Gale Warning 164, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
457 AM AKST Wed Feb 7 2024

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3/Today
through Friday night)...

A long-wave trough is centered over the Bering Sea, with short-
waves ejecting out of the trough and across the Gulf and Southcentral.
One short-wave is lifting northward across Southcentral early
this morning. Radar imagery shows a narrow band of snow marching
inland ahead of the trough. This will bring a dusting to a inch of
snow, with the best chance of accumulation in the Susitna Valley
due to upslope flow. Two more short-waves along the Alaska
Peninsula this morning will consolidate into a single marginally
stronger short-wave late this afternoon and evening. This will
lead to development of a surface low in the Gulf, but it will
remain offshore. The southern end of the short-wave will drive
eastward across the Gulf, leaving a much weaker trough to pass
through Southcentral late tonight through Thursday. Expect a
brief period of rain for Kodiak Island Wednesday and some snow
pushing onshore of the Kenai Peninsula Wednesday night into
Thursday. It's looking like the rest of Southcentral will likely
remain dry with this weak trough.

A much stronger storm system is on track to affect the region
Thursday night through Friday night. Models have trended eastward
with the low track over the past 24 hours, now tracking the low
to near Kodiak Island Friday before then moving into Bristol Bay.
The leading frontal system cross the Gulf Thursday night and
moving onshore of Southcentral Friday looks a bit stronger,
while the overall airmass behind the warm occlusion looks warmer.
Expect moderate to heavy precipitation for Kodiak Island and
Prince William Sound/Eastern Kenai Peninsula. Kodiak will see
mainly rain while coastal Southcentral will experience a
transition from snow to rain as warmer air arrives on Friday.
There is some threat for low visibilities along the Seward Highway
corridor on the eastern Kenai Peninsula as snow and wind arrive
Thursday night. However, temperatures at and near sea level will
be right around the freezing mark (or possibly even a bit above),
so it looks marginal. The transition to rain will limit snow
accumulation, with the best chance for heavier snow accumulation
in Turnagain Pass.

Meanwhile, strong east to southeast low-level flow will initially
lead to significant downslope drying for the western Kenai up to
Anchorage and the Mat-Su. As the low heads inland across Southwest
Alaska Friday night, flow over Southcentral will shift to
southerly and a trailing upper level short-wave will help spread
precipitation inland. While colder air will move in aloft, some of
the remnants of the warmer air combined with southerly surface
winds pushing onshore could be just enough to produce a mix of
rain/snow or possibly even pockets of freezing rain as
precipitation first arrives. This seems most likely from Anchorage
and the Mat Valley south to the western Kenai Peninsula. If this
does occur, it should be short-lived as the air aloft looks cold
enough to change precipitation back to all snow. Those places that
do observe the southerly winds will likely see temperatures rise
to freezing or above, which will be the warmest temperatures since
January 14th.

&&

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

Broad cyclonic (counterclockwise) flow remains in place across
the entirety of the Bering this morning under the influence of a
960 mb vertically stacked low, roughly 225 northwest of the
Pribilof Islands. Associated winds around the low remain at small
craft to gale speeds. The low lifts north and immediately west of
Saint Matthew Island through tomorrow morning. For this morning,
an occluded front has moved onshore of the Southwest Alaska coast
and is now also pushing into the Alaska Peninsula further to the
south. The front will maintain scattered light snow showers in
vicinity of the front before tapering off later this evening into
the overnight hours. In the short term, gusty conditions along the
Kuskokwim Delta coast and Nunivak Island are combining with light
snow to reduce visibility down to one half mile. Despite winds
gusting at or above 40 mph, warm temperatures just below freezing
will limit the threat of blowing snow. Instead, periodic reduced
visibility will be limited to the presence of light scattered snow
showers, which will gradually taper off for most areas later this
afternoon and evening.

The next front lifts out of the North Pacific and over the Alaska
Peninsula on Thursday. Easterly gales with storm force gusts are
forecast on the Pacific side of the Alaska Peninsula, with gales
spilling into the Bering side of the Alaska Peninsula through
Thursday afternoon. Warm temperatures on the Pacific side, due to
continued southerly flow, will see above freezing temperatures and
subsequent precipitation into King Cove and Sand Point, fall
largely as rain, with a mix of rain and snow on the Bering side. A
strong pressure gradient then forms over Greater Bristol Bay
region Thursday night into Friday morning, which will allow for
enhanced easterly winds to spread from the Kamishak Gap and across
Iliamna, New Stuyahok, and Koliganek. Gusts of 50 to 60 mph will
be possible, with 30 to 40 mph gusts reaching Togiak and
Dillingham.

&&

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

Large scale features persistent through the forecast period
include upper level ridging over northwestern Canada and the
eastern interior of Alaska, with an area of low pressure over the
Bering Sea and the western coast of Alaska. Saturday morning a
surface low over the Kuskokwim River Delta continues on a
northbound track and weakens. Sunday afternoon into Monday morning
a North Pacific low crosses the Alaska Peninsula into the Bering
Sea with storm force winds. Several shortwave features pass over
Kodiak and the western Gulf through Tuesday morning.

&&

.AVIATION...

PANC...Potential snow over the next few hours will briefly lower
cloud decks and visibility, but will quickly rebound above VFR
thresholds after the showers pass. Conditions will improve
throughout the day as the shortwave trough passes, increasing
cloud decks above 10000 feet by the afternoon hours. Light winds
will also persist through the duration of the TAF period.

&&