Winter Weather Advisory 89, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
207 PM AKDT Mon Sep 20 2021

.SYNOPSIS...
The first significant snowfall of the season over the Eastern
Interior is underway. Fairbanks received measurable snow this
morning with a few tenths around town. Heavier snow is occurring
from Eielson AFB east and along the Alaska Range. This heavy snow
will spread to the Alcan border by this evening. Winter Storm
Warnings and Advisories remain in effect for the Interior from
Denali east to the Upper Tanana Valley and the Fortymile region.
Snow squalls will continue over the North Slope and NW Arctic
coast. A front approaching southwest Alaska will bring a chance
for significant snow to the lower Yukon Valley on Tuesday night.

&&

.DISCUSSION...
All models initialized well and are in general agreement with the
main synoptic features for the next few days. An upper level low
over the Arctic Coast has come into phase with a 2nd upper in the
Gulf of Alaska, resulting in a longwave trough that persists over
mainland Alaska the next couple of days. The combination of
moisture being pumped northward into the Eastern Interior and
unseasonably cold air spilling south from the Arctic is bringing
widespread snowfall over that area into Tuesday night. The trend
is for this to end by Wednesday. Further north, vigorous cold,
onshore flow over the open water continues to produce heavy snow
showers along the North Slope and Arctic Coast. As the main upper
low drifts northeast into Wednesday the onshore flow will
gradually diminish. The last remaining feature of interest a
tightly wound up low that skirts along the Arctic frontal
boundary in the Bering Sea. This low moves southeast past St.
Lawrence Island late tonight, then into the Yukon Delta Tuesday
afternoon. Models are coming into line with with track of the low
and possibility for a narrow footprint of heavy snow in the Lower
Yukon Valley.

Central and Eastern Interior...
The highest impact weather the next couple days will be from the
Delta Junction area eastward with snowfall. We did not make any
changes to the ongoing Winter Storm Warnings. For the Eastern AK
Range, AK highway, and Taylor Hwy corridors for 4-8" of snow, with
higher amounts in Isabel Pass along the Richardson to 6-11".
Strong north winds to 50 mph are also expected along the southern
corridor of Isabel Pass, but snow will also be somewhat lighter
there, so there will be some blowing snow, but not expecting major
blowing snow/drifting snow. Otherwise, partly to mostly cloudy
skies and below normal temperatures are expected over the
remainder of the area.

West Coast and Western Interior...
Northwest flow and snow showers along the Chuckhi Sea Coast will
diminish some on Tuesday as the flow turns more northern, although
some showers will linger along the northern Seward Peninsula. Low
pressure passing over St. Lawrence island on Tuesday will bring
gusty winds and a few inches of snow to the island. As the low
moves into the Lower Yukon Valley Tuesday afternoon, 4-6" of snow
and possibly higher amounts are possible over a narrow band from
Emmonak to Russian Mission. The western Interior will otherwise be
dry and cool with some clouds.

North Slope and Brooks Range...
Strong northwest winds and snow squalls will continue into Tuesday
and and diminish some on Wednesday. Visibility will be up and
down especially along the coast from Prudhoe Bay west with the
heavy snow showers. These winds will also bring elevated surf from
Utqiagvik to Point Hope through Tuesday morning. Further inland
and along the Brooks Range, where there are breaks in the clouds,
temperatures will be quite chilly for September. Morning lows in
the lower teens and single digits are likely from Anaktuvuk Pass
to Toolik Lake.

Coastal Hazard Potential Days 3 and 4...the tight low mentioned
above moving into southwest Alaska will bring strong north winds
to the Yukon Delta coast on Wednesday. The winds will be
generally parallel to the coast no immediate concerns with
erosion.

Extended Forecast Days 4-7...
A cold arctic high will be in place over mainland Alaska with
another low moving into the Gulf of Alaska on Thursday. Expect
temperatures to continue to be cool for late September. Models
continue to hint at a chance for another snow event for the
Interior Friday and Saturday, but the track of the gulf low as it
lifts north is still highly uncertain among the three major
global models.

&&

.HYDROLOGY...
None.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning for AKZ223-AKZ224-AKZ226.

Winter Storm Watch for AKZ214

Winter Weather Advisory for AKZ225.

Small Craft Advisory for PKZ210-PKZ215-PKZ220-PKZ225-PKZ230-
PKZ235-PKZ240-PKZ245.
&&

SEP 21