Gale Warning 540, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
524 AM AKDT Mon Sep 22 2025

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

Discussion:

Water vapor imagery shows a complex low still spinning over the Gulf
with several shortwaves rotating around the a rather elongated
center. The stronger of these shortwaves are positioned to the south
and east. A weaker wave is slowly pushing westward across Prince
William Sound and the eastern Kenai Peninsula, but will be hard-
pressed to make it too much farther westwards before stalling as the
parent low shifts off to the east. Back to the west, a trough moving
inland from the Seward Peninsula will bring a front across the
Alaska Range and the Susitna Valley today. Radar reflectivity has
picked up again over the Cook Inlet up into the Mat-Su Valleys this
morning as convergence increases between the two aforementioned
features. However, precipitation chances will start drop off as the
Gulf low moves off to the east with the exception of the Copper
Basin.

In addition to lingering showers over much of Southcentral this
morning, a moist boundary layer will allow for some areas of fog to
develop. Any fog that develops should scour out by mid to late
morning as drier air starts to work in. Shortwave ridging over the
Inlet this afternoon will strengthen the gradient over the Kenai and
Chugach Mountains resulting in a period of gusty winds for Whittier
and Passage Canal through tonight. Gale force winds are also
expected to to continue along the east side of the AKPEN today and
the Barren Islands through tonight.

Tuesday brings cooler and drier conditions for western Southcentral,
but continued unsettled weather for the north Gulf Coast and Copper
Basin as troughing reestablishes over the northern Gulf. There is a
chance that a bit of light snow could fall in some of the higher
elevations of the Talkeetna and Chugach Mountains as the upper
trough moves through tonight into Tuesday morning. A strong Bering
low and associated front will bring widespread rain to the Gulf
coast midweek, while cross-barrier flow likely leaves much of inland
Southcentral downsloped and mainly dry.

- PP

&&

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

Currently, there is a ~990 mb surface low meandering just east of
Kodiak Island coupled with a transient ridge draped farther west
across the Central Aleutians. The pressure gradient between the
two features is ushering in reinforced northerly to northwesterly
small craft winds across Bristol Bay, along with the continuation
of gap winds for the AK Pen through favored bays and passes. The
prolonged northerly flow has worked to cool much of Southwest
Alaska due to cold air advection, which in turn will keep
overnight low temperatures to near freezing for the next few
mornings. Looking westward to the Western Aleutians, satellite
imagery shows the outer fringes of a gale force front from a
rapidly deepening low pressure system moving into the western
Bering Sea.

By midday today, the front will reach the Adak and Atka islands
with a corridor of southeasterly gales. Due to a deep tropical
moisture fetch, there will be likely be locally heavy rainfall
rates as the front passes from west to east. A theta-e ridge
builds in this afternoon across the waters of the Pacific side of
the Central Aleutians, which warrants the threat of lightning
strikes from any isolated thunderstorms. This localized area of
instability moves eastward and just south of the Chain through
Tuesday morning. Progression of the front is expected to be
relatively fast, which will limit rainfall totals to an inch or
less for just about any given location along the Chain through
Tuesday morning. Gap winds for the AK Pen also subside at around
this time as ridging begins to flatten to the west and the low in
the Gulf of Alaska moves farther away and weakens, which will help
to decrease the pressure gradient.

From Monday night into Tuesday, a corridor of even stronger winds
wrapping into the southern side of the Bering low will spread
across the entire southern Bering Sea and Aleutian Chain in the
wake of the front. Guidance develops a sting jet curling southeast
around the low late Monday into Tuesday, which coupled with
additional support from multiple shortwaves transiting over the
Chain, will support a region of storm force sustained winds. Storm
force winds will arrive near Adak and Atka by noon Tuesday. Peak
wind gusts around this timeframe for Shemya, Adak and Atka are
between 55 and 70 mph. By Tuesday night, the low center will reach
the Pribilofs as it finally begins to weaken, while high-end gale
force winds persists across much of the southern Bering and along
the central/eastern Aleutians. However, a shortwave rounding the
upper levels of the low may promote another push of storm-force
winds into the Nikolski and Unalaska islands. The westerly wind
core is currently expected to move over Nikolski and Unalaska
directly by early Wednesday morning. This feature does have some
degree of uncertainty in the model guidance, so stay tuned as we
resolve the rest of this event. By Wednesday afternoon, the low
will likely weaken significantly as 500 mb negative (anti-
cyclonic) vorticity advection moves north to south over the
Bering. A ridge looks to build across the central Bering Sea in
the wake of the surface low.

-AM/CL

&&

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

The latter half of next week will see a lingering trough over the
Gulf of Alaska while high pressure builds into the western
Bering. A strong pressure gradient between the two features,
situated atop the Eastern Aleutians and Alaska Peninsula, should
finally be weakening, with small craft to gale force northerly
winds to persist over portions of the Aleutian Chain Thursday and
Friday. Ongoing northerly flow into Southwest Alaska will also
help to usher in colder temperatures for the duration from
Thursday into Sunday with potential overnight lows dipping into
the upper 20s/low 30s for some locations.

Due to how far south ensemble guidance is putting the trough over
the Gulf of Alaska, Southcentral should be relatively dry with
the exception of the locations along the Gulf Coast and within
upslope flow over the coastal mountains. Similarly, the Bering is
also favored to be less wet while high pressure overspreads the
region, though low stratus and fog may prevail in the place of
precipitation. Elsewhere, southwest flow into the Western
Aleutians may maintain a chance for at least isolated showers
through the end of next week into the weekend.

BL

&&
.AVIATION...

PANC...Variable to light northerly winds expected through the
period. Rain showers will gradually dissipate through Monday
afternoon with periods of scattered to broken IFR/MVFR this
morning becoming VFR after 00Z.

&&

SPECIAL WEATHER STATEMENT
National Weather Service ANCHORAGE AK
106 PM AKDT Mon Sep 22 2025

AKZ781-785-787-231300-
Southern Alaska Peninsula-Eastern Aleutians-Central Aleutians-
Including the cities of Cold Bay, Sand Point, False Pass,
Unalaska, Akutan, Nikolski, Atka, and Adak
106 PM AKDT Mon Sep 22 2025

...STRONG GUSTY WINDS EXPECTED THROUGH WEDNESDAY NIGHT...

A rapidly strengthening storm-force low will bring a prolonged
period of strong, gusty winds as it moves across the Bering Sea
through Wednesday. Expect south to southeasterly winds along the
low's front, followed by a longer duration of westerly winds
behind the front. Forecast wind speeds and timing:

- Central Aleutians (Adak and Atka): This afternoon through late
  tonight, south to southeasterly winds gusting up to 50 mph.
  Tuesday morning through Tuesday night, westerly winds gusting up
  to 70 mph. Winds peak Tuesday afternoon and slowly diminish
  through Wednesday morning.

- Eastern Aleutians (Nikolski, Unalaska, and Akutan): Late tonight
  through early Tuesday morning, south to southeasterly winds
  gusting up to 50 mph. Late Tuesday afternoon through Wednesday
  morning, westerly winds gusting up to 70 mph. Winds peak late
  Tuesday night/early Wednesday morning and slowly diminish
  through Wednesday evening.

- Southern Alaska Peninsula (False Pass, Cold Bay, King Cove):
  Tuesday morning, southeasterly winds gusting up to 50-60 mph.
  Wednesday morning through late Wednesday afternoon, westerly
  winds gusting up to 65 mph. Winds peak late Wednesday morning
  and diminish through Wednesday evening.