternoon hours.
In other words, confidence is increasing for an invigorated
area of increased precipitation through the evening hours as
the area of moisture, reflectivity, and meager instability lifts
north and abuts the drier air filament. Given the near freezing
surface temperatures snow amounts and impacts remains in
question. Very near term trend has been the increased forcing
with a near freezing low level isothermal layer overcoming any
melting whilst tapping into a near freezing DGZ. Radar
correlation coefficients have shown a quick easterly exit to the
wintry mix as snow becomes the may precipitation type.
Regardless, overall residence time is expected to be limited.
Cooler Through Thursday:
As the winter storm system exits east tonight into Thursday morning,
the upper level trough axis pushes through the Northern Plains and
the Upper Mississippi River Valley, bringing colder temperatures
with it. A further upstream ridge shunts the coldest low level temperatures,
seen in POES derived temperatures, north of the International Border.
With the tightened pressure gradient sticking around into Thursday
morning, wind chill temperatures may dip into the single digits
in spots. While skies are expected to clear near peak diurnal
cooling, increased wind gusts will keep surface temperatures
from plummeting and therefore likely limiting bitterly cold wind
chills.
The colder air will remain in place for Thursday, keeping below
normal daytime highs in the 30s. A slightly slower pattern in
high resolution model dProg/dt suggests even cooler conditions
are possible as low level warm air advection doesn`t initiate
until Thursday night. Eventually, the upper level ridge axis,
over the Pacific coast on early afternoon water vapor imagery,
does progress through the Mississippi River Valley, initiating low
level warm air advection into Friday morning according to long
term global ensemble confidence (100%). Above freezing 850mb temperatures
(100% confidence EPS/GEFS) ushers in more seasonable daytime highs
in the 50s for Friday.
Light Precipitation Chances Friday:
As the upper level ridge progresses east Thursday, remnants of an
amplified trough down the California coast early this afternoon
on GOES upper level water vapor imagery, works to deamplify the
ridge and usher in precipitation chances locally on Friday. Confidence
between and within long term global ensembles is near certain for
a mid level trough progressing southeast through the Central Plains
on Friday. As has been the trend, ensemble disagreement for
depth of the transient trough is resulting in differences in
precipitation potential. The deeper GEFS solution with 100%
confidence for the 540 dam isoheight as far south as central
Iowa, a jog south in dProg/dt, advects a plume of moisture from
Texas through the Mid Mississippi River Valley and results in
widespread 50-80% confidence for measurable precipitation across
the forecast area. Whereas a shallower trough solution in the EPS
keeps <50% confidence for the same.
Sunday Precipitation Chances:
The active pattern continues into the weekend with 100% confidence
in long term global ensembles for a mid level low closing from the
Northern Plains through the Upper Mississippi River Valley. Similar
to Friday, a deeper solution in the GEFS is resulting in higher
confidence of 70-90% for 0.1" of QPF in 24 hours through much of
Sunday. While ensemble dProg/dt exhibits quite a bit of variability,
still suggests moderate confidence. Regardless, with a widespread
100% confidence for 0.01"+ of QPF in 24 hours, have continued
with National Blends precipitation probabilities, painting a
widespread 80%+ across the forecast area. Additional result of
these differences in synoptic forcing is affecting precipitation
type. Current confidence places the surface freezing isotherm
bifurcating the forecast area from west to east. Therefore,
current confidence (60-90%) in the GEFS and EPS extends in a
west- northwest to east-southeast band of 1"+ (10:1 SLRs) across
our northern half of the forecast area.
&&
.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1040 PM CDT Wed Mar 19 2025
VFR conditions will prevail at both taf sites through the taf
period. Gradient will begin to slacken overnight into Thursday
morning with sustained wind speeds diminishing to around 10 knots at
both taf sites by 15z Thursday.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Wind Advisory until 1 AM CDT Thursday for WIZ061.
MN...None.
IA...Wind Advisory until 1 AM CDT Thursday for IAZ029-030.
&&
$$
UPDATE...DTJ
DISCUSSION...
AVIATION...DTJ
Area Forecast Discussion
National Weather Service Bismarck ND
944 PM CDT Wed Mar 19 2025
.KEY MESSAGES...
- Breezy southwest winds and low relative humidity may lead to
critical fire weather conditions across portions of the
southwest and south central Thursday afternoon.
- There`s a low to medium chance (30 to 50 percent) for some
light rain and snow across the west and central Thursday
evening through Friday morning. Little to no snow accumulation
expected.
- Expect medium chances (40 to 60 percent) for some rain and
snow Saturday and Sunday across most of western and central
North Dakota. Some light snow accumulations are possible.
&&
.UPDATE...
Issued at 942 PM CDT Wed Mar 19 2025
No changes to the forecast for tonight. Quiet night ahead with
some upper level clouds moving into the area late. Some patchy
fog will be possible in the Turtle Mountain region, though this
is uncertain enough where we will hold off on introducing to the
forecast for now, and will monitor through the overnight.
UPDATE
Issued at 647 PM CDT Wed Mar 19 2025
Fire weather conditions have improved southeast, so removed
near-critical fire weather wording in the HWO for that area.
S/WV mid level ridge now over the Rockies will develop east into
the Great Plains tonight into tomorrow, flattening later in the
day tomorrow as a vigorous mid level trough crosses the Northern
Rockies. WAA associated with the ridge will bring mild
temperatures to western and central ND for Thursday, with a
sometimes breezy west/southwest wind. Precipitation chances
increase Thu night as the aforementioned wave moves into our
region.
Overall, forecast elements are on track for tonight.
&&
.DISCUSSION...
Issued at 315 PM CDT Wed Mar 19 2025
Western and central North Dakota currently sits under the
influence of northwest flow aloft and high pressure at the
surface. This pattern has led to plenty of sunshine and
temperatures in the mid 30s to lower 40s. A few sites across the
west could end up seeing some highs in the mid 40s before the
afternoon is over.
We could still see a couple more hours of near critical fire
weather conditions across portions of Logan, McIntosh, LaMoure,
and Dickey counties this afternoon. Highs will mainly be in the
lower 40s here with minimum relative humidity in the 25 to 30
percent range. Sustained northwest winds in this area will also be
in the 20 to 25 mph range.
An upper level ridge axis will approach the west early on
Thursday as it deamplifies. Attention then turns to potential
critical fire weather conditions during the afternoon hours
across portions of the south central and southeast, including
much of the James River Valley on the North Dakota side.
Temperatures will be warmer with highs mainly in the mid to
upper 50s and dewpoints mixing out into the low to mid teens.
These dewpoint spreads will lead to minimum relative humidity
values dipping into the 18 to 25 percent range. Winds will
become breezy out of the southwest with sustained values around
25 mph and gusts to around 35 mph. This overlap could lead to a
few hours of critical fire weather conditions in the afternoon.
Any fires that ignite on Thursday here could spread rapidly and
could quickly become difficult to control. A Fire Weather Watch
has been issued. Further west, across the rest of the south
central and far southwest, winds will not be as strong but
temperatures and humidity will be similar. Thus, near critical
fire weather conditions will be possible here Thursday
afternoon.
Later in the day, a weak Clipper system will approach,
transitioning us into near zonal flow aloft. As the upper wave
and surface low approach in the evening, precipitation chances
(30 to 50 percent) will increase across the west, spreading
into the central overnight. A few of the latest CAMs suggest
that there may be a brief window (low chance) for a
thunderstorm or two across the west in the early evening. RAP
soundings showing MUCAPE values of 100 to 200 J/kg in the 00z to
02z time frame would help support this non-zero chance. All
precipitation should start as rain, but snow will start to mix
in overnight, changing to mainly all snow by Friday morning.
While there is a signal for some stronger omega in the dendritic
growth zone and some modest mid-level frontogenesis, weak
synoptic forcing and the progressive nature of the wave will
keep liquid amounts rather light, generally around a tenth of an
inch or less. Little to no snow accumulation is expected at
this time, maybe a dusting to a couple tenths of an inch at
most.
Friday will be a bit cooler behind the Clipper with highs
currently forecast to range from the lower 20s in the vicinity
of the Turtle Mountains, to the mid to upper 40s southwest. The
next ridge axis then approaches the Montana/North Dakota border
Friday night into Saturday morning with a stronger Clipper on
it`s heels. Precipitation chances (40 to 60 percent) will
increase once again Saturday afternoon, spreading into the
central and east in the evening, and eventually moving out early
in the day on Sunday. Precipitation will once again start out
as rain before mixing with some snow, and eventually
transitioning to mainly all snow. Guidance suggests there may be
a little bit better of a signal for some organized
precipitation with this next Clipper. Modest synoptic forcing,
decent mid-level frontogenesis, and steep lapse rates may all
contribute to some higher precipitation rates with this system.
That being said, liquid amounts are still expected to be
relatively light given the progressive nature of the wave.
Depending on how the temperature profile evolves, some light
snow accumulations will be possible but it is still a bit too
far out to glean much regarding specifics. Another weak wave or
two is possible to start the next work week with only low
precipitation chances expected at this time (20 percent).
Highs Saturday through Tuesday will mainly range from the mid
to upper 30s northeast to the mid to upper 50s southwest. The
one exception will be on Sunday behind the Clipper, when highs
are forecast to range from the lower 30s northeast to mid to
upper 40s southwest.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 647 PM CDT Wed Mar 19 2025
VFR conditions are expected through the 00Z period. Some fair
weather cumulus through early this evening, with then upper
level clouds at times tonight into Thursday.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Thursday afternoon through Thursday
evening for NDZ035>037-046>048-050-051.
&&
$$
UPDATE...NH
DISCUSSION...ZH
AVIATION...NH
Area Forecast Discussion...Updated
National Weather Service Billings MT
550 PM MDT Wed Mar 19 2025
.KEY MESSAGES...
- Periods of breezy to strong winds through the weekend,
especially Thursday and Saturday.
- Multiple periods of mountain snow through the weekend. Light
rain and snow showers possible elsewhere.
- A rumble of thunder is possible Thursday, particularly near
Miles City and Baker
- Warmer than normal temperatures return next week.
&&
.DISCUSSION...
Tonight through Thursday Night...
Ahead of an approaching shortwave trough, skies tonight should
start off mostly clear before clouds build in west to east. These
clear skies will allow for a surface high to develop over
Yellowstone National Park. The resulting pressure gradient
between IDA and LWT will max out anywhere between 12-15mb early
Thursday morning depending on which model is to be believed. With
700mb winds steadily increasing out of the west to 40kts by
daybreak the only question mark is how strong the nocturnal
inversion will be. Visible satellite and webcams show minimal to
no snow cover in the lower elevations around Livingston which
will inhibit the development of a truly strong inversion. That
being said, the clear skies to start the overnight period should
be enough to allow for sufficient radiational cooling. This event
is by no means a slam dunk for gap winds, however, it is likely
that winds will gust to 60mph during the early morning hours
Thursday morning and thus, a wind advisory has been issued.
After daybreak and the clouds build in, the chance for
snow returns for the western mountains. By 16z the shortwave axis
should be roughly in line with the ID panhandle per the 15z run
of the RAP. This will allow for snow to fill in across the
mountains and foothills west of Billings. Although clouds will be
thick across the area, temperatures will still warm above
freezing below 6000` through the morning resulting in more of a
rain/snow mix as we approach midday. A brief lull in precip may
occur in the early afternoon in these locations as the relative
vort max slides off to the east. A reinforcing shot of vorticity
then rapidly slides through the CWA around 00z. This will bring a
higher chance for precip in the aforementioned areas around
sunset. The Bighorn & Pryor mountains will also get in on some of
the snow throughout the day, but totals should be less that 3".
As the first vort max slides off to the east during the afternoon,
it could help bring a chance for convective precip and possibly a
thundershower. The greatest chance for the convective precip will
occur roughly around KMLS and KBHK between 4-10pm MDT. While I do
not expect a true thunderstorm, low level lapse rates will be in
excess of 8C/KM per the RAP and HRRR forecast soundings with
MUCAPE around 250J/KG on these same soundings. The HRRR tries to
put 1 or 2 decent updrafts in Custer and Fallon counties around
22z which is the closest to a "thunderstorm" that any model wants
to produce. A very weak vort max will then trail the shortwave
which could give places near the Dakotas a few snow showers
Thursday night. WMR
Friday through Wednesday...
Brief period of ridging Friday will be followed by what looks to
be a fairly sharp trof passage late Friday night and Saturday.
There will again be potential concerns with pre- and post-frontal
gusty winds. Livingston & Nye should see 50+ mph gusts (70%
chance) Friday night but mid level winds may not support advisory
gusts. W-NW winds arrive Saturday behind a cold front, and it
looks generally windy everywhere but highest gusts should be close
to the western foothills. Current probability of 50 mph gusts at
Big Timber & Harlowton is about 50%. With the sharp trof and
expected shift to more northwesterly surface winds, these
locations aren`t as favored as with west winds. Something to watch
though.
Synoptic scale forcing seems strong enough (in addition to cold
pool aloft to -32C at 500mb) for some lower elevation rain-to-snow
showers, perhaps with a little wet snow accumulation near the
foothills and over the higher hills further east. In addition, as
the trof deepens in the Dakotas, there may be a brief push of
Canadian cold advection and a little snow & wind for our far east
by Saturday night. Lots of uncertainty with any lower elevation
snow right now, but with more confidence we seem to be looking at
a 4-8" snowfall for our mountains (greatest west). Cooling aloft
seems to support a low risk of a few lightning strikes as well.
By early Sunday we should begin transitioning to rising heights as
ridge strengthens over the PacNW. At least initially, the NW flow
is dirty and may yield a few light rain/snow showers in the
Sunday-Monday time frame. By Tuesday & Wednesday the ridge axis
shifts east brings us warmer and drier conditions. There is ample
spread in ensembles with how warm it may get, but confidence is
high for dry conditions and above normal temperatures moving into
the middle of next week. With enough downslope warming and 700mb
temps rising to near +2C to +4C we could see temps reach or exceed
70F for the first time this year (currently a 30-40% chance by
Wednesday). It is also possible that Pacific flow thru BC/AB/SK
keeps the ridge suppressed a bit, and maybe even introduces weak
backdoor east winds at some point. All of these details remain to
be seen. Prior to next week`s warming trend, temps will be
seasonable Friday thru Monday.
JKL
&&
.AVIATION...
00z Update:
VFR will prevail into early Thursday under high pressure aloft.
There is a small (10%) risk of localized valley fog near the MT/WY
state line late tonight, including near KSHR. This is something
to monitor through the night. Breezy west winds along the western
foothills (25-35 knot gusts) will continue until sunset. SW winds
will increase to 40-50 knots at KLVM tonight into early Thursday.
Tomorrow, a passing Pacific cold front will bring scattered
rain/snow showers at lower elevations and a period of snow for the
mountains. Local MVFR is possible with these showers, and
mountains will be frequently obscured. Because of the scattered rain/snow
showers, have added VCSH to the terminals north of the MT/WY
border. For KSHR, the probability of precipitation looks low at
less than 20% through 00z Friday, so leaving VCSH out of the TAF
there for now, but will monitor and could add VCSH if the
probability increases. Furthermore, there is a small chance of a
rumble of thunder or lightning Thursday from instability in the
atmosphere but the probability is so low that we have kept it out
of the TAFs for now. In addition, the front will also bring a
push of gusty west winds across the region. Look for 35-45 knot
gusts along the western foothills, and 25-35 knot gusts over the
central and eastern plains.
JKL/RMS
&&
.PRELIMINARY POINT TEMP/POPS...
Thu Fri Sat Sun Mon Tue Wed
-----------------------------------------------------------
BIL 032/051 032/056 037/050 031/054 039/064 044/066 040/066
03/W 20/N 16/W 10/B 21/N 11/B 00/B
LVM 029/043 027/050 034/041 024/046 038/056 038/061 037/062
06/J 20/N 58/J 11/N 32/W 11/B 00/B
HDN 024/052 030/056 033/051 030/054 038/065 042/066 036/066
03/W 10/U 17/W 21/B 22/W 11/B 00/B
MLS 027/054 033/055 034/051 030/051 036/062 042/060 035/061
03/T 30/B 15/W 20/B 21/E 20/B 00/B
4BQ 024/053 032/051 030/050 030/049 033/059 042/059 036/062
01/B 20/U 05/W 21/B 21/E 10/B 00/B
BHK 024/053 028/050 028/050 024/046 026/055 034/055 029/055
01/N 51/N 14/W 41/B 21/E 21/B 00/B
SHR 016/050 022/050 024/048 023/045 028/058 038/061 033/062
02/W 20/U 08/W 31/B 22/W 11/B 00/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Wind Advisory in effect from 9 PM this evening to noon MDT
Thursday FOR ZONES 65-66.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1155 PM EDT Wed Mar 19 2025
.KEY MESSAGES...
- After a late night to early morning break, precipitation changes
over to a period of wet/melting snow during Thursday morning,
especially north of a line from Adrian to Port Huron.
- Gusty winds in excess of 30 mph are expected both this
afternoon and Thursday.
- Dry, breezy, and mild Friday.
&&
.AVIATION...
Low pressure system on pace to track across the region during the
early morning hours. This will maintain a lingering window for
possible convective shower development, with a limited opportunity
for embedded thunder give lack of greater instability. A brief
stronger wind gust remains plausible should a more organized storm
or heavy shower emerge. Conditions to largely hold at VFR outside of
any reduction in visibility with passing activity. Wind shift to
northwesterly accompanies passage of a trailing cold front early
Thursday. Deeper low level moisture takes residence within the
deformation axis, leading to an increase in coverage of
precipitation mid-late morning Thursday. Rapidly declining thermal
profile affords a transition from rain to snow from PTK northward,
with a mix favored across the Detroit corridor. Widespread MVFR
expected during this time. Afternoon gust potential into the 30 knot
range.
For DTW...There remains a low chance for thunderstorms through 07Z.
Window exists for a transition to a rain/snow mix or snow late
morning into the afternoon Thursday. No accumulation expected.
.DTW THRESHOLD PROBABILITIES...
* High confidence in ceilings at or below 5000 feet overnight
through Thursday.
* Low confidence in thunderstorms overnight.
* High for ptype as rain through mid morning Thursday, then a
mix/snow late morning into the afternoon.
&&
.PREV DISCUSSION...
Issued at 427 PM EDT Wed Mar 19 2025
DISCUSSION...
Impressive satellite presentation of the powerful Midwest low
pressure system is shown this afternoon, complete with a lengthy dry
slot dust plume. The system remains on schedule to bring a wide
range of conditions to SE Mi tonight through Thursday, beginning
with a round of showers and thunderstorms tonight and finishing with
rain changing to wet/melting snow Thursday morning until ending in
the afternoon.
Upstream convection since mid morning has been elevated across IL/WI
transitioning to surface based toward the mid MS valley judging by
areal coverage of CAPE in hourly mesoanalysis. RAP based MUCAPE
analysis suggests sub 1000 J/kg HREF ensemble forecasts are too low
as of mid afternoon but provide a reasonable tracer for the timing,
areal coverage, and intensity trend of instability into Lower Mi
this evening. Based on these upstream observations and the latest
radar trends, it is prudent to adjust model forecast instability
upward enough to allow a few stronger updrafts the opportunity to
reach SE Mi with respectable intensity, whether surface based or
slightly elevated. There are still challenges with that assessment
based on best timing of arrival around 03Z from the Tri Cities to
Adrian and the potential condition of the surface based stable layer
post sunset. It is crucial to establish the character of instability
as the wind field/shear profile is more than respectable for
organized convection presenting both a damaging wind and low end
tornado hazard. Low level shear and curvature will be maximized
closer to the front/surface low track where sub cloud base wind is
backed more SE. Farther south/east into the warm sector, RAP
soundings indicate 50 kt wind speed through a substantial amount of
the 850 to 500 mb layer. This is where updrafts of sufficient
strength could briefly orient normal to the flow and present a
damaging wind hazard. All of this is again strongly conditional on
sufficient instability holding post sunset which will be closely
monitored through the evening with the assumption that storms will
approach severe intensity until they prove unworthy.
The leading moisture axis sweeps eastward and the mid level dry slot
follows for a break in precipitation activity late tonight into
early Thursday morning. Trailing mid level deformation then brings
phase two of rain showers by late morning still with a transition to
rain/snow mix and even all snow until ending around mid afternoon.
Consensus of model soundings do indicate an all snow sounding but
with a shallow above freezing surface based layer. This, along with
warm ground, results in melting snow as the primary outcome. Blended
model guidance provides a coating of accumulation west and north of
metro Detroit, and this looks Ok with a few brief increases in rate.
Dry weather moves in with high pressure and a clearing trend
Thursday night. Open sky and light wind help low temperatures drop
into the 20s across the area. Readings are then projected to rebound
back a few degrees above normal to finish the week as south wind
returns into the 20 to 30 mph range Friday afternoon.
MARINE...
Low pressure tracking northeast out of the Midwest remains on track
to move through Central Lake Huron between 6-12z Thursday. There
looks to be a chance of strong storms out ahead of the low,
especially over Lake Erie/Lake St. Clair. Strong northwest winds and
cold advection behind the low Thursday morning, with mixing depths
expected to increase sufficiently over Lake Huron in the afternoon
to support gusts to gales. Surface ridge quickly arrives Thursday
evening leading to diminishing winds. However, at least moderate
southwest winds will develop on Friday behind the ridge axis, with
Saginaw Bay/Central Great Lakes gusting in the 30-35 knot range.
However, warm advection pattern through the day will help stabilize
the near surface profiles, capping/limiting gust potential in the
afternoon. Strong cold front sinks south through the Central Great
Lakes Friday night, with a brief period of strong northerly winds
over Lake Huron Saturday morning, as 850 MB temps plummet into the
mid negative teens. Brief gusts to 30 knots appear likely before
surface high arrives by early Saturday evening.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Gale Warning until 5 PM EDT Thursday for LHZ361-362.
Gale Warning from 8 AM to 10 PM EDT Thursday for LHZ363-462>464.
Small Craft Advisory until 4 AM EDT Friday for LHZ421-422-441>443.
Lake St Clair...Small Craft Advisory until 10 PM EDT Thursday for LCZ460.
Michigan waters of Lake Erie...Small Craft Advisory until 10 PM EDT Thursday for LEZ444.
&&
$$
AVIATION.....MR
DISCUSSION...BT
MARINE.......SF
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Green Bay WI
636 PM CDT Wed Mar 19 2025
Updated aviation portion for 00Z TAF issuance
.KEY MESSAGES...
- A potent spring storm will impact the region through late
tonight, bringing heavy snow to central, north- central, and far
northeast WI, and rain changing to sleet and snow elsewhere this
evening. A few thunderstorms are also possible late this
afternoon and evening in the Fox Valley and central WI. Winter
Storm Warnings and Winter Weather Advisories have been issued
across most of the forecast area.
- Strong northeast to north winds gusting to 30 to 45 mph may
produce pockets of blowing snow in open areas through tonight.
The combination of wet, heavy snow and strong winds could cause
tree damage and produce sporadic power outages as well.
Hazardous travel conditions are expected region-wide.
- A prolonged period of snow mixed with rain at times is expected
Sunday into Monday. At this time, there is a 40 to 70% chance of
3 inches of snow from Sunday and Sunday night across the entire
area, and a 30 to 50% chance of 6 inches across the north.
&&
.DISCUSSION...
Issued at 348 PM CDT Wed Mar 19 2025
Short Term...Tonight and Thursday
Water vapor imagery shows a strong low pressure system moving across
northern Missouri this afternoon creating widespread areas of snow,
sleet, and rain across the upper Midwest. Regional radar and RAP
analysis shows a band of heavy snow developing due to an area of
strong mid-level frontogenesis extending from northern Iowa into
central WI. Within this band of 1-hr snow rates are likely 1-2" per
hour which is in like with the 12Z HREF. As the stronger forcing
moves northeast expected those higher snowfall rates to develop from
central to far northeast WI, where a Winter Storm Warning is in
effect. RAP analysis also shows increase mid-level instability across
central WI leading to some convectively enhances snow in those
regions. Overall snowfall amounts remain highest (4-8")along a line
from AUW to ESC. The biggest question for the remainder of the
afternoon is when will rain transition to snow in the Fox Valley
and along the lakeshore. With temperatures still the mid 30s in the
Fox Valley it may take another hour or two to cool enough for the
transition to occur. For areas in the Fox Vally and along the
lakeshore snow accumulations are expected to reach 3-6" with locally
higher amount possible in Door Co. Area web-cams show snow has also
been slow to accumulations roads, however, once the sun begins to
set may see a rapid deterioration in road conditions this evening.
There is going to a sharp cut off in snow amounts across north-
central WI as drier air is winning our north and west of an RRL to
LNL line.
Winds are also starting to increase across the region this afternoon
with gusts pushing 30-40 mph. Northerly winds across the region will
continue to increase late this afternoon evening. Blowing snow may
cause sporadic reductions in visibility across the open areas of
central WI this evening. Sporadic power outages and tree damage are
also possible and winds increase and wet snow accumulations are
trees and powerlines.
Snow is expected to come to an end from west to east overnight with
most of the region expected to turn dry by day break Thursday.
Breezy west winds will linger through Thursday morning before
starting to diminish during the afternoon.
Long Term...Thursday Night Through Wednesday
Tranquil conditions will prevail Thursday night into Friday
morning as a cold front approaches from the northwest. As
the front moves into the area, this feature will bring a chance
of light rain during the afternoon and evening. The rain could
end as light snow as temperatures fall during the evening.
The main system of concern is a prolonged period of light snow
mixed with rain at times Sunday into Monday. A 500mb trough is
expected to close off and become negatively tilted Sunday
afternoon into Monday. On Sunday, the GFS model indicated 145
knot jet streak passing south of the area, with much of the area
in the favorable left exit region of the jet which will enhance
lift across the area. Models did show weak 850mb warm advection
of the upper level disturbance that should move across the
area. Temperatures are expected to warm into the 30s, however
some large temperature/dewpoint spreads in the guidance would
suggest temperatures will fall back closer to freezing once the
precipitation arrives. Snowfall accumulations difficult to
determine this time of year due to higher sun angle, air and
ground temperatures above freezing. Snowfall rates will also be a
determining factor, especially during the day. Looking at the
DESI, probabilities of 3 inches of snow Sunday and Sunday night is
between 40-70%, highest chances across the north. There is a
30-50 of 6 inches across the north. The chances for mainly snow
will continue Monday as the upper low moves across the state. Will
need to watch to see if there are more significant snow shower
activity with this feature that could impact visibilities for
motorists.
The northwest flow pattern will continue Monday night
into Wednesday which results in low to medium confidence
in the dry conditions as the model have small features dropping
southeast into the central portion of the country during this
time frame. Seasonable temperatures will continue into the middle
of next week.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 636 PM CDT Wed Mar 19 2025
Rain has changed over to snow across most locations early this
evening, save for the far southeastern portion of the area
including KMTW. A mix of rain, snow, and sleet is possible at KMTW
until precipitation changes over to all rain around 01Z. Snow will
continue across the area this evening with LIFR/VLIFR conditions
eventually improving to IFR/MVFR as the snow ends later this
evening into the overnight hours from west to east. Conditions
should then eventually improve to VFR by Thursday morning as high
pressure builds in across the area.
Surface winds will continue to be very gusty through Thursday
morning, with gusts of 30 to 35 knots at times from a northerly
direction. Winds will eventually back to a northwesterly direction
Thursday morning as they gust to 20 to 30 knots then back further
to a westerly direction Thursday afternoon with gusts around 20
knots. LLWS will continue this evening as winds just off the
surface gust to 40-50 knots.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 1 AM CDT Thursday for WIZ010-018-
038-045-048.
Winter Storm Warning until 1 AM CDT Thursday for WIZ011>013-
019>021-030-031-035>037-073-074.
Winter Storm Warning until 7 AM CDT Thursday for WIZ022.
Winter Weather Advisory until 7 AM CDT Thursday for WIZ039-040-
049-050.
&&
$$
DISCUSSION.....GK/Eckberg
AVIATION.......Kurimski
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
847 PM CDT Wed Mar 19 2025
.KEY MESSAGES...
- Severe weather threat will move from west to east across the
forecast area through 7 pm. Tornadoes, damaging winds and hail
are all a concern.
- On the back side of the storm system, a switch from rain to snow
will occur, starting as early as 10-11 pm around Galesburg, with
all precipitation moving out before sunrise. Accumulations of 1
to 2 inches are possible north of a Macomb to Bloomington line.
- While the strong wind gusts will taper off for a time this
evening, another period of wind gusts 40+ mph are expected after
midnight.
&&
.UPDATE...
Issued at 847 PM CDT Wed Mar 19 2025
996 mb low pressure was analyzed over northwest Indiana early this
evening, with the upper level low farther west over west central
IL. Storms associated with the surface low and cold front have
pushed well east of the area, while rain associated with the
upper low was moving into the western CWA. Winds will back west to
northwest over the next few hours, with the resulting cold
advection changing the rain over to snow from the northwest
overnight. Periods of wet heavy snow are likely, mainly north of
a Canton to Bloomington line. Based on latest high-res guidance,
have increased snowfall accumulations to 1-3" (highest north of a
Galesburg to Lacon line). Where snowfall rates can remain high,
they may be able to overcome warm pavement to produce slushy
accumulation on roads. Tightening MSLP gradient on the back side
of the low will produce wind gusts near 45 mph, which can produce
sharply reduced visibility in areas of snow. Have issued a Special
Weather Statement (SPS) to highlight these condtions for our
northern CWA overnight.
25
&&
.SHORT TERM... (Tonight)
Issued at 322 PM CDT Wed Mar 19 2025
Severe weather threat:
Line of strong to severe thunderstorms has formed across the
Illinois River valley this afternoon, in an area of 500-1000 J/kg
SBCAPE. Low level lapse rates in this area are fairly steep,
generally near 9C/km, and some timely sunshine following the
morning dust canopy (now seen on dust channel satellite imagery
about to exit east central and southeast Illinois). Surface
analysis shows the dry line has reached Quincy, and HRRR guidance
brings it to near Champaign before sunset. Storms will continue to
move eastward ahead of this dry line, and should be along the
Indiana border toward 6-7 pm. Tornado watch runs until 9, but will
be trimmed from west to east as the threat ends.
Wind concerns:
No changes are being made to the wind headlines at this time, with
areas south of I-70 dropping off at 7 pm. There will be a period
of less intense winds this evening behind the storms, before the
deep upper trough behind the departing low arrives. Wind gusts
come back up to around 40 mph from west to east after midnight.
Overnight snow threat:
As the aforementioned upper trough moves in, another round of
precipitation arrives. High-res models have been in good agreement
that a switch to snow arrives by late evening around Galesburg,
with the changeover reaching Bloomington toward 2-3 am. A narrow
band of heavier snow is of concern, with HRRR focusing it from
about Macomb-La Salle, but getting a handle on the exact placement
is still a challenge at this point. Did some coordination with
neighboring offices on the need for a Winter Weather Advisory as
some indications of 2-3 inch amounts aren`t out of the question,
but will hold off for now and watch it closely over the next
several hours.
Geelhart
.LONG TERM... (Thursday through Next Wednesday)
Issued at 322 PM CDT Wed Mar 19 2025
Next trough is scheduled to arrive Friday night. While this
doesn`t have as much moisture available, a subsequent trough later
in the weekend still looks to have widespread rain with it on
Sunday. Can`t rule out a bit of snow as it ends late Sunday night,
but no impacts are expected.
Temperatures will be much cooler through the period, with mainly
40s and 50s for highs.
Geelhart
&&
.AVIATION... (For the 00z TAFs through 00z Thursday Evening)
Issued at 713 PM CDT Wed Mar 19 2025
TSRA have pushed east of the central IL terminals. MVFR to IFR
ceilings associated with the upper level low moving into west
central IL will overspread the terminals over the next few hours.
This will initially be associated with -SHRA, but as colder air
filters in a mix or change to SN is forecast. Currently lowest
(IFR) visibility in SN looks to occur at KPIA, with lower
probabilities of this occurring farther southeast. The back edge
of the lower ceilings should work east of the terminals from
11-14z. West-southwest winds to gust near 30 kt this evening, then
will veer northwest tonight, gusting at 30-35 kt well into
Thursday.
25
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 7 AM CDT Thursday for ILZ027>031-036>038-
040>057-061.
&&
$$
Area Forecast Discussion
National Weather Service Indianapolis IN
1106 PM EDT Wed Mar 19 2025
.KEY MESSAGES...
- Windy today with gusts 35 to 45 mph, Wind Advisory in effect until
9pm.
- Numerous T-storms later this afternoon and evening, with a few
severe storms possible. Damaging winds are the primary threat,
though isolated tornadoes and severe hail are also possible.
- Becoming cooler, with rain and snow showers Thursday morning.
- More showers are expected at times this weekend and next week as
temperatures hover mostly around normal.
&&
.FORECAST UPDATE...
Issued at 1103 PM EDT Wed Mar 19 2025
Active evening of strong and severe thunderstorms is winding down
across central Indiana...although cold front currently crossing
region from west to east has been bringing down some briefly strong
to isolated severe gusts which are still possible over eastern zones
through 530Z. Temperatures displaying staunch drop with boundary
with upper 40s now entering far western portions of area. Lower
ceilings towards pre-dawn hours will accompany arrival of mainly
scattered rain to snow showers from Northwest to southeast. Winds
should drop off slightly with gusts expected to stay mainly under
25-30KT through 12Z Thursday morning.
&&
.MESOSCALE UPDATE...
Issued at 457 PM EDT Wed Mar 19 2025
The atmosphere out ahead of the approaching low in continuing to
develop parameters conducive to organized convective cells this
afternoon. This had led to widespread thunderstorm initiation over
central IL. Initially, the thought was the dry mid level air would
inhibit initial updraft growth leading to more of a discrete
convective mode, but observational analysis is showing very little
limitations with a the beginning formation of a QLCS. This is
expected to continue the surge of moisture pushes into central
Indiana over the next few hours.
VWP observations show low level veering quickly increasing as the
LLJ strengthens. This is aligning with the more aggressive CAMs like
the HRRR and FV3. This could allow for the more discrete cells out
in front of the main QLCS to become organized including the
potential for organized mesocyclones. These more discrete cells
within the drier mid-levels would also have the best chance of
producing severe hail. The hail threat is likely to diminish some as
the QLCS arrives.
As far as the QLCS, the bulk shear vector will be best aligned for
segments that are oriented slights west of north, and these segments
will be the most likely to produce damaging winds and isolated
tornadoes. Overall storm motion will generally be around 230 degrees
at about 50kt. This will become more westerly with time and as the
cold pool strengthens.
&&
.SHORT TERM (This evening through Thursday)...
Issued at 315 PM EDT Wed Mar 19 2025
Current surface analysis and satellite observations show a strong
surface low centered near northwest Missouri with thunderstorms
developing ahead of an advancing cold front across Illinois. This
front will continue to push eastward towards central Indiana during
the afternoon. Moisture advection combined with additional diurnal
heating supports the development of numerous thunderstorms around
the 5-7pm timeframe. Severe storms are possible as strong deep-layer
wind shear and modest instability favor supercells capable of all
hazards. A Tornado Watch is in effect across west-central Indiana
through 10pm.
The greatest threats later this afternoon and into the evening are
damaging wind gusts and tornadoes, especially across west-central
Indiana. Forecast soundings show slightly backed surface flow beneath
a strong southwesterly LLJ promoting veering low-level hodographs.
This setup will lead to strong SRH around 200-300 (m^2/s^2) favoring
supercells and an increasing tornado threat. Steep 0-3km lapse rates
along with organized rotating updrafts also favors the potential for
damaging wind gusts. The hail threat is somewhat limited due to
modest instability, but severe hail is still possible with any
organized storms. The severe weather threat tapers off early tonight
once the aforementioned front shifts east.
PBL mixing into a strong LLJ overhead will continue to produce
strong wind gusts through this evening. A Wind Advisory remains in
effect through 9pm for the potential of southerly wind gusts up to
45 mph. Isolated higher non-thunderstorm wind gusts cannot be
completely ruled out. Despite PBL stabilization overnight, winds
remain elevated into Thursday with a strong pressure gradient in
place.
A lull in precipitation is expected tonight due to dry air filtering
in behind the front. However, rain quickly returns late tonight as
moisture wraps around the surface low. Model guidance suggest
precipitation remains mostly confined to areas near or north of I-70
where stronger low-level convergence should be. Colder air advection
on the backside of the low will likely allow light snow to mix in.
No accumulations are expected due to warm ground temperatures.
Isolated lake enhanced rain or snow showers may then continue
through the early afternoon hours before quiet weather conditions
return. Highs ranging from the upper 30s to mid 40s combined with
breezy conditions will make it feel more like Winter on Thursday.
&&
.LONG TERM (Thursday night through Wednesday)...
Issued at 315 PM EDT Wed Mar 19 2025
The long term period will see steadier and nearer to normal
temperatures than we`ve had the last could of weeks. This will be
paired with a couple of upper waves moving through that will bring
multiple chances of precipitation through next week.
Temperatures are forecasted to be pretty consistent through the
period with highs in the 50s each day and lows in the 30s. The
coldest night of the period will be Thursday morning with lows below
freezing.
The first round of precipitation will be Friday night, due an upper
wave extending south into the region. Central Indiana will have
minimal moisture and lift to work with while better precipitation
chances will be to the north. Likely only the northern half of the
forecast area will see light rain from this system, but at this time
confidence isn`t high so have kept PoPs at slight chance and chance.
Saturday will be quiet and dry as a quick upper ridge passes over
the region.
The next system will be an upper low tracking across the Great
Lakes, coming from the northern Plains. This system will see greater
moisture than the previous one as models show a line of showers and
potentially thunderstorms to track across the eastern U.S. and
prompting PoPs from Sunday morning through Monday. At this time, not
seeing indicators of severe weather for central Indiana but breezy
non-thunderstorm winds with gusts of 25 to 30 mph are expected
especially for Monday... SPC shows that there could be some day 5
severe down in the ArkLaTex/Mississippi region so will continue to
monitor should the risk expand northward.
Finally, another weaker system could bring additional rain chances
mid-next week.
&&
.AVIATION (00Z TAF Issuance)...
Issued at 715 PM EDT Wed Mar 19 2025
Impacts:
- Strong wind gusts to 25-35KT into this evening...with isolated,
embedded higher gusts possible in few strong/severe TSRA thru 02Z
- MVFR CIGs possible in/near stronger cells through 02Z...with
widespread MVFR CIG returning 08-09Z late tonight
- Winds veering slowly to SW this evening...and quickly to NW pre-
dawn Thursday
- LLWS at KLAF/KHUF through 02Z this evening
Discussion:
Gusty southerly gradient winds gusting to 25-35KT early this
evening, courtesy of a strong low-level jet...will wane slightly
through the early evening while veering to southwesterly...with
gusts to 20-25KT from 04Z through dawn Thursday. Higher gusts in a
few strong/severe storms tracking from southwest to northeast
through 02Z will be an isolated yet locally more potent hazard, with
gusts briefly to 55KT and small hail possible near terminals at
times.
VFR this evening will drop to MVFR and possibly brief IFR in
stronger convection...before widespread MVFR returns from NW to SE
around 08-09Z late tonight amid mainly scattered rain/snow showers.
MVFR CIGs Thursday...should lift back to low-VFR during 19-22Z from
west to east...before scattering out.
Northwest winds Thursday will increase slightly through the morning
despite cloudy skies...with sustained winds at 15-17KT at most TAF
sites through the majority of the daytime...and gusts as high as 24-
30KT. Northwest winds at KIND should diminish to under 7KT by late
Thursday evening.
&&
.IND WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
UPDATE...AGM
SHORT TERM...Melo
LONG TERM...KF
AVIATION...AGM
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
650 PM CDT Wed Mar 19 2025
.KEY MESSAGES...
- Level 3 of 5 severe thunderstorm into early this evening.
Main threat being possible tornadoes.
- Accumulating wet wind whipped snow late tonight across
portions of the area. Hazardous travel possible late tonight
into the early Thursday morning commute.
- Seasonal conditions this weekend into early next week with
several chances for precipitation, highest on Sunday
&&
.MESOSCALE...
Issued at 349 PM CDT Wed Mar 19 2025
Convective mode question seems to be getting clearer for our CWA as
QLCS is quickly organizing to our southwest. There has been a
dramatic improvement in low level shear profiles in the KILX
VWP with 0-1km SRH near 200 m2/s2, so despite the QLCS mode,
there remains a tornado threat with MVs or even transient
supercellular features embedded within the line along and
especially south of the strong quasi-stationary front roughly
located near I-80. Besides that, damaging winds will be possible
with this line as it moves across about the southern half of
our CWA.
Farther south, there are some more isolated cells south of the
developing QLCS. These cells will have a better chance of evolving
into discrete supercells, with some potential they could clip our
extreme southeast CWA if they don`t turn right too quickly.
Obviously any discrete right moving supercell in this strongly
sheared environment would pose a supercellular tornado risk.
- Izzi
&&
.DISCUSSION...
Issued at 250 PM CDT Wed Mar 19 2025
Mid evening Through Thursday:
As the dryline moves east of the area this evening, the severe
threat will depart with it. While there may be a brief lull in
the precipitation, the surface low will slowly move east through
the area. North winds will drive cold air advection and drop
temperatures below freezing overnight, with a wet bulb
temperatures falling to the freezing mark across the I-39
corridor as far south as northern La Salle county. Precipitation
will change over to wet slushy snow accumulations through
Thursday morning.
The storm system`s deformation axis will be fairly potent, and
there will be a period of heavy wet snow accumulation with
several hour period of 0.75-1" per hour rates. However, there
are several limiting factors preventing higher confidence in the
forecast: location of the heavier snow and moisture. Over the
last couple days, models have trended the corridor of higher QPF
with the better forcing along with the center of the low a bit
farther south. Even at this time window, it is difficult to
have high confidence in the exact location. Additionally, the
amount of QPF will drive snow totals, and model guidance has not
been in great agreement. The RAP remains on the higher end of
the QPF spectrum, and if this solution were to manifest itself,
forecasted snow totals could be underdone. Right now the highest
confidence in higher totals, currently forecast between 2 to 3
inches, is from southern Lee County to northern Livingston
County northeastward approaching the west and southwest suburbs,
with 1 to 2 inches fore the rest of the forecast area. Finally,
the low level thermal profiles are marginally supportive for
rapid road accumulations, though that could be overcome by the
heavier snow rates.
Impacts during the overnight period will not be just from the
snow. Winds will switch to the north tonight and eventually to
the northwest around midnight. A strong northerly low level jet
will increase with winds at 925 mb 50+ knots. Surface wind gusts
are expected to be up to 45 mph overnight. A wind advisory was
issued last night on the midnight shift and that seems
reasonable. And while snow totals are on the lower side, when
coupled with winds this strong, visibilities can be lowered and
with the potential for some convective snow showers increasing
snow rates at times up to an inch an hour. It can make fore
slippery, if not hazardous, travel. Strong consideration was
given to potentially issuing a Winter Weather Advisory with the
mix of brief heavy rates and visibility reductions from wind.
But given the uncertainty on the location of the heaviest rates,
short lived period, and the window being an unfavorable time of
day and marginal low level temperatures, it was held off for
now. This is something the evening shift can hone in on for the
thermal profiles during the period of heavy snow rates.
The last bit of uncertainty with this system is the exact time
that this low moves through and east of the area. There is a
strong possibility that this system is still lingering over the
Chicago Metro area during the early part of the morning rush.
With the potential for snow showers having slightly higher
rates, some slippery travel is still possible tomorrow morning,
especially across the Chicago metro area into Northwest Indiana.
Once the low exits to the east, conditions will dry for a
quieter Thursday. Winds will remain out of the northwest driving
cooler temperatures maxing out in the 40s (maybe only in the
upper 30s for areas closer to the Wisconsin stateline). For
more information about the extended forecast, see the previous
discussion below.
DK/KMD
Thursday Night through Wednesday:
Following a much cooler day on Wednesday behind the departing
storm system, winds will turn southerly and modest low level
warm advection will commence ahead of an upper Great Lakes low
and impending cold front. This should keep temperatures from
dropping off too much during the night. Nonetheless, Thursday
night will be cool with lows forecast in the upper 20s, maybe
staying up near freezing in and around the city. The continued
feed of mild low level air during the day will pull highs back
into the middle and upper 50s in the afternoon. Friday also
looks to be on the breezy side with a potent low level jet
moving over ahead of the front. Made the decision to again bump
winds in the forecast beyond the NBM`s solution to include some
30-35 mph gusts area-wide during the afternoon. Although,
looking at forecast soundings, gusts could possibly be closer to
40 mph for a majority of the afternoon. Some filtered sunshine
during the morning will give way to building cloud cover through
the day in anticipation of this front and an associated precip
potential.
Guidance is in better agreement on this system than 24 hours
ago and the GFS has finally dropped the idea that a surface low
pressure center will embed itself along the front before moving
overhead. The front should move into our northwest late Friday
evening and work across the CWA through the night. There remains
quite a bit of discrepancy in precip coverage; the GFS and NAM
are more aggressive than the Euro coming in with a sharper front
and more layer moisture. Anywhere from isolated to a period of
densely scattered showers are on the table. It`s possible too
that a brief window of snow or a rain/snow mix materializes
toward the end of the event as the low levels cool behind the
front. At this point, no noteworthy impacts are anticipated with
this system. Saturday will be dry with clearing skies and highs
back down in the 40s.
Another, more interesting northern stream Pacific origin trough
will pass through the Great Lakes region on Sunday. This system
packs a bit more punch than Friday night` system, and will
likely have a bit better moisture feed and thus precipitation
chances are correspondingly in the likely category. There are
still some timing discrepancies to resolve. Confidence is high
that temperatures Sunday night into early Monday will support a
mix or even a changeover to snow (across north central IL),
though it is not clear how much of the storm`s deformation axis
will affect northern IL.
Northwest flow will remain in place behind this system early
next week, and this will keep temperatures cooler than normal.
Subtle weak waves may bring low end precipitation chances at
times.
Doom/KMD
&&
.AVIATION /00Z TAFS THROUGH 06Z FRIDAY/...
Issued at 650 PM CDT Wed Mar 19 2025
Forecast concerns include...
Snow, possibly heavy at times, early Thursday morning.
Lifr/vlifr vis with the snow. Blowing snow also possible.
Strong/gusty north/northwest winds through the period.
The bulk of the thunderstorms have moved east of the terminals
and there remains an isolated thunderstorm potential early this
evening and mainly south of the terminals. Scattered showers
will also be possible through mid/late evening.
Attention is turning to the potential for a narrow band of
moderate to possibly heavy snow right across the terminals.
There remains some uncertainty for the exact placement/location
of this band but there remains high confidence for a band of
snow developing in the early overnight hours and ending during
the predawn hours and just before sunrise Thursday morning.
Visibilities are likely to drop into the 1/2sm range in this
band and its possible brief 1/4sm vis will develop as well.
Trends will need to be monitored for possible lower prevailing
vis. Ahead of the snow, there will likely be a short period of a
mix of light rain/light snow and sleet. The strong
north/northwest winds will likely lead to blowing snow, mainly
while the heaviest snow is falling since the snow is likely to
be on the wetter side with temps in the lower 30s.
Northerly winds are expected this evening, possibly turning to
the north/northeast for a short time this evening, before
turning back to the north/northwest. Only medium confidence for
specific wind directions. Speeds/gusts will steadily increase
through the mid evening hours with gusts into the lower 30kt
range. By the time the snow starts, gusts into the 35-40kt range
are expected. Speeds/gusts will slowly diminish through Thursday
morning, into the upper 20kt range for gusts. Speeds/gusts are
expected to rapidly diminish with sunset Thursday evening. cms
&&
.MARINE...
Issued at 413 AM CDT Wed Mar 19 2025
A period a gale fore winds and very hazardous waves is
anticipated along southern Lake Michigan nearshore waters today
into Thursday. Southerly gales will be possible as early as this
afternoon along the Indiana nearshore waters and maybe reaching
as far north as the Chicago shore. The northward extent of
gales during the day today will be dictated by the position of a
warm front that will cut across the far southern reaches of the
lake this afternoon. A period of gusty, potentially severe
thunderstorms is also expected over the lake from mid-afternoon
through early evening today. As the front pulls away to the
south this evening, a surge of gale force winds will drive down
the lake from the north and remain into Thursday morning before
winds steadily subside. The NNW flow will lead to significant
waves up to 16 ft and occasional waves over 20 ft along the
Indiana nearshore waters Thursday morning.
Doom
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Wind Advisory from 10 PM this evening to 7 AM CDT Thursday for
ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-ILZ012-
ILZ013-ILZ019-ILZ020-ILZ021-ILZ103-ILZ104-ILZ105-ILZ106-
ILZ107-ILZ108.
Wind Advisory until 7 AM CDT Thursday for ILZ023-ILZ032-ILZ033-
ILZ039.
IN...Wind Advisory from 10 PM this evening to 7 AM CDT Thursday for
INZ001-INZ002.
Wind Advisory until 7 AM CDT /8 AM EDT/ Thursday for INZ010-
INZ011-INZ019.
LM...Gale Warning until 1 PM CDT Thursday for the IL and IN
nearshore waters.
Small Craft Advisory until 9 PM CDT this evening for the IN
nearshore waters.
&&
$$
Visit us at weather.gov/chicago
Area Forecast Discussion
National Weather Service Nashville TN
633 PM CDT Wed Mar 19 2025
...New UPDATE...
.KEY MESSAGES...
Updated at 631 PM CDT Wed Mar 19 2025
- A Wind Advisory is in effect through 10 PM tonight for all of
Middle Tennessee for gusts of 35 to 45 mph.
- There is a low chance of severe thunderstorms this evening.
- River levels are coming down, but remain aware if you are going
to be near any bodies of water.
&&
.UPDATE...
Issued at 631 PM CDT Wed Mar 19 2025
Showers have developed ahead of the surface trough in West Tennessee
up through Kentucky. GLM shows that lightning activity has increased
in Kentucky. HRRR shows activity further increasing in the next one
to two hours. Currently there is a plume of around 500 J/kg or less
mlCAPE ahead of the surface trough. Shear is ample and actually a
bit too much. With the lack of more robust updrafts, storms are
likely to be sheared off. Modeled soundings show some dry air from
850-700 mb which could produce a strong wind gust with a storm, but
the gradient winds have already been strong this afternoon. Although
the helicity values are high this evening (0-1 km SRH around 300
m2/s2), the tornado threat is very low given the weak vertical
distribution of CAPE along with LCLs 1250-1500 m high.
The wind advisory is in effect until 03z and no changes are
anticipated with that. While it will still but gusty, the gust
should not be as high as the gradient slightly decreases as the
surface low lifts northward and diurnal mixing decreases.
&&
.SHORT TERM...
(Rest of today through Thursday)
Issued at 1133 AM CDT Wed Mar 19 2025
Temperatures are warming up quickly this morning with most sites
around 65 F. A gradient of much drier air is evident along the
Plateau with dew points nearly 20 degrees lower than surrounding
locations due to more mixing of winds. A Fire Danger Statement has
been issued for portions of the Cumberland Plateau through 6 PM
because of this drier air and gusty winds ahead of the line of
storms this evening. Outdoor burning is highly discouraged today.
Current surface analysis shows a deep 988mb surface low over
Missouri with a trailing cold front extending down through the
ArkLaTex region. Ahead of the line, we will see temperatures
warming into the 70s with some moisture advection. The lack of
deep moisture advection combined with the very dry airmass
currently in place means instability will be the limiting factor
today in terms of severe potential. There will be ample shear with
bulk shear values approaching 70 kts this evening ahead of the
line, but with lower CAPE in place and rather unimpressive mid-
level lapse rates around 6-6.5 C/km, the overall severe threat
remains low. If a storm is able to tap into higher instability,
damaging winds will be the primary threat. The HREF gives a 70%
chance of surface-based CAPE exceeding 200 J/kg, so will be
something to monitor through the evening. Timing for
thunderstorms will be from roughly 5 pm across the west through
midnight to 1 am as the line exits east. Much cooler air will move
in behind the front overnight, dropping lows into the upper 30s.
Wraparound moisture on the back side of the departing low will
result in a few snow flurries/mixed wintry precip Thursday. No
accumulation is expected. Outside of the light precip, Thursday
will blustery, cloudy, and cool with afternoon highs in the 40s -
nearly 20 to 25 degrees cooler than today.
&&
.LONG TERM...
(Thursday Night through next Wednesday)
Issued at 1133 AM CDT Wed Mar 19 2025
Temperatures will drop below freezing for everyone Thursday night as
skies clear and winds calm. We will dry out and warm back up
Friday and Saturday as upper level ridging moves across the Ohio
River Valley. Highs will be in the 60s with ample sunshine Friday
with Saturday featuring even warmer temps and increasing clouds.
Our next rain and thunderstorm chances will come Sunday as an
upper level low traverses the Great Lakes region bringing a cold
front across the area. Too early to talk about severe potential,
but rain chances are high with the latest NBM giving an 80-90%
chance. Current rainfall amounts during this time are around 1
inch.
There will be additional rounds of showers and thunderstorms as we
move into the middle of next week. At this time, severe weather does
not appear to be a concern. Temperatures will be near normal with
daily highs in the 60s and overnight lows in the 40s.
&&
.AVIATION...
(00Z TAFS)
Issued at 624 PM CDT Wed Mar 19 2025
Gusty south winds around 30KT will continue as an approaching
cold front brings a broken line of showers and isolated
thunderstorms across Middle TN. Mainly VFR conditions are
expected this evening with brief MVFR in the heavier showers.
Later this evening behind the front, skies will be partly cloudy.
Winds will become more southwesterly with continued gusts near
30KT.
Early Thursday morning, winds will become northwest and cigs will
lower to MVFR with scattered light showers.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 42 50 33 63 / 60 30 0 0
Clarksville 40 51 31 61 / 50 30 0 0
Crossville 38 43 25 56 / 80 40 0 0
Columbia 39 49 29 61 / 50 20 0 0
Cookeville 39 44 27 56 / 80 60 0 0
Jamestown 38 44 26 56 / 80 50 0 0
Lawrenceburg 39 48 29 60 / 60 20 0 0
Murfreesboro 39 48 28 61 / 70 40 0 0
Waverly 39 50 31 61 / 40 20 0 0
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 10 PM CDT this evening for TNZ005>011-
023>034-056>066-075-077>080-093>095.
&&
$$
UPDATE.......Reagan
SHORT TERM...Baggett
LONG TERM....Baggett
AVIATION.....13