755
FXAK68 PAFC 231339
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
539 AM AKDT Sat Aug 23 2025

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

Southcentral is generally under clear skies with just a few areas
with patchy fog. Cloud cover will increase through the day as a
short wave rides across the elongated upper level ridge that is
over Southcentral. This is not a strong shortwave and any rain is
expected to remain along the Alaska Range for today. This ridge
will be weakening and edging farther to the south by Sunday as a
front moves into Southwest Alaska and tries to edge a little
farther south into Southcentral. This could bring rain as far
south as Talkeetna by Sunday afternoon, but more likely on Sunday
night. The rest of Southcentral is still expected to remain dry
with the rain mostly likely for the Susitna Valley.

The gap winds in the typical locations such as Turnagain Arm and
near the Copper River are expected to develop today and mainly
keep going into Monday.

Looking ahead to early next week... Zonal flow will transition
back to meridional as a trough digs into the Bering and down
towards the Northern Pacific. While this system looks to bring
moderate to heavy rainfall for Southwest Alaska, it is a bit too
early to really zero in on how impactful this system will be for
Southcentral. Right now, it seems probable that western areas of
Southcentral, the Kenai Peninsula, and Kodiak Island will see some
rainfall from this system by midweek.

&&


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

Key Points:

* Continued widespread fog and low stratus clouds across the
  Bering Sea, Aleutians, and affecting mainland Southwest Alaska
  each night/morning through the weekend.

* A persistent tap of tropical Pacific moisture combined with
  multiple storm systems will lead to a much wetter pattern across
  mainland Southwest Alaska starting Sunday for northern parts of
  the southwestern mainland.

* Confidence is increasing that the corridor of heaviest rain
  Sunday night through Monday will be across the Kuskokwim Delta.
  The corridor of heavy rain shifts south to Bristol Bay starting
  Monday evening through Tuesday.

* Strong onshore flow and southerly winds early next week will
  also lead to higher surf across the Kuskokwim Delta Coast along
  with the likelihood of higher water levels.


Currently, an upper-level ridge over the North Pacific extends
northeastward over the Central and Eastern Aleutians, the Pribilof
Islands, and across the Alaska Peninsula (AKPEN) and into
mainland Southwest Alaska. Thus, fog and low stratus continue to
rule the roost across a large portion of the Bering Sea,
Aleutians, AKPEN, and across portions of mainland Southwest. A
weak frontal system continues to move inland of the Kuskokwim
Delta and Kuskokwim Valley this morning. Light rain associated
with this system will taper off from west to east through this
afternoon.

The next big weather-makers to affect mainland Southwest Sunday
through Tuesday first take shape along the Western Aleutians and
western Bering. The first of which is a strong tropical Pacific
moisture tap that is currently surging northward across the
Western Aleutians and western Bering this morning. Precipitable
water values with this moisture plume, according to the CIMSS
MIMIC Layer Precipitable Water satellite product, are between 1 to
1.5 inches across portions of the Western Aleutians and western
Bering this morning. Moderate to heavy rain will slowly work
eastward across the Bering and Western Aleutians today. Steady
rains reach the Pribilof Islands and Central Aleutians Sunday
morning and to Nunivak Island and the northern Kuskokwim Delta
Coast by Sunday afternoon.

Meanwhile, a low pressure system spins up in the North Pacific
Sunday morning and moves into the Bering through Sunday evening.
This will bring more moderate to heavy rain across the Western
Aleutians through Sunday evening. There is increasing confidence
that the system will track to just west and northwest of the
Pribilof Islands by early Monday morning and to the vicinity of
Saint Lawrence Island/Norton Sound by Monday evening. With this
track, a long fetch of southerly winds, up to gale-force, is
likely along the eastern Bering Sea and into the northern
Kuskokwim Delta Coast Monday morning through Monday night before
gales diminish back to small-craft winds Tuesday morning. Lower
than normal tides should help preclude coastal flooding from
occurring during this southerly push Monday morning through Monday
night. However, elevated wave heights (4 to 8 feet) are likely in
the coastal waters of the Kuskokwim Delta Monday morning through
Monday night as well as moderate to heavy rain.

The heavy rain threat then pushes eastward and inland to Bristol
Bay and the Kuskokwim Valley, as well as along the southern AKPEN
for Tuesday. In general, from Sunday morning through Tuesday
morning, 1 to 2 inches of rainfall is looking likely across
portions of Southwest. The higher-end totals look to be across the
northern coast of Bristol Bay and the Kuskokwim Delta Coast with
lower-end totals for the Kuskokwim Valley and the southern AKPEN.
Rain will continue for Wednesday though. Stay tuned as further
updates will likely be made as more details become clear with this
wet pattern shaping up.

&&


.LONG TERM FORECAST (Monday through Friday)...

The long term forecast is complex with an atmospheric river and
multiple waves bringing heavy rainfall and gusty winds to coastal
Southwest Alaska and eventually into Southcentral Alaska. Monday
has the main tongue of moisture along a front stretching from the
Central Aleutians, the Pribilof Islands, and the coastal Lower
Kuskokwim Delta. Heavy rain is expected wherever the moisture
tongue sets up. Gusty southwesterly winds will also impact the
coastal Lower Kuskokwim Delta especially around Nunivak Island.
Gale force winds are possible. Tuesday will see the front enhanced
by a longwave trough with its associated surface low that swings
into the Bering. Now, heavy rainfall additionally impacts the
Alaska Peninsula and the western capes of Bristol Bay. Gusty
southerly small craft winds will additionally affect the marine
areas of Bristol Bay. Wednesday is similar to Tuesday, with the
low in the Bering slowly moving eastward. Heavy rain continues in
Southwest Alaska. The gusty winds along the coast become more
southeasterly.

Thursday brings even more excitement. The tongue of moisture from
the atmospheric river now crosses into Southcentral Alaska.
Kodiak Island and the surrounding areas including Augustine Island
will receive heavy rainfall through Friday. Gusty winds up to
small craft are also possible in gap regions. Meanwhile, the low
will have moved into the eastern Bering just off the shore of the
Southwest Alaska mainland. Rainfall will extend further into the
mainland in southwest Alaska. The back end of the low will drive
gusty gale force winds in the Pribilof Islands and through gap
regions of the Eastern Aleutians and Alaska Peninsula. This day is
more uncertain as guidance has varying solutions regarding the
low`s position and the full extent of the atmospheric river in
Southcentral. Friday will finally see a ridge build into the
Bering, which will shut off rainfall and quiet down winds in
Southwest Alaska. The ridge will also bend the atmospheric river
away from the Gulf of Alaska, stopping rainfall there as well.
However, behind the ridge rides a new low that may bring another
bout of heavy rain and gusty winds to Southwest Alaska in the
future. Monitor the forecast for updates with this complex
pattern.

-JAR

&&

.AVIATION...

PANC...VFR conditions continue into the weekend. Coastal ridging
developing over the Gulf this afternoon, and a passing trough
through interior Alaska, will see Turnagain Arm winds return later
today. The strongest winds will remain offshore, but
southeasterly winds will increase over the terminal by this
evening and especially tonight, with gusts approaching 15 to 20
knots.

BL

&&


$$