Gale Warning 6, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
520 AM AKST Wed Jan 1 2025

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)...

Discussion:

Very quiet over most of Southcentral this morning...with the
exception of Kodiak Island and the central Gulf where strong winds
and rain continue this morning. With that said, however, winds are
starting to decrease as the center of the stacked low has moved to
just south of Dutch Harbor/Unalaska area. Kodiak may see a brief
uptick of winds as a shortwave rotates around the east side of the
low, lifting up towards Kodiak Island and the AKPEN later this
morning. Steady rainfall and gusty winds will then rapidly decrease
behind the shortwave. Across Southcentral, generally clear skies and
colder temperatures prevail, though some fog has redeveloped in the
lower valleys of the Copper River Basin.

Beyond today, the main focus will turn towards very cold
temperatures working into Interior Alaska and pouring into the
Copper Basin as an Arctic airmass surges southwards Thursday night
into Friday. This airmass will eventually spread across most of
Alaska, Canada, and the Northern Plains and Great Lakes Region. The
Copper River Valley is already seeing temperatures in the negative
20s this morning, but will see even colder temperatures by Friday
morning as the cold air really begins to settle in. While Thursday
morning also looks very cold, it may depend on fog potential as to
how low temperatures will fall. Right now, temperatures look to
readily fall between minus 30 to minus 35; however, if fog holds off
and the area sees maximum radiational cooling and light
winds...Thursday morning lows could be lower. Friday morning looks
to have better conditions as the Arctic airmass moves in, and will
may see an uptick in winds. As such, a Cold Weather Advisory may be
warranted if temperatures continue to trend towards 40 below. And
while not as cold as the Copper Basin, the rest of Southcentral will
also see much colder temperatures by late this week into the first
weekend of the new year.

The other focus will be the north-to-south gap flow winds to
increase in response to steepening gradient over the coastal
mountains, and the cold, dense Arctic airmass surging southward.
Thompson Pass could see gusts of at least 50 mph with Valdez and the
associated gap regions also seeing winds increase Thursday into
Friday. The Copper River Delta and Knik areas will also see
increasing winds, and may see some dust being lofted depending on
the extent and depth of existing snow cover.

- PP

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days
1 through 3)...

Precipitation is clearing out this morning for the Pribilofs as
the band moves west and a ridge builds across the Bering Sea from
Mainland Alaska. A low continues to linger near the Alaska
Peninsula and eastern Aleutians with its center just south of
Unimak Pass. Gusty easterly winds and rain showers associated with
this low will continue to weaken through tonight, though
precipitation is not expected to completely clear out of the area.

With offshore flow across Southwest Alaska, expect cooling
temperatures and clearing skies over the next few days. The
breeziest locations look to be through Bristol Bay from about
Koliganek to the Dillingham (gusts around 25 to 30 mph) and the
Kuskokwim Delta (gusts up to 30 to 35 mph) through the rest of
the week. Friday and Saturday are expected to be the coldest days
this week with morning wind chills dipping into the minus 20s
(degrees Fahrenheit) for the Kuskokwim River communities. Locally
colder locations near Stony River and Sleetmute could dip just
below minus 30. Cold, offshore winds will promote heavy to extreme
freezing spray (2 to 4 cm per hour) near Nunivak Island Thursday
night and expand west of Nunivak Island, to approximately 50
nautical miles off the ice edge by Saturday morning.

Looking at the western Aleutians/Bering Sea, a short wave trough
is lifting north and south of Kamchatka, a low is tracking toward
the western Aleutians. This low is expected to bring gale force
winds tonight into early Thursday morning with storm force gusts
possible. As the front lifts north, flow becomes predominantly
zonal across the Bering Sea. Easterly gales will spread across
the central Aleutians and most of the southwestern Bering
for Thursday. This trend continues to spread northward and
eastward through Friday, though confidence decreases with
determining the strength and location of the strongest wind
speeds. A swath of storm force gusts is possible across Adak and
into the southern Bering Sea, but models differ with the
characteristics of the low. Easterly gales could spread as far as
the Alaska Peninsula Friday and Unalaska has the potential to get
east winds gusting to 50 mph as the front moves through. If
compact low centers develop around the periphery of the parent
low, the chances of exceeding 50 or 60 mph will become more likely
for the eastern Aleutians and the southern Bering Sea to about
the Pribilofs.

Rux

&&

.LONG TERM FORECAST (Days 4 through 7: Saturday through Tuesday)...

A broad upper level low stretches from Eastern Asia across the
Bering into Western Alaska through the forecast period. This low
area will be meandering around the Bering through next week. Most
of the Arctic regions remain under an equally broad upper level
ridge, while another ridge over Southeast Alaska and Western
Canada sets up over most of Interior Alaska. Temperatures as low
as 40 below are expected across the upper and Central Copper River
Valley Saturday and Sunday. The Gulf of Alaska section of the
ridge helps sustain deep onshore flow from the Alaska Peninsula
and Kodiak Island across the Southcentral coastal zones through
the weekend.

Transitory North Pacific lows and fronts will bring some moderate
rains from the Eastern Aleutians to the Canadian border through
Tuesday. Areas away from the coast will remain cold enough to add
some additional snow. A strong North Pacific low Monday will
spread heavy rain and gusty winds across the Gulf with winds
approaching gale force near Kodiak Island. Affected rain areas
include from the Eastern Aleutians, AKPEN/Bristol Bay and
Southwest Alaska to Kodiak Island and Prince William Sound over to
the Canadian border through Tuesday. This low will sweep Westward
over the Shumagin Islands for Tuesday. In the West, a moderately
strong surface low and its elongated front press along the Western
and Central Aleutians spread locally heavy rains and gusty winds
through the period. The pressure gradient across the Bering
combined with outflow winds from Western Alaska will be sufficient
for widespread gale force winds over the Central and Western
Bering through Monday morning, diminishing Tuesday.

&&

.AVIATION...

PANC...VFR conditions and light northerly winds will persist.
Mid-level clouds may increase for a brief period this morning.

&&