Blizzard in Alaska, February 3 to 4, 2021

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
418 AM AKST Wed Feb 3 2021

SYNOPSIS...Cool temperatures will continue across most of the
forecast area with some areas along the Arctic Coast reaching the
40s below. Wind chill will continue to be an issue, but winds will
be slowly diminishing. Conditions on St Lawrence Island have
improved for now, but another round of Blizzard conditions will
develop tonight and continue into Friday morning. Snow in the
Lower Yukon Delta this morning will be spreading east into the
Interior. Heaviest snowfall will be in the Lower Yukon Delta,
Upper Kuskokwim, and the Western Alaska Range.

.DISCUSSION...

Models...03/12Z solutions are in good agreement through Thursday
then get a bit messy with the wave approaching the West Coast
Friday as a low develops along the wave over the Southwest Coast.
Solutions come back together as they move through the midrange,
then diverge again as a wave moves south around a low that will be
near Banks Island. The precipitation solutions are in good
agreement as a front moves north into the state pushing the
precipitation north. Precipitation will generally be south of the
Yukon River with the heaviest amounts over the Upper Kuskokwim
Basin and the Western Alaska Range. Temperatures warm a bit on
Wednesday night and Thursday in the southern Interior with the
snow, then cool Thursday night before warming Friday and Saturday
before another strong push of cold air into the Arctic and
Interior Sunday. Winds in the Interior are diminishing and will
continue to do so. Winds will Winds on the West Coast will
diminish a bit Thursday, then increase Thursday night and Friday
as another front moves to the area.

Aloft...At 500 hpa...A 495 dam low over the Canadian Archipelago
has spun a wave south of Banks Island over the Northern Yukon
Territory to Arctic Village to Selawik. The wave will be pushed
north by ridging over the northeast Pacific and will lie over the
Brooks Range with a 509 dam closed low developing over Anaktuvuk
Pass this afternoon. Ridging over the Northeast Pacific extends
northwest over Kodiak Island to the Seward Peninsula to a 546 dam
high 500 nm northwest of Wrangel Island. A shortwave associated
with a 481 dam low over Southern Kamchatka has moved over the
Northeast Bering Sea and the Lower Yukon Delta south of St
Lawrence Island. The ridging will be pushed west by this afternoon
and will extend from Unalaska northwest over the Gulf of Anadyr
to the 547 dam high that will be 900 nm northwest of Wrangel
Island. Thursday morning the closed low over the Brooks Range will
weaken to 512 dam over Anaktuvuk Pass with a trough extending
west over Cape Lisburne, and east then northeast to the 492 dam
low over the Canadian Archipelago. A 546 dam low will develop 200
nm south of Sand Point, and the ridging over the Northeast Pacific
will extend northwest over Bristol Bay to St Lawrence Island and
the Western Gulf of Anadyr. By Thursday afternoon the low over the
Brooks Range will fill and the weakening trough will be dragging
east out of the area as another shortwave swinging around the low
will move over the Arctic Coast. The ridging that was over the
southwest coast will move east to lie over Kodiak Island to the
Chukchi Sea. A developing wave will move over the Central Bering
Sea. At 850 hpa...Temperatures remain cool with the -20C isotherm
lying from the AlCan Border crossing over the Eastern Alaska Range
to Minchumina to Huslia to Point Lay. The cold will continue to
push south over the West Coast as the -20C isotherm will lie
Minchumina to St Michael then west Wednesday evening. Temperatures
will start warming slowly Thursday.

Surface...At 03/06Z High pressure associated with a 1058 dam high
700 nm northwest of Utqiagvik extends southeast across the Arctic
to Demarcation Point and across MacKenzie Bay to a 1030 mb high
in Northeast British Columbia. Low pressure lies over the
southwest mainland with a 1001 mb low in the Southern Gulf of
Alaska, and a 1002 mb low near Cape Romanzof with low pressure
extending west across the Bering Sea to a 958 mb low on the
Kamchatka Peninsula. A strong pressure gradient persists over the
state between the ranges. By Thursday morning it becomes a bit
messy over the state as the low pressure pushes north into the
Interior. The high over the Arctic will move 200 nm west with the
high pressure extending southeast over the Central and Eastern
Arctic to a 1035 mb high over the Northwest Territories. As the
front moves into the Interior a 1018 mb low will develop in the
Middle Tanana Valley Thursday morning with the front extending
southeast in the Upper Tanana Valley, and southwest from the low
to the Lower Yukon Delta. The low will move east as the front
weakens and a 1044 mb high will develop in the Upper Yukon Flats.
On the west coast the decaying front will move north and dissipate
as it moves into the Chukchi Sea. Another low will develop in the
Bering Sea Thursday evening along a front that will move to the
West Coast late Thursday night or early Friday morning.

Arctic Coast and Brooks Range...Wind chill will be letting up a
bit as the winds slowly diminish to around 10 mph. But still
expect them to be in the 40 to 60 below range. Some patchy stratus
and fog in the area, but nothing extensive showing up on the
Nighttime Microphysics products. Temperatures will remain cold
with highs in the 20 to 30 below range and lows in the 25 to 45
below range for most areas. Coldest temperatures in the plains
with lows falling to around 60 below.

West Coast and Western Interior...Weather front has moved north
to Norton Sound and will move over the Southern Seward Peninsula
Coast then stall as a 1007 mb low moves into the Lower Yukon Delta
and the Upper Kuskokwim Basin as it dissipates. Heaviest snowfall
will be in the Lower Yukon Delta, Upper Kuskokwim, and along the
north slopes of the Western Alaska Range. Conditions on St
Lawrence Island and in the Bering Strait have improved and will
continue to improve this morning. Winds will be picking back up in
the afternoon with deteriorating conditions tonight and a return
of Blizzard conditions to the area with winds gusting to around 40
mph. Winds diminish Friday morning with improving conditions.
Winds for the remainder of the area will be 5 to 15 mph from the
northeast and east. Cooler air pushing south over the area with
temperatures falling tonight under mostly clear skies from
Unalakleet north. Temperatures on the rise by late Thursday as the
next front moves into the Eastern Bering Sea.

Central and Eastern Interior...Increasing clouds for areas south
of the Yukon River, that do not already have stratus cloud cover,
as front moves north into the Interior. Snow developing later this
morning around Minchumina and in the Alaska Range will spread
north to the Yukon River and east across the area. Heaviest
snowfall will be in the Central Alaska Range around Denali Park.
Snow will taper off Thursday evening with only a few lingering
flurries in the Alaska Range Thursday night and Friday. Northeast
winds diminishing, but will remain fairly strong on summits at 10
to 20 mph, except to 30 mph along the Dalton Highway near the
Yukon River. Temperatures will remain cool through Friday morning
then start warming.

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

Extended forecast for days 4 to 7...Warmer temperatures Saturday
then cooling Sunday as a strong push of cold air from the the
Arctic moves south down the West Coast while the cold air hangs on
in the Interior. While temperatures will remain fairly steady in
the Interior temperatures on the West Coast and in the Western
Interior will fall into the 20s and 30s below. Temperatures in the
Arctic will be warming, but only into the teens to 20s below for
most areas. The front moving south over the Arctic will being some
light snow to the Arctic Saturday with it tapering off Sunday. A
front moving northeast into the Interior will bring snow to the
Interior the middle of next week.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

Wind Chill Advisory for AKZ206-AKZ218-AKZ219-AKZ220-AKZ221-
AKZ222-AKZ223.

Blizzard Warning for AKZ213.

Wind Chill Warning for AKZ201-AKZ202-AKZ203.

Winter Weather Advisory for AKZ225.

&&

SDB FEB 21