Gale Warning 181, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
546 PM AKST Tue Feb 13 2024

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

A ridge of high pressure over the Gulf of Alaska will continue
to bring southerly to southeasterly winds to most of the area
for the rest of this week. Strong wind gusts will continue in the
Anchorage Hillside through late this evening. Breezy conditions
are expected to continue though in Southcentral through Thursday
in Turnagain Arm, Mat- Su Valley and over higher elevation areas
of Southcentral Alaska.

Southerly flow resulting from the aforementioned ridge will
continue to bring a series of low pressure systems to Kodiak
Island during the next few days. A wave of moisture will move
north and west away from Kodiak Island resulting in a westward
shift in the heaviest precipitation. This will bring a brief
respite from the heavy showers tomorrow morning and early
afternoon. Steady rain and snow showers are expected to return
Wednesday afternoon into Thursday evening for Kodiak Island as
precipitation from another wave of moisture moves northward over
Kodiak Island. The return of precipitation will be accompanied by
increased winds too.

&&

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

Satellite indicates a strong ridge extending westward from the
Gulf of Alaska to just east of Kodiak Island. A deep trough in the
Bering Sea nudges up against this ridge. The result is a deep
southern moisture tap and one that is pointed directly towards
Southwest Alaska and the Alaska Peninsula (AKPEN).

The trends today have been a little bit wetter and a little bit
colder with the atmospheric river. While the southern push of
moisture continues tonight, cold air will be advecting eastward
into coastal Southwest from the Bering Sea as well as northward
off the Bering into the AKPEN. As such, snow totals have been
increased overall tonight through the end of the week. Winter
Weather Advisories have been issued for Bristol Bay and the AKPEN
to address the potential for heavy snow over a long duration as
well as potential blowing snow, especially along the AKPEN
including Nelson Lagoon. A short-fused Winter Weather Advisory
was also issued for the Kuskokwim Delta Coast now until 10PM AKST
to account for blowing snow and reduced visibilities for Kipnuk
and northward to Toksook Bay.

In general, the highest snow totals are anticipated to occur in
the Bristol Bay zone with the northern AKPEN (Pilot Point/Port
Heiden) getting heavier snow tonight through the day Wednesday.
The rest of the Bristol Bay zone, particularly areas west of
Dillingham, including Togiak, Goodnews Bay, and Platinum look to
receive heavier snow Wednesday evening into the day on Thursday.
While the majority of precipitation is expected to be snow
throughout Southwest Alaska, there is a chance that rain could
mix in at times Thursday evening into the day on Friday. However,
if precipitation intensity remains high, this mix could be mitigated
and all snow could be maintained. Precipitation looks to linger
across Southwest through Friday evening.

Meanwhile, the Aleutians as well as the Central and Western
Bering Sea remain mostly quiet. A weak low pressure in the Western
Bering is currently producing light snow showers and gusty
westerly winds across the Western Aleutians this afternoon. As
this low moves out, another North Pacific low lifts northward over
the area giving another round of snow showers and gusty winds
Wednesday through early Thursday morning. The front then makes it
to the Central Aleutians by Thursday and weakens into Friday
morning. A stronger North Pacific low looks to impact the Western
Aleutians/Bering by Friday. The front looks to make it to the
Central Aleutians by Friday evening. There is still some
uncertainty on the exact track as well as the timing of a possibly
occlusion. Regardless, precipitation looks to start as snow, but
details on a transition to rain/snow mix, or even rain are unclear
at this point.

&&

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

The upper level Canadian ridge extending over Mainland Alaska is
slowly losing its amplitude and edges to the East through Tuesday.
The Western Aleutian low loops past the Western Alaska Coast on
it way back over Kamchatka by the end of the forecast period.
Forecast confidence remains good, even in the face of the
transitory changes. These changes maintain the East to Southeast
airflow across the Gulf of Alaska into Southwestern Alaska. This
prolongs the amounts of locally heavy precipitation across Kodiak
Island and the upper Alaska Peninsula, and extends the spread of
precipitation into Bristol Bay and Southwestern Alaska through the
forecast term. Rain will be predominant across Kodiak Island and
the Eastern AKPEN, becoming mixed to all snow for much of the
Bristol Bay coasts. Locally heavy precipitation expands over the
Southcentral coast into Prince William Sound and the Kenai
Peninsula late Sunday into Tuesday. Gusty Easterly winds diminish
late Saturday over the Gulf. Another area of gusty Southwesterly
winds arrive with the upper shortwaves spinning away from the
Bering low for Monday and Tuesday.

Several shortwaves accompany the Bering low on its track through
the forecast period. These shortwaves bring locally heavy
precipitation, mostly rain or mixed at the lower elevations and
gusty winds with locally gale force gusts over the Aleutians and
Bering, diminishing late Sunday. A developing North Pacific
surface low approaches the Western Aleutians for Tuesday, and
brings another round of gusty winds and precipitation beyond the
forecast period.

Kutz

&&

.AVIATION...

PANC...VFR conditions are expected to continue through Wednesday
as high pressure continues to build into Southcentral from the
east. Gusty southeast winds across PANC are also expected to
continue through Wednesday morning.

-CC

&&