Unalaska, Alaska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

260
FXAK68 PAFC 060100
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
400 PM AKST Fri Dec 5 2025

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

Weather still remains very active across Southcentral Alaska with
the threats of snow, blowing snow, strong winds, and dangerously
low wind chills through the end of the weekend.

...Active Warnings and Advisories...

- A High Wind Warning has been issued for the Matanuska Valley
  from 8PM this evening to 11PM Sunday for 30 to 40 mph winds with
  gusts up to 80 mph.

- A Wind Advisory has been issued for Anchorage and the NW Kenai
  Peninsula from 11PM this evening to 11PM Sunday. North winds of
  20 to 30 mph with gusts to 50 mph expected. Strongest winds
  expected along the Knik Arm and West Anchorage and out along the
  coast of the northern Gulf coast.

- A Blizzard Warning has been issued for Thompson Pass until 6AM
  Sunday for blizzard conditions and 7 to 14 inches of snow. Winds
  could gust as high as 60 mph. Wind chills falling to as low as
  35 below zero by Sunday morning.

- A Blizzard Warning has been issued for Broad Pass, Richardson
  Highway from south of Isabel Pass to Paxson, and along the Tok
  Cutoff from Mentasta Pass to north of Gakona from 6PM this
  evening to 9PM Sunday due to blowing snow with winds gusting to
  50 mph. Wind chills dip as low as 15 to 25 degrees below zero,
  falling further to 25 to 40 degrees below zero by Sunday.

- A Winter Weather Advisory remains in effect for the Copper River
  Basin until 5PM Saturday for 2 to 10 inches of snow and blowing
  snow. The lowest totals will be west of Glennallen, and the
  highest totals will be south and east of Glennallen.


Discussion:

As of 3PM this afternoon, the remnants of a lingering surface
trough draped across the coast coupled with a Gulf low and its
front is producing widespread snowfall across eastern Prince
William Sound areas as well as the southern half of the Copper
River Basin, mainly south of the Glennallen. The original
thinking was the front/surface trough was going to move farther
inland, keeping the coldest air locked away for a little longer.
That did not materialize, which in effect has dragged the areas of
highest amounts of snow southward. Because of these players just
mentioned, the advertised arctic airmass is spilling into
Southcentral a little quicker than expected, as shown by latest
500 mb heights showing a faster progression of a digging arctic
trough. With the airmass coming in faster, this should allow for
much of the Copper River Basin`s snowfall to be confined south and
east of Glennallen with a northerly dry wind shutting off
snowfall sooner than expected. The 850 mb temperature gradient is
tightening as the Copper River Basin continues to dive into the
deep freeze with temperatures a good 10-15+ degrees warmer for
areas on the southern side of the Chugach. As the arctic trough
pinches off into a closed upper level low and greatly amplifies
the 500-850 mb pattern, a very strong northeasterly low level jet
and a roaring 500 mb jet begins to develop this evening. At the
surface, a strong thermal and pressure gradient will frame the
setup for a high wind event for the Matanuska Valley tonight into
Saturday morning - and to a lesser extent, the Anchorage area and
a few points north and south. For the Matanuska Valley, though the
most impactful element here will be wind, one cannot ignore the
magnitude of the arctic air moving across the region. Falling
temperatures and high winds mean the threat of dangerously low
wind chills, potentially pushing 20 degrees below zero. Likewise,
high winds will easily blow around the recent powdery snowfall
from last night along with any other transportable snow. Southward
to Anchorage and the NW Kenai Peninsula, the lower/upper level
jet looks to move over the Knik Arm, Glenn Highway, clip
Anchorage, and affect western most parts of the NW Kenai
Peninsula. The other big story with much colder air spilling
across the region is a significant increase in drainage gap winds
out of typical gap locations, which introduces the likelihood of
heavy freezing spray for marine areas such as the Copper River
Delta. For areas across eastern Prince William Sound into the
Valdez area, accumulating snowfall is looking increasingly less
likely, except for perhaps a short period late Saturday morning to
Saturday afternoon.

The sharp upper trough/upper level low digging well into the Gulf
will help to spin up a a complex area of low pressure with
multiple compact low pressure centers Saturday morning. Windy
conditions along with a shield of snow will continue to overspread
eastern Prince William Sound to the lower Copper River Basin
through Saturday afternoon. Some of the high resolution guidance
wants to spin up a low much closer to the Prince William Sound,
and tries to retrograde the low and bring precipitation back
across the eastern Kenai Peninsula - though this solution is
looking less likely. Blowing snow and the threat of ground
blizzards is what prompted the Blizzard Warning for Broad Pass,
Richardson Highway from south of Isabel Pass to Paxson, and along
the Tok Cutoff from Mentasta Pass to north of Gakona. Again, this
is not for additional snowfall, but rather transportable snow that
has already fallen that will be kicked up with high winds. The
last main takeaway from this weather pattern shift is the
dangerously cold wind chills. In areas with wind chills falling to
as low as 35 below zero, frostbite may occur in as little as 10
minutes on exposed skin.

-AM

&&


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

The short term forecast is characterized by an Arctic trough
dropping into Southwest Alaska, bringing gusty winds and very cold
temperatures to much of the mainland and snow showers to the
Aleutians and Alaska Peninsula regions this weekend. Strong winds
in the Kuskokwim Delta may loft snow on the ground from the
previous weather event from Kipnuk north and west and north and
west of Bethel during the weekend. Due to the threat of blowing
snow, a Blizzard Warning has been issued for the aforementioned
regions. Also, the very cold air will move over considerably
warmer ocean temperatures (30s), leading to numerous snow showers
initially over the Eastern Aleutians and the Alaska Peninsula and
later the rest of the Aleutians. This, combined with strong winds
could lead to blowing snow and low visibility. A Winter Weather
Advisory has been issued for the Alaska Peninsula due to this
potential for blowing snow. Another threat with the cold and winds
is wind chill. The Kuskokwim regions could see wind chills 35F
below zero for a period. Bristol Bay will see wind chills from 20F
to 30F below zero, especially in the Dillingham region. A Wind
Advisory as been issued for the Dillingham area highlighting the
gusty winds and wind chill threat this weekend.

Monday sees winds start to lighten up as the Arctic trough moves
south of the Bering. However, the Arctic air mass will remain in
Southwest Alaska, so negative temperatures in the mainland will
persist into next week. It is likely that a long duration of cold
temperatures will persist even past next week as a large blocking
high sets up in the Bering, allowing Arctic air to continue
spilling into Southwest Alaska.

-JAR

&&


.LONG TERM FORECAST (Days 4 through 7: Tuesday through Friday)...

The long-term pattern will favor mostly quiet conditions across
the Southern Mainland. However, gusty gap winds will continue to
filter through the favored terrain and gaps as a cold airmass
looks to linger across the area. This is especially true for the
gaps across Southcentral such as Seward, Valdez Narrows, Whittier,
Thompson Pass, and the Matanuska Valley. Where some active
weather will occur will be across the southern Alaska Peninsula
and Eastern Aleutians as a shortwave drives southward from Siberia
to over the area Wednesday. This weak system could bring brief
visibility reduction with snow showers moving from north to south
off the Bering Sea. Also on Wednesday, a Kamchatka low sends a
front eastward across the Western Aleutians bring a round of gusty
southeast winds and gale-force winds across the marine zones of
the Western Aleutians. This front weakens as it moves eastward
through Friday. There is still some uncertainty on the eastward
progression due to the strength and progression of a broad ridge
over much of the Bering and mainland Southwest Alaska.

&&
.AVIATION...

PANC...VFR conditions will persist through the afternoon today.
Northerly winds coming out of the Matanuska Valley look to
increase this evening and clip the terminal. Initially, with
freshly fallen snow from last night, visibilities may be reduced
to high-end MVFR in blowing snow this evening into the overnight.
Any lingering MVFR conditions due to blowing snow will abate very
early Saturday morning with VFR returning predominantly through
the rest of the TAF period. Northerly wind gusts between 40 and 50
mph will be common Saturday morning. Wind gusts diminish to 30 to
40 mph Saturday afternoon before picking back up to 40 to 50 mph
late Saturday evening through Sunday morning.

&&


$$