Ice Storm in Alaska, December 24 to 28, 2021

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
355 PM AKST Fri Dec 24 2021

.SYNOPSIS...
Active weather is beginning to ramp up across northern Alaska this
afternoon as a weather front is bringing snow, freezing rain, and
rain to the Yukon Delta and the Lower Yukon Valleys. This front
will push snow eastward into Fairbanks by tomorrow morning, with
snow persisting into Sunday. At that point, a different and
stronger front will move across the West Coast and Western
Interior beginning Saturday night, with more widespread snow,
freezing rain, and rain concerns reaching as far east as Fairbanks
by Sunday night as the front moves east across the Interior.

Numerous Advisories and Warnings are now in effect for the winter
weather set to impact northern Alaska, with snow amounts ranging
from 5 to 12 inches across the Lower Kobuk and Noatak Valleys to
16 to 24 inches along the Parks Highway through the Alaska Range.
The larger concern is the amount of freezing rain that is expected
to move into the Interior, with one quarter to one half inch
possible in the Fairbanks area beginning on Sunday.

&&

.DISCUSSION...
Strong ridging in the northern Pacific will create the conditions
to tap into tropical air as the next strong trough impinges on
the western side of the ridge going into the weekend. This will
result in a seasonably abnormal amount of moisture that will push
into northern Alaska going through the weekend.

This pattern has been the persistent feature advertised by model
guidance for quite a few days, but the latest details for the
winter weather situation across northern Alaska has changed. The
surface low that had been tracking north from the Bering Sea to
the Chukchi Sea is now tracking across the Seward Peninsula on
Saturday night. Thus, the outlook has changed, particularly
across the North Slope, where the expectations are now less snow
and weaker winds. The outlook remains similar across the West
Coast and Interior through the weekend, with widespread heavy snow
with large snow accumulations, freezing rain, and rain.

The outstanding uncertainty at this point for the winter storm
over the weekend is the amount of freezing rain that could extend
into the Interior, particularly over Fairbanks. At this point,
guidance is indicating larger amounts of freezing rain reaching
the Interior, so the latest forecast and Winter Storm Warnings
issued reflect this increase in freezing rain amounts.

Central and Eastern Interior...
Light snow is beginning to move into the Central Interior this
afternoon. This snow is the beginning of significant weather
concerns for the region going through the holiday weekend. Heavy
snow with significant snow accumulations are expected, with the
Fairbanks area receiving anywhere from 12 to 20 inches. The Alaska
Range will get hammered with up to 24 inches of snow. With that
said, freezing rain possibilities have increased across the
Interior, with an additional one quarter to one half inch of
freezing rain on top of the large snow accumulations beginning as
early as overnight Saturday and into Saturday morning across the
Interior. The highest amounts are expected from Fairbanks south
along the Parks Highway through Nenana and into the Alaska Range
through Sunday night. Expect a sharp warming trend over the
weekend, with temperatures reaching the low to mid 30s during
this period of freezing rain.

North Slope and Brooks Range...
The outlook for the region has changed drastically, with sub-
advisory impacts expected through the weekend. However, a Winter
Storm Warning is in effect for the Northeastern Brooks Range from
Saturday afternoon to Monday morning for 6 to 10 inches of snow,
with blowing snow concerns from Sagwon south on the Dalton Highway
and Anaktuvuk Pass. Elsewhere, there will be snow across the North
Slope ranging from 3 to 6 inches from Deadhorse west. Winds will
develop out of the east Saturday night, but not expected to cause
significant visibility issues. Temperatures are expected to warm
through the weekend, but remain near normal.

West Coast and Western Interior...
The Lower Yukon Valleys and the Yukon Delta currently are
experiencing snow, freezing rain, and rain conditions this
afternoon and will continue into tomorrow morning. This region
will remain warm going into the weekend, with the next front
resulting in more widespread freezing rain and rain concerns
across West Coast from the Seward Peninsula south and reaching
eastward into the Western Interior. General freezing rain amounts
up to one tenth of an inch along the West Coast, with between one
tenth and one quarter inch of accumulation into the Western
Interior beginning tonight and lasting into Sunday night. In areas
further north, large snow amounts are expected across the Western
Interior with snow amounts ranging from 7 to 10 inches for the
Lower Kobuk and Noatak Valleys to 9 to 13 inches for the Upper
Kobuk and Noatak Valleys beginning tomorrow morning and lasting
into Sunday night.

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

Extended Forecast for Days 4 Through 7...
The progressive pattern that has caused active weather across
northern Alaska over the last week and a half or so will continue
into the middle of the week. The next winter storm is showing
possibilities of impacting the West Coast by Tuesday.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning for AKZ206-AKZ208-AKZ209-AKZ216-AKZ217-
AKZ218-AKZ219-AKZ220-AKZ221-AKZ222-AKZ223-AKZ224-AKZ225.

Winter Weather Advisory for AKZ211-AKZ212-AKZ214-AKZ215.

Brisk Wind Advisory for PKZ210-PKZ215-PKZ220-PKZ225-PKZ230-
PKZ240.
&&

DEC 21