Area Forecast Discussion
Issued by NWS Fairbanks, AK

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000
FXAK69 PAFG 232323
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
223 PM AKST Thu Jan 23 2020

.SYNOPSIS...
Snow chances continue through Friday for much of the eastern
Interior, with snow tapering off Saturday as a low in the northern
Gulf of Alaska pushes waves of moisture north and west across the
eastern Interior. Highest snow accumulations will be along the
AlCan border where an additional two to two and a half inches will
be possible through Saturday. A very cold airmass will continue
to dive south and east out of Siberia, dropping temperatures
through the remainder of the week and into next week. As high
pressure builds east across the Chukchi, the pressure gradient
tightens, leading to increasing winds along the West Coast and
summits in the Interior. The combination of the winds and dropping
temperatures will result in wind chill values of 40 to 50 below
tonight and into the weekend in some locations and Wind Chill
Advisories have been issued.

&&

.DISCUSSION...
Aloft, at 500 mb, an Omega Block continues to set up over the
eastern Bering Sea. A trough extends south across the middle of
the state and into the northern Gulf of Alaska, while a strong
ridge builds north over the eastern Bering Sea through the
weekend. A very cold air mass will dive south and east out of
Siberia and across Alaska, with temps dropping through the
weekend. 850 mb temps are expected to range between -25C and -35C
for much of the Interior and North Slope by Sunday. Models
continue to show significant cloud cover across much of the
central and eastern Interior, which will limit the temperatures
realized at the surface. Surface temperatures are expected to fall
into the 30s and 40s below across much of the Interior and North
Slope this weekend.

Surface... Weak high pressure persists across most of the state.
Ridging will continue to build east north across the Arctic Plain,
as a 1028 mb high over Siberia strengthens and builds eastward
across the Chukchi. By Friday afternoon a 1035 mb center of high
pressure is centered over the Chukotsk Peninsula. This will
continue to push northeast a trough that stretches from a 1008 mb
low 300 nm N of Wrangel Island southeast to Cape Bathurst. The low
will weaken to 1013 mb as it moves into the high Arctic Friday
afternoon with the trough stretching southeast to Banks Island. An
area of low pressure stretches along the Gulf of Alaska coast
this afternoon from Sitka to Yakutat to Valdez with with a 992 mb
low 70 nm south of Cordova. The low will deepen Friday to be a 985
mb low 100 nm south of Cordova by Friday afternoon and persist in
the northern Gulf of Alaska through Saturday.

Models...
12Z model suite initialized well against the 12Z surface obs and
the 12Z RAOBS. Models continue to show a Omega Block over the Bering
Sea and Western Alaska and continue to exhibit good run to run
continuity. By Sunday, model spread increases with the placement
surface lows south of the Aleutians. Temperatures remain the
biggest challenge for the forecast period. Most model solutions,
with the exception of the 12Z and 18Z NAM, maintain mostly cloudy
to overcast skies across the eastern Interior through the weekend,
while the NAM clears skies out on Sunday. If clouds remain over
the area then temperatures will trend warmer but it the clouds
clear out, especially for an extending amount of time at any
location, then colder temperatures realized.

North Slope and Brooks Range: West to southwest winds will
persist through the weekend along the coast and range from 5 to 15
mph, with the exception for those areas east of Prudhoe Bay,
where winds will increase to around 25 mph tonight. In the Brooks
Range passes, winds will be from the north at 5 to 15 mph. Areas
of stratus, patchy fog, and flurries continue this afternoon along
the coast, with pockets of light snow over the eastern Brooks
Range. There will be a brief period tonight and Friday, when there
is weak high pressure aloft and at the surface, and skies may
partially clear from Utqiagvik west. Cloud cover will return by
Friday night for this area. Temperatures will be on a downward
trend through the weekend and highly dependent upon cloud cover.
Coldest temperatures will be across the Arctic Plain.

West Coast and Western Interior: Satellite imagery shows a mix of
clouds and clear skies across the region this afternoon. Flurries
and areas of light snow will likely persist where there are clouds
this afternoon and evening. As high pressure builds in from the
west, skies will clear overnight and mostly clear skies will
persist through the weekend. Temperatures will drop through the
weekend, with the coldest temperatures occurring from Ambler south
to Galena to McGrath, where low temperatures will fall to around
40 below zero. North winds of 5 to 15 mph expected along the coast
tonight. Winds increase Friday to 10 to 20 mph along the coast,
with areas along the Bering Strait Coast and northern Seward
Peninsula increasing to 15 to 25 mph Friday night. Inland north
winds up to 10 mph can be expected. Winds combined with colder
temperatures will result in wind chill values as cold as 45 below
tonight into this weekend. Wind Chill Advisories have been issued
for zones 207, 208, 210, and 217. Additional Wind Chill Advisories
may be needed over the weekend.

Central and Eastern Interior: Latest satellite imagery show a
large area of clouds across much of the area with pockets of clear
skies west of the Dalton Highway. Surface obs show areas of light
snow and flurries. Snow chances continue through Friday for much
of the eastern Interior, with snow tapering off Saturday, as a low
in the northern Gulf of Alaska spins several waves of moisture
north and west. Highest snow accumulations are expected along the
AlCan border, where an additional two to two and a half inches
are possible through Saturday. Temperatures around the Interior
will fall into the 30s to 40s below this weekend. In areas where
skies have cleared, temperatures have already fallen into the 35
below range. Temperatures in the Upper Koyukuk Valley will drop as
low as 45 below, while temperatures in the Middle Tanana Valley
will fall into the 20s to 30s below Sunday through Tuesday. Wind
increase along the higher terrain tonight and Friday. In the
Alaska Range passes, northerly gap winds of 15 to 30 mph are
expected to continue through Friday. This will cause some blowing
snow in the passes. Wind Chill Advisory have been issued for
zones 218, 225, and 226 for wind chills of 40 to 50 below.

Coastal Hazard Potential Days 3 and 4...None.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Wind Chill Advisory for AKZ207-AKZ208-AKZ210-AKZ217-AKZ218-
AKZ225-AKZ226.
&&

$$

JAN 20


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