Winter Storm Warning 35, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
506 AM AKST Sun Dec 13 2020

.SYNOPSIS...
The combination of a strong surface high pressure in the Arctic
and surface low pressure in the Bering Sea will work to keep
strong east winds across northern Alaska going into the work week.
Gusty winds with blowing and drifting snow are the main concerns,
particularly for highway summits in the Interior, portions of the
Western Interior, and the Western Arctic Coast.

&&

.DISCUSSION...
Aloft, ridging is breaking down across northern Alaska and into
the Arctic, as a shortwave swinging from the Canadian Arctic works
to reinforce troughing present across the North Slope. This
troughing feature, along with strong troughing over the Bering Sea
will work to squeeze out the remaining ridging over the state by
Monday morning. At that point, a strong shortwave will be moving
up along the Alaska Range creating southerly flow going into
Tuesday. The troughing present over the North Slope will slide
west as strong higher heights in the high Arctic remains in place
going into the middle of the week. Progressing through the middle
of the week, a strong upper level low over the Canadian Arctic
will retrograde to the west over the Northwest Territories and
into the Yukon by Wednesday. Troughing will continue to encompass
northern Alaska during this period as a longwave trough remains in
the Bering Sea.

At the surface, a strong 1054 mb high continues to dominate
across the Arctic, while a 982 mb has moved to near St. Matthew
Island this morning. These two features have increased the
pressure gradient across northern Alaska, resulting in strong
easterly flow. Strong surface high pressure will remain in the
Arctic into the middle of the week, slowing moving north and west.
Continued troughing in the Bering Sea during this period will
allow easterly flow to persist.

At 850 mb, temperatures will remain relatively steady through the
short term, with -10 to -20C in the Interior and North Slope,
while the West Coast ranges from the -1 to -10C range. A strong
cold core low will retrograde west across Canada, bringing
potential for widespread -20C in the Interior and North Slope by
the middle of the week.

Overall, temperatures will remain warmer than the last few days as
winds remain strong, with continued cloud cover and increasing
moisture, particularly across the West Coast and Western
Interior. Temperatures will take a downward trend going into the
middle of the week, with the level of how cold varying from model
to model at this point. A weather front will remain stationary
just off the West Coast today, before a new front pushes north
into the Western Interior by Monday night, bringing increasing
chances for snow anywhere south of the Brooks Range into Tuesday
morning.

Central and Eastern Interior...
A number of Winter Weather Advisories are in effect for highway
summits as blowing snow and winds gusting to 45 mph will remain an
issue for the next couple days. Chances for snow will increase for
portions of the Interior as a front moves north of the Alaska
Range on Monday. Snow amounts of 1 to 3 inches possible for areas
north and east of Fairbanks by Tuesday morning. Temperatures will
remain near normal going into the middle of the week.

North Slope and Brooks Range...
Strong east winds are causing areas of blowing snow down to a half
mile for areas of the Western Arctic Coast, resulting in a Winter
Weather Advisory through this evening. Winds are expected to
remain in the 25 to 35 mph range for the short term, concentrated
mostly along the western portions of the North Slope. Temperatures
remaining near normal going into Wednesday.

West Coast and Western Interior...
A weather front over the Bering Sea is causing snow, blowing snow
and strong east winds over St. Lawrence Island this morning. Total
snow accumulations of 1 to 3 inches with localized amounts up to 5
inches are expected for St. Lawrence Island through this
evening. Strong east winds will continue for the region through
the short term, with areas in the Western Interior expected to
have occasional visibility issues in blowing snow. Temperatures
will be above average today, then decrease and be below average by
the middle of the week.

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

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory for AKZ201-AKZ213-AKZ216-AKZ217-AKZ218-
AKZ219-AKZ220-AKZ221-AKZ222.

Heavy Freezing Spray Warning for PKZ210-PKZ220-PKZ225.

Gale Warning for PKZ200-PKZ210-PKZ220-PKZ225-PKZ230.

Brisk Wind Advisory for PKZ215-PKZ235-PKZ240.
&&

DEC 20