Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 04/01/24
Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
221 PM AKDT Sun Mar 31 2024
.SYNOPSIS...
An anomalously strong area of low pressure moving through the
Interior continues to bring rain, snow, and strong winds to the
interior. An intense baroclinic zone from the Chukchi sea into the
Bering is resulting in widespread blizzard conditions along the
West Coast and storm force northerly winds through the Bering
Strait. Strong southwesterly winds 30 to 50 mph through much of
the Central and Eastern Interior, including Fairbanks, continue
this evening before diminishing overnight. An arctic front shifts
east Monday night and Tuesday for the Interior with snow showers
and rapidly cooling temps. A gale force low moves into the
Northern Bering Tuesday night and Wednesday swinging another front
into the West Coast with warmer temperatures, rain, and snow
expected.
&&
.DISCUSSION...
Upper Levels and Analysis...
While the track of the anomalously strong developing low shifted
slightly east of what guidance depicted over the past couple days,
the majority of the forecast has verified well for the state. As
of early this afternoon, the 983mb surface low is centered near
Coldfoot and will continue to slowly weaken as it heads north into
the Brooks Range tomorrow. The majority of the upper level
forcing and jet energy has pushed well to the south and east into
Canada with negatively tiled upper troughing now in place from
the Chukchi sea southeastward through the state. RAOB and ACARS
soundings show very steep low and mid level lapse rates with a
30-40 kt 925-850mb low level SW jet south of the low. This
environment has supported widespread convective snow, and even
rain, showers through the interior today with accumulations
anywhere from a trace to 3 inches. Steep low level lapse rates
have resulted in strong southwest winds in excess of 40 mph mixing
down to the surface in Fairbanks and through the Tanana Valley as
well where Wind Advisories are already in effect. As the low
continues to weaken, expect snow showers and winds to be on a
diminishing trend tonight.
Across the West Coast, a very tight pressure gradient between the
Interior low and a high over eastern Russia has resulted in
anomalously strong winds from the Chukchi sea down through the
Bering and to the Aleutians. Storm force winds persist over the
Bering Strait and widespread Blizzard conditions continue today
from Point Hope, through much of the Seward Peninsula, and down
along the coast of the YK Delta. Low level ridging slowly pushes
eastward tonight, shutting off strong northerly winds from west to
east tonight into tomorrow.
Monday into Tuesday, upper troughing over the arctic strengthens
and deepens over the state as it slowly pushes south and east. At
the same time, weak upper ridging builds over NW Canada and
Eastern Alaska with mid and upper flow becoming southerly again
for the Interior. Guidance depicts low level flow from the SW/W
while mid and upper level flow is southerly ahead of that trough
axis leading to minimal downsloping winds off the Alaska Range and
mid and upper level moisture advection northward into the area.
BUFKIT soundings show strong omega through the dendritic growth
zone, steep low and mid level lapse rates due to cold air
advection, which should support numerous snow shower development
ahead of the trough axis in the Eastern and Central Interior and
into the Brooks Range. Light snow accumulations expected with the
greatest accumulations of up to 1-3 inches for the Eastern
Interior and upslope favored areas.
A gale force low moves into the Northern Bering Tuesday night
swinging an occluded front into the West Coast. Another round of
mainly snow is expected for the YK Delta and into the Seward
Peninsula. Strong southwesterly flow sets up behind the front
leaving the West Coast in an onshore flow, showery regime with
cold air advection.
Model Discussion...
Models have been in fairly good agreement today depicting
widespread snow showers across the state and strong southwesterly
winds developing. The official forecast did go over guidance for
winds through the interior as models do not handle these
anomalously strong winds in typical wind sheltered areas. Also
holding onto blizzard conditions into tonight for the West Coast
and near Barter Island, a few hours longer than what most guidance
suggests. For winds today used hi-res guidance in the near term to
add in the stronger gusts, switching to a blend of the
GFS/NAM/NamNest for days two and three.
Central and Eastern Interior...
Wind Advisories remain in place this afternoon for Fairbanks, the
Tanana Valley, and much of the Eastern Interior as strong
southwest winds continue to mix down to the surface. Expect winds
to begin to diminish in typical wind sheltered areas after sunset,
with higher elevations and more wind susceptible areas remaining
breezy through the night. Fairbanks already observed winds of
30-35 kts so far today, with wind gusts upwards of 50 mph near
Tok. Downgraded the High Wind Warning for Isabell Pass and areas
north of Trims Camp as the max gusts observed around there around
60 mph. Mixed rain and snow over the southern part of the
Interior and Alaska Range will turn back to all snow by this
evening. Additional snow amounts will be higher over the White
Mtns north and across the Alaska Range, with generally 1 to 3
inches, up to 5 inches in the AK Range. Snow amounts have been a
bit lower for the interior lower elevations, including Fairbanks,
where many locations may see a dusting to an inch at most. Expect
blowing and drifting snow to continue over the highway summits
into late this evening. Winds across the board weaken by Monday
morning with the departing low.
Attention turns to an arctic trough shifting east Monday evening
through Tuesday, which will bring in blustery and colder westerly
winds, with 850mb temps plummeting to -20C. Tuesday and Tuesday
night will be substantially colder than it has been lately with
temps falling into the single digits to negative single digits
Monday night and Tuesday night. As mentioned above, with the
colder air and trough approaching, expect a decent shot at light
accumulating snow showers and maybe even some snow squalls Monday
evening and Tuesday over most of the Interior. NW winds will blast
across the Upper Tanana Valley and there will likely be some
blowing and drifting snow from Dot Lake to Tok to Northway.
West Coast and Western Interior...
Storm force winds continue to blast across the Bering Strait and
coast with widespread blizzard conditions occurring at the usual
suspect locations such as Kivalina, Point Hope, Brevig
Mission/Teller/Wales. Added Blizzard Warnings to Buckland and the
Northern Seward peninsula and then along the coast of the YK Delta
where gusts to 60+mph are occuring with whiteout conditions. Temps
continue to plummet today and tonight with colder temps
persisting through Tuesday. Light snow showers and blowing snow
generally wane Monday and Monday night, but the dangerous whiteout
conditions over the coastal regions end earlier by Sunday night,
although there will still be localized blowing and drifting.
Attention turns to a Bering front which shifts inland along the
West Coast Tuesday evening and Wednesday, bringing gale force
east to southeast winds, turning to southwest Wednesday. This
storm will bring in more accumulating snow and blowing snow,
which will likely see more potential winter hazards.
North Slope and Brooks Range...
The pressure gradient is ramping up across the Arctic, although
the strongest winds are from Cape Lisburne to Point Hope and then
over near Kaktovik. Blizzard Warning remains in effect for
Kaktovik and have been extended through this evening as the
pressure gradient remains tight and snow begins to push north
with the approaching low. Strongest winds push offshore into the
Arctic as the low in the interior heads north into the North Slope
tonight into tomorrow. Despite strongest winds moving offshore,
increasing snow showers may keep low visibility around Monday.
Blizzard warning is also still in place for Point Hope, and has
been extended through early Monday morning, with winds beginning
the diminishing trend through the night. The low shifts offshore
Monday night and colder air from the west shifts over the coast.
Snow tapers off Monday night although snow chances will continue
over the E Brooks Range as a weak trough shifts overhead. Much
colder air filters in with falling temps over the next few days,
back below seasonal norms.
Extended Forecast Days 4-7...
A Bering front shifts inland Wednesday with a broad southwest flow
regime setting up for the West Coast and Interior into the end of
the week. Increased snow chances expected for the Mainland and
West Coast, along with more clouds and warmer temps, although not
well above normal like they have been recently. While the parent
low slowly weakens and meanders around Eastern Russia and the
Bering Straight through the end of the week, another wave within
the SW flow regime pushes into the West Coast Thursday into
Friday. Still a lot of discrepancies among the models where the
majority of the energy will be directed, but confidence is
increasing that the energy may be directed south of the Alaska
range. The threat for snow showers remains across the West Coast
through the end of the week with lower snow chances for the
Interior. Snow does not look significant, but it will be more
"wintery" like as the polar front shifts south again by the
weekend and arctic flow aloft reestablishes itself over the
northern portion of the state.
Coastal Hazard Potential Days 3 and 4...
Southwest winds increase along the YK Delta into Norton Sound
Wednesday night and Thursday as a Bering low moves to near Saint
Lawrence Island. This may bring elevated water levels of 2 to 3
feet above the normal high tideline, although since ice is in
place, it will likely just mean water seeping through cracks in
the ice nearshore.
&&
.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Blizzard Warning for AKZ801-815-818-820-821-825.
Wind Advisory for AKZ822-849.
Winter Weather Advisory for AKZ832-848-850-852.
Winter Weather Advisory for AKZ816.
Winter Weather Advisory for AKZ817.
Winter Weather Advisory for AKZ823.
Winter Weather Advisory for AKZ831-846.
Winter Weather Advisory for AKZ834.
Wind Advisory for AKZ835-838-842-843.
Wind Advisory for AKZ836.
Wind Advisory for AKZ837-839>841-844-845.
Blizzard Warning for AKZ805.
PK...Gale Warning for PKZ801-811-816-817-857.
Gale Warning for PKZ802-803-807>810-850-855-856.
Heavy Freezing Spray Warning for PKZ802-806.
Brisk Wind Advisory for PKZ804.
Gale Warning for PKZ805-806-852>854.
Brisk Wind Advisory for PKZ812.
Brisk Wind Advisory for PKZ813-815.
Brisk Wind Advisory for PKZ814.
Heavy Freezing Spray Warning for PKZ816.
Brisk Wind Advisory for PKZ851.
Brisk Wind Advisory for PKZ858.
Brisk Wind Advisory for PKZ859>861.
&&
$$
CM