Gale Warning 781, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
514 PM AKDT Thu Oct 31 2024

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

A triple point low that currently sits to the east of Kodiak
Island is tracking to the northeast with the upper level support
of a negatively tilted shortwave trough. Winter Weather Advisories
are in effect until tomorrow morning for multiple zones across
southcentral due to snow, mixed precipitation, and/or freezing
rain potential. Today, a mesoscale low developed in western Prince
William Sound (PWS) which drastically affected the snow rates in
the region. The location of this feature is promoting a westerly
component to air flow, keeping the anticipated warmer
southeasterly winds at bay and giving us a likely "all-snow" event
for western Kenai Peninsula north up through the Anchorage Bowl
and Mat-Su Valleys. Precipitation should continue to fall as rain
for eastern Kenai Peninsula and PWS communities (Seward, Whittier,
Valdez). The mesoscale low looks to linger until Friday morning,
giving the possibility of a steady light snowfall through the
night.

On Friday night and into Saturday morning, a strong but occluding
low will move south of Kodiak Island and into the Gulf, tracking
toward PWS by Sunday morning. Light upslope flow along mainly the
eastern Kenai Peninsula will promote rain at sea level and upper
elevation snow, with overall warm temperatures. Downsloping and
northerly winds at the surface should keep most other areas dry.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA AND THE BERING
SEA/ALEUTIANS (Today through Sunday)...

The North Pacific low has begun to impact the Central Aleutian
Islands. Winds speeds and precipitation chances are gradually
increasing in the Fox Islands in response. There is high
confidence in the low's track remaining in the North Pacific
waters south of the Aleutians and Alaska Peninsula. The low will
bring storm force winds and heavy rainfall as it travels along the
Aleutian Islands and Alaska Peninsula before departing into the
Gulf of Alaska by Saturday. The High Wind watch for the Alaska
Peninsula on Friday has been canceled due to a lack of instability
for winds. Despite this cancellation, winds are still expected to
potentially gust to 60 to 70 mph. Winds on the back end of the low
are expected to be weaker. This is due to mild cold air advection
which will result in lower lapse rates near the surface and less
vertical mixing of winds.

As the low makes it into the Gulf of Alaska, cold air advection
will flow into Southwest Alaska on Saturday. The cold air
advection combined with lingering moisture from the low will
allow for snow in the inland Kuskokwim Delta and Bristol Bay
regions and rain in southern Bristol Bay. Freezing rain is not
expected due to a colder vertical profile of temperatures. Snow
accumulations will range from 2-4 inches depending on terrain and
distance from the coast.

Sunday looks to be much calmer weather-wise. As the low moves into
the Gulf of Alaska, lingering small craft gap winds in the Alaska
Peninsula region is the main impact for Sunday. There will be a
couple of weak lows in the Bering Sea, which will produce light
rain and 10-20 mph winds. Looking ahead to Monday, a low that is
associated with the remnants of Typhoon Kong-rey will take a
somewhat similar track as today's low. Much uncertainty exists on
the exact track of this low and how strong it will be. Stay tuned
for updates as we continue to monitor this low.

-JR

&&
.LONG TERM FORECAST (Days 4 through 7: Monday through Thursday)...

On the Alaska Weather map, a broad upper level low spreads across
the Bering into Western Alaska through the forecast period.
Forecast model ECMWF and GFS have the best handle on feature
strengths and tracks. The first low deepens as it moves into
Bristol Bay by Tuesday. This low will loop around the Southeastern
Bering through Thursday. The surface feature associated with this
low is a well developed low that moves from the North Pacific on
Monday across the Southern Alaska Peninsula along the Southwest
Alaska coasts through Thursday. Widespread rain or rain and snow
mixed through Thursday and gale force winds over the Aleutians,
AKPEN to Kodiak Island and the Southeast Bering through late
Tuesday. Locally heavy rains are expected along the Southcentral
coasts from the Eastern Kenai to the Canadian Border through
Tuesday. A second well developed North Pacific low slides to the
South of the Aleutians before recurving along the Pacific side of
the AKPEN late Wednesday into Thursday. This low brings another
round of locally heavy rains and gale force winds extending into
the Gulf of Alaska through the end of the forecast period.

&&

.AVIATION...

PANC...IFR conditions and snow will persist through the evening.
There is a slight chance of freezing rain through the evening, but
it looks unlikely at this time. MVFR ceilings are likely through
at least Friday morning.

&&

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Preliminary Local Storm Report
National Weather Service Anchorage AK
1146 PM AKDT Thu Oct 31 2024

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

1045 PM     Snow             1 NE Anchorage (Campbel 61.19N 149.79W
10/31/2024  M4.8 Inch        Anchorage          AK   Public

&&

Preliminary Local Storm Report
National Weather Service Anchorage AK
1158 PM AKDT Thu Oct 31 2024

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

1158 PM     Snow             Upper Rabbit Creek      61.06N 149.76W
10/31/2024  M8.5 Inch        Anchorage          AK   NWS Employee

&&