Area Forecast Discussion
Issued by NWS Anchorage, AK

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884
FXAK68 PAFC 060033
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
333 PM AKST Wed Feb 5 2025

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

Discussion:

A weak shortwave trough will continue to work its way around the
eastern periphery of the upper ridge, and across the Copper Basin,
this afternoon and evening. The system will allow a slight
reinforcement of colder air to filter in on the backside of the
system allowing temperatures across the upper Susitna Valley and
Copper Basin to see lows drop back down to zero to ten below by
Thursday morning as cloud cover mostly clears overnight. The wave
did little but dampen the ridge amplitude slightly, and the upper
ridge will quickly build back over the the Gulf and much of mainland
Alaska by this weekend. This will allow for continued dry weather
for Southcentral with periods of low stratus or fog for some of the
interior valleys and areas along the Cook Inlet that typically like
to fog in with a strong low-level inversion set-up. With surface low
out in the Gulf quickly dropping southwards tonight, gusty winds in
Whittier/Passage Canal and Seward/Resurrection Bay will decrease as
gradient slackens. The gradient looks to linger a bit longer along
the northern Gulf coast keeping winds gusty for the Copper River
Delta and Valdez areas.

-PP

&&


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

The large ridge of high pressure that has persisted all week
continues to persist in the southwest mainland. As a result of the
stable air mass, chances for fog remain in The Kuskokwim Delta
and especially Bristol Bay. Once again, the fog becomes sporadic
in the daytime hours as solar heating increases in magnitude each
day due to higher solar angles. The fog usually builds back in
during the nighttime hours and will continue to do so for the
next couple of days, particularly in Bristol Bay. Moisture is
flowing around the ridge and some of it is making into the Bethel
region, especially closer to the coast. Temperatures in this
region are around freezing, but temperatures aloft are expected to
remain cold enough to prevent freezing rain from becoming an
issue. Precipitation that falls will likely be in the form of a
rain/snow mix. By Thursday afternoon, the ridge will expand
northwards, markedly decreasing chances for precipitation in this
region, though lingering showers could be possible through Friday.

The eastern Aleutians`, Alaska Peninsulas`, and Pribilofs`
weather are currently influenced by the giant ridge that is in
place, bringing drier, warmer weather with some fog as well. On
the other hand, the western Aleutians from Shemya to Adak are
currently experiencing rainfall and higher wind speeds as a north
Pacific low rises from the south. As this low rises, it will start
attacking the ridge, slowly pushing it eastward. Heavier
precipitation and gale force winds will impact the Adak region by
Thursday afternoon. By Friday, a second low center will swing
around the first one, pushing the ridge even further and breaking
its hold on the eastern Aleutians and Alaska Peninsula as more
shortwaves follow from behind. Gale force winds and heavy
precipitation will impact the Fox Islands, Pribilof Islands and
the Cold Bay region by Friday afternoon.

By Saturday, the ridge will be in full retreat eastward, allowing
frontal systems to impact the southwest mainland. Wind speeds will
increase along the coast, including the Kuskokwim coastline, where
coastal flooding could occur by Sunday as multiple frontal waves
impact the area over the weekend and beyond, keeping wind speeds
elevated. Warm air will stream into the southwest mainland,
increasing temperatures over the weekend. However, temperatures
aloft will rise above freezing first as the surface flow remains
offshore, while winds aloft become onshore. This could give the
Bristol Bay region around Dillingham a chance of a snow/freezing
rain mix by Saturday afternoon before winds shift more southerly
on the surface and warm the area above freezing.

-JAR

&&

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

On the Alaska Weather map, a broad upper level low over the
Bering continues to weaken with several shortwaves troughs
rotating through the pattern. A low center over the Western
Aleutians slowly retreats towards Kamchatka through midweek. The
active weather events have been slowly spreading Eastward through
the forecast period. An broad upper level ridge remains over
Mainland Alaska, slowly weakening as the shortwaves transit across
the Northern edges. A deterministic GFS/ECMWF and Canadian blend
supports the larger scale elements into the new week, with the
most uncertainty associated with the smaller details moving
through the flow. Forecast models change over to an ensemble blend
to carry the features through Wednesday.

The forecast period opens with the first of a series of lows and
fronts These systems will bring widespread snow over most of the
Northern Bering changing to locally moderate rain and gusty winds
across the Eastern Aleutians, Alaska Peninsula, Kodiak Island and
into Bristol Bay and Southwest Alaska Sunday. A well developed low
and front moving into the Western Aleutians Sunday spreads a
repeated round of locally heavy rain and gusty winds across the
Aleutians and Bering through Wednesday. An opening period of gale
force winds are expected over the Western Aleutians diminishing
Monday. A third low and front repeats the process across the
Western Aleutians and Bering for Wednesday. Mainland Alaska`s
relatively quieter weather continues through midweek.

-KZ

&&

.AVIATION...

PANC...Light winds will persist. Periods of fog and low stratus
will likely develop again overnight and then slowly dissipate late
morning to early afternoon Thursday.

&&


$$