Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/11/25
Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
439 PM AKDT Mon Mar 10 2025
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3:
Monday through Wednesday evening)...
A 983 mb compact, occluded low pressure system is currently
located around 200 miles east of Kodiak Island this afternoon with
its frontal boundary rounding the South-Central coast from just
south of the Prince William Sound, eastward to near Cordova and
Yakutat, and draped farther southeastward down into the Alaska
panhandle. Ahead of the front, an easterly to east-southeasterly
flow off of the Gulf has moderated temperatures into the mid to
upper 30s, yielding a mix of rain and snow showers for the
immediate South-Central coast, while Kodiak Island is seeing snow
showers with a gusty, northwesterly flow that is helping to usher
in modest cold air advection on the backside of the low. An
easterly wind also flowing through the Turnagain Arm is bending
southward towards lower pressure and is resulting in a down-inlet
flow, which is helping to reinforce northerly to northwesterly
winds across Kodiak Island. To the north across the rest of South-
Central, conditions are mostly quiet from the Mat-Su Valleys to
the Copper River Basin with much less cloud cover and thus
considerably more spread in diurnal temperature range.
Also this afternoon/evening, a secondary compact low has
developed over the Northern Gulf within the frontal zone/trough
axis as it has aligned with a 500 mb shortwave trough that will
pivot across Southcentral. This low has quickly lifted northward
and has moved across Kayak Island onto the mainland coast this
afternoon/evening. While there still remains uncertainty on timing
and placement of this low, the overall consensus is that the
immediate Southcentral coast will see another round of showery
weather and gusty winds this evening. As the front falls apart and
trough axis flattens tonight due to the lack of a baroclinic
zone, the initial surface low east of Kodiak Island will slowly
weaken and begin to drift southeastward across the central Gulf by
Tuesday morning, which in turn will cause snow shower activity to
start to taper off and winds to slowly decrease for Kodiak
Island. All said, Kodiak Island could see 1-2" of snow before the
low moves farther southeast late Tuesday, which will effectively
end precipitation for the area.
By Wednesday morning to early afternoon, the operational models
depict an upper level low and another shortwave beginning to trek
southward over the Mat-Su Valleys, resulting in a weak surface
low/trough to form near the Prince William Sound. However, models
are somewhat split on the timing and QPF of this system. The GFS
shows the upper low moving in Wednesday afternoon to early evening
and a drier solution, while the NAM seems to be the wetter
solution and shows precipitation breaking out earlier in the day.
The HRRR as of now is mostly siding with the NAM, but it does show
precipitation beginning to form a tad later than the NAM.
Overall, this does not look to be an impactful system, but could
bring a period of light snow for Western Kenai, the Anchorage
Bowl, and Mat-Su Valleys given minimal downsloping, a favorable
northerly wind direction, and some degree of cold air advection on
the backside of the low. One region in particular to watch for
the possibility of more impactful snow will be the
windward/eastern side of the Kenai Mountains due to an easterly
and upslope flow that could ring out more QPF than in other areas.
-AM/TM
&&
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days
1 through 3: Tonight through Thursday)...
The most notable feature across the outlook area this afternoon
continues to be the now weakening low moving steadily west across
the central and eastern Bering Sea. A mesoscale low embedded in
the broader circulation is now moving between the Pribilofs and
the eastern Aleutians, leading to localized enhancement of gusty
west winds and scattered snow showers already in place along much
of the Aleutian Chain. Intense snow shower activity near and
south of this low coupled with winds gusting as high as 50 to 60
mph will soon shift from the eastern Aleutians to the southern
AKPen as the small low advances east overnight tonight. Both the
smaller embedded low and the larger scale system will continue to
shift east and weaken during the day on Tuesday, allowing high-end
gale force winds currently in place from the central Bering Sea
down into the eastern Aleutians and southern AKPen to diminish to
below gale force range by Tuesday afternoon.
By Tuesday evening, attention shifts to another low moving up from
the North Pacific that will push a front northeast into the
Aleutians. Low level temperatures will initially be cold enough
for snow to fall as frontal precipitation spreads into the central
and western Aleutians Tuesday evening as easterly winds along the
front also pick up to low-end gale force range. However,
temperatures will steadily warm overnight into Wednesday morning,
allowing snow to change over to rain for spots including Adak and
Atka. At this time, it appears surface temperatures will be warm
enough (roughly 33 to 36F) to prevent significant blowing snow
along the central Aleutians for Tuesday night, but an inch or two
of accumulation will still be possible before the changeover to
rain early on Wednesday. The low and front will continue east
towards the southern AKPen from Wednesday to Thursday. Easterly
winds in mainly small craft range along with a rain/snow mix will
shift into the eastern Aleutians and southern AKPen as the low
progresses east through Thursday evening.
Turning attention briefly to Southwest, much quieter and cooler
conditions will persist for the next few days. Snow showers over
the Kuskokwim Delta and western Bristol Bay along a portion of
the Bering low`s occluded front will diminish as the front falls
apart overnight tonight. Areas of low stratus and fog over Bristol
Bay should also tend to clear up from north to south as light
northerly flow develops through Tuesday morning. Temperatures will
steadily cool each day as northeast winds advect cooler air into
place from the Interior and as skies become clearer from Wednesday
into Thursday.
-AS
&&
.LONG TERM FORECAST (Days 4 through 7 - Friday through Monday)...
The forecast opens with a somewhat convoluted upper level trough
extending from Siberia to the Central Aleutians, then curving over
Mainland Alaska into the Northern Canadian Provinces. This
pattern draws down to a smoother medium amplitude trough by the
end of the forecast period. An upper level low transits the Gulf
of Alaska before slipping Southeast by Sunday. A weak upper ridge
rides over the Aleutians into the Eastern Gulf by Monday. A
clustered ensemble of GFS / ECMWF and Canadian maintains good
support through the weekend, with some increased uncertainty over
the North Pacific where models diverge for the new week.
Most of Interior Alaska remains free from precipitation through
the weekend. A series of weak surface lows slide along the
Aleutians and Southcentral areas, bringing rain, mixed rain and
snow or snow over the Aleutians and Alaska Peninsula, and
continuing along the Southcentral coasts into Prince William Sound
and the Copper River Delta, diminishing Sunday. A well developed
North Pacific low and front moves along the Aleutians to Kodiak
Island by Monday, injecting some locally moderate precipitation
over the Aleutians late Saturday and Sunday, moving Eastward to
the AKPEN and Southcentral through Monday. Some areas of snow
spread inland over Southwest Alaska Sunday and Monday.
- Kutz
&&
.AVIATION...
PANC...VFR conditions and light, primarily northerly, winds will
persist with some scattered to broken ceilings of about 15-20 kft
through Tuesday.
&&
$$
Area Forecast Discussion
National Weather Service Quad Cities IA IL
644 PM CDT Mon Mar 10 2025
.KEY MESSAGES...
- Very high to critical fire danger today with near record
warmth and gusty winds.
- A strong storm system certain to impact the region Friday into
the weekend with the potential for storms Friday late PM/night
(severe?), windy conditions, and another significant fire
weather threat.
&&
.SHORT TERM /THROUGH TUESDAY/...
Issued at 125 PM CDT Mon Mar 10 2025
Thin cirrus has streams overhead today, but this has not held
temperatures back very much, with the increasingly strong March
sunshine. As of 1 PM, temperatures are in the mid to upper 60s
in most of the CWA, and highs in the 70 to 75 range remain on
track for eastern Iowa, and southern areas this afternoon. Winds
thus far have been lower than forecast, but looking west, we`re
beginning to tap some higher gusts in central Iowa in the 30 to
40 mph range, and that should begin mixing eastward soon, with
the warming temperatures. Thus, we`re on pace for a period of
critical fire danger this afternoon, which will last to around
sunset. The Red Flag Warning continues through 8 PM. - Please
refer to the fire weather section below.
An approaching cold front from the north will arrive after
midnight tonight, resulting in some CAA by morning and a wind
shift to the north. Lows in the mid 30s north to lower to mid
40s central and south are forecast, largely based on the frontal
timing.
Behind the front Tuesday, highs will be cooler than today, but
not too cold for sensible weather. In fact Tuesday`s highs in
the lower 50s north to lower 60s south are warmer than we had
just two days ago, so this cool down is only relative to short
term conditions.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 125 PM CDT Mon Mar 10 2025
The next warming trend will begin Wednesday, with initial air
mass modification and highs in the 60s, followed by a return to
strengthening southerly flow and much warmer highs Thursday and
Friday. Dry weather remains forecast through Friday morning, as
the storm track will be well south of the CWA.
Friday stands out as a high impact weather day!
As is often the case when strong low pressure moves through a
region, many elements of the forecast appear hazardous. There
remains excellent agreement in both deterministic and ensemble
data for the late week storm having surface low pressure at
least as strong, if not stronger than the system that moved
through Iowa around March 4th, which was around 980mb. This
looks to be another big time wind producer, with winds
potentially requiring a headline Friday and possibly Saturday.
The warm sector Friday also will not be overly moist, thus, wind
and record highs Friday in the mid to upper 70s (80s?), are
likely +60% to bring another significant fire weather risk.
By late afternoon, or early evening, incredibly strong forcing
is set to arrive, coincident with moisture return, and with that
strong to severe storms are possible. While it`s days out, the
look of shear along the boundary alignment support development
of a squall line, potentially with some embedded tornadic
potential. This threat is still pretty far out there time-wise,
but the event remains a synoptically evident severe weather
risk, our office history of early season events shows several
examples of such events. CSU-MLP day 5 aggregate severe risk
places the severe weather risk within the 30 to 35% range for
the Friday / Friday night period.
As always the case for an extended forecast for severe storm,
please stay tuned for this forecast to be refined and
timing/details to become better known as this event approaches.
Confidence on any event rarely is nailed down before it enters
the day 2 period.
Behind the low`s passage east Saturday, windy conditions remain
expected, possibly requiring a headline. Cooler and cloudy
conditions should keep fire weather conditions subdued by that
time. Below normal to near normal temperatures are then expected
Sunday, with warming beginning again Monday. March weather certainly
won`t be boring!
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 635 PM CDT Mon Mar 10 2025
A cold front passing through tonight will switch winds from the
southwest to the NNW, with occasional gusts around 25 kts
possible through Tuesday morning. Additionally, there will be a
period of low-level wind shear at CID/MLI/BRL for the overnight
period as strong W winds near 45 kts continue aloft (~2000 ft
AGL), coincident with much lighter winds at the surface.
&&
.FIRE WEATHER...
Issued at 312 AM CDT Mon Mar 10 2025
Near record warmth, gusty winds, low relative humidity and dry
fuels will lead to very high to critical fire danger today.
Much of the deterministic model guidance seems to be too high on
dew points for today, given the good mixing, abundant solar
insolation and dormant vegetation. Without any evapotranspiration
or strong moisture advection it`s hard to imagine dew points
climbing 10-20 degrees in these conditions as would be suggested
by guidance. Looking back at yesterday the RAP seemed to do well
with dew points, and based on experience the HRRR and RAP tend
to do better in these situations with deeper mixing/full sunshine
and followed closely along with NBM 10th percentile to get dew points
lowering into at least the upper 20s to lower 30s (based on upstream
obs from yesterday in similar regime), with the potential to be
lower in some areas (low to mid 20s possibly). Given the dew point
adjustments owing to lower RH, and the gusty winds and warm temperatures,
this is leading to extreme GFDI values and critical fire weather
conditions into portions of eastern Iowa this afternoon. As a result,
I have issued a Red Flag Warning (RFW) from 17z-00z for all of eastern
Iowa, a couple of IL counties in the QC metro and our 2 NE Missouri
counties. The extreme GFDI values are mainly focused west of the
Mississippi River, but with concerns that dew points could be lower,
I gave a buffer and included in the RFW the QC metro down to Burlington
and NE Missouri. The potential for fast fire growth exists this afternoon
particularly in the warning area, and so any outdoor burning is strongly
discouraged!
&&
.CLIMATE...
Issued at 312 AM CDT Mon Mar 10 2025
Record highs for March 10
Dubuque.......73 in 1894
Cedar Rapids..72 in 1894
Moline........74 in 1955 and previous years
Burlington....76 in 1955
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Red Flag Warning until 8 PM CDT this evening for IAZ040>042-
051>054-063>068-076>078-087>089-098-099.
IL...Red Flag Warning until 8 PM CDT this evening for ILZ015-024.
MO...Red Flag Warning until 8 PM CDT this evening for MOZ009-010.
&&
$$
SHORT TERM...Ervin
LONG TERM...Ervin
AVIATION...Uttech
FIRE WEATHER...Ervin/McClure
CLIMATE...McClure
Area Forecast Discussion
National Weather Service Pueblo CO
532 PM MDT Mon Mar 10 2025
.KEY MESSAGES...
- Dry and mild Tuesday, with spotty areas of increased fire
danger possible, especially in the San Luis Valley.
- At and above seasonal temperatures with a few showers along the
Continental Divide Wednesday.
- Warm and windy Thursday ahead of another potentially high impact
storm system developing across the region Friday.
- Unsettled weather for the early weekend and again into early
next week.
&&
.SHORT TERM /THROUGH TUESDAY/...
Issued at 224 PM MDT Mon Mar 10 2025
Very dry and warm air mass across southern Colorado this afternoon,
with deep mixing producing pockets of gusty winds across the area.
Most consistent winds have been through the Arkansas Valley from
Salida east to Pueblo, where gusts in the 20-30 kt range and single
digit humidity were verifying the Red Flag Warning, while farther
east of the plains, winds have been not as strong and gusty so far.
Will keep current Red Flag Warning in place into this evening
(expires at 6 pm mdt), though far eastern portion in Kiowa County
might struggle to verify as HRRR shows a downward trend in winds
after 3-4 pm. Winds decouple after sunset, with improving humidity
and decreasing winds overnight, though likely still just enough of a
breezy to keep east mountain slopes and plains min temps from
falling much below freezing. On Tuesday, flat wly flow aloft slowly
turns swly by afternoon as upper trough moves into the swrn U.S. Mid
level flow looks weaker than Mon across most of the area, though a
slight increase in 7h winds develops by late afternoon across the
San Luis Valley and swrn mountains. While relative humidity will
remain low another day, winds should be weak enough to prevent
widespread critical fire weather conditions, so no new fire weather
highlights issued this forecast cycle. Will acknowledge portions of
the San Luis Valley could get close to criteria, especially if winds
increase earlier than forecast. With slightly less mixing, max temps
Tue will fall back a few degf across the region, though most
locations will still end up well above seasonal averages.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 224 PM MDT Mon Mar 10 2025
Tuesday night-Wednesday night...No needed changes to the current
forecast through the middle of the week, with a weak disturbance
within the westerly flow moving across the southern Rockies, bringing
a low end chance (15-25%) of showers across the higher terrain,
mainly the Southwest mtns, on Wednesday. Temperatures to remain
above seasonal levels, with patchy critical fire weather conditions
possible across portions of the plains Wednesday afternoon.
Thursday-Friday...Models are still n good agreement of increasing
southwest flow across the region on Thursday ahead of deep low
pressure system digging across the Great Basin. This will bring
moderate to heavy snow across the ContDvd, especially for the
Southwest mtns Thursday night, where DESI/NBM data still indicates
75-85 percent probabilities of >8 inches of snow Friday morning along
with 30-50 percent probabilities of >12 inches. Breezy to windy
conditions ahead of the system also looks to bring critical fire weather
conditions to much of south central and southeast Colorado Thursday
afternoon and into the evening.
How the system develops as it moves across the Rockies Thursday
night and Friday still remains uncertain, however latest model data
continues to strengthen the developing mid level cyclone too far east
across western Kansas, and lifts it north and east away from the area
to too quickly, to bring the highest impacts from snow and wind to
southeastern Colorado.
At any rate, GEFS ensemble mean remains the quickest and furthest
north and east with a closed low across west central Kansas Friday
morning, which is further south than previous runs. Where as the
latest EPS and GEPS data remains further south with a closed low
developing across southwest Kansas Friday morning. All solutions
quickly lift the cyclone north and east through the day Friday.
Latest model data does not indicate a lot of cold air with this
system and will likely see light rain showers and higher elevation
snow spreading across southeast Colorado Thursday night and early
Friday, before the system wraps up further east bringing the
strongest winds to the region later Friday morning and afternoon.
These winds will likely be more west to northwest, which would
limit precipitation across the plains.
With that said, the location, timing, and temperature profiles will
still need to determined to see where the highest impacts from snow
vs rain and wind will be across region. The latest DESI/NBM data
continues indicates 50-80 percent probabilities of >1 inch of snow
Friday across the SE Mtns and the Pikes Peak/Palmer Dvd region,
which quickly diminishes to 5-30 percent probabilities of >3 inches
of snow, with the highest probabilities for both criteria being
across the SE mtns. Again, time will tell on how this storm system
evolves, with shifts in the location of the system potentially
bringing higher impacts across southeast Colorado.
For Saturday into early next week, model data supports a passing
disturbances within modest west to northwest flow on Saturday
bringing chances of precipitation to mainly the higher terrain.
Short wave ridging brings warmer and drier conditions for Sunday
with more unsettled weather in the offing as another long wave
trough translates across the Rockies.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 531 PM MDT Mon Mar 10 2025
VFR at all TAF sites the next 24 hrs. Breezy w-sw winds (g20-25
kts) likely until 01z-03z at KPUB and KALS, while winds at KCOS
may stay lighter and more variable, with only a brief period of
stronger sw winds until 01z and then start to diminish. Towards
the end of the period, winds will start to increase out of the
west-southwest at KALS and KCOS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 6 PM MDT this evening for COZ220>222-
227>229-231-234.
&&
$$
SHORT TERM...PETERSEN
LONG TERM...MW
AVIATION...CLOUSE