Gale Warning 20, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
230 PM AKST Mon Feb 17 2020

.SYNOPSIS...
Snow from the second of a progressive series of weather systems in
the Bering Sea has made its way into the West Coast. Moderate to
heavy snow is falling across St Lawrence Island and the Y-K Delta,
with lighter snow falling across the western Interior and further
north along the West Coast. Snowfall will progress north and east
as the low in the Bering tracks to the north and weakens, and snow
is expected along the North Slope Tuesday. Tanana Valley jet winds
have developed with gusts approaching 40 mph, and southerly gap
winds across the Alaska Range have been increasing and are
expected to exceed 70 mph at times. Temperatures will increase
across the state to well above average. Temperatures in Fairbanks
may approach 30 above zero, a far cry from the 30s and 40s below
over the past weekend. Southerly flow will weaken Wednesday, with
widespread snow showers expected across northern Alaska. A cold air
mass will push into the state from the north Thursday however, and
temperatures will gradually cool toward the end of the week.

&&

.DISCUSSION...

Aloft at 500 hPa...
Large ridge extends from the Gulf of Alaska north and west to the
Chukchi Sea, with a low over the Bering sea southwest of Nunivak
Island. The low will turn northeast and move into the Y-K Delta
tonight as it slows down and occludes. A shortwave oriented along
the Alaska Range will enhance the southerly flow, which will
strengthen the Alaska Range gap winds tonight and Tuesday. The
ridge will move east Tuesday as the low again turns north, making
its way up the west coast to the Seward Peninsula and weakening,
before it is absorbed in a deeper low making its way south into
the Chukchi Sea Wednesday and Thursday. Thursday and Friday, weak
ridging will be present across the eastern Interior, and general
troughing over the Bering and Chukchi Sea, as well as the West
Coast and western Interior. Friday, general longwave troughing
will be preset statewide, allowing for cooler temperatures to take
hold.

North Slope and Brooks Range...
Temperatures will remain cold across the region overnight. With
the arrival of a front from the southwest Tuesday, temperatures
will increase significantly with highs reaching 0 to 10 below.
With northeast to east winds increasing tonight ahead of the
approaching front, a brief period of very cold wind chills are
still possible overnight tonight. With approximately 2 to 4 inches
of snow expected fron Tuesday morning to Wednesday morning and
winds increasing to 35 mph, Winter Weather Advisories are in
effect for the western and northern Arctic coast as blowing snow
may significantly reduce visibility for a time. Wednesday, a front
extending from a low pressure in Canada will extend over the
eastern North Slope, bringing light snow to the eastern North
Slope. Deepening low pressure by the end of the week will bring
cooler temperatures once again to the region.

West Coast and Western Interior...
Heavy snow and blowing snow associated with another low in the
Bering Sea has impacted much of southwest Alaska. St Lawrence
Island, the Y-K Delta, and Eastern Norton Sound have all
experienced blizzard conditions with near zero visibility today.
As the low continues north, snow will spread northward but
intensity should decrease throughout the day Tuesday. Still, storm
total snowfall is expected to be around 6 to 12 inches with
isolated higher amounts through the Yukon Valley through the
western Brooks Range, and 4 to 7 inches along the West Coast.
Winds will still be strong through Tuesday, with gusts as high as
35 to 45 mph. This will reduce visibility to half a mile or less
at times. Expect fairly warm temperatures through Wednesday, then
temperatures fall again Thursday and into the weekend.

Central and Eastern Interior...
The forecast strong pressure gradient across the Alaska Range has
set up and southerly gap winds have begun to increase. Winds
through Windy pass may exceed 70 mph and winds through Isabel
Pass may exceed 80 mph, and these winds will bring much warmer
temperatures to the area. Additionally, Tanana Valley jet winds
supported by lee side troughing developed this morning and are
expected to continue, with gusts up to 40 mph. There may be some
interaction with the southerly winds coming out of Isabel Pass, so
these gusts may be somewhat erratic near Fort Greely and Delta
Junction. Southerly winds will drop below 60 mph in the passes Tuesday
night, but will remain gusty through Thursday. Snowfall amounts
within Isabel Pass are expected to only be 2 to 3 inches, but
along the Richardson Highway south of Black Rapids 6 to 8 inches
of snow are expected. Light snow will spread east from the front
over the West Coast and produce around an inch or two across much
of the Interior Wednesday, mainly north and west of a line from
Tanana to Fairbanks to Fort Yukon. Fairbanks may see some snow
showers Wednesday morning, but accumulations should remain at or
less than half an inch.

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

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Wind Advisory for AKZ223.

High Wind Warning for AKZ225-AKZ226.

Winter Storm Warning for AKZ215-AKZ216-AKZ217.

Blizzard Warning for AKZ212-AKZ213-AKZ214.

Winter Weather Advisory for AKZ201-AKZ202-AKZ207-AKZ208-AKZ209-
AKZ210-AKZ211-AKZ218-AKZ219.

Gale Warning for PKZ210-PKZ220.

Brisk Wind Advisory for PKZ200-PKZ215-PKZ225-PKZ230.
&&

HICKFORD FEB 20