Area Forecast Discussion
Issued by NWS Anchorage, AK

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000
FXAK68 PAFC 190049
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
449 PM AKDT Mon Mar 18 2024

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

Light snow and sea-level rain will continue to diminish this evening
as the responsible low dissipates in the Gulf of Alaska. A ridge of
high pressure will amplifying across southcentral Alaska today and
tomorrow and remain in place through midweek. This will result in
generally quiet weather for the area.

The biggest forecast challenge in the short term will be the extent
of lingering low stratus and/or fog across Cook Inlet and the Copper
River Basin tonight into Tuesday morning. There is also the
potential, if low clouds and fog do linger, for pockets of freezing
drizzle from Kenai to Anchorage Tuesday morning. Forecast confidence
in this scenario is low; however, there continues to be support for
this in forecast model soundings.

&&


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


Rain, snow and gusty winds will persist in the Bering Sea through
tomorrow as a strong front continues its northward progression.
Observations on the Central Aleutians showed a changeover to rain
earlier today at Dutch Harbor and Cold Bay with wind gusts in the
30 to 40 mph range. Strong southerly winds in the North Pacific
and Bering Sea will continue through Wednesday evening. Gap winds
are forecasted to range from 50 to 60 mph in the Eastern Aleutian
Islands; fastest from Dutch Harbor east to Nelson Lagoon.

Snow and wind gusts ranging from 30 to 40 mph that created
blizzard conditions in the Pribilof Islands this afternoon are
slowly diminishing. Warmer air will continue to flow into the area
increasing temperatures above freezing and change the lingering
snow showers to rain. Wind gusts also continue to diminish quickly
this afternoon. Looking ahead across the Bering Sea and
Aleutians, southerly to southwesterly wind flow is expected to
continue through mid- week with decreasing winds after Thursday.

Later tonight, snow and wind gusts ranging from 30 to 40 mph in
will arrive in Toksook Bay and northward along the
Kuskokwim Delta coast. A blizzard warning is in effect this
evening through tomorrow morning in this area.  Snowfall amounts
here are forecasted to reach 5 inches and combined wind gusts as
high as 40 mph, will create visibility reduction to a quarter
mile at times.


&&
.LONG TERM FORECAST (Days 4 through 7: Friday through Sunday)...

A highly amplified pattern, featuring deep troughing over the
Bering Sea and Aleutians and a strong ridge across much of
Mainland Alaska and the Gulf remains throughout the period. This
large scale weather pattern will favor above average temperatures
across all of Southern Alaska. While drier weather and mainly calm
conditions are expected for Southcentral Alaska under the ridge,
a warm and stormy pattern is in store for the Bering Sea, Aleutian
Islands, and Southwest Alaska as multiple waves and storms move
through. The biggest challenge in the long term will be honing in
on the track and evolution of these storms, and the timing on when
the ridge begins to break down, allowing for any moisture to make
its way into Southcentral Alaska.

The first major storm complex will be on Friday as models show a
sub-980 mb North Pacific low/low complex moving north and crossing
the Aleutians sometime Friday into Saturday. However, confidence
in the exact details of the low(s) itself still remains low,
leading to high model variability in the location and timing of
the heaviest precipitation and strongest winds. The GFS and
various ensemble members show a single strong, occluding low,
while the EC/Canadian begin to form a low complex with multiple
precipitation and wind maxima.

Forecast confidence continues to decrease by Saturday, with the
question of whether the aforementioned low and troughing is strong
enough to begin to break down the ridge extending across much of
Alaska and the Gulf. Due to the single low, the GFS/GEFS keep the
ridge in place continuing drier and calmer conditions across
Southcentral, while the Canadian/EC and some of their respective
ensembles push a front from the easternmost low eastward, bringing
stronger winds and widespread precipitation into Southcentral.

-ME

&&

.AVIATION...

PANC...The MVFR-level stratus in upper Cook Inlet is expected to
persist around the airport for the overnight hours and may lower
to IFR for the early morning hours. With this low stratus and a
very dry midlevel airmass moving in, there is a chance for some
periods of freezing drizzle to develop late tonight into the
early morning hours. This is not a sure thing by any means, but
the atmospheric set-up is conducive for freezing drizzle,
especially if the stratus does thicken and lower late tonight.

The other big question is if the stratus will finally clear out
Tuesday afternoon or mainly stick around into Tuesday night.

&&


$$


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