Gale Warning 919, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
449 AM AKST Sun Dec 8 2024

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

The remnants of the weak surface trough over Cook Inlet yesterday
is sitting along the immediate Southcentral coast east of Cordova
this morning.Scattered showers along this feature are moving back
to the northwest over Prince William Sound as both a coastal
ridge of high pressure and a southeasterly flow develop out ahead
of a frontal system moving into the western Gulf this morning.
Cloud cover is also beginning to overspread Southcentral once
again this morning, following some clearing overnight between the
front and lingering trough. Temperature this morning have fallen
back below freezing for many locations that did see prolonged
clear skies overnight. Temperatures have also fallen back below
zero for parts of the Copper River Basin.

The increase in the south to southeasterly flow both aloft and
nearer the surface ahead of the front today will usher in copious
amounts of moisture to coastal Southcentral through the next 48
hours. The generally southerly flow will also bring about another
warming trend in temperatures, especially for coastal locations
that will see an increase in winds off the waters of the Gulf.

Widespread gale-force winds, with a small core of storm-force
winds for the Barren Islands, are expected along the front with
ample moisture with this system. Again, warm southeasterly air
looks to advect into Southcentral, so any locations near freezing
initially will quickly warm into the 30s and 40s with snow levels
again rising to 2,000 ft or higher by Monday. Turnagain Arm winds
will also be on the increase, as well as winds at higher
elevations, including the Anchorage Hillside where gusts 55 to 70
mph are possible beginning Sunday night. Strong wind gusts
approaching 45 to 60 mph area also possible for Whittier and
Portage.

The front then weakens, slows, and stalls near Prince William
Sound early Monday morning. However, a strong upper-level wave
moving north into the Gulf will advect more moisture toward
coastal Southcentral as a surface low spins up along the stalled
frontal boundary and drives north toward Prince William Sound.
This low will drive the front to the coast with a storm-force
barrier jet developing from Cordova into western Prince William
Sound. Any slight lull in the gusty winds from the initial frontal
push late Sunday into early Monday will be short-lived as the low
and front continue to push inland by Monday afternoon with a
second peak of strong winds likely from Cordova to Whittier,
Portage and Turnagain Arm.

Upwards of 2 to 4 inches of rain could fall for coastal
communities from Whittier to Kodiak Sunday through Tuesday. Lesser
amounts are expected farther east toward Cordova. For locations
in the lee of the coastal mountains, a strong cross barrier flow
and downsloping should limit any chance for accumulating
precipitation. However, there is a good chance that precipitation
falling in overnight hours in the lee side of the mountains will
be in the form of freezing rain with surface temperatures dropping
below freezing overnight and warm air above freezing aloft.

-TM

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

A north Pacific low pressure system is moving to enter the
southeastern Bering Sea, pushing a front of moderate moisture
content, gusty winds, and warmer air into the Eastern Aleutians
and mainland Southwest Alaska early this morning. This system has
begun a pattern change towards a warmer, rainier pattern across
Southwest, the Alaska Peninsula, and the Eastern Aleutians. The
Bering is expected to see a period of mixed rain/snow early this
morning, and as warmer air moves in transitioning the
precipitation fully to rain. Southeasterly gale force winds are
expected accompany this low and will set up on the southern coasts
of the Aleutians and the Alaska Peninsula as well as in Bristol
Bay and the Southern Bering through Sunday. Locations such as Cold
Bay are expected to see a period of strong winds with gusts to 50
mph possible late Sunday morning.

In Bristol Bay, the initial push of moisture is producing areas
of snow showers, however later this morning as warmer air
continues to move in, a brief period of freezing rain is expected.
Freezing rain has already been observed early this morning in the
King Salmon area around 3 am, however has already transitioned to
plain rain as temperatures at the surface are quickly pushing
above the freezing level. Locations such as Dillingham, Togiak,
and New Stuyahok may see a delayed signal later this morning,
however the pattern is expected to remain consistent, with a brief
period of freezing rain followed by a quick transition to plain
rain later in the morning.

Locations along the Kuskokwim river from Quinhagak to Sleetmute
are expected to see a similar trend, with ongoing snowfall early
this morning transitioning briefly to freezing rain, then to plain
rain by the early afternoon. Any ice accumulations from these
bouts of freezing rain are expected to be trace, quickly melting
by the late morning. This will be followed by a prolonged period
of rain showers to cover much of Southwest for the next several
days, with snow showers at elevation. Temperatures are expected
to remain above freezing, even low temperatures overnight through
much of Southwest are expected to remain near 35 degrees. As the
low lifts northward this morning into Monday, a favorable
pressure gradient will increase the winds through Kamishak Gap
into portions of Bristol Bay with wind gusts up to 40-50 mph.

Back along the Aleutians, another north Pacific low pressure
system is expected to approach the Eastern Aleutians and Alaska
Peninsula by Monday afternoon, re-initiating the rainfall over
the area, with light snowfall possible at elevations. This system
will continue the new, warmer, rainier pattern across the
southeastern Bering and Southwest Alaska into the mid-workweek.

-CL

&&

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

At the start of the long-term forecast period, a storm force low
centered south of Kodiak Island early Wednesday morning will push
its front from the northern Gulf inland over Southcentral Alaska.
The front may briefly peak at storm force, though the bulk of the
strongest winds will be located south of the low center. Moderate
to heavy precipitation will accompany the front along the
Southcentral coast, primarily in the form of rain. Downsloping
will keep inland areas mostly dry, though a trace or few
hundredths of an inch of precipitation in the form of rain,
freezing rain, or snow cannot be ruled out, particularly as the
front lifts inland Wednesday/Wed night. The best chances for
precipitation at lower elevations will be some light snow in the
Copper Basin. The low weakens as it tracks into the Gulf
Wednesday and Thursday, with precipitation trending down along the
coast. However, there are divergent model solutions beyond this
point suggesting continued southerly flow sustaining rain/snow
shower activity along the coast into the weekend (GFS) or a
continued drying trend with a moisture tap directed more toward
Southeast Alaska (EC/GEM).

Along the Southwest coast, Alaska Peninsula, and in the eastern
Bering Sea, the weakening low's warm/occluded front lingers
through at least Thursday, producing primarily rain for marine
areas and snow inland. Colder air works in behind the weakening
Gulf low, tending temperatures downward for the latter half of the
week. Weak cold air advection will enhance northwesterly gap
winds across the Alaska Peninsula potentially to marginal gale-
force through Thursday night. The front along the Southwest coast
may shift inland Friday or Saturday, but this will be at odds with
the potential for a significant push of cold air dropping
southward across the Interior. Either solution will increase the
chance of light snow for inland areas of southern mainland
Alaska, despite different meteorological causes. Out west, low
pressure looks poised to arrive in the western Bering Sea late
Thursday into Friday, pushing into the central or even eastern
Bering Sea by Saturday. This looks to bring another surge of
warmer air and rain to the area through the weekend.

Quesada

&&.AVIATION...

PANC...VFR conditions will prevail along with light northerly
winds increasing to 10 kt by Sunday afternoon. LLWS is also
likely by late Sunday afternoon or evening as southeasterly winds
through Turnagain Arm and at elevation along the Anchorage
Hillside increase in magnitude. A few sprinkles are possible later
this morning; however, the developing strong southeasterly winds
aloft accompanying this next frontal system should allow for
enough downsloping off the mountains to keep any significant
precipitation away from the terminal.

&&

Preliminary Local Storm Report
National Weather Service Anchorage AK
326 PM AKST Sun Dec 8 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0323 PM     Freezing Rain    Willow                  61.74N 150.06W
12/08/2024  E0.10 Inch       Matanuska-Susitna  AK   Public

            Willow DOT called reporting freezing rain
            for the last three hours (12:00-15:00).

&&

TK

SPECIAL WEATHER STATEMENT
National Weather Service ANCHORAGE AK
352 PM AKST Sun Dec 8 2024

AKZ145-090600-
Susitna Valley-
Including the cities of Talkeetna and Willow
352 PM AKST Sun Dec 8 2024

...AREAS OF LIGHT FREEZING RAIN FROM WILLOW TO TALKEETNA THROUGH
EARLY THIS EVENING...

Very light freezing rain has fallen this afternoon and will
continue to fall until early this evening. There have been reports
of slick conditions on the Parks Highway around Willow.
Temperatures will remain below freezing through the night, thus
slick conditions are likely to continue on untreated surfaces from
approximately mile marker 60 north through Talkeetna. Please
exercise caution if traveling in this area.

For the latest road conditions call 5 1 1 or visit
511.alaska.gov.