Blizzard in Alaska, January 21, 2021

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
525 AM AKST Thu Jan 21 2021

.SYNOPSIS...
Active weather across the West Coast and the Western Interior
continues this morning, with gusty winds and heavy snow. Areas in
the Yukon Delta have warmed to above freezing with mixed
precipitation and rain observed for places like Marshall and
Scammon Bay. Conditions along the West Coast expected to improve
through today as winds subside and the initial front moves north.
However, there is a second surge of precipitation, with the Yukon
Delta expected to receive mixed precipitation, while areas along
the Nulato Hills extending west into Norton Sound and north to the
foothills of the Brooks Range will see more heavy snow going into
tomorrow afternoon.

&&

.DISCUSSION...
A large longwave trough centered over the Bering this morning will
continue to be the focal point for active weather going into the
weekend for northern Alaska, particularly for the West Coast and
Western Interior. Ridging across the Central and Eastern Interior
will persist through today before sliding off to the east by
Saturday morning. A strong upper level trough currently centered
over St. Lawrence Island will continue to push north off the
northwest Arctic Coast by tonight. This shortwave will begin a
prolonged period of southerly flow for the West Coast and Western
Interior. Another trough digging into the northern Pacific today
will begin to swing north and be centered near the Kuskokwim Bay
by Saturday morning. This trough will also lead to more southerly
flow to develop across the Central and Eastern Interior going into
Saturday night.

At 850 mb, temperatures have warmed over the last 24 hours across
the state and will continue to warm with the strong southerly
pushing north of the Arctic Coast today. These warmer temperatures
ranging from 0C to -7C will slowly moderate and cool to around -8C
to -12C by Sunday morning, as the second strong shortwave trough
ushers in cooler Arctic air.

At the surface, a strong low over St. Matthew Island this morning
is causing strong winds across the West Coast this morning. This
low will track north west of St. Lawrence Island this afternoon
and eventually into the Chuckchi Sea by tomorrow morning. The
front associated with this low will spread snow inland to the
Nulato Hills and the foothills of the Brooks Range into this
afternoon, with areas along the Seward Peninsula receiving mixed
precipitation. Snow will spread into Kotzebue Sound and the
northwest Arctic Coast this morning and through the afternoon.

A second push of moisture from the south will bring larger snow
amounts to the Nulato Hills and the foothills of the Brooks Range
late this afternoon and last into tomorrow morning. Areas in the
Yukon Delta will remain warm through tomorrow, resulting in
mainly freezing rain. Models have come into better agreement with
this feature, with the front eventually moving west into Norton
Sound tomorrow morning and then lifting north with precipitation
tapering off tomorrow evening.

Another surface low is set to move into the Bering Sea tomorrow
afternoon, with the next front moving north across the Yukon Delta
tomorrow night. This front will push north into Norton Sound by
Saturday morning before models begin to diverge on the track of
this low going into Sunday.

Central and Eastern Interior...
Overall, quiet weather continuing in the short term. The exception
would be southerly gap winds that developed yesterday in Alaska
Range passes. Wind Advisories through the Alaska Range are in
effect into tomorrow afternoon with gusts to 60 mph. Temperatures
will continue to remain well above normal for this time of the
year going into next week.

North Slope and Brooks Range...
Generally quiet conditions along the Arctic Coast this morning,
with areas of low stratus and fog. Easterly flow expected to
strengthen today as a strong low will track north into the
Chuckchi Sea. Winter Weather Advisories are in effect for the west
and central Arctic Coasts for mainly blowing snow concerns with
half mile visibilities at times with gusts to 40 mph into tomorrow
morning. Temperatures will be trending up with the push of warmer
air from the south, remaining well above climatological normals
through the weekend.

West Coast and Western Interior...
Active weather for this region continues this morning. A number of
Winter Storm Warnings are in effect across the entire area.
Coastal areas will see strong winds with times of quarter mile
visibilities in snow and blowing snow through this evening. Areas
further inland, most notably along the Nulato Hills north to the
foothills of the Brooks Range, will receive a large amount of snow
going into tomorrow afternoon. Areas in the Yukon Delta are
reaching into the mid-30s this morning, with those areas expected
to remain above freezing going into tomorrow, so expect those
areas to receive freezing rain as a second wave of moisture moves
into the area this afternoon. Improving conditions are expected to
occur tomorrow afternoon ahead of another front that will swing
north bringing more precipitation to portions of the West Coast
and the Western Interior tomorrow night.

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

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Wind Advisory for AKZ225-AKZ226.

Winter Storm Warning for AKZ207-AKZ208-AKZ209-AKZ211-AKZ212-
AKZ213-AKZ215-AKZ216-AKZ217.

Winter Weather Advisory for AKZ201-AKZ202-AKZ210.

Gale Warning for PKZ200-PKZ210.

Brisk Wind Advisory for PKZ215-PKZ220-PKZ225-PKZ230-PKZ235-
PKZ240-PKZ245.
&&

JAN 21