High Wind Watch 10, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
426 AM AKST Thu Dec 18 2025

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

No big changes in the forecast or forecast reasoning. Winds in
the typical channeled areas including, the Matanuska Valley,
Valdez, Seward, and Whittier are expected to remain elevated
today. A Wind Advisory has been issued for the Matanuska Valley
and Valdez due to persistently gusty winds. Winds in the Matanuska
Valley should diminish this evening (though remaining elevated to
some extent), but Valdez is expected to have higher winds due to
a shortwave dropping from the north.

With the pressure gradient remaining tight along the Gulf coast, gap
winds around Kodiak Island, Seward and Whittier will remain gusty
for the foreseeable future with only short-lived breaks in wind
at times. The continued northerly flow means that dry conditions
remain, with occasional high clouds moving in. Cold air advection
and lower winds will allow temperatures to cool to the single
digits across Southcentral with low spots in the Copper River
Basin dropping below -20F and -30F.

Friday into the weekend will see a couple of shortwaves dropping
in from the north. Friday's shortwave will allow for increased
wind speeds in Valdez. The Matanuska Valley could see a period of
gusty winds on Friday, but that is starting to look less likely.
The stronger shortwave arrives Saturday evening into Sunday. This
one is expected to track more to the west, meaning that more
significant gusty winds are possible for the Mat-Su Valley and
Anchorage at that time, but winds are not expected to be as strong
as either of the past two weekends. Valdez will still see gusty
winds with this shortwave as well. Confidence is growing in the
track, but some changes are still possible.

&&

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

Key Messages:

- A weak trough brings snow to the Kuskokwim Delta and rain/snow
  mix to the Eastern Aleutians/Alaska Peninsula today

- Warming trend begins today and continues into Saturday morning.

- Gusty northerly winds continue for the AK Pen and Eastern
  Aleutians through the weekend.

Discussion:

A flattened ridge of high pressure will allow for a fast-moving
trough to cross the Kuskokwim Delta, Eastern Aleutians and Alaska
Peninsula today. Light snow will overspread the Kuskokwim Delta
this morning through the evening hours. Beginning in the afternoon
hours and continuing into Friday morning, this front will bring
rain/snow mix to the Alaska Peninsula and Eastern Aleutians.
Snowfall amounts in the Mainland range from a half an inch to as
much as three inches in the mountains. A trace of snow is expected
for the AKPen and Eastern Aleutians before warmer air changes the
snow to a rain/snow mix. Warmer air remains in these areas
through Saturday morning when an Arctic airmass returns.

Northerly winds persist into the weekend in the AKPen and Eastern
Aleutians as the aforementioned high and trough remain quasi-
stationary through Saturday. Saturday, another trough moves onto
the Mainland bringing the return of precipitation.

- Johnston

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

Strong high pressure continues to be situated over the North
Pacific and extend north into the Bering Sea. To the east, over
the Gulf of Alaska, lower pressure dominates. As a result, gusty
gap winds will continue across the Alaska Peninsula and through
the western Gulf into next week. There continues to be good
agreement that a shortwave trough diving south across Southcentral
Alaska this weekend leads to another period of enhanced winds. As
a result, there is some potential for high winds through typical
areas, including the Matanuska Valley and the Valdez area/Thompson
Pass. Notably, however, this event looks to be fairly short-
lived in comparison to recent events, with winds peaking overnight
Saturday night and diminishing into Sunday.

Temperatures remain below average across Southcentral
Alaska, with the coldest area being the Copper River Basin, where
ambient temperatures will hover in the range of 20 to 40 below
zero. Southwest Alaska, however, will see warmer, somewhat moist
air ride up and over the ridge, bringing increased potential for
precipitation. A series of low pressure systems track up the
coast of Far Eastern Russia toward Western Alaska through mid-week.
This increases chances for precipitation in Southwest Alaska
Sunday onward. Precipitation is likely to be mostly snow, though
rain is possible along the coast and is increasingly likely
southward along the Alaska Peninsula. Southcentral Alaska looks to
remain mostly dry and downsloped in northwesterly flow, though
chances for some light snow to make it past the Alaska Range
increase for Tuesday night and Wednesday as low pressure
potentially tracks into the Gulf from Southwest Alaska.

Quesada

&&

.AVIATION...

PANC...VFR will prevail through the TAF period. Northerly winds will
taper off by late this morning.

&&