Winter Storm Warning 22, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
317 PM AKDT Wed Oct 14 2020

.SYNOPSIS...
Winter has returned to the southeast Interior where a band of
light snow continues. Light accumulations have been reported
with webcams verifying the light snow accumulating on grass and
roads. Elsewhere, dry northeast low level flow dominates as
"average" temperatures finally encompass the Mainland after a
long period of well above average temperatures.

&&

.DISCUSSION...

Upper Levels and Analysis...
Broad upper level northwest flow dominates the Mainland as the
overall surface pressure gradient remains "offshore" which tends
to be dry for Mainland areas. Arctic air has settled back into
place with temps running near normal for the first time in a long
time. The Pacific jet is shunted well south over the North
Pacific, around 40N, with the only active area of light snow over
the southeast Interior. This is associated with a remnant upper
level front which will remain in place over the next 48 hours.
There is a digging shortwave trough over the Arctic which will
move into the Mainland tonight and tomorrow, bringing the next
slug of colder air southward.

Central and Eastern Interior...
Temperatures for most of the Mainland will continue on a downward
trend as another reinforcing arctic trough digs in tomorrow. This
will push overnight lows below normal for the first time in a
long time, with many areas seeing the first single digits of the
fall by Friday morning. Another band of snow will bring more
accumulations Wednesday through Thursday to the same areas that
got snow with the first band, mainly from Eielson AFB south to
the Eastern Alaska Range and east to the Fortymile Uplands. The
heaviest snow looks to occur over Mentasta Pass with much lighter
amounts in lower elevations valleys.

West Coast and Western Interior...
Dry and cool offshore flow continues through tomorrow. The pattern
shifts on Thursday as a front moves into the coast, bringing
southerly winds and increasing chances for mixed rain/snow to
coastal areas, especially the Seward Peninsula north to Kotzebue
Sound. The front will strengthen Thursday night and Friday as
winds reach gale force along coastal areas.

Extended Forecast Days 4-7...
Beginning the extended period forecast on Friday night, there will
be a large trough over the Bering with the front moving up along
the West Coast, and a shortwave ridge of high pressure over the
Mainland. Clear and cold will still be in place with below average
temps over the Mainland. The large Bering trough will slowly shift
east with a stronger southerly flow developing across the Alaska
Range. This will allow for a gradual warming trend with
increasing inland chances for precipitation Sunday through early
next week.

Coastal Hazard Potential Days 3 and 4...Elevated surf will
develop across northern Norton Sound as strong south winds
develop Friday. However, short fetch and no storm surge will keep
impacts minimal with no flooding or major erosion anticipated.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Heavy Freezing Spray Warning for PKZ230-PKZ235.
&&

AHSENMACHER OCT 20