Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/27/25
Area Forecast Discussion
National Weather Service Boston/Norton MA
1016 PM EST Wed Feb 26 2025
.SYNOPSIS...
Frontal system will bring a period of rain and snow late
tonight before changing to all rain Thursday. A weak low
pressure system will bring a few rain or snow showers Saturday,
followed by blustery and cold weather Sunday and Monday. Milder
air returns by the middle of next week along with another chance
of rain.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Mainly minor tweaks to the forecast this evening. Latest HRRR
and NationalBlend guidance appeared to match up well with
regional radar data. Their timing for precipitation onset was
close to the what was already in the forecast. Still thinking
some light snow across central and wester MA, mainly north of
the Mass Pike, and especially along and north of Route 2.
Snowfall forecast kept unchanged.
620 PM Update:
Key Points:
* Minor travel impacts in northern MA for Thu AM commute
* 18z models trended slightly warmer especially near Mass Pike
No significant changes. Higher clouds were streaming into region
this evening but we`ll still see temps drop a bit before thicker
clouds and warm advection get underway overnight. Timing of 3-5
AM Thu for onset looks reasonable based upon HRRR. Model
soundings support light rain for Providence-Boston corridor,
light rain/snow mix for Hartford-Springfield into Worcester and
Lowell, and light snow for higher elevations and Route 2
corridor. Wet bulb cooling could mean a mix into NW RI and
western suburbs of Boston but these areas should change to rain
fairly quickly. Looking for no more than 1-3" in higher terrain
near Berkshires and northern Worcester County and less than an
inch elsewhere north of the Mass Pike.
Not seeing much of a potential for freezing rain during
transition with isothermal soundings so we still don`t see a
need for any Winter Weather Advisories but morning commute may
be a little slower than usual near Route 2 corridor in northern
MA, especially early on.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Steady light rain continues through Wednesday morning before the
dry slot begins to work in and scatterers out the rain into hit-
or-miss showers. Hit-or-miss showers continue into the afternoon
before the cold front pushes showers offshore by Thursday
evening, drying things out. Some guidance does show 100-300 J/kg
of MUCAPE over Cape Cod and the Islands on Thursday, which could
bring a rumble or two of thunder with the passage of the cold
front. High temperatures will warm again into the upper 40s to
low 50s, with blustery south winds gusting around 20mph.
A cold front moves offshore by Thursday night, allowing for
drying conditions under westerly flow. Winds around 10 mph
should keep ideal radiational cooling conditions from occurring.
Overnight lows should hover right around freezing across the
region.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Key Messages:
* Few rain or snow showers Saturday.
* Blustery and colder Sunday and Monday.
* Milder with rain possible toward the middle of next week.
Fairly good agreement among longer range guidance with respect
to larger scale pattern into next week. Another short wave
rounds base of broad trough in place across eastern states over
the weekend, which is followed by a quick shot of colder air,
then we should see a change to a split flow pattern over CONUS
which favors milder air returning by the middle of next week.
Additionally, the pattern favors a number of southern stream
systems emerging from desert SW into southern Plains which
eventually eject toward Great Lakes. First of these arrives
sometime around middle of next week and may set stage for an
overall milder and wetter pattern for the first half of March.
Clipper system on Sat is expected to track through northern New
England and should have little moisture to work with, so overall
any precipitation will be light and trending more toward rain
vs snow, but there should be enough cold air at start to allow
for scattered snow showers late Fri night along and north of
Mass Pike before a quick change to rain from S to N Sat morning
- overall little impact on travel with odds favoring an inch or
less of accumulation north of the Pike.
Behind this system, a brief shot of cold arrives on gusty NW
winds Sunday into Monday. Core of coldest air comes through
Sun night when we should see lows zero to 10 above, and in teens
along immediate coast, with wind chills to start day Mon
morning as low as zero to 10 below across higher elevations.
Probably not enough for cold weather headlines but certainly a
reminder that winter isn`t done just yet.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
00Z TAFs: Moderate confidence, mainly due to timing of changing
conditions.
VFR conditions most of the night give way to MVFR/IFR after 06z
with -RASN across inland sites and -SN at higher elevations
which changes to rain 12z-14z Thu. Closer to coast -RA is
expected. Conditions lower to IFR areawide Thu morning in -RA
before tapering off Thu afternoon, though another round of -SHRA
possible later in the day. Improvement to VFR Thu night.
Light winds tonight become SE Thu morning then S/SW and increase
Thu afternoon with 25-30kt gusts along coast. LLWS expected near
coast as well with 020 winds S/SW 50-60kt, strongest near Cape
Cod.
KBOS TAF...High confidence in TAF. Changed -RASN to -RA at onset
as it appears it will stay too warm for any frozen precip.
KBDL TAF...High confidence in TAF.
Outlook /Friday through Monday/...
Friday: VFR. Breezy.
Friday Night: Mainly VFR, with local MVFR possible. Breezy.
Chance SN, chance RA.
Saturday: Mainly VFR, with local MVFR possible. Breezy. Chance
RA.
Saturday Night: VFR. Breezy. Slight chance RA.
Sunday through Monday: VFR. Breezy.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight and Thursday night...High confidence.
Winds diminish this evening and become southerly late tonight,
then increase to 20-30 kt Thu as low level jet moves across the
waters. Seas build to 6-9 ft over the outer waters Thu. Periods
of rain late tonight into Thu with vsbys reduced at times. Cold
front crosses the waters Thursday night, turning winds westerly
at 10-20 knots. There could be some thunderstorms over the
waters with the cold front, with precip ending by Friday
morning.
Outlook /Friday through Monday/...
Friday: Winds less than 25 kt. Areas of rough seas.
Friday Night: Winds less than 25 kt. Seas up to 5 ft.
Saturday: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of rough seas. Chance of rain.
Saturday Night: Winds less than 25 kt. Areas of rough seas.
Slight chance of rain.
Sunday: Low risk for Small Craft Advisory winds with gusts up
to 20 kt. Seas up to 5 ft. Chance of freezing spray, slight
chance of snow.
Sunday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Chance of freezing spray,
slight chance of snow.
Monday: Winds less than 25 kt. Areas of seas approaching 5 ft.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 10 AM to 10 PM EST Thursday for
ANZ231-251.
Small Craft Advisory from 7 AM Thursday to 7 AM EST Friday for
ANZ232>235-237.
Small Craft Advisory until 7 AM EST Friday for ANZ250-254>256.
&&
$$
SYNOPSIS...KP/JWD
NEAR TERM...Belk/KP
SHORT TERM...Belk/KJC/KP
LONG TERM...JWD
AVIATION...JWD
MARINE...KP/JWD
Area Forecast Discussion
National Weather Service Wilmington NC
1010 PM EST Wed Feb 26 2025
.SYNOPSIS...
Above normal temperatures are expected Thursday as high
pressure shifts offshore. A cold front will bring some
showers Thursday evening followed by a brief cooldown on
Friday. A quick rebound in temperatures is expected on
Saturday ahead of a dry cold front moving across the area
Saturday night. High pressure will bring colder weather
early next week, followed by another warm up and chance
of rain by mid-week.
&&
.UPDATE...
Raised a 12 hr SCA from Noon Thu thru Midnight Fri, mainly for
SW winds gusting to 25+ kt ahead of the approaching cold front.
And for some periodic 6 foot, very short period, seas. May need
to look at the gustiness that occurs briefly after the FROPA for
continuing the short term SCA. Latest high res HRRR guidance
continues to illustrate this short term SCA wind conditions.
Trended mins upwards by a degree or 3, especially closer to the
coast, based on winds staying active from the S-SSW and likely
not decoupling.
&&
.NEAR TERM /THROUGH THURSDAY/...
This has been the warmest day since February 9 with observed
temperatures reaching the mid 70s from Wilmington westward
across the entire Pee Dee region. Surface high pressure just
offshore and a very dry atmospheric column should continue to
provide clear skies and large diurnal temperature ranges
tonight. Forecast lows are generally along the low end of the
guidance envelope: upper 40s to near 50 outside of normal cold
spots.
Low pressure moving across the eastern Great Lakes will drag a
weak cold front into the interior portions of North and South
Carolina during the afternoon Thursday. Increasing southwest
winds are expected within a warm and well-mixed airmass with
gusts potentially reaching 25-30 mph during the afternoon.
Forecast highs are again in the 70s if not close to 80 degrees
near Florence, several degrees below records across the area.
Record highs for Thursday Feb 27:
Wilmington.........82 in 2021
Lumberton..........80 in 2011
Florence...........85 in 1997
N Myrtle Beach.....81 in 1951
The quality of low level moisture will remain suspect: despite
southwest winds there`s no real connection to Gulf moisture of
any consequence and the airmass should remain dry and capped to
convection through mid afternoon. By late in the day, ascent
just ahead of the the approaching upper trough could begin to
erode the convective cap near and west of I-95 opening the
possibility of convective showers to develop. GFS forecast
soundings show this explicitly at the FLO and LBT forecast
points after 21z when surface- based CAPE of 200-400 J/kg could
develop as cooling mid level temperatures remove the cap. Prior
to 7 PM rain chances are forecast at 20-30 percent here, but
remain < 10 percent closer to the coast.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
H5 shortwave axis will sweep across the area Thu evening pushing
a cold front off the coast. Moisture is rather limited as this
feature moves through and with PVA mainly impacting northern
zones to areas farther north plan to cap PoPs in the 40-50%
range (20-40% for SC zones). In the air-mass behind the front
expecting more seasonable temperatures for Friday. By Friday
night, return flow will begin thus favor leaning toward warmer
the warmer guidance.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
The extended will be like a roller coaster regarding
temperatures as a couple cold fronts move across the region.
Expect breezy/windy conditions during Saturday as the pressure
gradient tightens ahead of the next cold front. Ensembles
suggest that this frontal passage will be dry given the moisture
limitation. High pressure will build across the area from the
Midwest by early next week with another shot at freezing
temperatures, especially Sun night into Mon morning. The high
will migrate off the coast during Tue allowing for return flow
to become established ahead of the next cold front. Better
moisture return is expected with this front thus better chances
for rain late Wed if the current timing holds. Also, think highs
will be slightly above normal during Tue, but more-so during Wed
given the warm air advection.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
There is high confidence of VFR conditions thruout the 00Z TAF
Issuance period. There is a low confidence risk of patchy ground
fog possible between 08Z and 12Z. At this point it`s fcst patchy
at best and not enough to place in any of the terminals at this
time. Active synoptic S to SSW winds at 5 kt or less expected
thru the night as center of high pressure moves further
offshore. FEW/SCT cirrus to periodically move overhead
overnight, becoming BKN by the aftn. Approaching sfc cold front
and mid-level s/w trof late in the day to result in ceilings
lowering to around 10k ft, especially inland terminals by early
evening. Days heating, tightened sfc pg and mixing to result in
SW winds increasing to 10-20 kt with gusts 25+ kt by midday and
continuing into the evening.
Extended Outlook...Low confidence remains in effect for MVFR
ceilings and visibility in showers Thu evening as a cold front
pushes across the Carolinas. There is high confidence VFR
conditions return Fri morning after the CFP as drier air and
brief high pressure overspreads the area. VFR to dominate Sat
thru Mon which will include a moisture starved CFP Sat night.
&&
.MARINE...
Through Thursday...Surface high pressure centered just east of
Cape Fear will move farther out to sea tonight. Weak low
pressure centered near Chicago will move eastward tonight and
Thursday, dragging a cold front through the interior portions of
North and South Carolina Thursday afternoon. Light south winds
tonight should veer southwest ahead of the front Thursday with
speeds increasing to 15-20 kt during the afternoon. It`s
possible gusts could approach 25 knots, especially across the
Cape Fear area waters late Thursday afternoon where we could
approach Small Craft Advisory criteria. Confidence is not high
enough to issue the advisory yet.
There is also potential that sea fog could develop during the day
Thursday. The setup is not ideal, but very cold nearshore water
temperatures and a favorably oriented south-southwest wind fetch
blowing up the South Carolina coastline could create patchy fog
and reduced visibility across the water. The quality of low
level moisture within the incoming airmass may be the limiting
factor.
Seas currently 2-3 feet should build to 4-5 feet Thursday
afternoon mainly in short period southwest wind waves.
Thursday night through Monday...The cold front will be pushing
farther away from the coast during Thu evening as winds veer to
an offshore direction. High pressure along the Gulf Coast will
briefly ridge into the Carolinas during Fri allowing wind speeds
to diminish. As the high becomes suppressed south of the area
during Fri afternoon a SWly pressure gradient will increase
ahead of the next cold front. GFS ensemble prob for winds >20
knots increase overnight into Sat morning supporting a round of
Small Craft Advisory conditions. As high pressure builds into
the Southeast U.S. from the Midwest during Sunday maritime
conditions are expected to improve through Monday.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
NC...None.
SC...None.
MARINE...Small Craft Advisory from noon Thursday to midnight EST
Thursday night for AMZ250-252-254-256.
&&
$$
SYNOPSIS...ILM
UPDATE...DCH
NEAR TERM...TRA
SHORT TERM...SRP
LONG TERM...SRP
AVIATION...DCH
MARINE...TRA/SRP
Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
530 PM CST Wed Feb 26 2025
.KEY MESSAGES...
- Warmer than normal conditions stick around through the end of
the week. Temperatures dip down to near or just below seasonal
normals by the weekend followed by another warm up next week.
- Breezy conditions will be common each afternoon through
Saturday, with the strongest winds anticipated on Friday. The
NBM features a 30-60% chance for wind gusts in excess of 35 mph
by Friday afternoon.
- After today, precipitation chances will be minimal through the
weekend with the next best chance on Tuesday.
&&
.DISCUSSION...
Issued at 221 PM CST Wed Feb 26 2025
A surface low centered over northern Illinois this afternoon will
continue to push east into northern Indiana this evening. A cold
front tied to this system is roughly located just east of I-55 as of
2 pm with breezy west-northwest winds behind it. The front will
continue to plow east through the rest of today, reaching the IN/IL
state line by early this evening. Scattered showers will be common
just ahead of the front with the potential for a few thunderstorms
in far southeast Illinois later this afternoon into early this
evening. Both the HRRR and RAP continue to show at least 500 J/kg of
MUCAPE paired with steep ~7 deg/C mid-level lapse rates. The latest
CAMs show storm activity developing right on our doorstep (Near/east
of a Robinson to Olney line) around 22-23Z before dropping southeast.
Upper troughing will linger over the area through Thursday then work
into the Mid-Atlantic states by the end of the week. Cloud cover and
even some isolated showers late tonight into Thursday will linger
under the cyclonic flow, especially over northern parts of the
state. Surface ridging will begin nosing in from the southwest on
Thursday, with the pressure gradient becoming pinched between these
two features. West-northwest winds with gusts as high as 30 mph will
be common Thursday afternoon then ease briefly Thursday night as
they begin to back to the west-southwest.
Another deep trough will replace the upper ridge by the end of this
week, pushing the surface high into the Southeast US toward the
Gulf. A surface low will quickly slide southeast into the Great
Lakes Region, with the pressure gradient tightening once again over
central Illinois. West-southwest winds will ramp up by mid to late
Friday morning with a cold front shifting winds to the west-
northwest by late Friday afternoon into evening. Wind gusts up to 40
mph look common through most of the day, with the NBM showing a 40-
80% chance for gusts exceeding 30 mph and a 30-60% chance they
exceed 35 mph. Southwest wind events historically struggle to reach
Wind Advisory Criteria here, but forecast soundings show a brief
window late Friday afternoon into early evening behind the cold
front where deep mixing up to ~800 mb could mix down close to 40 kt
winds. Despite a headline or not, precautions should be taken to
prepare for strong winds on Friday.
Temperatures will cool to near or slightly below seasonal normals
this weekend as upper troughing/northwest flow remains situated
aloft. Canadian high pressure will settle into the Midwest with lows
Saturday night potentially being the coldest we have seen in several
days, especially if we are able to clear out and radiational
cool. Upper ridging will push the surface high into the northeast
US by the start of the new week with southerly return flow
bringing another push of above normal temperatures next week. A
couple systems will bring the chance for precipitation to the area
by the early to middle parts of the new week. The stronger of the
two weather systems could potentially bring thunderstorms on
Tuesday. The CSU machine learning product has a 5% chance
(equivalent to a SPC Marginal Risk) for severe storms in southern
Illinois on Tuesday.
Aside from some brief dips in temperatures, outlooks for the
beginning to middle of March favor above normal temperatures
across much of the state of Illinois.
NMA
&&
.AVIATION... (For the 00z TAFs through 00z Thursday Evening)
Issued at 530 PM CST Wed Feb 26 2025
A cold front has pushed through central Illinois leaving breezy
west to northwest winds in its wake. Stratus is spilling
southeast into central Illinois this evening. Variable MVFR/VFR
ceilings from 025 to around 040 are noted in area obs and the
best chance for any MVFR on station will be along the I-74
corridor with lower but non-zero chances further south. While
winds should diminish some overnight, they are expected to become
gusty to around 25kt much of the day Thursday.
Deubelbeiss
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
606 PM CST Wed Feb 26 2025
.KEY MESSAGES...
- Blustery northwesterly winds expected tomorrow (Thursday) with
a slight chance (20%) of rain/graupel showers.
- This Friday will be mild and windy with gusts possibly
reaching 40 to 45 mph from mid-morning through the afternoon.
- Conditions will be much cooler this weekend with highs in the
30s expected on both Saturday and Sunday.
&&
.DISCUSSION...
Issued at 259 PM CST Wed Feb 26 2025
Through Thursday Night:
While most of today`s rain has departed our forecast area,
light rain/drizzle wrapping around the backside of the weak
surface low trekking across northern Illinois this afternoon is
expected to filter into the area this evening before ending
overnight. Coverage is generally expected to remain
isolated/patchy with the odds of measurable precipitation
occurring at any one location remaining relatively low overall,
so have continued to carry slight chance PoPs during this time
period. Temperatures are expected to be in the mid 30s to mid
40s during any precipitation, so the expectation is for
precipitation to remain of the liquid variety and not carry much
of any threat of freezing on roadways. Couldn`t rule out some
patchy fog development tonight too, but it appears that
sustained winds may remain elevated just enough to preclude this
from potentially being a greater issue.
Another shortwave trough will drop through the Upper Midwest
tonight, reaching our vicinity tomorrow morning. An associated
cold pool of air aloft will barge in as the trough arrives,
causing low- to mid-level lapse rates to steepen a good bit,
possibly even yielding a scant amount of true surface-based
instability. The quality and depth of low- to mid-level moisture
remains a question mark, however, with guidance still offering
up mixed opinions on what that might look like tomorrow. The
latest HRRR and RAP runs remain much more bullish than other
models on more-than-adequate moisture profiles being realized
tomorrow. While it`s possible that these models may be a bit
overdone in their simulated reflectivity output, their
consistent signal for convective showers occurring coupled
with the spotty light QPF being output by some of the more
subdued guidance makes it difficult to justify maintaining a dry
forecast for tomorrow, so with this forecast package, have
added slight chance PoPs to the forecast grids across most of
our CWA. If the thermal and moisture profiles advertised by the
HRRR or the RAP were to verify, then graupel would be a distinct
possibility within the deeper convective showers, and there
could even be a non-zero chance for isolated lightning strikes
too. Otherwise, the current expectation is for there to be at
least some splotchy spits of rain across our forecast area
during the mid-morning to late afternoon time frame.
The other sensible weather of note tomorrow will be the
blustery northwesterly winds, with gusts likely approaching and
possibly exceeding 30 mph at times. The modest cold air
advection off of these winds coupled with more stratocumulus
than sunshine will likely prevent temperatures from rising a
great amount during the daytime, though highs are still likely
to reach the 40s across our forecast area and could still
possibly tag 50F in our southern counties if enough breaks in
the clouds are realized there.
Ogorek
Friday through Wednesday:
The forecast in the long term picks up on what will be a windy
Friday. A deep, tightly-wound surface low will track across the
Upper Great Lakes during the day. Despite the storm`s cold front
passing over during the day, precip should be confined to areas
north as sufficient moisture looks to remain north of the
trough base. With efficient low level deformation being modeled
along the front on its way to the area, we`ll see a strong low
level jet develop just out ahead of the front. Upwards of 60 kt
of flow are being modeled at around 900mb early Friday when it
moves over the CWA. Between the warm advection ahead of the
front and the time of day, forecast soundings hold onto a rather
steep inversion not far off the surface through around mid-
morning. With the jet building down so close to the surface,
breezy conditions should get going around daybreak even amid
shallow mixing. But this inversion should largely resist tapping
into the core of this jet during the earlier part of the
morning. Low level flow should be a bit lighter overhead by the
time mixing looks to really take off closer to mid morning while
the front work across.
Mid-morning through the afternoon is when we`re expecting the
strongest winds. There is some uncertainty in what the magnitude
of those winds will be with disagreements on both mixing
heights and the strength of the LLJ, however guidance is largely
clustered around 30 to 40 mph gusts during the better part of
the day. The LREF (GEFS/GEPS/ENS conglomerate) paints 60-80%
probs for at least 35 mph gusts across the area. The greatest
potential for anything much stronger than 40-45 mph would
probably come in the morning right as areas begin to mix.
The forecast is calling for highs in the upper 50s to near 60 in
our south on Friday promoting afternoon RH values as low as
the upper 30% range. Given these winds, if expected RH were to
drop any lower between now and Friday, we may need to consider
messaging some sort of elevated fire risk for parts of the area.
Winds will gradually ease during the evening as the LLJ relaxes
and mixing heights drop, but conditions will remain breezy
through the night and into Saturday.
High pressure will fill in behind this windy storm system paving
the way for a quiet, but cool weekend. Highs on both Saturday
and Sunday look to be stuck in the 30s. Saturday should see a
mix of clouds and sun with mostly clear skies expected on Sunday
as the high center moves nearby. The high also keeps rain and
snow out of the forecast for the weekend.
Models are locking in on a large synoptic system impacting the
region next Tuesday and Wednesday as a longwave, high-amplitude
trough traverses the southern and central CONUS. There is still
tons of disagreement regarding this system among model guidance
from the track to the timing to the strength of the low pressure
center. Really the only near-certainties are that this storm
will track somewhere through the region and that it will have a
sizable presence. A big majority of the precip we see out of
this system should be in the form of rain, although a little bit
of snow is also on the table, especially later Wednesday or
Wednesday night in the CAA behind the storm. The deep,
vertically-stacked nature of the upper trough will promote steep
mid level lapse rates and a large region of at least marginal
elevated CAPE. Some model camps are more aggressive with the
instability than others, but a couple give the look of a
possible marginal severe setup somewhere around the region,
likely south of the low track. P-types and thunder potential
will become a lot more clear as the storm track does over the
next several days.
Doom
&&
.AVIATION /00Z TAFS THROUGH 06Z THURSDAY/...
Issued at 540 PM CST Wed Feb 26 2025
Key Aviation Messages for the current TAF period:
- MVFR cigs move in this evening with scattered SHRA/DZ
- VFR expected after midnight before MVFR returns around
daybreak with the next chance for scattered SHRA
- Northwest winds expected through the TAF period, but strong
gusts 20 to 30 knots possible on Thursday
As a surface low currently sits over Illinois/Indiana (moving
east), winds are slowly flipping from northeast to northwest.
There is higher confidence in persistent northwest winds as the
next wave passes overhead. Showery/drizzle activity that is
currently on radar over NE Iowa/SW Wisconsin is expected to move
over northern Illinois over the next several hours. Given the
sight on radar, the PROB30 group was switched over to a TEMPO.
MVFR cigs can be expected as the precipitation moves in. And
while IFR cigs cannot be completely ruled out, a lack of surface
obs upstream provided lower confidence.
Cloud cover is expected to break up behind the precip for a
return to VFR conditions after midnight. Winds will remain out
of the northwest and light. As models have started to zero in on
an upper level short wave passing over northern Illinois,
soundings are looking more saturated with a better chance of
forcing in the morning. The amount of saturation still remains
the question and lowers confidence. For now, a PROB30 group
seems the best option, just simply moving it earlier in time.
It should be noted that some hi-res models are suggesting there
could be some convective showers in the afternoon, but with
weaker forcing and drier model soundings, the afternoon period
was kept dry at this time.
Lastly, winds are expected to increase tomorrow morning as the
wave moves over and continue into the afternoon. Wind gusts 20
to 25 knots can be expected but cannot completely rule out the
occasional gust to 30 knots. Wind gusts are expected to
gradually diminish after 00Z.
DK
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory from 9 AM to 6 PM CST Thursday for the IL
and IN nearshore waters.
&&
$$
Visit us at weather.gov/chicago
Area Forecast Discussion
National Weather Service Pueblo CO
609 PM MST Wed Feb 26 2025
.KEY MESSAGES...
- Critical fire weather conditions are still likely across the
San Luis Valley through this evening.
- Light, to occasionally moderate, snow showers this evening
mainly across the higher terrain.
- Dry with another warming trend through Saturday with spotty
critical fire weather conditions.
- Active pattern returns for Sunday into next week with a
couple of systems expected to impact the region though
confidence on timing and impacts is still low.
&&
.UPDATE...
Issued at 608 PM MST Wed Feb 26 2025
While gusty winds continue across the San Luis Valley, humidities
values have steadily increased over the past couple of hours, and
will continue to do so as showers and increased moisture
overspread the localized area throughout the evening.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 328 PM MST Wed Feb 26 2025
Latest radar imagery showing some light returns across the
higher terrain, and this is in response to a southward moving
upper trough/low along with increasing 700mb flow and moisture.
Current obs are indicating this is light at this time, and while
I do think the anticipated snows across the higher terrain into
this evening will remain mostly light, am monitoring the
possibility for some isolated locations to observe some periods
of more moderate snowfall intensity. Latest RAP analysis is
showing a 700mb low taking shape across the southwest mountains
and San Luis Valley at this time, with this low anticipated to
further deepen into the evening. This will likely increase 700mb
flow into the higher terrain, and subsequent orographic lift.
This increased focus along with steep low/mid level lapse rates
in place would support better focus and this more intense snow.
At this time, this looks to be across the central mountains into
the southwest mountains, from around late this afternoon into
mid evening. Overall snowfall amounts still look low though,
given the small window of snow development expected in anyone
location.
RH values across the San Luis Valley remain critical at this
time, and while the winds have not been as strong as previously
forecast, still seeing some sporadic gusts across the Valley at
this time. So, with critical RH values still in place, have
opted to let keep the Red Flag Warning in place. Ridging and
warming then expected on Thursday, with warmer temperatures
returning. Very dry air settles in and have lowered dew points
for Thursday, with RH values likely critical across southern
Colorado. The winds will be lighter though, and don`t expect any
critical fire weather conditions at this time.
&&
.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
Issued at 328 PM MST Wed Feb 26 2025
Ridging and warmer temps still likely to occur at the start of
the period, with another day of above normal temperatures.
Another day with critical RH values and while flow is trying to
increase on Friday, shouldn`t be enough to support widespread
critical fire weather conditions at this time. No big change
into Saturday, with continued dry weather and above normal
temperatures. Again, widespread critical fire weather conditions
don`t look likely at this time.
Still keeping an eye on the late weekend into early next week
time frame, particularly, with the next upper system to impact
the region. Guidance continues to be inconsistent with its
track, with confidence not overly high on details at this time.
Temperatures for Sunday into Monday do look to remain above
normal at this time, though with more normal conditions
returning for the remainder of the period. Guidance fairly
consistent with longwave trough settling across the region
through the remainder of the forecast period. While confidence
on any specifics are low at this time, higher confidence is in
place for cooler and more unsettled conditions to return.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 428 PM MST Wed Feb 26 2025
KALS...a few showers will impact the San Luis Valley this
evening, which could impact the terminal briefly through 08z.
Clearing and quiet conditions are forecast late tonight through
tomorrow afternoon.
KCOS and KPUB...VFR conditions through the next 24 hours at both
terminals. A few wind gusts may be possible this evening near 25
kts. Skies will clear with light winds late tonight through
tomorrow afternoon. Mozley
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...SIMCOE
SHORT TERM...RODRIGUEZ
LONG TERM...CLOUSE/RODRIGUEZ
AVIATION...MOZLEY
Area Forecast Discussion
National Weather Service Las Vegas NV
721 PM PST Wed Feb 26 2025
.SYNOPSIS...Mostly sunny skies, above-average temperatures, and
breezy northeasterly winds continue today, with the strongest winds
along the Colorado River Valley. Strongest winds expand to include
southern Mohave and eastern San Bernardino on Thursday, with speeds
generally between 25 and 35 mph. A weak weather system will increase
cloud cover this weekend, while a stronger system returns slight
precipitation chances to the region next week.
&&
.UPDATE...
Latest water vapor imagery and 500 hPa RUC analysis indicates the
shortwave responsible for today`s breezy conditions continues its
slow southward progression across the Four Corners Region, still
progged to jog southwestward, closing off over Arizona late
tonight. In line with high-resolution guidance, winds have started
diminishing across much of the region early this evening, in part
due to the shortwave`s progression as well as diurnal
stabilization. However, speeds do remain elevated, with
intermittent gusts to around 15 to 20 mph still observed across
portions of the Las Vegas Valley and along the Colorado River.
These winds will continue to diminish through tonight for most,
with gusts expected to linger along the Lower Colorado River
Valley given terrain influences. Overall, the forecast remains on
track this evening, with lows on target to bottom out in the 40s
and 50s across lower elevations and upper 20s and 30s across
higher elevations by early Thursday morning. No updates are
warranted at this time.
&&
.PREV DISCUSSION...317 PM PST Wed Feb 26 2025...
.SHORT TERM...Today through Saturday.
A shortwave will drop through Utah today before closing off over
Arizona tonight, taking an "Inside Slider" type trajectory. This
shortwave has increased northerly winds along the Colorado River
Valley, where speeds generally between 30 and 40 mph have been
observed so far this afternoon. Corresponding wave heights on Lake
Mead will range from 2 to 3 feet, making recreation hazardous for
small craft. Elsewhere, this shortwave will increase northeasterly
winds areawide today and Thursday, with the greatest speeds in the
southern and eastern Mojave Deserts. Gust speeds will range from 25
to 35 mph, with isolated instances of 40 mph or greater in the
higher terrain of southern Mohave and eastern San Bernardino
counties. That said, the HREF is quite a bit more bullish, with 70-
90% chances of 40+ mph in these same areas including portions of
Interstate 15 and Interstate 40 in eastern San Bernardino. Looked at
ensemble meteograms, and decided to hold off on any products, as it
looks like speeds at or above 40 mph will be isolated in space and
time.
This shortwave will allow temperatures to drop a few degrees across
the region, but they`ll still remain 5-8 degrees above seasonal
averages heading into the weekend.
Friday into Saturday, a closed low will move into southern
California from the southeastern Pacific, which will usher
atmospheric moisture into the region. The moisture`s trajectory will
result in the bulk of moisture hitting the Sierra Nevada, with
minimal spillover. PoPs range from 0-10% across the forecast area,
with up to 20% in the mountains. Primary impact will be increased
cloud cover over the region.
.LONG TERM...Sunday through Wednesday.
An open wave will push into northern California on Sunday, which
will provide an additional source of increased moisture to the
region. Looking at forecast Integrated Water Vapor Transport (IVT)
plumes, the trajectory looks favorable for moisture to make it
counter-clockwise around the Sierra Nevada, which will bode well for
precipitation chances in the Mojave Desert. That said, the
deterministic GFS shows a more substantial moisture plume than the
ECMWF. Looking at ensemble means, there`s a similar trend, with the
GFS ensemble bringing +130% PWATs to the region, while the ECMWF
ensemble shows near-normal PWATs. The NBM seems to have taken a
middle-of-the-road solution, with widespread 20-40% PoPs Sunday
through Monday and widespread forecast rainfall totals between 0.01"
and 0.10". In addition to the chance of light rainfall, gusty
southwest winds will pick up Sunday through Monday, along with a
stark afternoon temperature drop back into the 60s for desert
valleys.
The active weather pattern continues through next week, though
confidence in details remains low at this time. Remember to check
the forecast if you have travel or outdoor recreation plans!
&&
.AVIATION...For Harry Reid...For the 00Z Forecast Package...15 to 25
knot northeasterly wind gusts will continue into the evening hours.
Wind gusts will drop off early this evening with winds continuing to
favor a northeasterly direction. Winds will become more north-
northwesterly early Thursday morning before picking up and swinging
back to the northeast later in the morning. These 15 to 25 knot
northeasterly wind gusts will continue through the afternoon before
dropping off and swinging back to the northeast during the late
afternoon/early evening.
For the rest of southern Nevada, northwest Arizona and southeast
California...For the 00Z Forecast Package...Gusty northerly-to-
northeasterly winds will continue affect the Las Vegas Valley and
Colorado River Valley TAF sites into the evening hours. Wind gusts
in the Las Vegas Valley will drop later tonight before returning
again tomorrow morning. Gusts will hand on overnight in the Colorado
River Valley, although they will decrease in magnitude through the
overnight hours before picking back up tomorrow morning. DAG will
see east-northeasterly winds become light and variable during the
evening and overnight hours before settling back in from the east-
northeast tomorrow morning. Light and variable winds will continue
through the evening hours at BIH. Winds will remain light, settling
in from the northwest in a typical diurnal fashion later tonight.
These light northwesterly winds will continue through late Thursday
morning when winds will swing around to the southeast and pickup
with 15 to 20 knot wind gusts through the afternoon.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
UPDATE...Phillipson
DISCUSSION...Soulat
AVIATION...Stessman
For more forecast information...see us on our webpage:
https://weather.gov/lasvegas or follow us on Facebook and Twitter