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FXAK68 PAFC 140022
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
422 PM AKDT Sun Jul 13 2025

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through
3/Today through Wednesday evening)...

Currently, Southcentral is being influenced by an upper ridge
that is slowly moving eastward. The ridge is allowing for calm and
mostly clear skies during the day across Southcentral. However,
elevated instability from weak shortwaves is allowing showers and
thunderstorms to form in the western and northeastern parts of
the Copper River Basin.

This all changes on Monday as a pattern shift occurs. The ridge
will move eastward into Canada and replacing it is a troughy type
of pattern. Shortwaves push in and shift flow southwesterly,
which will advect moisture into the inland areas of Southcentral.
This will allow for widespread cloud cover and occasional rainfall
across most areas of Southcentral, with higher elevations seeing
more rain. There still is a bit of uncertainty with the spread of
the rainfall, so some areas may get more or less depending on
which scenario pans out. However, most guidance does have a line
of rainfall stretching from Anchorage to Palmer by Tuesday
morning, so there is some more confidence in that region. Wind
speeds will increase to an extent, but will remain on the lighter
side for inland areas. Gap areas and the Cook Inlet will have
breezy winds. A weak Turnagain Arm wind is possible in Anchorage
Monday afternoon due to coastal ridging east of the Chugach
Mountains. This pattern continues into Tuesday morning. By Tuesday
afternoon, a ridge builds into the Gulf of Alaska. This ridge
will cause much of Southcentral to dry out. Higher elevations
could see some lingering light rainfall through Tuesday evening.

On Wednesday, a north Pacific low will approach from the west.
This is where things get complicated as model agreement decreases.
Some guidance has the low swing into the Gulf of Alaska, whereas
other guidance has it crossing Kodiak and then taking a northward
turn. Regardless, an associated front will move into Southcentral,
bringing rainfall to the coast and into the Kenai Peninsula.
However, it is uncertain how wide the front will be and how far
inland it will travel. It may track more eastward and bring
more rainfall to Prince William Sound or it may stay more to the
west and bring greater rain chances to Anchorage and the Mat-Su
Valleys.

-JAR

&&


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

Afternoon showers persist across Southwest Alaska, while fog and
low stratus have relented in the Bering Sea. A weak low south of
the Aleutian Chain will bring additional showers to the Eastern
Aleutians and Alaska Peninsula. Farther west, a front pushes into
the Western Bering Sea.

For Southwest Alaska, continued onshore flow today will bring in
cooler and more stable conditions, increasing potential evening fog
and low stratus in coastal areas. Slight chances for afternoon/evening
thunderstorms continue Monday, continuing across the Lower
Kuskokwim Valley and Western Alaska Range before a broad shortwave
trough lifts through the region, which will promote widespread
showers. Increased stability is expected to reduce the chances for
thunderstorm development. Expect high temperatures near 60
degrees for much of Southwest Alaska, with slightly higher
temperatures for the Lower Kuskokwim Valley and interior Bristol
Bay. By late Tuesday, a low lifting up from the North Pacific will
bring steady rainfall to the Alaska Peninsula and Bristol Bay for
Wednesday morning.

For the Bering Sea and Aleutian Islands, the front moving in from
the west will bring southwesterly winds of 20-30 knots with gusts
up to 40 knots and steady light to moderate rain. By Monday
afternoon a strengthening low near the Kamchatka Peninsula could
bring gales to the Western Bering Sea. Enhanced southerly gap
winds appear likely as the front sweeps across the Aleutian chain
as far east as Unalaska. Current guidance indicates weakening
winds on Wednesday prior to the front reaching the Southwest
mainland.


&&

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

The long range forecast for the region starts with a low in the
northwestern Gulf of Alaska and another low in the western Bering
Sea. Models are continuing to struggle with the placement and
evolution of the low in the Gulf of Alaska. The GFS moves the low
to the northeast into Canada by Friday afternoon, the Canadian
shows the low tracking to the north and being absorbed into the
aforementioned Bering low, and the ECMWF has the Gulf low moving
due east then dissipating before reaching the Alaska Panhandle by
Friday evening. Therefore, confidence on precipitation and sky
conditions is still low. Towards the end of the longterm, a
blocking high pressure pattern builds across the Copper River
Basin and should promote a better chance for less clouds and drier
conditions. With little mixing, air quality could become an issue
in the region.

In the Bering Sea, the low pressure system generally remains over
the Bering during most of the longterm while high pressure
strengthens over the AK Mainland. The main uncertainty with the
Bering low is in regards to how it interacts with surrounding
shortwaves/lows and the speed of its surface front. The GFS
solution would push the front quickly across SW AK and portions of
Southcentral (with the bulk of precipitation across SW on
Saturday morning), whereas the Canadian front is slower (with the
bulk of precipitation across SW on Sunday morning). Nonetheless,
expect an active pattern out west during the long term period.

-DD

&&


.AVIATION...

PANC...VFR conditions will generally persist throughout the TAF
period. Uncertainty remains if the previous ~4.5kft marine
ceilings will move back into ANC with tonight as much of the deck
has eroded this afternoon. A shortwave trough lifting into
Southcentral amidst southwest flow will bring lower ceilings and
some rain into the area Monday morning, though cats are by and
large expected to remain VFR to high-end MVFR.

&&


$$