Gale Warning 294, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
531 AM AKDT Sat Apr 5 2025

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

A very large area of low pressure with multiple embedded centers of
circulation continues to swirl across the North Pacific and into the
Gulf of Alaska. Southcentral Alaska will continue to be impacted as
several rounds of rain (and high elevation snow) focusing along many
trough axis rotating about the low push into Southcentral Alaska.
Locations adjacent to the Gulf of Alaska from Kodiak Island
northeast through the eastern Kenai Peninsula and Prince William
Sound regions will receive multiple rounds of precipitation through
early next week. The lee side of the mountains will continue to
experience dry downsloping conditions, though sprinkles and
isolated showers are possible today into tomorrow.

One of the aforementioned troughs will rotate into Southcentral this
afternoon, with a non-zero chance of rain for Anchorage/Mat-Su area,
as well as the Copper River Basin. Ensemble probabilities paint the
most likely areas (outside of the coast) to receive precipitation
will be across the mountain ranges, as well as north towards
Isabel and Broad Passes. Precip should be light, as well as
remaining rain given very high snow-levels today. Then on Sunday,
a more potent shortwave brings a chance of rain to the Cook Inlet
region. Near freezing temperatures in Thompson Pass allow for a
few inches of snow near the road summit.

Model spread and forecast uncertainty begins to grow Sunday night
due to complex interactions between the Gulf of Alaska low and an
upper-level trough extending down from the Arctic. Several models
and ensemble members put a stout low center into the northern Gulf
and Prince William Sound region, which would result in likely
precipitation in the interior portions of Southcentral, while a few
solutions such as the GFS are maintaining dry scenarios. Have raised
chances of precipitation through this period due the number of
models favoring the former. Precip is likely to begin in rain for
non-mountain locations, but cool air gradually filtering in from
both the north and wrapping around the low will gradually lower snow
levels late Sunday through Monday. It's not out of the question a
dusting to a few inches of snowfall may happen across the western
Kenai north into Anchorage and the Mat-Su, though surface
temperatures at or above freezing may inhibit accumulation.

-Brown

&&

&&

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

The highly impactful storm across the Eastern Aleutians and
Kuskokwim Delta coast is beginning to wind down, but active
weather will continue to linger in western Alaska as this system
slowly meanders eastward into the Gulf. The Winter Storm Warning
for the Eastern Aleutians has ended, but there remains a Special
Weather Statement out highlighting the continued threat of
deteriorated conditions through this morning. An additional 1 to 3
inches of snow accumulation is possible for Unalaska/Nikolski
while Akutan will see periods of rain and rain/snow mix with
little additional accumulation. Winds will continue to gust up to
45 mph at times through the morning before slowly diminishing into
the afternoon hours.

Another wave of moisture is moving over the Kuskokwim Delta
today, delivering a wintry mix through the overnight hours before
a change over to snow later this morning as cold air works back
in. The best chance for light freezing rain will be between Kipnuk
and Quinhagak, northeastward through Bethel. The best chance for
reduced visibilities and blowing snow will be across the Kuskokwim
Delta Coast from Kipnuk north, including Nunivak Island.
Conditions should improve by this afternoon as this wave moves
through.

High pressure over the western Bering Sea will build eastward in
the wake of the departing system. Lingering showers and easterly
winds will shift to drier northerly flow across Southwest and the
Alaska Peninsula on Sunday and into the new week. Cold air
advection will usher in cooler temperatures for the region, and an
increased chance of fog and low stratus is expected under the
ridge.

A weak front will clip the Western Aleutians this weekend, but
should mostly stay south of the Chain. Finally, a wave digging
down from the Bering Strait looks to bring enhanced winds and
precipitation to the Kuskokwim Delta coast and eastern Bering
starting Monday afternoon.

&&

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

The main feature on the Alaska Weather map is the elongated upper
level trough stretching from the Arctic through Mainland Alaska
to the Gulf of Alaska and Eastern North Pacific through the
forecast period. A number of shortwaves slide through the flow,
partially eroding the upper ridge across Western Canada. The
Bering ridge continues to build through the week, becoming a
closed center across Northern Kamchatka by Friday. A blend of
ECMWF and Canadian models maintains good continuity over most of
the trough and the rest of the region through the forecast, while
the GFS becomes an outlier drawing its focus on the Arctic upper
low.

A decaying low South of Prince William Sound pushes locally heavy
rain over coastal zones from Prince William Sound to the Canada
Border, with moderate to heavy snow mostly over higher elevations
inland, diminishing Wednesday. A second low over the Kuskokwim
Delta spreads snow over the Southwest Alaska coasts and across the
Alaska Peninsula Tuesday. Gusty winds over the Eastern Bering
move across the AKPEN for midweek. This low crosses Kodiak Island
before swinging across the Gulf of Alaska through Friday. This
round of precipitation tapers off late Thursday over Kodiak Island
and the Kenai Peninsula before moving into open waters. In the
West, a well developed low over Southern Kamchatka extends a front
over the Western Aleutians Wednesday. Locally heavy rain and
windy conditions with gale force gusts expected to spread across
the Western and Central Aleutians and Bering through Friday.

- Kutz

&&

.AVIATION...

PANC...VFR conditions will continue despite a low moving through
the Gulf of Alaska this weekend. Northerly winds will dominate at
the surface with easterly winds aloft. Therefore, wind shear is
possible through tomorrow morning though most likely this
evening. There is chance for snow early next week with the return
of cold air.

&&