High Wind in Alaska, December 22 to 23, 2017

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
409 AM AKST Fri Dec 22 2017

.DISCUSSION...

Models...Very good run to run continuity continues for the short
term as all the models are doing well in developing the ridge and
agree on its evolutions. Beyond the short term, models continue
to struggle, but at least with this set of solutions there is some
agreement on moving the long wave trough over the state in the
extended periods. Current surface solutions initialized well
against the 22/06Z surface analysis. Solutions are all pretty
similar in the short term precipitation locations, so will use
the SREF to get slightly higher probabilities.

Aloft...Ridging continues to build over the state with the axis
lying from a 563 dam high the Northeast Gulf of Alaska to Tok to
Fort Yukon to Prudhoe Bay and north over 150W. Ridging extends
west over the Gulf of Anadyr, northwest over the Chukchi Sea and
Dateline, north to 80N, and northeast over the Beaufort Sea. 540
dam or greater cover most of mainland Alaska. By Friday evening
the high will be just south of Beaver Creek YT at 562 dam with
ridging extending west over the Eastern Bering Sea and Gulf of
Anadyr, northwest over the Siberian Arctic, north over the high
Arctic, and northeast over the western Canadian Archipelago with
540 dam heights over most of mainland Alaska and extending north
to 80N in the Arctic. By Saturday night the high moves just
northeast of Eagle at 562 dam and ridging extends west over the
Bering Strait and Eastern Bering Sea, northwest over the Siberian
Arctic, north over the high Arctic, and northeast over the
Canadian Archipelago, and heights start falling below 540 dam over
the southwest mainland. And by Sunday evening the high will be
400 nm northeast of Point Barrow at 559 dam with ridging extending
north over the Pole, and south over the Southeast Panhandle, and
heights continue to fall over the southwest mainland, Lower Yukon
Delta and Western Seward Peninsula. At 850 hpa...Temperatures
slowly warming with a large bubble of warm air developing over the
interior and extending over the Arctic. The warm air will remain
in the area through Sunday morning then a cooling trend will bring
temperatures back below zero by midweek.

Surface...Active pattern continues over the Eastern Bering Sea
with several lows and fronts that will move northwest over the
Eastern Bering Sea bringing precipitation to the lower Yukon Delta
and St Lawrence Island through the weekend. Pressure gradient gets
pinched over the northeast Bering Sea and Bering Strait today as
a 976 mb low moves from Cold Bay to the Gulf of Anadyr by late
this evening. A 987 mb low will move to Cold Bay late this
evening, and move to St lawrence Island by Sunday morning at 994
mb. Over mainland Alaska High pressure pushing east out of the
Yukon Territory will be dominant with a 1044 mb high in the Upper
Tanana Valley and Central Yukon Territory and a 1039 mb high in
the Copper River Basin. Leeside troughing remains in place north
of the Brooks and Alaska Ranges and will persist into Saturday.
Gap winds through the ranges and with the high building over the
Upper Tanana Valley and Yukon Territory, Tanana Valley Jet winds
have kicked in and extend from Delta Junction west to Nenana. The
south flow over the interior will bring warm air aloft to the
hills which will enhance the inversion in the Middle Tanana
Valley as good radiation cooling, and the lack of solar heating
contributes to the heat loss at the surface around Fairbanks.

Arctic Coast and Brooks Range...A relatively quite period the next
couple days as the main activity will be west of Wainwright. Some
clouds moving through, but not expecting much precipitation. Ridge
will move north along the AlCan through the weekend, so not much
change through at least Monday. As the ridge moves offshore, the
low stratus will return and that will bring a chance of Freezing
Drizzle starting Monday. Temperatures on the coast a bit cooler
with offshore flow sending the cold interior air over it. Winds
will generally be southeast becoming east to northeast Sunday
night. Strong winds in the Brooks Range passes continue so Winter
Weather Advisories remain in effect.

West Coast and Western Interior...Strong northeast to southeast
winds will continue today and even strengthen a bit as a low moves
to the west of St Lawrence Island and into the Gulf of Anadyr
pinching the pressure gradient across the area. Not expecting much
blowing snow south of Nome, but from Nome north Blowing snow will
be impacting visibilities with near Blizzard conditions possible.
No change in the current hazard products, or strong wind headlines
that are currently in effect. Temperatures not changing much, but
like the Arctic it will be mainly offshore flow, so cooler air
from the interior will help to cool the temperatures a few degrees
over the next couple days. Coastal Flood potential continues
around the Gambell Airport.

Central and Eastern Interior...Some clouds moving across the area
today, but clearing later this afternoon across the area. Gap
winds continue in the Alaska Range Passes and the Tanana Valley
Jet has kicked in, but winds will continue to increase into the
afternoon. Still expect some local blowing snow to reduce
visibilities today. Winds have settled down on the Steese Highway
Summits, but the should pick up a bit on the Elliott Highway
Summits west of Livengood tonight as a bubble high develops north
of the Ray Mountains, so expect some local blowing snow issues,
especially in the Ptarmigan Pass area tonight and Saturday.
Inversion will remain strong in the Fairbanks area, so even with
the strong winds in the Alaska Range no warming expected in the
valleys around Fairbanks. The hills will remain much warmer
enhancing the inversion.

&&

Coastal Hazards for days 3 and 4...None.

&&

Extended Forecast for days 4 to 7...There is a little better
agreement in the models than there has been the last few days with
the long wave trough moving over the state on day 6 with a chance
of snow across the area.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

Coastal Flood Advisory for AKZ213.

Winter Storm Warning for AKZ211-AKZ213-AKZ214.

Winter Weather Advisory for AKZ205-AKZ206-AKZ225-AKZ226.

Heavy Freezing Spray Warning for PKZ210-PKZ220.

Gale Warning for PKZ200-PKZ210-PKZ215-PKZ220-PKZ225-PKZ230.

&&

SDB DEC 17