991
FXAK68 PAFC 070051
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
451 PM AKDT Mon Oct 6 2025

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 2)...

A passing trough through Southcentral led to some light rain
during the morning hours across much of the region. An area of low
pressure, induced by leeside troughing over the Western Alaska
Range, has shifted east from Cook Inlet and is now passing
Montague Island south of Prince William Sound. This low will scoot
into the eastern Gulf tonight with precipitation largely coming
to an end across Southcentral by Tuesday morning. The pattern
becomes increasingly amplified on Tuesday with high pressure
ridging over the Gulf and interior Alaska, while a broad trough
tracks across the Bering.

While no significant weather is forecast in the short term, an
increasing pressure gradient tonight between a ridge building
from the west and a surface low in the northern Gulf will allow
for gusty westerly winds through Whittier to near 30 knots. The
pressure gradient will do an abrupt 180 degrees on Tuesday night
as the Bering trough and its front push into the Western Alaska
Range and high pressure builds over the Gulf. Beginning in the
evening hours tomorrow and increasing through the overnight hours
will be the development of an easterly Turnagain Arm wind that may
persist into the morning hours on Wednesday. The arrival of the
trough will also see the pressure gradient tighten from the
Shelikof Strait up into Cook Inlet, with 25 to 35 knot southerly
winds gusting to as high as 40 knots. Southerly winds across the
higher elevations of Southcentral will increase through the day on
Wednesday as the trough lifts northeastward. The Copper River
wind, in particular, is expected to intensify Wednesday morning
with southerly gusts along the Richardson Highway in the 35 to 40
mph range.

The biggest forecast uncertainty over the next few days entails
precipitation amounts across Southcentral on Wednesday. The highly
amplified pattern will result in a strong baroclinic zone
extending from the Alaska Peninsula up into the Western Alaska
Range. This zone will be characterized by broad difluent flow
aloft and a plume of deeper moisture advecting into interior
Alaska within the stronger southwesterly flow within the
baroclinic zone. Forecast models have a shortwave trough ride over
the Gulf ridge, with moisture spilling into the Susitna Valley
initially, before expanding east and southeast into the Talkeetnas
and Western Chugach. As a result, the Anchorage Bowl could see a
few hundredths of an inch to up to a tenth of an inch of rain,
while areas on the hillside may see a quarter of an inch of more.
The mountains will likely see the the most rainfall with the bulk
of precipitation to fall through the morning hours. Further north,
the Mat-Su Valleys could see anywhere from a tenth to two-tenths
of an inch of rain.

BL

&&


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

Key Messages:

* Upgraded Coastal Flood Watch to a Coastal Flood Advisory for
  the Kuskokwim Delta Coast and Nunivak Island from Tuesday
  morning through Wednesday morning.

* Special Weather Statement for strong gusty winds along the
  Southern Alaska Peninsula Tuesday through Tuesday night.

Discussion:

NE-SW oriented front tracks over the Western coast of Alaska on
Tuesday. A surge of gusty southwesterly winds 45 to 55 mph will
bump against the Kuskokwim Delta coast Tuesday afternoon through
Tuesday night, beginning to diminish into Wednesday morning. This
push of gusty winds will raise water levels along the coast,
resulting in potential coastal flooding in low lying areas.
Elevated water levels are expected during the high tides on
Tuesday morning across Nunivak Island, and later Tuesday night
along the Kuskokwim Delta coast. Thus, the Coastal Flood Watch has
been upgraded to a Coastal Flood Advisory for Nunivak Island and
the Kuskokwim Delta Coast Tuesday morning through Wednesday
morning. Strong gusty southerly to south-southwesterly winds are
also expected along the southern AKPEN Tuesday through Tuesday
night where winds could gust between 50 to 65 mph. Winds along the
southern AKPEN also diminish Wednesday morning.

An area of low pressure is currently spinning up in the North
Pacific south of the Western Aleutians. This new low will quickly
deepen as it moves into the western Bering by this evening. This
new Bering low will also absorb the low near the Kamchatka
Peninsula tonight as it lifts northward while continuing to
deepen. Tropical Pacific moisture and plenty of warm air will also
be drawn northward as an atmospheric river looks to bring
moderate to heavy rain across the Western Aleutians today and the
Central Aleutians and Pribilof Islands for Tuesday. Moderate to
heavy rain makes it to the Eastern Aleutians for Tuesday evening
with light to moderate rain for coastal Southwest Alaska and the
AKPEN. Rain lingers along the AKPEN and Southwest before tapering
off to showers during the afternoon with more persistent showers
remaining confined to the mountain ranges through Wednesday
evening.

Cold air will begin to filter back into Southwest Alaska on
Wednesday.

&&


.LONG TERM FORECAST (Days 4 through 7: Friday through Monday)...

Southcentral Alaska will see high pressure build in on Friday,
leading to a decrease in precipitation chances and lower wind
speeds. Saturday sees a front move into the Gulf of Alaska in the
evening. This front will come with a large fetch of moisture,
allowing rainfall to begin in Kodiak Island, eventually moving up
into Cook Inlet. Sunday is more uncertain, but steadier rainfall
may move into the Anchorage and Mat-Su Valley regions. Winds will
increase, but are not expected to be very gusty. Lighter winds
aloft means that rainfall is more likely in the aforementioned
areas due to a lack of downsloping. Prince William Sound should
see heavy rainfall at this point as the front progresses eastward.
Sunday night sees a bit of a break in active weather due to
slight ridging before another front from the west moves into
Southcentral Alaska. This front will bring even more rainfall and
this time, gustier winds.

Starting from the beginning in Southwest Alaska has a front moving
through the Bering. By Friday night/early Saturday morning, gusty
winds will push into the Kuskokwim Delta Coast, causing water
levels to rise and may cause low level flooding. Weak ridging
builds in on Saturday over the Southwest mainland and the Eastern
Aleutians. This is short lived and a strong low that is associated
with the remnants of Halong moves up into the Bering. There is
some uncertainty with its intensity, but a swath of storm force
winds in the Central and Eastern Aleutians, then the Pribilof
Islands is likely. The low will quickly move northward and then
weakens by Monday. Behind the low is yet another low. Gale force
winds along the Aleutian Islands and along the Southwest Mainland
coast are possible by Monday afternoon. There is some
disagreement with the track and strength of the low, but models
are not too far off from one another.

-JAR

&&
.AVIATION...

PANC...Scattered showers will linger into this evening as an area
of low pressure moves over the Kenai Peninsula and out into the
northern Gulf. Periods of IFR to MVFR stratus will move in behind
the low with ceilings expected to then improve by early Tues
morning. Turnagain Arm winds with the potential to bend into the
terminal will again be possible Tues night into Wed.

&&


$$