Storm Warning 168, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
550 AM AKST Fri Dec 12 2025

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

Key Messages:

- Winds increase again tonight for most locations, especially in
  Valdez, Seward/Resurrection Bay, as well as the waters around
  Kodiak Island. Northeast winds increase Saturday afternoon
  through Monday across the Matanuska Valley. Confidence is
  increasing that wind gusts approach 60 mph in the Matanuska
  Valley for Sunday night and Monday. Still some uncertainty on
  the duration of how long gusty winds last.

- High Wind Watches were upgraded to Warnings for both Valdez
  (northeast gusts up to 70 mph) and Thompson Pass (northeast
  gusts up to 75 mph) starting early Saturday morning into
  Saturday night.

- Cold temperatures and wind chills persist through next week,
  despite a slight warm up for today. The Cold Weather Advisory
  has been extended through next Fri afternoon for the Copper
  River Basin and through the Thompson Pass area. Cold air across
  Southcentral has caused some rivers to begin freezing quickly.
  There could be some ice jamming of rivers as they freeze over. A
  hydrological outlook has been posted.

Preparedness Actions:

- Prepare for the strong winds returning later today and
  persisting through the near future. Be sure to secure anything
  that could blow around by strong winds.

- You can reduce your risk of hypothermia or frost bite by
  protecting your skin from exposure and wearing appropriate
  clothing while outdoors. Keep emergency supplies with you in
  your home and while traveling whenever possible. Consider
  wearing your cold weather gear while you are driving through
  frigid temperatures. Know the signs of hypothermia and check on
  others.

Discussion:

Strong high pressure continues to take up real estate over the
Bering Sea with northerly flow spanning across Alaska. A trough is
over the Gulf with a weak low circulating well offshore towards
Southeast Alaska. As this trough moves out of the area to the
south and high pressure builds in, winds will gradually decrease,
becoming mostly calm until later today, except for a few
lingering gusts across Whittier/Passage Canal, Valdez, and
Seward/Resurrection Bay.

The relatively calm, but very cold conditions will continue
through this morning. However, by later this afternoon, a strong
upper trough drops into Southcentral. The first effect of this
trough is gusty winds in Whittier and Seward, reaching over 40 mph
through Saturday. Then, gusty winds return to the Matanuska
Valley, mostly picking up in earnest Saturday afternoon and
evening with gusts up to 50 mph, and Valdez, picking up beginning
overnight tonight with gusts 60 mph to 70 mph. Higher gusts up to
75 mph are likely across Thompson Pass. Snow showers may occur
Friday across the Copper River Basin and northern Susitna Valley
as the 500 mb trough arrives. Any snow is expected to be light in
nature, up to 0.5 inch.

Another round of cold air also arrives on Saturday with this
trough. Apparent temperatures have the potential to be just as
cold or perhaps even colder with this arctic airmass. The Climate
Prediction Center's outlook for the next couple weeks continues to
favor towards colder than normal for most of the state. Cold
temperatures with the overall synoptic pattern persisting also
favors gap winds. Timing and intensity of the cold and winds will
continue to be the primary forecast challenge across Southcentral
through the next week.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3/Today
through Sunday)...

Very little change to the forecast is noted across Southwest
Alaska and the Bering Sea this morning. A digging trough through
interior Alaska will bring a reinforcing shot of Arctic air
southward across the region through tonight. The strongest cold
air advection (and associated gusty winds) will be across the
interior Southwest AK, Bristol Bay and the Alaska Peninsula.
Increasing winds will ramp up over the latter half of the day
today, then persist through the weekend. The north-northeast
orientation of the low level flow should be unfavorable for gap
winds along the Alaska Peninsula. Instead, winds will be uniformly
strong (not just confined to gaps), particularly for the coastal
marine zones south of the Alaska Peninsula and Kodiak Island.

After warmer morning low temperatures on Friday, temperatures
will steadily cool through the remainder of the weekend with highs
returning to the single to below zero temperatures. The warmest
temperatures will be found across the Western and Central
Aleutians. Southeasterly to southerly flow around the base of a
blocking ridge will bring above freezing temperatures in the upper
30s/low 40s from Unalaska to Shemya.

BL/SEB

&&

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

This weekend, an expansive area of high pressure will be centered
over the northern Bering Sea and extend across the rest of the
Bering Sea. This high pressure will aid in pulling Arctic Air
south across the state, causing a trough to dig across the
southern mainland and around a low in the Gulf of Alaska. This
will create the potential for another round of prolonged high
winds through gaps and passes, cold temperatures, and wind
chills. A shortwave low will descend from eastern Russia Monday
afternoon, but remain offshore until it crosses the Alaska
Peninsula by Tuesday morning. A complex surface low in the Gulf of
Alaska could retrograde just enough early next week to bring some
light snow to the north Gulf coast and parts of the Copper River
Basin, but forecast confidence is still low. Otherwise, dry
conditions continue region-wide, which could persist for the next
several weeks as this general pattern of cold, dry weather looks
to stick around.

&&

.AVIATION...

PANC...Light northerly winds and VFR conditions persist today.
Northerly winds will begin increasing this evening and continue
into Saturday. Wind gusts 30 to 40 knots are expected at the
terminal by Saturday afternoon.

&&