Unalaska, Alaska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

705
FXAK68 PAFC 050240
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
540 PM AKST Thu Dec 4 2025

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

...Products Issued...

1) A Winter Weather Advisory is in effect for Anchorage and Eagle
River (all elevations), and the lower Matanuska Valley until 7AM
Friday for 1 to 3 inches of snow (higher amounts on the Anchorage
Hillside, Eagle River, and Palmer) and a glaze of ice.

2) A Winter Storm Watch has been issued for the northern Copper
Valley, northern Susitna Valley, and Tok Cutoff from 6PM Friday to
3AM Monday for possible blizzard conditions. Up to 3 inches of
snow for Mentasta Pass and wind gusts up to 50 mph.

3) A Winter Storm Watch has been issued for Thompson Pass from
6AM Friday to 6AM Sunday for possible blizzard conditions and 8 to
16 inches of snow. Winds could gust as high as 55 mph.

4) A Winter Weather Advisory has been issued for the Copper River
Basin from 5PM this afternoon to 5PM Saturday for 4 to 12 inches
of snow. The lowest totals will be west of Glennallen, and the
highest totals will be south and east of Glennallen.

...Arctic airmass moves in this weekend...

A pattern shift will bring significantly colder temperatures for
everyone. The most affected locations will be the northern Copper
Valley, northern Susitna Valley, and Tok Cutoff. Northerly winds
will pick up this weekend and gust as high as 50 mph. Wind chills
will drop to 15 to 25 degrees below zero Friday night, and falling
further to as low as 25 to 40 degrees below zero by Sunday.

...Discussion...

This afternoon, the pattern continues to remain showery in
nature. A mixed bag of precipitation today is now showing signs of
tapering off across the Cook Inlet region, though the radar has a
difficult time resolving really low level precipitation. Most of
what is falling now is freezing drizzle mixed with a few sleet
pellets, but as advertised in the Winter Weather Advisory for the
area, a changeover to snow will ensue this evening and overnight,
resulting in mostly light snowfall and a glaze of ice. The 00z
sounding from PANC shows that dynamic cooling is helping to cool
the column, which has caused a reduction in the warm nose, and
steeper lapse rates overall as somewhat colder air moves in aloft.
500 mb heights help explain why precipitation has diminished some
across the Cook Inlet areas; the Cook Inlet region currently sits
in a col, which represents a lack in forcing in meteorology.

A positively tilted arctic trough digging across the mainland
from the northwest nears the Cook Inlet region Friday morning.
Upper level forcing just downstream of the trough will help to
spin up a surface low southeast of Kodiak Island, which will
quickly make its way northeastward across the northern Gulf
towards Yakutat Friday morning. Weak surface troughing and the
upper trough will also work in tandem to give the Cook Inlet areas
light to moderate snowfall rates overnight, accumulating to 1 to
3 inches, with higher amounts for the Hillside and northward up
the Glenn Highway. Any snow will come to an end Friday morning as
the trough moves away from the region.

The Arctic front pushes through Southcentral on Friday with
temperatures rapidly falling from north to south as the Arctic
airmass works into the region. These temperatures will likely be
the coldest so far this cold season with many areas across
Southcentral seeing temperatures fall below zero. The Copper Basin
could see temperatures fall into the minus 20s and dangerous wind
chills of -30 to -35 degrees. Lastly, the Arctic airmass will
also result in strong north/south gap winds for the Alaska Range
and typical spots across the southern Southcentral.

Heading into the weekend, Arctic air will become further
entrenched across much of Southcentral as an Arctic trough drives
south into the Cook Inlet and western Alaska Range. The intrusion
of very cold temperatures into interior valleys will continue to
fuel very strong and gusty winds through north-south oriented
gaps, including out of the Mat Valley, Thompson Pass, and all the
major passes along the northern Alaska Range. Wind gusts could
peak as high as 45 to 60 mph across parts of the Mat Valley and
through Thompson Pass, and up to 40 mph through Broad Pass,
Isabel Pass and Mentasta Pass. These intense gap winds coupled
with plenty of transportable snow at pass level could lead to
significant blowing snow, including potential for ground blizzard
conditions along the northern mountain passes starting as early as
Friday and persisting well into Sunday. Thompson Pass is more
likely to see both falling snow and blowing snow as moisture near
a quasi-stationary low developing over the Gulf wraps northwest
around the digging upper low/trough shifting into the western
Gulf. Prolonged blizzard conditions are likely through Thompson
Pass starting by Friday night and likely persisting until at least
Sunday morning.

Meanwhile, light to moderate snowfall will also continue across
much of Prince William Sound and out across the Copper Basin as
multiple shortwaves pivot northwest into the region around the
deep Gulf low and trough setting up to the southwest. Temperatures
across the Copper Basin most notably will nosedive as Arctic air
continues to stream in from the north, dropping from the single
digits on Friday night down to the -10s to low -20s by Sunday.
Where we see the gusty winds, wind chill values will become even
colder, dropping to as low as -30 to -40 from Saturday into
Sunday.

Across the Mat Valley, Anchorage and greater Cook Inlet region,
the main story heading into the weekend will be the plunge into
below average temperatures and bitterly cold wind chills, where
conditions will stay mostly dry but still quite windy in some
spots through Sunday. Air temperatures will drop from the 10s and
20s above late Friday down to around 0 to 10 above by Sunday, and
possibly colder for places protected from the gusty north winds.
Wind chill values will likely drop to around -10 to -20 over the
weekend as well, particularly where the winds are strongest across
the Mat Valley, west Anchorage and along much of the Cook Inlet.
Stay tuned to the forecast for updates as well follow this major
pattern change over the next several days.

-AM/PP/AS

&&


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

The low that has brought much active weather to Southwest Alaska
continues to weaken. The Kuskokwim Delta has seen skies clear with
wind speeds remaining elevated. Bristol Bay continues to see some
lingering showers as moisture remains over the area. The
Dillingham region is seeing periods of freezing rain showers as
surface temperatures have cooled below freezing, but aloft
temperatures remain above freezing. Conditions are expected to
improve this evening as drier air filters into the region. A front
will push into the Western Aleutians, allowing for precipitation
and gusty winds, but it will be blocked in by a Siberia High that
is extending over the Bering.

On Friday, an Arctic trough will drop into Southwest Alaska,
causing winds to become northeasterly and plummeting temperatures.
By Friday night, temperatures will drop to the negatives in the
Kuskokwim Delta and the Lower Kuskokwim Valley while Bristol Bay
will drop to the single digits. The northeasterly winds will also
become gusty over and offshore of the Kuskokwim Delta. The weekend
has temperatures remaining in the negatives in the Kuskokwim
regions. The combination of these very cold temperatures and
gusty winds will allow for the potential for extreme freezing
spray from Nunivak Island to Cape Newenham starting Saturday and
lasting through Tuesday. Another potential threat is blowing snow
west of Bethel including Kipnuk as snow on the ground becomes
lofted from the gusty winds. As the colder air flows over the
warmer ocean in the Bering and with the upper trough, convective
snow showers will begin in the Alaska Peninsula and the Aleutians.
Gusty winds in these regions could blow this snow around and
reduce visibility through Tuesday. This cold air mass is expected
to persist through next week, so more impacts from the cold could
be seen.

-JAR

&&


.LONG TERM FORECAST (Days 4 through 7 - Monday through
Thursday)...

The long term outlook will favor below normal temperatures for
both Southwest and Southcentral Alaska from Monday into the latter
half of next week. An arctic airmass will spill into all of
interior Alaska and the the southern Bering over the weekend.
Below normal temperatures will change little as a trough over the
western Gulf of Alaska brings a North Pacific low close to the
northern Gulf Coast on Monday. This area of low pressure will stay
in place through the latter half of next week. Ultimately, very
cold temperatures across Alaska will result in strong gap winds
from Seward to the Copper River Delta. Northerly flow will bring
in renewed colder temperatures across the Kuskokwim Delta and
Bering Sea by the middle of next week. Precipitation chances will
be below normal due to the drier northerly flow into the state,
but occasional snow showers will be possible along the Gulf Coast.
Additional snow will be possible across the Eastern Aleutians and
Alaska Peninsula, where ocean effect snow chances will increase
through the period.

-BL

&&

.AVIATION...

PANC...A weak low pressure system is spinning in northern Cook
Inlet within a region of weak flow through the atmosphere. Thus,
ceilings have been allowed to lower to IFR with occasional BKN
LIFR conditions. Freezing rain and or freezing drizzle will
continue through the rest of the afternoon before a second round
of steadier precipitation moves across the terminal tonight. This
round should be predominantly snow along with MVFR to IFR
conditions. Snow becomes more confined to the Chugach
Range/Anchorage Hillside mid-Friday morning. VFR conditions look
to return late Friday morning to early afternoon as colder and
drier air moves in then.

&&


$$