Gale Warning 546, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
514 PM AKDT Tue Sep 23 2025

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

Discussion:

It has been an active day of weather across Southcentral with
snowfall occurring from Paxson up into Isabelle Pass. Morning
webcams also revealed light snow accumulations up on several
mountain peaks across the Chugach and Talkeetnas with snow levels
at around 4000 feet. The passage of a trough has contributed to
off and on light rain for much of the lower elevations of
Southcentral. Here at the office we received 0.05 inches of
precipitation along with some very small graupel, the latter which
will be recorded as trace snowfall.

A front is overspreading Kodiak Island this afternoon and will
continue into Southcentral tonight. In addition to more rain,
gusty winds are forecast along and ahead of the front. A pre-
frontal trough will promote a brief period of easterly small craft
winds along the northern Gulf Coast into Prince William Sound
closer to midnight tonight. The bigger surge of winds will
accompany the Gulf front's arrival early tomorrow morning. A
barrier jet remains forecast to develop along the coast with high
end gales gusting to 50+ knots. Whitter and Portage Valley can
anticipated gusts ranging from 45 to 60 mph, with the Portage to
experience the higher end gusts as easterly winds are squeezed
through the terrain. Winds should peak in intensity late Wednesday
morning/early Wednesday afternoon, before quickly diminishing
tomorrow evening.

Winds across the Copper River Basin have already developed this
afternoon in response to the departing trough to the north and
coastal ridging ahead of the approaching Gulf front. Gulkana winds
have been gusting to 35+ knots with a peak wind near 40 knots.
Elevated winds will persist into Wednesday, but the stronger gusts
should gradually diminish through the overnight hours. Further to
the west, there had been an expectation for southeasterly
Turnagain Arm winds to develop and bend into Anchorage later this
afternoon. While Turnagain Winds have been blowing out over the
arm, the current thinking is that Cook Inlet winds will remain
down-inlet, sparing Ted Stevens and the southwest side of
Anchorage from the gustier conditions.

The pattern remains unsettled the next few days as Southcentral
remains largely on the downstream side of broader troughing. This
will keep rain chances in the forecast for the foreseeable future
as several smaller disturbances track through the region.

- BL

&&

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

Generally windy weather continues for the Bering Sea, Aleutian
Islands, and Alaska Peninsula. Minor shifts in the track and
behavior of the storm-force low in the Bering Sea have led to
adjustments to the forecast. This has primarily affected the
timing of peak winds, with forecast max gusts changing little from
the previous forecast package. Gusts of up to 65-70 mph are still
expected for the Central Aleutians, Eastern Aleutians, and
Southern Alaska Peninsula, with winds diminishing from west to
east by Wednesday night. More information about the timing of
these winds is provided in the Special Weather Statement. Gusty
winds continue for these areas after the passage of the low, but
winds will be lower than they've been for the past 24 hours.

For the remainder of Southwest Alaska, rain chances and winds have
been reduced as the low is forecast to elongate, with most of the
energy being shunted into the Gulf with a developing triple point
low. The next chance for more active weather will arrive late
Thursday into Friday, as a low moves off the Chukotsk Peninsula
in Russia and into the Eastern Bering Sea. There remains some
uncertainty with the track of this low, though the latest model
solutions suggest the strongest winds will remain offshore in the
Bering Sea. Still, with forecast confidence a bit lower at this
time, it's possible that the low track may shift eastward and
bring windier and wetter conditions to Southwest Alaska than
currently forecast. Stay tuned.

-KC

&&

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

Active weather will continue to be the mainstay through next week.
Out east, a big low pressure system that transited the AKPEN
Friday will move into the Gulf and slowly weaken through Monday as
it remains nearly stationary. Winds across mainland and most sea
locations are not expected to be strong, through some flow through
the Barren Islands may be elevated. Weak upper level waves may
rotate through the flow bringing showers to coastal locations, but
it is starting to look like there may be a reprieve from the
nearly continuous month of rain for the rest of the eastern
region. While there may be some light showers, it is looking as
though there will be more time of no rain than rain.

Further west, low pressure will dive from Norton Sound and merge
with the aforementioned Gulf of Alaska low into the weekend.
Meanwhile, high pressure south of Shemya will slowly drift east,
slowly dipping deeper into the Pacific. Between these two will be
strong northeasterly winds that will persist through for the AKPen
and western Alaskan coast. Beyond Sunday, model guidance falls
apart as they attempt to transition typhoon Neoguri, which is
currently east of Japan, into an extra-tropical cyclone that
advances on our western domain. Present thinking is that it should
remain south of the Aleutians Monday and Tuesday, not making an
impact for the Bering. Because of this, weather should be dry for
most of the period for mainland, with cold northerly wind keeping
temperatures down.

&&

.AVIATION...

PANC...An upper level short-wave trough will slowly lift from
Cook Inlet northeast across interior Southcentral through the
evening hours. Scattered showers around the terminal out ahead of
the trough will continue to move north and west away from the
terminal through late afternoon or early evening as the flow aloft
shifts southeasterly and increases. Ceilings are expected to
remain VFR, although ceilings could drop below 5,000 ft briefly in
any steadier rain shower.

Light northerly winds will continue into this evening. Winds may
then shift out of the southeast for a few hours tonight (between
6pm and midnight) as the aforementioned trough lifts north of the
region. Winds will then shift back around out of the north in
response to a down inlet pressure gradient as a potent frontal
system moves into the western Gulf.

Winds will remain northerly through Wednesday. A strong
southeasterly flow aloft will allow for downsloping, keeping most
of the precipitation associated with this front over the higher
terrain. Given the strong dynamics with this system, however, it
is not out of the question that some very light rain, or
sprinkles, may spill over the mountains and move over the terminal
for Wednesday.

Weak LLWS is possible early Wednesday morning. However, there
should be enough of a north-south pressure gradient to keep the
strongest southeasterly winds at mountain top level away from the
foothills of the Chugach Mountains.

-TM

&&