Funnel Cloud in Alaska, August 29, 2024

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
506 AM AKDT Thu Aug 29 2024

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

A low residing across southcentral Alaska will continue to weaken
today, with rain coverage gradually decreasing across the
central/eastern Chugach and Prince William Sound area. Today will be
a generally pleasant day for much of the area with perhaps some
sunshine breaking through clouds. Can't rule out a few showers
across higher terrain, but coverage will be limited.

Another low pressure system will move into the Gulf of Alaska on
Friday. Kodiak Island will be the first affected, with rain
beginning Friday and continuing throughout the day. 1-2 inches of
rainfall is expected for much of the island. Precipitation will
then spread into the Kenai Peninsula and Prince William Sound and
then north to the western Prince William Sound/eastern Kenai
Peninsula through the day. Rain will be light to moderate, mostly
along the coast with upslope flow. Expect the rain to slide slowly
east towards Valdez and Cordova by Saturday, with chances of
inland rain late Saturday as the upper level low center reaches
the southern Mainland.

-Brown

&&

.SHORT TERM FORECAST FOR SOUTHWEST ALASKA, THE BERING SEA/ALEUTIANS
(Today through Sunday morning)...

The forecast remains on track with a vertically stacked low in
the Bering Sea between the Central and Eastern Aleutians this
morning. This low is poised to track east-southeast into the
North Pacific by this afternoon. The core of strongest winds looks
to be on the backside of the storm in the form of gale-force
north to northwesterlies across the Eastern Aleutians this morning
through this afternoon. Winds will begin to diminish back to
small-craft tonight through Friday morning as the storm continues
to weaken and pull away to the east in the North Pacific. The
majority of rain with this system looks to fall across portions of
the Southern Alaska Peninsula (AKPEN) through Friday morning as
good southerly upslope flow helps to enhance precipitation there.
The Eastern Aleutians look to remain showery through Friday
morning as additional shortwaves rotate through the area on the
backside of the storm. Scattered showers are also possible today
and Friday through mainland Southwest Alaska as shortwaves move
over the area in association with the Bering/North Pacific system.
Showers could persist in portions of interior Southwest Saturday
when light northwesterly upslope flow ensues behind the storm that
will now be in the Gulf of Alaska by then. Quieter and benign
conditions are then expected for Sunday across mainland Southwest
as drier air arrives from the north.

A ridge of high pressure builds into the Western Bering behind
the departing low starting tonight. This ridge looks to remain in
place through much of the short-term period with the Western and
Central Aleutians seeing quieter weather. A weak upper-level
system dropping southward out of Siberia looks to bring showers
back into the forecast for most of Saturday for the Eastern
Aleutians and Southern AKPEN. Meanwhile, a Kamchatka front
approaches the Western Bering and Western Aleutians Sunday
bringing rain and gusty winds back into the forecast. Winds at
this time do not look to be overly strong with this system.

&&

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

The Alaska Weather Map continues under a broad upper level
cyclonic flow extending from Eastern Russia to the Canadian
Provinces. A moderately developed low center over the Southern
Alaska Peninsula swings into the Southern Gulf of Alaska, becoming
nearly stationary and forming a moderate amplitude trough through
midweek. A weaker low center South of Prince William Sound Sunday
dissipates into a trough over the Eastern Gulf of Alaska and
moves into Canada Monday. This pattern continues an energetic and
progressive pattern across the region, bringing locally stormy
conditions across the Southern portions of the state through the
forecast period. A well clustered model ensemble of the GFS/ECMWF/
Canadian products maintain good detail through Tuesday before
diverging in storm tracks. A second intensifying low approaches
the Western Bering for Wednesday morning.

With the low's movement along the Gulf coasts, generally direct
onshore flow spreads locally heavy rainfall into the coastal zones
across Kodiak Island into the AKPEN, and Northwards along the
Eastern slopes of the Alaska Range through Wednesday. The heavier
rainfall continues to migrate across the Eastern Kenai Peninsula
and Prince William Sound to the Canadian border. In the Far West,
another low center out of Eastern Russia and its front approaches
the Western Aleutians Tuesday. Gusty winds with the front
increases to gale force by Wednesday, as the front spreads from
the Western Aleutians for Wednesday. Locally heavy rains are
expected over the Western Aleutians and Bering Tuesday and
Wednesday.

-Kutz

&&

.AVIATION...

PANC...VFR conditions prevail, though areas of fog and low stratus
have developed in the general vicinity of Cook Inlet in the wake
of yesterday's rain and a fairly saturated environment. Any fog
that does develop will dissipate by midday as weak high pressure
overspreads Southcentral today. VFR conditions then likely to
persist into Friday with light winds prevailing.

&&