Heavy Snow in Alaska, November 5 to 6, 2020

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
248 PM AKST Wed Nov 4 2020

.SYNOPSIS...
A busy weather pattern continues for Northern Alaska through the
weekend. A storm off the Kamchatka Peninsula will continue to
deepen this afternoon and bring a surge of wind and water across
the Bering Sea with aim for the western Alaska coast as it moves
poleward up the Russian coastline through Saturday. An associated
front will impact the coast and break up slowly as it progresses
inland... however with that noted it still will bring wintery
impacts well inland to the Eastern Interior for the end of the
weekend into the weekend. On a positive note temperatures will be
on the rise from near record lows in the Tanana Valley!

&&

.DISCUSSION...

UPPER LEVELS...
A cold trof in the upper levels is noted across the eastern
interior and in the Yukon. Ridging building in front of the
Kamchatkan strong upper low driving the weather pattern. an upper
low near 85 North is being deflected by the amplifying ridge this
morning. The pattern progresses with the ridge moving into the
interior of Alaska. The Upper low elongates and stays in place in
the vicinity of the Kamchatkan Peninsula. A strong north Pacific
Ridge begins to win and pushes the Jet northward placing ridging
over the Gulf of Alaska and strong SW flow from the Bering Sea
into the interior.

SURFACE...
High Pressure over the Eastern Interior will bring another cold
day on Thursday for the eastern areas. A strong front from a large
Siberian low pressure system will swing across the Bering Sea and
hitting the west coast starting on Thursday and then moving inland
on Friday as it weakens. Offshore flow will continue on the North
Slope.

North Slope and Brooks Range...
Light snow and breezy continues will continue this evening as a
weak front rotating around a low pressure system north of the
coast pushes east over the North Slope tonight. Wind will continue
to offshore as system move through the region from the southwest
to northeast. The pressure gradient will set up for southern gap
winds through the Brooks Range passes.

Central and Eastern Interior...
The arctic airmass is beginning to modify as temperatures aloft
slowly warm. Temperatures will rise dramatically Thursday night
and Friday as clouds and snow move into the area and the upper
level trough pushes to the east. A strong storm in the Bering Sea
will push deep moisture into the Interior forcing the moisture to
rise up over a deep arctic airmass on Thursday and Friday. This
will set up the potential for a significant snow event over the
Central and Eastern Interior beginning late Thursday and
continuing into Saturday. Strong gap winds will develop through
the Alaska Range passes on Thursday afternoon into Friday as a
strong pressure gradient develops across the Alaska Range. The
Tanana Valley Jet will develop as well. The upper level support
should keep the wind speeds under warning levels.

West Coast and Western Interior...
A major storm system over the Russian far east will push a strong
front across the Bering Sea tonight into Thursday. This
strengthening system will bring multiple impacts to the region
during the next 72 hours. This storm is expected to bring heavy
snow, blizzard conditions, and southerly gales to the region, and
to the remainder of the West Coast of Alaska tonight through
Friday. Snow will mix with rain Thursday and Friday in some
coastal areas mainly south of the Bering Strait.

Coastal Hazard Thursday and Friday...
After the initial front moves through the region a long 1000 km
fetch along with gale force wind from the southwest will continue
over a long duration. The YK Delta looks to have the highest
impacts with some storm surge with the peak later on Thursday and
staying high through very early on Saturday. Norton Sound area
will peak Thursday overnight and lasting into early Saturday.
North of the strait to the western Arctic coast a little later
with peak on Friday lasting into Saturday. Multiple advisories,
watches and warnings are in effect for all the western coastal
regions. See statements for higher resolution details.

Coastal Hazard Potential Days 3 and 4...
On Saturday day 3 of the forecast the event will be on the decline
for the region as the water pulls back and wind diminishes.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
High Wind Warning for AKZ214.

Winter Storm Watch for AKZ222.

Coastal Flood Watch for AKZ201-AKZ202-AKZ213.

Coastal Flood Advisory for AKZ207-AKZ209-AKZ210.

Winter Weather Advisory for AKZ210-AKZ215-AKZ216-AKZ221-AKZ227.

Coastal Flood Warning for AKZ211-AKZ212-AKZ214.

Winter Storm Warning for AKZ207-AKZ208-AKZ209-AKZ211-AKZ212-
AKZ213-AKZ217-AKZ219.

Heavy Freezing Spray Warning for PKZ200-PKZ215-PKZ220-PKZ225-
PKZ230-PKZ235-PKZ240.

Gale Warning for PKZ215-PKZ220-PKZ225-PKZ230.

Storm Warning for PKZ200-PKZ210-PKZ220-PKZ225.

Small Craft Advisory for PKZ235.

Brisk Wind Advisory for PKZ240-PKZ245.
&&

PROTON NOV 20