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FXAK68 PAFC 121302
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
502 AM AKDT Fri Apr 12 2024

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

The frontal system that brought widespread southerly winds to
Southcentral yesterday into the overnight hours last night is
finally falling apart as it approaches the Prince William Sound
and Copper River Basin this morning. Farther west, an upper level
shortwave trough is moving into the Susitna Valley, with snow
ongoing near and north of Talkeetna. To the south, a band of light
snow has pushed into Anchorage and the Mat Valley as what`s left
of the frontal system pushes through. This snow should quickly
taper off from west to east this morning as drier air moves in
from the west, but snow could still linger much of the day over
the mountains. Gusty gap winds are in the process of weakening
quickly weakening in Palmer, Anchorage and Gulkana as the pressure
gradient along the Gulf coast weakens. Gusty south to southwest
winds will likely continue for much of the day along the Cook
Inlet up into Anchorage, but gusts across the Anchorage area will
be nowhere near as strong as what came in yesterday.

By this afternoon and evening, a broader, positively-tilted upper
trough will push southeast across the Alaska Range into
Southcentral. Some afternoon snow shower activity could develop as
cooler air aloft moves in and low level temperatures warm with
peak daytime heating. The best chances will be focused over the
Copper Basin and Susitna Valley, but a stray shower moving down
into the Mat Valley or Anchorage area can`t be ruled out through
tonight. From tonight into Saturday morning, the trough axis will
push farther southeast towards the Gulf as a weak low forms out
ahead of it and begins to drift south and away from the coast. An
upper level ridge will build in behind it with along with dry
northwesterly flow by Saturday afternoon, allowing clouds to
gradually clear out from northwest to southeast. Fairly pleasant,
mostly sunny and dry conditions with seasonable highs in the mid
30s to low 40s will continue well into Sunday as the upper level
ridge further strengthens.

-AS

&&


.SHORT TERM FORECAST SOUTHWEST ALASKA, BERING SEA, AND ALEUTIAN
ISLANDS (Days 1 through 3)...

Gusty southwesterly winds and snow showers continue this morning
ahead of a cold front draped from Norton Sound to the Pribilof
Islands. These snow showers will diminish in coverage and
intensity as the front reaches the Aleutians and AKPen this
afternoon. The southwesterly winds will also diminish across
Southwest Alaska and shift to the northwest in the wake of the
front. These northwesterly winds, though, will remain gusty,
especially through gaps along the AKPen into Sunday morning.
Areas of blowing snow also remain a possibility along the
immediate Kuskokwim Delta coast through Saturday due to the gusty
winds.

The shift in the winds is also the result of a stout ridge of high
pressure moving from the western Aleutians today to the AKPen by
Sunday. This ridge will allow for generally quiet weather, with
widespread low stratus, across the Bering into the weekend.

By late Saturday, a North Pacific low will move north toward the
Western Aleutians with its front moving over the western and
central Aleutians into the western Bering for Sunday.

&&


.LONG TERM FORECAST (Days 4 through 7: Monday through
Thursday)...

A pattern shift is the looming potential in the long-term period,
with the degradation of the ridge built over Southern Alaska
beginning Monday. This is furthered by multiple North Pacific Lows
pushing towards our area, replacing the calm pattern with an
active wet and windy one. However, model agreement regarding the
pacing of this transition is poor so timing the return of
stronger winds and precipitation is difficult until the guidance
comes to a better agreement. It is likely however that by
Tuesday/Wednesday, gusty southeasterly winds would return to
Kodiak Island and through the Barren Islands. This would come in
the form of a frontal boundary on the northern leading side of a
north pacific low moving in. Given its origin and potential
orientation, this may also lead to another precipitation event for
the Prince William Sound communities. Expectations further west
in the Bering suffer from even worse model agreement, with
drastically different solutions being advertised by the models
even as soon as Wednesday morning. Agreement does not improve
throughout the region by mid-to-late next week.

-CL

&&

.AVIATION...

PANC...Snow showers moving past the terminal early this morning
will quickly clear out with conditions improving to VFR in the
next hour or two, if not sooner. The persistent southeast winds
will also weaken and become more south to southwesterly this
morning, then slowly diminish through this evening. Some 25 to 30
kt gusts will be possible until winds more fully subside this
evening, but they should remain much weaker than the winds we saw
yesterday.

-AS

&&


$$