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FXAK68 PAFC 220035
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
435 PM AKDT Sat Sep 21 2024

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

Conditions across Southcentral and the Gulf of Alaska remain
mostly dry and clear this afternoon, although areas of cloud cover
linger across the Copper River Basin. Active weather ramps back
up again on Sunday morning when a front reaches Kodiak Island and
the western Gulf. Steady precipitation and increased winds with
the front will spread across the rest of the Gulf and Southcentral
coast through Sunday. Northeasterly winds up to storm force are
expected across portions of the northern Gulf Sunday evening and
overnight. The low itself enters the western Gulf early Monday
morning and tracks into the northern Gulf where it is expected to
linger through mid week. Most of the precipitation with this
system will be focused along the north Gulf coast for Sunday,
although some precipitation will spread north to portions of
interior Southcentral on Monday and Tuesday. Wind strength and
precipitation intensity generally start to decrease heading into
mid week as the system gradually weakens.

&&


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

A deep occluded low will continue to be the focus for the
forecast as it tracks along the Aleutians and into the Alaska
Peninsula through late Sunday. Showery conditions as well as small
craft to gale force easterly winds will clip the Central and
Eastern Aleutians tonight and tomorrow as the chain sits
immediately north of the low`s progress. Conditions further east
and across Southwest Alaska will remain cool and dry through at
least Saturday night. By Sunday morning, however, an occluded
front will reach the Western Alaska Range with some precipitation
expected for the AKPEN on Sunday. Models have trended slightly
south with the track of the low, which may allow the rest of
Southwest Alaska to maintain dry conditions into Monday while the
low and its associated front shift into the Gulf. Behind and north
of the low, persistent northerly flow is forecast to develop
through the eastern Bering. The rest of the forecast will entail
the southward movement of a cooler airmass across Southwest Alaska
and into the Eastern Aleutians. Portions of the Kuskokwim Delta
and Lower Kuskokwim Valley will flirt with freezing overnight low
temperatures Monday and Tuesday night, though precipitation
chances will remain minimal.



&&


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

The long-term pattern across the area generally looks to be
characterized by a longwave trough over the Bering with numerous
shortwaves rotating around the base of the trough and lifting into
the Gulf of Alaska and into Southcentral Alaska. The result will
be unsettled weather; especially across the North Gulf Coast
where most precipitation looks to fall for Wednesday into Thursday
as a surface low in the Gulf throws moisture northward. This low
weakens a slides to the southeast Thursday evening as additional
weak shortwaves lift across the area helping to keep light shower
chances going through Friday.

A shortwave drops out of Eastern Russia Thursday night and helps
to re-energize the Bering trough for Friday. The associated
surface low moves from northwestern Bering Sea Wednesday to the
southeastern Bering by Friday. This system looks to bring cold air
down from Russia and across the Bering on its journey from north
to south. Scattered showers and windy conditions are anticipated
across the Aleutian Chain and Pribilof Islands with steadier rain
along the Southwestern coast. The front then looks to enter the
western Gulf of Alaska by Saturday delivering another round of
rain likely to Kodiak Island, the Eastern Kenai Peninsula, as well
as Prince William Sound. There is still a lot of uncertainty with
how far rain could make it inland with this system. And, with
likely southeasterly flow aloft, rain would be light.

The pattern will become favorable for cyclogenesis to occur in
the North Pacific on Saturday as the cold air driving southward
from the Bering interacts with warm air from the sub-tropical jet.
While a storm system does look to form, confidence is very low on
exactly where in the North Pacific it will form, where it will
track, and how fast the system will strengthen.

&&

.AVIATION...

PANC...VFR conditions and light winds will persist. A strong
occluded front will lift northward across the Gulf Sunday which
will lead to increasing winds across the Kenai and Chugach
Mountains. However, strong down-Inlet pressure gradients will
keep these winds away from the terminal.

&&


$$