Gale Warning 34, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
438 AM AKST Mon Jan 1 2024

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

The strong low southwest of Kodiak Island and a weak upper level
high near the AlCan border this morning is keeping easterly flow
over Southcentral Alaska today. This pattern is clearing out the
inland regions of Southcentral with some light rain and snow
showers around the coastline of the eastern Kenai Peninsula.
Except for the lowest few hundred feet of elevation at the
immediate coast, precipitation that does fall in the eastern
Kenai today should be all snow. Kodiak is a another story as it is
right in the track of the front associated with the strong low
and will see rain and increasing winds through the day. As of
early this morning, this low has already tracked about as far
north as it is going to as it runs into the surface high pressure
over the Interior of the state and then rapidly weakens by Monday
night. Something that remains a bit of an uncertainty is that, in
spite of the low weakening, there will be a wave that develops
along the front in the Gulf Monday night into Tuesday afternoon.
The models all indicate this wave, but the GFS model has been
fairly consistent with strengthening it enough to become a closed
low that moves to the north Gulf coast Tuesday afternoon. This
would likely bring Gale force winds to the marine areas along the
Gulf coast at that time and increase the precipitation along the
coast for Tuesday. It will also increase significantly the winds
through the Matanuska River Valley and into the Palmer and Wasilla
areas Tuesday into Wednesday as the pressure gradient increases
and the cold, dense air from the Copper River Basin gushes through
the gap due to the pressure gradient.

This wave or closed low will rapidly weaken with the original low
as a much larger low tracking just south of the Aleutians usurps
the upper level energy and becomes the dominate system for Tuesday
night through late in the week.

&&

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

Longwave troughing extends over the Alaska Peninsula and eastern
Bering Sea today. There is a band of precipitation along the front
that is set up over the southern Alaska Peninsula that is bringing
rounds of snow to the region. A Winter Weather Advisory was issued overnight to
account for snow accumulations of 5 to 8 inches possible across
the southern AKPen, namely Cold Bay, False Pass, and King Cove.
Temperatures will gradually increase, leading to a transition to
rain or a rain/snow mix by this afternoon. Winds across Bristol
bay and the Kuskokwim Delta coast will remain elevated through
much of today, will come down briefly for a few hours overnight as
the trough lifts north, and then increase again with the next
front extending off a strong North Pacific low. This next system
is looking to be on the stronger side, with some models showing
pressures as low as 935-940 mb. High winds to storm force along
the Aleutian Chain and Southwest coast is expected as early as
this evening and is anticipated to persist into Tuesday afternoon
in some areas. The High Wind Watches for both the Eastern
Aleutians and the Bristol Bay coast remain in effect. Winds on the
backside of the low look to ramp up to storm force over the
Central Aleutians, Adak especially, overnight Tuesday through
Wednesday afternoon. BY Wednesday afternoon the system will cross
over the southern AKPen into the Bering Sea and continue to
slowly weaken as it dawdles northeastward through the end of the
week.

KM

&&

.LONG TERM FORECAST (Days 4 through 7: Thursday through Sunday..

An active pattern is developing across the Bering Sea with two
strong upper lows to move through the region over the course of
the next week. The first upper low arrives early Tuesday, with
forecast guidance continuing to show potential hurricane force
wind gusts for portions of the Aleutians. The low will likely have
peaked by Tuesday afternoon, with a slightly weaker, but very
large upper low sitting over southern Bering from the start of the
long term forecast period on Wednesday through Thursday night. A
large wind field will see gales and storm force winds impacting
much of the Bering Sea with the potential for snow and blowing
snow from the Western Aleutians to the Eastern Aleutians. By
Wednesday the low's eastward progress will position the strongest
winds south of the Eastern Aleutians. Gale force winds gusting to
50+ knots will promote seas up to 35 feet on the Pacific side of
the Eastern Aleutians early Wednesday morning. Winds diminish into
Thursday with an axis of westerly gales stretching from north of
the Western Aleutians, southeastward across the Eastern Aleutians,
to the south side of the AKPEN. Attention then turns to the
weekend, where yet another strong low is forecast to emerge from
the North Pacific into the Aleutian Chain. This latter low does
not look to be as strong as the Tuesday low, but model discrepancy
abounds.

For Southcentral, Tuesday's Aleutian low will bring a stout front
into the Gulf of Alaska by Wednesday morning. This front will see
somewhat warmer temperatures associated with it, though with the
front already occluded the warm-up will likely be underwhelming.
Instead, expect to see a mix of rain and snow accompanied by gale
southeasterly winds moving across the Kenai Peninsula into Prince
William Sound through Wednesday afternoon. What have been largely
drier conditions across Southcentral will gradually transition to
a more unsettled pattern, with increasing snow chances across
Prince William Sound and the Copper River Basin. Precipitation,
while heaviest on Wednesday, will linger, especially along the
Gulf Coast, through early Friday. A second front arrives over the
weekend and closer to Sunday with renewed rain and snow chances
for Southcentral.

BL

&&

.AVIATION...

PANC...VFR conditions and light winds will persist.

&&

SPECIAL WEATHER STATEMENT
National Weather Service ANCHORAGE AK
146 PM AKST Mon Jan 1 2024

AKZ112-021400-
Matanuska Valley-
Including the cities of Palmer, Wasilla, Sutton, and Chickaloon
146 PM AKST Mon Jan 1 2024

...STRONG GUSTY WINDS AND LOCALIZED AREAS OF BLOWING AND DRIFTING
SNOW TUESDAY MORNING THROUGH WEDNESDAY MORNING...

Northeast winds will steadily strengthen across the Matanuska
Valley Tonight through Tuesday, then peak Tuesday night into
Wednesday morning. Wind gusts will reach 40 to 50 mph Tuesday
night. Recent cold and dry weather has allowed the snowpack to
harden, so there is not a lot of transportable snow to blow
around. Still, the winds will be strong enough to produce
localized areas of blowing and drifting snow.

Winds will diminish Wednesday, but won't completely die down.
Northeast winds gusting 20 to 30 mph will persist through at
least Thursday.