562
FXAK68 PAFC 221233
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
433 AM AKDT Sun Sep 22 2024

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

Clear skies overnight has led to numerous locations around
Southcentral, including Soldotna, east Anchorage, and Glennallen,
to drop into the 20s for low temperatures this morning. This will
not be the case again tonight as the next weather system is
moving rapidly toward Southcentral today. Expect increasing clouds
for the entire region today with Kodiak starting to rain later
this morning and that rain spreading to the north Gulf coast this
afternoon into this evening. While this low will bring widespread
Gale force winds to the Gulf, with some Storm force winds in the
barrier jet that will develop overnight along the north Gulf
coast, this low will rapidly weaken as it moves into the northern
Gulf on Monday. However, it will be slow to leave the area,
remaining quasi-stationary into Wednesday. That leaves the next
few days with rain along the north Gulf coast the next few days
and clouds inland. Cross barrier flow should cut off most of the
rain from moving too far inland, but this flow will weaken and
then probably allow more showers into inland areas Monday and
Tuesday.

The most challenging aspect of the forecast will be around Kodiak
for Monday into Tuesday night. While the rain should shut off on
Monday as the passing low puts Kodiak into northwest flow the
uncertainty is whether the front wrapped around the weakening low
will be able to edge westward enough to bring in more rain on
Tuesday or Wednesday. Models are a real mixed bag with this as
they appear to be struggling with what to do with the colder air
filtering into the Gulf from Southwest Alaska on those days. At
this point, have the keeping the main rain farther east of Kodiak,
but it is worth looking into as this system moves through the
area.

&&


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

Our deep occluded low just south of the Alaska Peninsula will
spend the next 24-hr working its way into the Gulf of Alaska. Gale
force winds will spread along the front, pushing across the Alaska
Peninsula and into the southeastern Bering Sea. Elevated winds
will push along the backside of the low and produce gale force
gusts through the gaps and passes of the southern AKPen and the
Eastern Aleutians. Additionally, gales will push their way into
Bristol Bay through the Kamishak Gap. Conditions across Southwest
Alaska will remain cool and dry. The exception is, an occluded
front will reach the Western Alaska Range with some precipitation
expected for the AKPEN on today. As the front moves out through
Monday morning, precipitation chances will diminish. 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.

&&


.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 today 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.

&&

$$