Unalaska, Alaska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

412
FXAK68 PAFC 041351
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
551 AM AKDT Fri Apr 4 2025

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

Precipitation along/ahead of a strong occluded front has now spread
into the Kenai Peninsula and north into much of Southcentral Alaska.
Strong downsloping easterly flow has kept much of the western Kenai,
Anchorage, and Mat-Su dry as this wave pushes north, though a brief
period of light rain cannot be ruled out today. Observations around
the area suggest snow-levels are likely above the road system across
the Kenai and closer to 2000ft. Heavier rates of precipitation today
may result in snow levels dropping briefly to the highway in
Turnagain Pass, though accumulation is not anticipated at this time
given such warm air in place.

Another shortwave rotating around the large North Pacific low will
swing northward into the Copper River Basin tonight, allowing for a
brief shot of rain/snow down to the valley. Accumulations are likely
to remain light outside of the mountains. The biggest forecast
uncertainty is with regards to Thompson Pass- temperatures are
likely to remain very close to freezing where the road summits. This
would lead to at least a few inches of snow accumulation through
Saturday... though any periods above freezing or rain mixed with
snow would temper snow totals.

Sunday looks to be similar to Friday and Saturday, with the large
North Pacific low remaining well to the south, and an arctic trough
remaining positioned to the north and west. Continued southeast flow
with shortwaves rotating about the North Pacific low will result in
precipitation spreading into southern coastal areas, with interior
Southcentral largely remaining dry. A brief shot or two at cross-
mountain wind component decreasing may result in light precipitation
for Anchorage and the valley Sunday but details remain a bit
nebulous. Cold air intruding around the low should result in
slightly colder aloft beginning late Sunday, which could begin to
take snow-levels down closer to the road system by Sunday night.

-Brown

&&


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

...Key Messages...

 1) A Winter Storm Warning is in effect through 4PM AKDT this
afternoon for the Eastern Aleutians.

 2) A Blizzard Warning is in effect through 7PM AKDT this evening
for the Kuskokwim Delta Coast and Nunivak Island.

 3) A Special Weather Statement for snowfall and strong winds is
in effect through 7PM this evening for the Pribilof Islands.

The combination of a large low pressure system lifting up from
the North Pacific and an upper level low digging down from the
Bering Sea has set up an intense deformation band stretching
across the Eastern Bering. The Eastern Aleutians have seen heavy
snowfall and strong gap winds throughout the night, with intensity
expected to peak this morning. Total accumulations of 10-18" of
snow with winds gusting upwards of 60 mph is likely for these
areas by midday today. On the other hand, a robust southerly to
southeasterly flow will keep temperatures elevated into the upper
30s to lower 40s for Sand Point eastbound, making this primarily a
rain event for the AK Pen and Southwest.

Deteriorated conditions have also been observed along the
Kuskokwim Delta coast and Nunivak Island throughout the night.
Blizzard conditions are expected to persist today as snow
continues to fill in and winds increase this morning. These
conditions should finally begin to slowly wind down on Saturday as
the band breaks down and the low complex tracks farther east into
the Gulf of Alaska. Areas within the Blizzard Warning are
expected to see 5-9"+ of total snow accumulation with winds
gusting upwards of 45 mph.

A Special Weather Statement for blowing snow has been issued for
the Pribilof Islands due strong winds potentially reducing
visibility down to a half mile at times throughout the day. Model
consensus continues to suggest 1-3" of snowfall for the Pribilof
Islands by Saturday morning with winds gusting upwards of 65 mph
today.

Farther west, high pressure currently over the Western Aleutians
will bring in a dryer air mass as it marches eastward across the
Bering through the weekend. Precipitation will linger in locations
across Southwest into Monday, but much of the rest of Western
Alaska could see a brief reprieve in weather. A weak front
associated with a system originating from the Sea of Okhotsk will
clip the Western Aleutians this weekend, but most of the energy
should stay south of the Chain.


&&


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

The most significant feature on the Alaska Weather map is an
elongated trough stretching from the Arctic through Interior
Alaska to the Gulf of Alaska through the forecast period. Closed
lows over Northern Alaska and the Gulf weaken through midweek.
Although there is some oscillation within the elongated trough,
there is little movement. Ridges over the Western Canadian
Provinces and the Bering also weaken through the period. Forecast
continuity remains good with a GFS / ECMWF / Canadian blend, but
minor differences with shortwaves gliding through the pattern
represent the variations and short term changes in forecast.

A moderately strong surface low over the Southern Gulf of Alaska
spreads locally heavy rainfall from the Eastern Aleutians over the
Alaska Peninsula through Monday. Gusty winds over the AKPEN
linger through midweek. Locally heavy rains marches across Kodiak
Island and the rest of Southcentral Coastal zones through
Wednesday. Areas of locally moderate snow spread over Southwest
Alaska into the Interior, and diminish through midweek. A well
developed low and front approaches the Western Aleutians for
Sunday, but dissipates to the South of the chain by Tuesday.

- Kutz

&&

.AVIATION...

PANC...A frontal system north of a North Pacific low will bring
active weather, though generally VFR conditions to ANC through the
end of the week. Marginal low-level wind shear conditions will be
possible as long as northerly wind prevails at ANC, though a shift
to gusty east/southeast winds out of the Turnagain Arm are
possible once again this afternoon. It`s not out of the question
wind remains north through the period. Anchorage will remain
largely dry / downsloped.

&&


$$