Winter Storm Watch 14, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
307 PM AKDT Wed Mar 31 2021

.SYNOPSIS...

Active weather continues across the Interior with snow showers
falling from Galena to the AlCan Border and from the Alaska Range
to the Brooks Range. Heavy snow will continue through tonight from
Delta Junction to Dot Lake and south to the north side of the
Alaska Range. Visibility on the North Slope remains poor in wind
and blowing snow, though is expected to improve overnight as winds
diminish. Clearing skies and cooling temperatures will allow for
a pleasant, though short break in storminess on the West Coast and
Western Interior before a strong system brings heavy snow to the
West Coast on Friday and into the Interior for the weekend.

&&

.DISCUSSION...

Models...The forecast package today uses a general blend of
models for all fields. Models initialize well compared to
observations, though they under-do the strength of ridging aloft
in the Eastern Interior by about 2 decameters at 500 millibars.
Models remain in good agreement aloft through the the forecast
period, however large differences exist at the surface beginning
Friday morning. Forecast confidence is above average through that
time, but below average thereafter.

Aloft...At 500 hPa...Troughing is well established over the
mainland with a 514 dam low near Middleton Island and another near
Icy Strait. Weak ridging extends into the Eastern Interior, while
the West Coast south of the Bering Strait is under NW flow. This
pattern will persist as the low near Middleton Island moves SE
along the Panhandle before it gets far enough south to open the
door for westerly and southwesterly flow from the west coast into
the Interior. This happens as a 510 dam low moves from Siberia
into the Gulf of Anadyr on Saturday morning. The low near the
Panhandle continues moving south, forming a loosely bound Omega
Block over the north Pacific, with mainland Alaska in the
southwesterly flow area of the ridge.

Surface...A NW gradient is in place over the mainland with a 993
mb low in Prince William Sound, another 993 mb low over Burwash,
YT, a 1004 mb low near Anaktuvuk Pass, a 10 mb west to east
gradient across the Western Alaska Range, and a 1025 mb high 300
nautical miles north of Nuiqsut. High pressure from this extends
eastward over the Siberian Arctic and northern Chukchi Sea. This
setup along with easterly flow aloft in the Eastern Interior will
be favorable for snow wrapping in from the east for areas east of
Eielson AFB through tomorrow morning. A number of weaker surface
lows forming over the NE Brooks Range through Friday will keep
flurries and light snow possible in the NE portion of the state
through Friday. By late Friday morning, a 989 mb low will move
from the Kamchatka Peninsula to the Gulf of Anadyr, sending a
strong front to the West Coast. From this point, solutions differ
on the track of the low with the Canadian and NAM moving the low
to Norton Sound and inland much quicker than the GFS. The GFS
follows a similar track, but more slowly, allowing the low center
to collect more moisture from the North Pacific as it tracks
inland. The ECMWF has had the best run-to-run continuity with this
system, but sends the surface low north into the Chukchi Sea,
then inland across the Brooks Range. The NAM, GFS, and Canadian
all keep the low south of the Brooks Range.

All of these varying surface solutions tap a significant amount of
moisture from the North Pacific and bring it to the West Coast and
into the Interior. This gives us high confidence in an impactful
winter weather event this weekend throughout the entire Interior,
including Fairbanks. While the GFS/NAM/Canadian low track would
be favorable for mixed precipitation, enough cold air remains in
place that at this time the precipitation appears to all fall as
snow in the Interior, though this is something we will continue to
monitor. Storm total snow of 8 to 12 inches is possible from
Galena to McGrath to Fairbanks.

North Slope and Brooks Range...Easterly winds across the Arctic
Coast will ease overnight tonight and visibility will improve.
East winds will increase from Point Lay to Point Hope on Friday
and persist through Saturday. Light snow near Point Lay will
diminish overnight tonight, with just flurries possible east of
Atqasuk through Friday. Temperatures will cool to below normal and
remain below normal through the middle of next week.

West Coast and Western Interior...Snow showers in the Western
Interior today will diminish overnight tonight and give way to
clearing skies through tomorrow morning. Winds in the Kotzebue
Sound region will continue to diminish overnight. This break will
not last long though as another strong front will bring heavy snow
to St. Lawrence Island by late Thursday night, to the West Coast
by Friday, and to the Western Interior by Friday night.
Temperatures will cool through tomorrow night until warmer air
from the North Pacific is advected northward with the arrival of
the next system.

Central and Eastern Interior...Heavy snow falling from Delta
Junction to Dot Lake and along the north side of the Alaska Range
today will continue overnight. Accumulations will total 6-8 inches
in Delta Junction and east along the Alaska Highway, with a foot
of snow expected along the Richardson Highway from Delta Junction
to Black Rapids. North winds gusting to 35 MPH south of Black
Rapids may cause areas of blowing snow through tomorrow morning.
Accumulations of 3 to 5 inches are also expected from Eielson AFB
to Salcha, including the Salcha River drainage and surrounding
hills, as well as the Goodpaster River basin. Confidence is high
on an impactful winter weather event this weekend as the system
impacting the west coast on Friday progresses into the Interior,
though confidence in the details of it is low. See Discussion
above for current thoughts on models, tracks, and timing of the
heaviest precipitation. 8 to 12 inches of snow is possible from
Fairbanks to Galena to McGrath.

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

Extended Forecast days 4 through 7...Continued troughing over the
mainland with periods of westerly flow aloft will support chances
for additional snow next week throughout Northern Alaska.
Temperatures will remain below normal.

&&

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

Winter Weather Advisory for AKZ203-AKZ204-AKZ222-AKZ224-AKZ225.

Gale Warning for PKZ240-PKZ245.

Brisk Wind Advisory for PKZ200-PKZ210-PKZ215-PKZ220-PKZ225-
PKZ230-PKZ235.
&&

CHRIEST MAR 21