Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/20/25
Area Forecast Discussion
National Weather Service Denver/Boulder CO
615 PM MST Wed Feb 19 2025
.KEY MESSAGES...
- Last night of cold tonight, with moderating temperatures.
- Another round of snow for the mountains Thursday, spreading into
the foothills and plains Thursday evening. Watching the
potential for a snowy evening commute closely.
- Warming trend on the plains into the weekend and early next week.
&&
.SHORT TERM /Through Thursday/...
Issued at 226 PM MST Wed Feb 19 2025
Drier northwesterly flow today has led to quieter weather across
the plains. Temperatures have "warmed" into the upper teens to
middle 20s across the metro, while the far northeastern corner of
the state is still stuck in the low single digits. Satellite shows
a broad swath of mid/high cloud cover spreading into the region,
with little else of note.
Tonight should be cold again across the plains, with temperatures
dropping below zero east of the metro. There should be just enough
wind for some -20 to -25F wind chills across Sedgwick and Phillips
counties. The cold weather products will remain in effect until
Thursday AM as scheduled.
A weak storm system will bring snow back to the higher elevations
tomorrow, eventually spilling out into the foothills and adjacent
plains by late afternoon or early evening. Guidance tries to
develop a burst of organized moderate to heavy snow, associated
with a pivoting 500mb vort max that tracks across the Denver metro
or Palmer Divide. Most of the expected impacts will come Thursday
night... but those who have a later evening commute may want to
check back again for updates. More on the snow below...
&&
.LONG TERM /Thursday night through Wednesday/...
Issued at 226 PM MST Wed Feb 19 2025d at 226 PM MST Wed Feb 19 2025
Snow should continue across the high country Thursday night as an
upper level shortwave trough moves across Colorado. Snowfall rates
should generally be light due to a weak (10KT) northwesterly flow at
700 mb. However, there could be localized heavier bands in the
vicinity of a 500 MB vort max caught up in the flow. As the
shortwave moves east of the Continental Divide and closes off,
snow is expected to develop across the Front Range Urban Corridor
and Palmer Divide as upslope flow and lift increase.
At this time, there is quite a bit of uncertainty in the location
and amount of the heaviest snowfall with this system. This looks to
be due to how the models handle the track of the 500 MB vort max
which would effect where the best lift and upslope flow would occur.
The consensus of models is that the Front Range Foothills, adjacent
plains and Palmer Divide should see 1 to 5" of accumulation.
However, some of the models suggest much higher amounts in varying
locations due to some localized heavier snow bands. For example, the
NAM solution shows 6-12" of accumulation across Metro Denver by 12Z
Friday, while the NAM 3km has 2-6" across Metro Denver and 6-9"
across much of Boulder County. On the other hand, the latest HRRR
solution shows a broad area of 6-12 inches from the foothills
eastward across the western sections of the Front Range Urban
Corridor with 6+ inches extending eastward across Denver
International Airport.
Due to the potential for accumulating snow and possible travel
impacts, Winter Weather Highlights may be needed for Thursday night
into Friday morning across the Front Range Foothills as well as
portions of the Front Range Urban Corridor and Palmer Divide.
However, due to the uncertainty, have decided to hold off for
now.
In addition, the cold temperatures are expected to continue through
Thursday morning with Wind Chill Readings as low as -15 F across the
far eastern sections of the forecast area. Therefore, the Cold
Weather Advisory will continue through 11 AM Thursday
The Arctic airmass finally releases it`s grip on Northeastern
Colorado on Friday with dry weather along with moderating
temperatures into mid 30s to lower 40s. The gradual warmup should
continue through the weekend into early next week as upper level
high pressure builds over the Rocky Mountain Region. By Sunday, max
temperatures are expected to reach around 60 degrees on the plains
and into the middle 60s by Monday.
In addition, models are suggesting a mountain wave developing
late Sunday into Monday morning with the potential for wind gusts
to 65 mph across the Front Range Mountains and foothills.
The next storm system may affect North Central and Northeastern
Colorado Tuesday and Wednesday with more snow possible across the
high country and cooler temperatures on the plains.
&&
.AVIATION /00Z TAFS through 00Z Friday/...
Issued at 602 PM MST Wed Feb 19 2025
Areas of low clouds and fog may develop around Denver tonight.
There are light upslope winds, but some of the moisture mixed
during the day and high clouds will limit the cooling so the
forecast is quite uncertain. The air that`s coming is from an
area out towards Fort Morgan that didn`t mix as well today and
there`s more low levl moisture there.
There`s about a 70% chance of having some visibility restriction,
and about a 50% chance of having IFR conditions, possibly LIFR
ceilings, at the Denver terminals between 08z and 15z. There`s
some possibility (maybe 10%) of dense fog with conditions below
200ft and 1/2 mile.
If there is a solid area of fog/low stratus, it may be slow to
burn off with light and probably northeast winds in the morning
and thickening clouds above it. There would likely be some
improvement 15z-17z with VFR conditions by 19z. Snow showers and
MVFR conditions will likely hold off until after 23z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
Cold Weather Advisory until 11 AM MST Thursday for COZ042-044-
046>049.
Extreme Cold Warning until 11 AM MST Thursday for COZ050-051.
&&
$$
SHORT TERM...Hiris
LONG TERM...JK
AVIATION...Gimmestad
Area Forecast Discussion
National Weather Service Columbia SC
1050 PM EST Wed Feb 19 2025
.SYNOPSIS...
Cloudy and cold tonight with a chance for black ice due to wet
roads and subfreezing temperatures, mainly across the Midlands.
A brief period of freezing drizzle or snow showers is possible
across the northern Midlands Thursday morning from a passing
trough. Skies then clear out as bitterly cold air filters in.
This air mass will settle over the area by Friday morning with
temperatures well below normal.
&&
.NEAR TERM /UNTIL 7 AM THURSDAY MORNING/...
Key Message(s):
- Cloudy and cold tonight with areas of black ice possible.
- Another round of freezing drizzle or snow showers possible
across the north towards daybreak.
Precipitation is currently exiting the forecast area. Therefore,
the Winter Weather Advisory has been expired. However, the
combination of wet roads and subfreezing temperatures has
prompted a Special Weather Statement for the Midlands due to
possible black ice. Temperatures will continue to fall despite
the clouds due to cold advection. Much of the Midlands should
fall below freezing with forecast lows in the mid-20s to the
lower 30s. It`ll be a bit warmer in the CSRA with temperatures
falling into the lower to mid 30s. A shortwave trough will move
into the region early Thursday morning. It`s possible that this
could create enough lift to produce light freezing drizzle or
snow showers across the northern Midlands near daybreak. Any
accumulations are expected to be minimal.
&&
.SHORT TERM /7 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Key message(s):
- Chance for wintry precip/light snow showers Thursday morning
through early afternoon in the north Midlands and Pee Dee.
- Very cold temperatures expected on Thursday and Friday, with a
cold weather advisory possible Friday morning.
Deep upper trough (2-3 standard deviations below normal) over
the Ohio and Tennessee Valleys will be moving east across the
Mid Atlantic region in the afternoon. Strong 160kt west-east
upper jet across North Carolina. A weak trough will move through
in the morning with increasing cold advection in its wake.
Moisture appears limited to generally 850mb across central SC
and a little deeper near to the north along the NC border.
Models suggest a weak short wave trough will move through the
base of the upper trough to the north. The vorticity appears
channeled though. Temperatures at 850mb are quite cold -4C to
-8C north of CAE in the morning with the trough moving through.
Model soundings suggest steep low level lapse rates with
surface temps rising above freezing by mid morning and -10C at
the top of the cloud near 800 mb. It appears ice production
will be limited in both time and space and forcing not overly
strong with the main short wave trough channeled north of the
area. The model consensus suggests some light snow showers
possible but with the lack of deep moisture into the snow
growth zone, accumulation should be limited to a dusting in
some spots in the north Midlands/Piedmont/Pee Dee. The HRRR
continues to be the most aggressive with snow, but also shows
limited snow growth. Freezing drizzle/graupel or drizzle after
temps rise above freezing mid morning more likely into the
Columbia area. The overall impacts from this wintry precip
threat should be limited and confined to near the NC border.
Winds will be gusty behind the trough with max gusts possibly
25-30 mph. So, wind chills in the 30s.
Cold advection will continue overnight as the modified arctic
air mass builds southeast from the Midwest/Mississippi Valley
into the area by morning. Temperatures are expected to fall into
the upper teens to low 20s. A cold weather advisory may be
needed but should be limited to a couple of hours around
daybreak.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Key Message(s):
- Quiet weather through the period, with a slow moderation of
temperatures expected.
The long term period into the middle of next week looks to be
rather quiet across the Carolinas and Georgia. A large area of
high pressure will dominate the weather Friday through
Saturday. By Saturday night into Sunday the area of high
pressure will begin to weaken. In general, a weak broad area of
trofiness will remain over the eastern half of the country. Weak
shortwaves will move from west to east in the flow with very
little impact on the weather across the region. A gradual warm
up is expected to begin Saturday and last through the middle of
next week. Each day, the airmass will modify a bit more, with
Mon/Tues/Wed temperatures near to above normal. The next chance
for rain appears to be just beyond the long term period on
Thursday.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
High confidence in MVFR/IFR conditions tonight into Thursday.
Cigs have been lowering through the late afternoon hours as
light rain and drizzle continue across the area. Abundant low
level moisture remains in place while drier air moves in aloft
in the wake of a departing upper disturbance. Persistent
northeasterly flow on the back side of the coastal low will keep
wedge like conditions in place through the night with low cigs
and possible vsby restrictions. Northeast winds 5 to 8 knots
should diminish a bit during the predawn hours before shifting
to the northwest after 12z as an arctic cold front moves into
the region as the main upper trough moves into the Carolinas.
There could be some additional light precipitation Thursday
morning but likely remains north of the terminals and not result
in restrictions, given low probability of occurring. Winds
should pick up behind the front to around 10 to 15 knots and
become gusty (gusts over 20 knots) from the northwest with
clouds improving to VFR by mid to late afternoon as a much drier
and colder air mass builds into the region.
EXTENDED AVIATION OUTLOOK...Northwest winds expected Thursday
afternoon with gusts around 20 kts. Restrictions unlikely Friday
through Saturday. Moisture returns Sunday and may bring early
morning restrictions.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.
&&
$$
Area Forecast Discussion
National Weather Service Green Bay WI
600 PM CST Wed Feb 19 2025
Updated aviation portion for 00Z TAF issuance
.KEY MESSAGES...
- Up to an inch of light snow could lead to scattered slippery
stretches on roadways over Door County and far north-central
Wisconsin tonight.
- Light snow will be possible at times from Sunday through
Tuesday. The most favorable time for accumulating snow will
occur on Sunday night into Monday when there is a 20% chance of
greater than 1 inch of snow over northern Wisconsin.
- High temperatures will return to the 20s by Thursday and into
the 30s by Sunday.
&&
.DISCUSSION...
Issued at 143 PM CST Wed Feb 19 2025
Short Term...Tonight and Thursday
The latest RAP analysis and satellite/radar imagery show a broad
upper level low pressure centered over the northern Mississippi
Valley early this afternoon. Warm advection continues to across
across eastern Canada and Lake Superior from the northeast, and
clouds have been surging south into northern WI early this
afternoon. Meanwhile, high clouds are drifting across central and
northeast WI ahead of the upper low. Forecast concerns mainly
revolve around light snow chances tonight followed by wind chills
as the upper low moves across the western Great Lakes.
Light Snow Chances: With the upper low moving into the region,
moisture through the column will gradually increase this evening.
Veering low level winds from the northwest to more of a north or
northeast wind direction will advect in moisture from the Lake
Superior region. A period of deeper saturation is depicted in
model cross-sections to occur from about mid-evening through the
middle of the overnight over northeast WI when scattered light
snow showers will be possible. Passage of surface trough could
provide focus for the snow shower activity as well. Forecast snow
amounts up to an inch are possible over northern Door county.
North-central WI will also see scattered light snow showers and
flurries at times with persistent north flow continuing. Minor
amounts up to an inch also look possible over northern Vilas
county.
Most of the light snow shower activity should end by early Thu
morning. Then clearing skies are expected from north to south on
Thursday afternoon.
Temperatures/Wind Chills: A warmer night is forecast tonight due
to cloud cover and a moderating arctic airmass. Wind chills of 5
below to 15 below will be possible across much of the area, which
will not necessitate any Cold Weather headlines.
Temperatures continue the warming trend on Thursday with highs in
the low to mid 20s. Good radiational cooling conditions will be
present on Thursday night as lows fall back into the single
digits below zero away from Lake Michigan.
Long Term...Thursday Night Through Wednesday
The latest ensemble means indicate that the amplified upper air
pattern across North America, featuring a blocking ridge over
Greenland to northern Canada, will break down by the end of the
work week. The upper flow will then consolidate and deamplify
which will bring more mild, Pacific air into the region this
weekend and early next week. With no anomalous systems indicated,
generally low impacts can be expected and forecast concerns
generally revolve light precip chances and temperature trends.
Light precipitation chances: Arctic high pressure will drift from
the northern Plains to the lower Mississippi Valley through
Friday. This large surface high will ensure dry weather through
the end of the work week.
Jet energy, shortwave energy aloft, and warm advection in the low
levels will then arrive on late Friday night into Saturday.
Moisture will be more plentiful over the Lake Superior region, and
forecast soundings show a large dry wedge in the mid-levels over
far northern WI. Despite some favorable dynamics, soundings don`t
seem to favorable for precip, but there could be a short period
where light snow is possible near the Upper Peninsula border.
Another and more potent shortwave then rapidly digs across the
region on Sunday night into Monday. Models have different timing
with this shortwave due to a 130 kt jet streak along the US-
Canadian border. Dynamics look quite impressive, so impacts could
be more significant if the track shifts south. Right now, far
northern WI has the highest chance of light snow.
The unsettled weather pattern will continue on Tuesday when more
shortwaves arrive in the fast northern stream. Thermal profiles
suggest a wintry mix will be possible.
Temperature trends: As the surface high departs, temperatures will
undergo a warming trend from Friday through the weekend. After
highs in the lower to middle 20s on Friday, highs are expected to
reach the middle 30s by Sunday and possibly some 40s on Monday and
Tuesday.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 559 PM CST Wed Feb 19 2025
VFR clouds will lower to MVFR-VFR later this evening and overnight
as an upper level disturbance and low-level trough impact the area.
Snow showers and flurries are possible into the overnight hours
north of RHI and also east of a IMT-GRB-MTW line. Snow shower
chances are highest from late this evening into early overnight,
so have continued to include a PROB30 for brief MVFR visibilities
with the snow showers at GRB and MTW.
A mix of VFR and MVFR ceilings will continue into Thursday morning
before skies clear from north to south in the afternoon.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....MPC/MPC
AVIATION.......JLA
Area Forecast Discussion
National Weather Service Pocatello ID
228 PM MST Wed Feb 19 2025
.SHORT TERM...Tonight through Thursday night. Next Pacific system
rapidly moving into East Idaho this afternoon. Radar imagery shows
precipitation beginning to swing into Southwest Idaho early
afternoon. High-res models may be slightly behind developing
precipitation across the region based on the timing of the radar
returns and current observations just upstream. NAM is slightly
faster than the HRRR through the remainder of the afternoon, picking
up on the leading band of light snow moving through East Idaho
already. Of slightly greater concern is the NAM solution greatly
increasing the coverage and intensity of this band as it shifts
toward the northeast corner. Leading into the evening, the CAMS
come into better alignment on timing precipitation as it spreads
across the region along warm frontal feature. Temperatures and
surface wet bulbs across the Magic Valley/I-84 corridor are just
warm enough to support a mix of rain/snow this afternoon.
Overnight low temps remain just warm enough that the rain/snow mix
could shift all the way up the I-86 corridor toward Pocatello.
That said, projected surface wet bulbs drop back below freezing
when the heaviest bands are expected to move through.
The heaviest snow totals are expected across the northeast and the
highest elevations of the central mountains this evening through
tonight. Towards morning, the heaviest band shifts to along the I-
15/I-86/I-84 corridor. This does appear to be weakly suggestive of a
convergence event, and should support brief periods of heavier
snowfall totals surrounding the Thursday AM work/school commutes.
Have added the Lower Snake River Plain zone to the Winter Weather
Advisory. NBM and HREF ensembles still struggling with snowfall
totals, but in general, amounts should run in the 1-4" or 2-5"
ranges in this region. Given the timing, expect that even the
lower end range will be problematic, thus the Advisory. Have
extended it into mid afternoon for the Lower Snake Plain zone, but
could see it dropped earlier. Conversely, if current forecast
appears to be slightly underdone for the Eastern Magic Valley,
could see that zone added to the headline package overnight.
Snowfall continues across the southeast highlands for the remainder
of the day, with all models on board with timing the end of the
precipitation late afternoon or early evening even through Bear
Lake. Totals for the southern highlands above valley floors look to
be 6-8" inches, with some ridges likely overperforming even that.
90th percentile HREF supports 4-6" total for the I-15/I-86
corridors, and 8-14" for ridges south and east. DMH
.LONG TERM...Friday - next Wednesday
Friday and Saturday look mostly dry across the region as high
pressure builds over the area. Can`t rule out a very isolated shower
in the vicinity of the higher terrain around Yellowstone and the
Tetons but overall, things look dry. Temperatures will begin to warm
across lower valleys into the 40s as early as Saturday but become
more widespread by Sunday afternoon. Models show moisture moving in
to the area on Sunday, mainly focused across the central mountains
and eastern highlands, but just about everyone has at least a chance
for some precipitation. With the warmer temperatures, snow levels
will be high (6500-7000ft) so any precip in the lower elevations
would be rain. The warming continues into the start of the workweek
and some 50s appear very likely across the Magic Valley and into
parts of the lower Snake Plain. Low-end PoPs look to stick around
for the early part of the week with temperatures remaining on the
warmer side of normal. McKaughan
&&
.AVIATION...Expect a prolonged period of poor aviation conditions across eastern
Idaho as a storm system is moving through the region this afternoon
and will continue into much of the day Thursday. VFR conditions
currently will quickly give way to prevailing MVFR/IFR into Thursday
afternoon. Snow will be the dominant precip type although a brief
period of RASN is possible at KPIH and KBYI into the evening tonight
before p-type changes back to snow by Thursday AM. Winds will be
light, 10 kts or so, through daybreak tomorrow but begin to increase
during the daylight hours at KBYI up to around 15-20 kts with higher
gusts tomorrow. The other TAF sites should stay around 10 kts or so
with snow continuing through at least 18Z Thursday. KSUN will likely
see snow taper off just a few hours earlier than that however.
Bottom line, expect MVFR conditions (at best) with IFR most likely
across the area through the Thu afternoon. McKaughan
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 9 AM MST Thursday for IDZ053-
062>067.
Winter Weather Advisory until 2 PM MST Thursday for IDZ054.
Winter Weather Advisory until 9 AM MST Thursday for IDZ056>059.
Winter Weather Advisory until 5 PM MST Thursday for IDZ060.
&&
$$
Area Forecast Discussion
National Weather Service Reno NV
226 PM PST Wed Feb 19 2025
* A quick moving low continues to provide light snow shower
chances for the northern Sierra today. Gusty winds for Western
Nevada expect to continue this afternoon with light rain and
snow shower chances this evening.
* Cooler temperatures and breezy east winds across the Sierra
ridges are forecast on Thursday.
* High pressure will build in for the rest of the week, bringing
warmer, spring-like temperatures this weekend into next week.
&&
.DISCUSSION...
The latest RAP upper air analysis shows a Pacific Northwest upper
air low moving into WA this afternoon with a ridge ahead of it
just east of the CWA. The latest radar returns along with surface
observations show showers in eastern portions of the CWA ongoing
with some isolated showers also in Lassen, Plumas, and Northern
Washoe Counties this afternoon. Forecast guidance projects the
upper low progressing eastward while staying north of the CWA
going through the rest of the day and then placing the low to the
east of the CWA on Thursday. At the surface, gusty winds look to
continue this afternoon as a cold front moves across the region.
Lake Wind Advisories continue for Pyramid and Tahoe Lakes through
this evening as a good portion of the CWA sees west-southwesterly
winds gusting up to around 40-45 mph with the ridges seeing gusts
up to around 80 mph. With the cold front moving through,
convective shower chances persist generally for areas north of
US-50 through the evening hours today. With snow levels being
5500-6000 ft this afternoon, the northern Sierra crest will see
some light snow shower chances during the remainder of this
afternoon as the highest peaks see around a 25-50% chance of
accumulating 2 inches of snow or more by 4 PM. Precipitation type
for the lower areas looks to be mostly light rain with QPF values
ranging around 0.1 inches or less.
For tonight, overnight temperatures expect to cool to between the
lower teens and the lower 20s in the Sierra communities while the
valley areas have temperatures in the middle 20s to lower 30s range.
As for precipitation chances, they look to taper off for most of the
CWA by midnight with eastern Pershing County seeing chances continue
for a few hours into the new day. Snow levels late tonight and into
early tomorrow in Western NV look to drop to 5000-5500 ft, so light
snow could be mixed in should precipitation occur. Roads and
surfaces also could be a slick overnight with the cooling
temperatures along with recent precipitation, so please use
caution when traveling through the area.
The forecast for tomorrow calls for dry conditions along with cooler
high temperatures across the region compared to today`s high
following the cold frontal passage. The valley areas will see highs
in the upper 40s to the lower 50s with higher elevations
generally having highs in the lower 30s to middle 40s. While winds
across most of the CWA look to be light and variable during
Thursday, the ridges still can see some breezy gusts up to around
50 mph during the afternoon. Low temperatures for tomorrow night
expect to be slightly cooler than tonight`s lows as area
temperatures range between the lower teens and lower 20s.
Going through the weekend and into the beginning of next week,
ensemble guidance shows an upper air ridge moving over the CWA on
Friday, followed by a shortwave trough on Saturday, and then
another ridge building over the area on Sunday and Monday. With
this pattern aloft, temperatures take a warming trend going
through the weekend and may even see April-like temperatures by
Monday. The Reno area sees a 50-70% NBM probability for high
temperatures 65 degrees or higher on Sunday and Monday while
eastern portions of the CWA like Fallon see 60-80% chance of 70
degrees. While the region looks to stay mostly dry, Saturday shows
some slight chances for precipitation along the OR border with
the shortwave passing through the area. -078
&&
.AVIATION...
* A cold front is currently moving through the region this
afternoon allowing for some precipitation chances generally
north of US-50. A 30-50% chance of -SHRA/-SHSN continues through
06Z at KTRK/KTVL with snow accumulation unlikely. Other
terminals look to remain dry except for maybe a few light
showers reaching KRNO-KCXP-KMEV in the evening (03-07Z). Dry
conditions are expected to prevail for tomorrow.
* West-southwesterly winds gusting up to around 45-50 kts expect
to continue through 21Z with the cold front passage before winds
start to decrease going into the evening hours. LLWS along with
moderate to locally severe turbulence remains possible today
within the area, especially for smaller aircraft. For tomorrow,
generally light and variable winds are in the forecast for all
terminals with some increased gusts seen at the ridges.
-Fuentes/078
&&
.REV Watches/Warnings/Advisories...
NV...Lake Wind Advisory until 6 PM PST this evening NVZ002-004.
CA...Lake Wind Advisory until 6 PM PST this evening CAZ072.
&&
$$