Gale Warning 527, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
551 PM AKDT Wed Sep 17 2025

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

Much of Southcentral Alaska is experiencing a late-season,
summer-like day with mostly clear skies afforded by a mid-level
ridge lifting through the region this afternoon. Adding to the
feeling of summer is synoptic southwesterly flow aiding a sea
breeze along the western Kenai Peninsula. To the east, a compact
low is moving inland southeast of Yakutat. Its front, which
extends northwest into the Copper Basin is already beginning to
shift back to the east and precipitation has cleared out of all
but the southern Copper Basin along the Edgerton Highway and the
southwestern slopes of the Wrangell Mountains. This evening will
briefly be calm and dry before a series of upper-level shortwaves
eject out of a broader longwave trough shifting east from the
Bering Sea beginning tonight.

The details of the forecast remain unresolved in the upcoming
messy pattern. However, some things are certain. In general,
expect moist southerly flow with a series of weak features
traversing the Gulf of Alaska into Southcentral. This will promote
periods of rainfall over the Gulf with upslope showers along much
of the north Gulf coast Thursday and Friday. Periods of light
rain are also possible for inland locations as more potent
shortwaves lift past the mountains. However, the timing is unclear
at this time. There is some agreement in high-resolution guidance
suggesting that rain showers could spread past the mountains
Thursday morning with the first shortwave trough in the train.
Showers may also spread inland Thursday night as a weak front
lifts past the coastal mountains. Accumulations would be fairly
light. Friday night into Saturday, more coherent low pressure
tracks across the southern Gulf, weakening the southerly flow
along the north Gulf coast or even shifting flow to weak northerly
across Southcentral. This reversal of flow will result in a
drying trend both along the coast and inland for at least some
portion of this weekend.

Quesada

&&

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

Overcast to mostly cloudy skies persist across Southwest Alaska
this afternoon due to mid-level clouds streaming in from the
southeast from a remnant area of low pressure northeast of Kodiak
Island. Farther west, a nearly stationary 984 mb low just to the
north of the Western Aleutians, with its front extending southeast
across the Eastern Aleutians and Alaska Peninsula, and a weak
area of low pressure sitting to the south of Sand Point.

Jet level flow is mostly zonal with a mid-level shortwave lifting
northeastward from the North Pacific towards the front and a
larger upper low over the Western Aleutians. The low weakens
slightly before evolving into a complex low, which keeps showery
and windy conditions in place for the near term. By late
Wednesday, the shortwave reinvigorates the front and increases
rainfall coverage from the Pribilof Islands southward to Cold Bay.
Most of the operational models have the complex low moving
eastward across the central Bering and Pribilof Islands Thursday
morning. This feature lingers across the eastern Bering through
Friday afternoon, keeping low impact weather as the main story for
much of the western domain through the end of the short term.

-AM/ER

&&

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

Upper level low pressure is expected to linger in the Gulf of
Alaska from the weekend through mid-week. Shortwave troughs and
embedded surface lows will bring enhanced periods of rain and wind
to the north Gulf coast. The heaviest rain and strongest winds
look to stay in the Panhandle, but Prince William Sound and the
Eastern Kenai Peninsula will see plenty of moisture and wind in
coastal waters as well. There is some uncertainty in the
orientation of the low as it progresses through the beginning of
the week, which will greatly impact the ability for showers to
develop across inland areas. The suggestion of southwesterly
upper level flow would be favorable for precipitation up Cook
Inlet and into the Mat-Su Valleys, though rain should remain
relatively light in these areas if it does develop.

Persistent northerly flow across western Alaska and the Bering
Sea will bring a cooling trend to the region as overnight lows are
expected to dip into the 30's for portions of southwest Alaska.
The combination of cold air advection and a tight pressure
gradient will bring gusty winds through gaps and passes of the
Alaska Peninsula and Eastern Aleutians on Sunday and Monday. The
Aleutian Chain will see another round of rain and wind on Tuesday
while the rest of Southwest remains dry for the remainder of the
long term forecast period.

&&

.AVIATION...

PANC...VFR conditions will persist through the TAF period. Light
northwesterly winds this afternoon will shift to the southeast as
winds out of Turnagain Arm develop and move over the terminal.
Occasional gusts around 20 kts are possible late tonight through
early Thursday morning before diminishing. A stray shower is also
possible early Thursday morning. Any precipitation that does
develop looks to be be very light with ceilings remaining VFR.

&&