Winter Weather Advisory 63, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
257 PM AKDT Tue Mar 30 2021

.SYNOPSIS...
Snow will persist today across much of the state associated with
low pressure centered over the northwest coast. Strong east winds
across much of the North Slope in conjunction with widespread
light snow are causing blizzard conditions along the coast. Snow
will taper off from west to east tonight as the low moves slowly
eastward, followed by clearing conditions and cold Arctic air
from the northwest. Snow showers will linger across the Interior
this afternoon, picking up in intensity tonight along the Alaska
Range with significant accumulation expected though early Thursday.
The next major Bering Sea storm is expected to impact the West
Coast late Thursday with strong winds and heavy snow before racing
eastward into the Interior late Friday into Saturday.

&&

.DISCUSSION...

Aloft 500 mb...
The longwave pattern remains very progressive as a series of waves
continue to track east across the Bering Sea. A deep longwave
trough axis runs from the western Interior into the North Pacific
with the 540 dam line around 48N. Ridging will push east across
the Bering Sea tonight, facilitating cold northwest flow onto the
West Coast as much of the Interior remains under the influence of
a broad trough with weak flow aloft. By late Thursday, the ridge
begins pushing into the Interior, supporting increasingly zonal
flow into the weekend as a deep Arctic low holds firm over the
Arctic Coast. The effect will be continued light snow over the
southern half of the state along with below average temperatures
for much of mainland Alaska from Thursday onwards.

Models...
Models generally agree on the above synoptic narrative through
the weekend, however the ECMWF depicts a much stronger ridge
developing over the North Pacific Sunday with some Omega block
characteristics. This serves to strengthen and slow progression of
the ridge, causing the model to stall a front over the central and
eastern Interior, resulting in copious snowfall. This seems
unrealistic at this time, so we will lean on a more GFS centric
solution in the short to mid term.

North Slope and Brooks Range...
Blizzard Warnings are in effect for much of the North Slope
through midnight, although ending sooner west of Utqiagvik as
winds gradually diminish there. East winds gusting up to 50 mph
along a slow moving front will support this long duration event.
Winds will gradually diminish tonight but gusts up to 40 mph will
persist across the eastern Arctic coast as late as Wednesday
evening. Low pressure centered over the western Brooks range will
drift eastward and weaken slowly through Wednesday, supporting
light snow across the region and gusty winds along the coast. Cold
Arctic air will begin to infiltrate the northwest coast tonight
as the system continues east, resulting in near to below average
temperatures going into the weekend.

West Coast and Western Interior...
Low pressure centered over the western Brooks Range continues to
produce snow across much of the region, though this will
gradually taper off along the coast this afternoon and Interior
overnight as Arctic high pressure builds southeastward into the
eastern Bering Sea. This will also serve to bring below average
temperatures to the region. Another Bering Sea storm is expected
to impact St. Lawrence Island and the Y-K Delta beginning late
Thursday with heavy snow and gusty winds. Impacts from this system
are expected to remain generally confined south of the Bering
Strait and lower Yukon Valley south of Huslia, however there is
potential for another blizzard along the immediate coast, as well
as copious snowfall into the Interior Friday.

Central and Eastern Interior...
Snow showers remain across the region staying generally north and
west of Fairbanks. This will persist into tonight and gradually
diminish into Wednesday. Chances for snow again increase beginning
late Wednesday into Thursday as frontal passage initiates a
northwesterly shift in winds along with an influx of much cooler
temperatures. Accumulations of 4 to 8 inches are expected south
and west of Fairbanks to Dot Lake. Up to 12 inches of snow is
possible through Thursday along parts of the Richardson highway
south of Delta Junction and Winter Storm Warnings have been issued
accordingly. A brief respite in snow is expected late Thursday
into Friday before the arrival of another plume of moisture
associated with the next Bering Sea low. Guidance hints at a slow
moving front meandering across the Interior through the weekend,
though there is significant spread in timing and placement, and
thus a wide spread in QPF. We will keep an eye on the development
of this system as it approaches the coast Thursday.

Coastal Hazard Potential Days 3 and 4...
Strong southwest winds moving to the Eastern Bering Sea will help
break up the sea ice edge and may push sea ice up on the coast
and into Scammon Bay. Storm surge associated with the low may be
pushed up through open leads in the ice along the Lower Yukon
Delta Coast as well.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning for AKZ217-AKZ218-AKZ219-AKZ223-AKZ226.

Blizzard Warning for AKZ201-AKZ202-AKZ203-AKZ204.

Winter Weather Advisory for AKZ222-AKZ224-AKZ225.

Gale Warning for PKZ210-PKZ220-PKZ240-PKZ245.

Brisk Wind Advisory for PKZ200-PKZ215-PKZ225-PKZ230-PKZ235.
&&

COWMAN MAR 21