Winter Weather Advisory 28, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
353 AM AKST Sat Feb 13 2021

.SYNOPSIS...
The strong storm that has been hammering the West Coast over the
past several days, from the YK Delta north to the Bering Strait
including St. Lawrence Island, continues to wind down this
morning as it ejects west out of our forecast area and weakens.
This will be replaced with relatively benign weather conditions
for many locations across Northern Alaska as high pressure over
the Yukon builds and dominates conditions for the remainder of
the weekend.

&&

.DISCUSSION...
At the surface, models are in good agreement with a 969 mb low
west of Amchitka in the Aleutian Islands with a front draped
north and south across the Bering Sea, impacting portions of St.
Lawrence Island and the western tip of the Seward Peninsula this
morning with light snow. This front will continue a westward track
towards the Gulf of Anadyr and weaken through this evening,
bringing an end to light snow chances and strong winds. High
pressure from the Yukon will build west and encompass most of
Northern Alaska, bringing relatively tranquil weather conditions
across the region through the weekend. A 963 mb low will track
north through the Northern Pacific to near Unalaska by Saturday
evening. This low will swing a front north impacting portions of
the YK Delta and St. Lawrence Island late Sunday into early
Monday, increasing chances of light snow. By Monday, as the main
low slowly tracks east along the Aleutian Islands, it will feed
additional moisture north through the West Coast into the Western
Interior, bringing another round of light snow across the region.

Aloft, at 500 mb, models initialize well with the main features
being a 547 decameter (dam) high near Inuvik in the Northwest
Territories, while broad trough exists over the Bering Sea. As
the day progresses, the upper level high remains quasi-stationary
near Inuvik, building a ridge west across Northern Alaska. The
trough will spin over the Aleutians, rotating several weak
shortwaves into the Southern Bering before a deep 499 dam low
anchors itself near Atka. This low will then spin additional
shortwaves that will impact Western Alaska into the middle of next
week. Elsewhere, a shortwave will dive south out of the Arctic
into Northwest Alaska early next week, developing a 514 dam low
near Wainwright. At 850 mb, temperatures across much of Northern
Alaska will remain in the -5C to -10C range into early Sunday. By
Sunday afternoon, colder air will move south across the Arctic
Coast into portions of the Northern Interior Monday with 850
temperatures dropping to -20C and below.

North Slope and Brooks Range...
Light snow that has been falling over portions of the far Western
North Slope tonight will come to an end this morning as weak front
moves offshore. A weak shortwave will rotate north around high
pressure into the North Slope, affecting portions from Umiat to
Deadhorse with a chance of light snow late Saturday through Sunday
morning. Light snow accumulations of generally less than one inch
expected. Otherwise, relatively benign weather conditions for
most other locations across the area into early next week.
Temperatures will begin trending down once again starting Sunday
into early next week as colder air returns to the region.

West Coast and Western Interior...
A strong weather front that has been plaguing portions of the West
Coast and St. Lawrence Island over the last several days
continues to drift west this morning. Light snow falling over
portions of the Western Seward Peninsula and St. Lawrence Island
will come to an end by this afternoon. High pressure will build
in, creating relatively quite weather conditions into Sunday
afternoon. By late Sunday evening, a front will approach the YK
Delta from a large low over the Aleutians, increasing chances
light snow that will eventually spread into the Western Interior
Monday. Temperatures will begin to trend down Sunday into next
week as cooler air filters in from the north.

Central and Eastern Interior...
Nighttime microphysics satellite imagery this morning depicts
mainly clear skies across the region as high pressure over the
Yukon continues to build this morning. This will create
relatively benign weather conditions that will persist across the
region through the weekend with clear skies and generally light
winds. Strong gap winds through Alaska Range Passes have all but
ended, while winds along the Tanana River near Delta Junction may
gust to 35 mph through Sunday morning. Temperatures will trend
near normal to just below for the weekend into early next week.

Coastal Hazard Potential Days 3 and 4...
No concerns at this time.

Extended forecast for days 4 to 7...
Beginning the extended period on Tuesday, model concensus shows a
strong low near Atka in the Aleutian Islands, swinging a front
northeast into the Western Interior, increasing chances of snow
across the region. This low will track east, skirting along the
Aleutian Islands, then phasing with a low quickly moving north
through the Gulf of Alaska to just south of Cordova on
Thursday. The initial low near Atka, as it tracks east, will
continue to feed moisture into the Western Interior then into the
Central and Eastern Interior, mainly south of the Brooks Range,
Wednesday into Friday, keeping the threat of light snow in the
forecast across the region.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

Gale Warning for PKZ225.

Brisk Wind Advisory for PKZ210-PKZ220-PKZ230.

&&

RZ FEB 21