Extreme Cold in Alaska, February 1 to 5, 2021

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
330 PM AKST Sun Jan 31 2021

.SYNOPSIS...
Temperatures are expected to fall tonight across the forecast area
as an Arctic airmass pushes south and skies clear. Many locations
across the forecast area will see their coldest temperatures so
far this season. Easterly winds will pick up tonight along the
West Coast and Western Interior and over the central and eastern
Interior on Monday (especially over summits and channeled areas).
The combination of the strong winds and cold temperatures will
lead to periods of dangerously cold wind chill values for the
first part of the work week.

&&

.DISCUSSION...
The 31/12Z model suite initialized the surface high over the
Arctic Coast slightly too week when compared to observational
data. The models are in generally good agreement with the synoptic
scale pattern over the next 48 hours. There are still some
differences in the strength and placement of the upper level low
as it dives to the south along the Canadian Border on Monday.

Aloft, at 500 mb, a 512 dam low that is currently centered over
the eastern Brooks Range will push south tonight and will be
centered near Northway by Monday afternoon. This low will
continue to push to the south Monday night. We expect that much of
the Interior will see H850 temperatures colder than -30C tonight
into Monday as the low moves south overhead. Northerly flow looks
to persist over the Interior on Tuesday, while the west coast will
be under a high amplitude ridge. The models are hinting that
another cold upper low will spread southwest over the Brooks Range
on Wednesday and will push to southeast across the Interior on
Thursday.

Central and Interior...
Satellite imagery shows an area of stratus from Nenana east to
the Canadian Border. We expect this cloud cover to erode this
evening, especially after the flow aloft turns more northerly.
Snow flurries are expected at times underneath the area of
stratus this evening. Areas where the sky has already cleared out
have already fallen into the 20s or 30s below. By tomorrow
morning, we are expect temperatures across the Interior to fall
into the 30s below zero, and by Tuesday morning, many locations
(especially in the eastern Interior) will see lows in the 40s
below. Easterly winds will begin to pick up on Monday over summits
and other channeled areas. With the cold temperatures in place we
will see dangerously cold wind chill values. Wind chill products
are out for all of Interior, although the most severe values are
expected over summits.

West Coast and Western Interior...
A front moving north through the Bering Sea combined with high
pressure building south over the Chukchi Sea will bring strong
easterly winds this evening through Tuesday to the West Coast and
to a lesser extent to the western Interior. With cold temperatures
in place over the area, dangerously cold wind chill values will
develop over the area, with most of the area under a wind chill
product of some kind. The combination of falling snow and strong
winds gusting to 65 mph are bringing blizzard conditions to St.
Lawrence Island. A Blizzard Warning is out for St. Lawrence Island
through Monday evening. Snow will move into the Yukon Delta as
the front move inland early Tuesday, with the possibility of
significant blowing snow along the coast.

North Slope and Brooks Range...
High pressure over the area will help to keep very cold
temperatures through much of the week, with most locations seeing
low temperatures in the 30s to 40s below. Easterly winds will
ramp up on Monday causing wind chills to likely dip into the -60 F
or colder range along the West Arctic coast, and into the -40 to
-50 F range elsewhere through Tuesday night.

Extended Forecast Days 4-7...
There is a lot of uncertainty in the extended period at the
moment. The extended period begins Wednesday evening with a cold
trough draped over the Brooks Range. There is some potential for
snowfall pushing from west to east over the Interior Wednesday
into Thursday in the westerly flow on the south side of the
east-west oriented trough over the Brooks Range; however, there
is a lot of uncertainty in the details of this at the moment. The
models really begin to diverge as we go into the weekend. The GFS
brings another cold upper level low over the area, while the ECMWF
presents a more active pattern.

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

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Wind Chill Advisory for AKZ204-AKZ206-AKZ207-AKZ208-AKZ209-
AKZ210-AKZ212-AKZ215-AKZ216-AKZ217-AKZ224-AKZ225-AKZ226-AKZ227.

Blizzard Warning for AKZ213.

Wind Chill Warning for AKZ201-AKZ202-AKZ218-AKZ219-AKZ220-AKZ221-
AKZ222-AKZ223.

Gale Warning for PKZ200-PKZ220.

Storm Warning for PKZ210.

Brisk Wind Advisory for PKZ215-PKZ225-PKZ230.
&&

JAN 21