Gale Warning 774, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
535 AM AKST Thu Nov 30 2023

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

Model guidance continue to improve on the track and strength of a
low currently in the central Gulf of Alaska that will weaken from
982 mb located near 58N and 148W early this morning to an open
wave as it pushes north into Western Prince William Sound this
afternoon. This low will bring yet another round of rain and snow
to Eastern Kenai Peninsula and along the coast. Snow rates will
pick up again this morning with 1 inch per hour rates expected
through Turnagain Pass and where 8 to 10 inches of snow is
expected through late this evening. Heavy snow is also expected in
Whittier and along Turnagain Arm where up to 6 inches of snow is
expected through this evening. Gusty winds will develop along the
Anchorage Hillside as well as Turnagain Arm this afternoon. These
downsloping winds will win over upper level lift and will limit
snowfall in the Western Kenai Peninsula, Anchorage area as well as
the MatSu today as the low weakens and makes landfall as a trough
over Prince William Sound this evening. Expect Gale force winds
in the northern Gulf of Alaska and Prince William Sound to weaken
to small craft as the low pushes north and weakens this evening.

A second complex low pressure system in the Northern Pacific has
the models baffled on position and track over the next several
days with large spread on the track and to a lesser degree the
strength of the low. Regardless of the track of the low which at
this time takes it east along the southern portions of the Gulf of
Alaska, the pressure gradient between the low and a high pressure
system over the Yukon will help enhance off shore flow and gap
flows along the northern Gulf of Alaska Friday and into Saturday
while the precip shield with this low clips Kodiak Island and the
Southern Kenai Peninsula and stays south of Prince William Sound
and the Gulf Coast. A drier and colder pattern with more
seasonable temperatures and gusty outflow winds will lead us into
the weekend.

-CC

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA AND BERING SEA/ALEUTIANS
(Days 1 through 3: Today through Saturday night)...

A longwave upper-level trough with multiple embedded lows
stretches along the Aleutians and into the Gulf and central
mainland Alaska. The main embedded upper low and its attendant
surface low are located near Shemya this morning, while a
secondary low has formed south of the Pribilof Islands. A third
low south of the Alaska Peninsula is exiting into the Gulf today.
This system continues to produce widespread precipitation mostly
in the form of rain, although a rain/snow mix is occurring ahead
of the front for the Pribilof Islands, eastern Aleutians, and
AKPen this morning. Widespread easterly gales are located across
the much of the Bering while westerly-southwesterly gales blanket
the Aleutian Chain. A swath of storm force winds over the Pacific
waters just south of the western Aleutians will diminish to high
end gales later this morning. Generally active weather will
continue across the Bering and Aleutians into the weekend as the
main low near Shemya lingers and slowly drifts into the North
Pacific by the end of the weekend. The low currently south of the
Pribilof Islands is expected to weaken as it tracks east towards
Southwest on Saturday, enhancing changes for scattered
precipitation across land. By late Saturday, a ridge of high
pressure nudges eastward into the Bering and western Aleutians.

As for Southwest weather, intermittent light snow will continue
over interior Southwest through Friday. Expect mostly overcast
skies and seasonal temperatures to set in through the weekend,
with increasing chances for coastal snow showers as the trough
over the Bering slides east.

-AF

&&

.LONG TERM FORECAST (Days 4 through 7)...Sunday through Wednesday...

A broad upper level trough extends across the Bering into the
Gulf of Alaska for Sunday. A North Pacific low merges with a low
in the Eastern Bering through Tuesday, which continues into the
Gulf of Alaska by Wednesday. Widespread precipitation with periods
of locally heavier precipitation spreads across the Gulf Monday,
extending inland through Wednesday. Large areas of gale force
winds develop along the Alaska Peninsula and move over the Gulf
beginning Monday. Chances of higher surf along the Bering side of
the Alaska Peninsula Monday through the forecast period. High end
gales force gap winds around Kodiak Island expected Monday through
Wednesday, diminishing, but linger along the Alaska Peninsula
through Wednesday.

A short wave ridge pushes across the Bering for Sunday, briefly
breaking up the trough, but flattening out through Wednesday.
Further west, another closed low exits the Russian Far East sets
up its Eastward push. Gusty winds approaching gale force moves
into the Western Aleutians and Bering.

Kutz

&&

.AVIATION...

PANC...VFR conditions Thursday morning, then MVFR to IFR for
Thursday afternoon as a light wave of snow passes through the
terminal area. VFR conditions return Thursday evening and persist
through Saturday afternoon.

&&