247
FXAK68 PAFC 020316
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
716 PM AKDT Mon Sep 1 2025

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

Discussion:

The synoptic pattern persists. A ridge of high pressure remains over
the Gulf, a long wave trough and associated upper low over the
Bering, and continued jet level support flows up the Alaska
Peninsula and across the mainland interior. A good fetch of
moisture is still being pulled northwards between the Gulf high
and the Bering low. Since Sunday, several shortwave troughs have
moved around the base of the low and lifted north across western
Alaska. Light rain will continue along the western side of Cook
Inlet and Susitna Valley overnight into Tuesday. Gusty winds are
possible for the areas through Tuesday morning when the pressure
gradient is set to relax.

The quasi-stationary front over Bristol Bay and the AKPen will
receive an additional reinforcing nudge as the parent low opens
into a wave as it moves over Alaska. This will shift showers
eastwards through Tuesday morning. Models are honing in on the
next feature that lifts across the AKPen Wednesday morning,
bringing additional wind and rain that takes a track along the
western side of Cook Inlet and into the Susitna Valley. By
Wednesday afternoon, widespread rain is expected across
Southcentral with 0.25 to 0.50 inch for most areas, and 1 to 2
inches of additional rain across Talkeetna and Denali State Park.

- PP/ER

&&


.SHORT TERM FORECAST SOUTHWEST ALASKA / BERING SEA / ALEUTIANS
(Monday to Wednesday)...

Widespread rainfall continues to taper off this evening. A short-
lived ridge of high pressure builds in overnight and lasts
through tomorrow afternoon bringing dry conditions. Rain and
gusty winds return tomorrow evening continuing into Wednesday
evening.

Rainfall ends within the next few hours in Bristol Bay and
Southwest Alaska. In its wake, dry conditions, areas of fog and
calm winds can be expected through tomorrow afternoon for all of
Southwest Alaska, the Bering Sea and the Aleutians.

Model disagreement remains over the next low pressure system
pushing northward from the North Pacific. Its associated front
brings rain and gusty gap winds to the Eastern Aleutians, Alaska
Peninsula and Southwest Alaska coast beginning tomorrow afternoon
and lasting through late Wednesday evening. Forecasted wind gusts
with this storm in the Eastern Aleutians` gaps and passes are
trending higher and, the highest speeds are expected in Cold Bay
and portions of the Alaska Peninsula. Rainfall amounts across the
models range from 0.50" to 1.00" during the event though if the
ECMWF model comes to verify, rainfall amounts region wide would be
measured on the lower end of this range.

-DJ

&&

.LONG TERM FORECAST (Days 4 through 7 - Friday through Monday)...

True to early September, the weather will remain active for much
of Southwest and Southcentral Alaska through the weekend into
early next week. For the period beginning on Thursday night, the
pattern will be characterized by a ridge across the eastern Bering
Sea into the North Pacific and western Gulf of Alaska, with a
strong low across the Aleutians, likely centered somewhere near
the Rat Islands, and moving northeastward in the direction of the
Pribilof Islands. Meanwhile, Southcentral Alaska will be under the
influence of a departing trough. Rain will likely be diminishing
across Southcentral AK Thursday night into early Friday, with the
greatest uncertainty in how quickly it clears up depending on the
low timing.

Attention turns towards the gale-force low in the Bering Sea
Friday and Saturday as it treks northeast towards the Pribilofs
and then Southwest Alaska. The Aleutian Chain gets the worst of
the weather from this system as the attendant fronts draw
northward an atmospheric river from the North Pacific which will
bring heavy rain and strong gale-force winds to the chain as it
sweeps across.

Model agreement is surprisingly good with this system, suggesting
a `landfall` of the low near Nunivak Island Saturday evening,
weakening to somewhere in the vicinity of 995mb as it does so.
There`s also decent agreement that, while the first half of the
weekend might be dry for Anchorage and the rest of Southcentral,
precipitation then overspreads SC AK late Saturday and Sunday as
moisture is drawn northward from the North Pacific. At this time,
this looks like a widespread wetting rainfall, but the good news
is that the numbers/probabilities aren`t quite lighting up as an
anomalously heavy rain as we experienced at the end of last week.

What reasonable model agreement we had before is lost by the
start of next week. There are some signals of another strong low
marching across the Bering, while some models signal at a lower-
amplitude wave train. Either way, it`s September in Alaska- be
prepared for rains to glisten the yellowing foliage.

-Brown

&&

.AVIATION...

PANC...VFR conditions are expected to persist through the TAF
period. Ceilings of 5,000 feet with a scattered lower deck are
also possible through this evening and again early Tuesday
morning when chances for light rain also increase this evening
with periods of showers lasting into Tuesday morning.

Winds will turn southeasterly and increase as the Turnagain Arm
winds bend into the terminal this evening through Tuesday
morning. Peak winds look to occur this afternoon through tonight
with gusts up to 25 kts at times. Southeast winds remain Tuesday
morning but gusts should be below 20 kts before diminishing
further Tuesday afternoon.

&&


$$