Heavy Freezing Spray Warning 1, NWS Fairbanks, AK

Northern Alaska Forecast Discussion...CORRECTED
National Weather Service Fairbanks AK
128 PM AKST Thu Dec 31 2020

SYNOPSIS...Very strong low near Shemya has a pressure, 924mb at 1
pm, almost as low as the strongest Hurricane in 2020. The low
will slowly move into the Southern Bering Sea near the Dateline
and weaken. The low will send a weather front to the Lower Yukon
Delta and St Lawrence Island Friday. Expect some gusty offshore
winds in the Norton Sound Region tonight and early Friday.
Blizzard conditions developing on St Lawrence Island tonight will
continue into Friday evening. The Lower Yukon Delta will have snow
and blowing snow developing early Friday and ending in the
afternoon. The Arctic will be quiet except for the Northwest Coast
around Point Lay where ground Blizzard conditions will continue
into tonight before conditions improve. The Interior will be
mostly clear as the clouds will be clearing out with cooling
temperatures and Wind Chill near 40 below developing on summits.
Tanana Valley Jet developing will bring some gusty southeast winds
to the Delta Junction area.

.DISCUSSION...

Models...The 31/12Z solutions are in good agreement in the short
term. In the midrange and extended periods there is some spread
in the locations of the major features, but a blend of the
solutions should provide a good starting point. Will be using a
blend of the solutions for most elements while making minor
adjustments for current conditions. For the winds will need to
kick them up a bit on St Lawrence Island and in the Norton Sound
and Kotzebue Sound regions, but only a few knots as the gradient
is a bit tighter than solutions suggest.

Aloft...At 500 hpa...Stacked 468 dam low has moved over Shemya a
it slides into the Bering Sea. A 530 dam high is over the Central
Alaska Range, and ridging extends north over the Western Arctic,
while a stacked 487 dam low is over the Canadian Archipelago
north of Hudson Bay with a trough extending west then northwest
over the Eastern Arctic, and a 520 dam low is 600 nm south of
Prince William Sound. By Friday afternoon not much change in the
pattern as the low over the Bering Sea moves to 200 nm northwest
of Amchitka at 476 dam, the high over the Alaska Range moves over
McGrath at 521 dam with the ridging extending from Northway to the
low then northwest over the Chukchi Sea, the low over the
Northeast Pacific weakens and fills. The trough over the Arctic
will be pulled south over the offshore waters as a 530 dam low
develops over MacKenzie Bay. The trough will move over the Arctic
Coast Saturday morning as the low over MacKenzie Bay closes and
heights fall to 500 dam. By Saturday afternoon the low in the
Bering Sea will weaken over the Dateline with as heights rise to
492 dam, while the ridging over the state will be pushed southwest
to lie from the Kenai Peninsula to St Lawrence Island, and the
low over MacKenzie Bay will back to the southwest over Arctic
Village at 494 dam with a trough extending west over the Chukchi
Sea. At 850 hpa...The -10C isotherm lies from the AlCan Border
Crossing to Point Lay, while the -20C isotherm is northeast of
Arctic Village. Temperatures will be falling and by Saturday
afternoon the -10C isotherm will lie from Haines to Teller while
the -20C isotherm will lie from the AlCan Border Crossing to Cape
Lisburne. Temperatures will continue to cool through early next
week.

Surface...Stacked low in the Bering Sea is checking in around 925
mb this afternoon and will move near the Dateline by Saturday
afternoon at 960 mb. The low will send a weather front to the
Lower Yukon Delta and St Lawrence Island tonight with Blizzard
conditions developing on St Lawrence Island. A strong pressure
gradient persists over the Northwest Arctic Coast as a 1029 mb
high 600 nm north of Wrangel Island is pushing higher pressure
southeast to the Central Arctic and MacKenzie Bay to a 1022 mb
high in the Northwest Territories. Weak leeside troughing has
developed north of the ranges as high pressure from the Yukon
Territory pushes west over the Copper River Basin and the Upper
Yukon Flats. As the high pressure pushes in from the east over the
Upper Tanana Valley the Tanana Valley Jet will kick in with some
gusty winds developing around Delta Junction tonight. Gusty winds
will also develop near passes in the Eastern Brooks and Alaska
Ranges, but generally less than 30 mph. As the high pressure
builds in south of the Brooks Range expect the east winds along
the south slopes increase to 15 to 25 mph. As the high pressure
over the Arctic slips to the west Friday night the gradient over
the Northwest Arctic Coast will slide south over the Central
Chukchi Sea and Point Hope area, and the gradient over the Brooks
Range will switch with gusty north winds developing.

Arctic Coast and Brooks Range...Not a lot of change, so expect a
mix of clouds and patchy fog as northeast winds persist at 10 to
20 mph except for the Northwest Coast where winds will be east at
25 to 35 mph. Ground Blizzard continues, but conditions will be
slowly improving. Temperatures will be cooling through the
weekend.

West Coast and Western Interior...The low in the Bering Sea will
send a front to St Lawrence Island and the Lower Yukon Delta
tonight, but do not expect it to move much further north.
Blizzard developing on St Lawrence Island early Friday morning
with some blowing snow and near Blizzard conditions in the Lower
Yukon Delta. Winds gusting to around 50 mph on St Lawrence Island
and around 40 mph in the Lower Yukon Delta and the Norton Sound
Region south of Nome. Mostly clear for the remainder of the area
through Saturday. Temperature from Nome south a couple degrees
warmer through Friday, then falling. Temperatures will continue to
cool through the weekend.

Central and Eastern Interior...Mostly clear through the weekend
with temperatures continuing to fall. Winds on the Summits north
of Fairbanks along the Dalton Highway will be picking up, so Wind
Chill values will be falling this weekend as colder air pushes in
from the northeast. Winds near Delta Junction increasing to
southeast to 20 mph gusting to 35 mph tonight and diminishing
Friday. Some gusty winds near the passes in both ranges, but
generally less than 30 mph.

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

Extended forecast for days 4 to 7...A broad area of low pressure
will persist over the Bering Sea with high pressure over the
Arctic and most of mainland Alaska. A weak weather front will move
to the Eastern Arctic Coast Tuesday bringing some flurries to
Utqiagvik and the Eastern Arctic Coast, and a low will drop south
to Wrangel Island then dissipate as it brings some flurries to the
Northwest Arctic Coast, but nothing significant. The remainder of
the forecast area will be pretty quiet with mostly clear skies
and near climatological normal or slight cooler temperatures.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

Blizzard Warning for AKZ201-AKZ213.

Winter Weather Advisory for AKZ214.

Heavy Freezing Spray Warning for PKZ210.

Gale Warning for PKZ210-PKZ230.

Brisk Wind Advisory for PKZ200-PKZ215-PKZ220-PKZ225-PKZ235-
PKZ245.

&&

SDB DEC 20