Gale Warning 850, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
428 AM AKST Mon Nov 25 2024

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

An upper level trough is moving through this morning, bringing
light to moderate precipitation from Anchorage north into the
Mat-Su Valleys. Precipitation type has been a mixture of
everything from Anchorage to Wasilla overnight, mainly due to the
remnants of the strong inversion felt last week and warm air
moving up the inlet and through Turnagain Arm. Now that the winds
are subsiding a bit, there is a new "problem" in the lack of upper
level saturation and ice in the cloud that's leading to light
rain despite a cooling airmass. On satellite there is a clear lack
of upper level clouds, meaning the low-level stratus may be
mostly supercooled liquid droplets. This is particularly true over
Anchorage right now, while the Valley is teetering back and forth
between snow and rain. Areas closer to the mountains are likely
getting some extra lift and saturating more of the dendritic
growth regime. The only area that has been getting consistent
moderate snow is the Susitna Valley, where an estimated 4 to 6
inches has fallen so far.

As the trough moves east today, light snow will spread into
Valdez and the Copper Valley, while Cook Inlet areas and the Mat-
Su start to dry out. A broad 2-4 inches is expected for the Copper
Valley, mainly from the Richardson Highway east. Lingering
moisture will keep things cloudy and temperatures mild for
Tuesday, but northerly flow will help to dry things out and usher
in more cold temperatures starting Wednesday. Gap winds will also
return through Whittier, Seward, Valdez and Thompson Pass. It's
also looking likely that the Mat Valley will get some gusty winds
by Wednesday.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA AND THE BERING SEA/ALEUTIANS
(Days 1 through 3: Today through Thursday morning)...

A low pressure system system in interior Alaska continues eastward
this morning along with its front. Upslope snow showers will
continue today in the Lower Kuskokwim Valley mostly along the
Western Alaska Range as well as along the Kuskokwim Mountains in
the Kuskokwim Delta region. The upslope snow showers will also be
accompanied by a cool down as an Arctic trough drives
southeastward. Expect mostly quiet and cold conditions for
Tuesday through Thursday across mainland Southwest. With the
persistent off-shore northeasterly winds expected off the coast,
there is potential for some Heavy Freezing Spray Tuesday evening
into Wednesday morning along the near shore zone of the Kuskokwim
Delta, especially near the ice edge and through Etolin Strait.

Farther west, a North Pacific low continues to send its front
northwestward across the Central and Western Aleutians. This is
producing gusty conditions with steady rain across Adak and Atka
this morning. This activity is expected to move to Shemya by this
afternoon. Also of note are the east-to-west gradient gale-force
winds across the central and western Bering Sea. These winds will
become widespread on Tuesday along with storm-force gusts Tuesday
morning into Tuesday afternoon before the gradient between the
North Pacific low's front and high pressure to the north in the
northern Bering begins to relax.

Meanwhile, showers make it to the Eastern Aleutians by late this
afternoon into early this evening and to the southern Alaska
Peninsula by this evening into Tuesday morning. There is still
some uncertainty with the ultimate track of the low into
Wednesday. Because of the uncertainty in the track, there is
uncertainty in the Pribilof Islands precipitation forecast. The
Canadian and ECMWF guidance continue to insist on a more northern
track of the system across the Aleutian Chain and into the
southern Bering by late Tuesday/early Wednesday. This would be the
wetter solution for the Pribilofs while the the GFS/NAM solution
continues with the further south track in the North Pacific which
would prove drier for the area. This area of low pressure,
regardless of its position north or south of the Aleutian Chain,
will end up weakening and become more of a frontal system as it
moves west across the Chain into Wednesday afternoon. With that,
more light rain will be possible for the Central and Western
Aleutians into Thursday as another stronger North Pacific low
sends it front northward towards the Chain by then.

&&

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

For mainland Alaska, a period of relative calm remain a mainstay.
Thursday and Friday continue to see clear skies and cold
temperatures as high pressure stretches from the Bering Strait,
southeast through Kodiak, ushering cold and dry Arctic air. Out
west and in the Bering Sea, a decaying front will stall as it
slams against the high pressure over mainland on Thursday,
eventually losing steam and fizzling out. A large upper level low
will slowly move east from the northwestern Pacific on Friday,
starting to pinch the high pressure in the Gulf of Alaska. Warm
and moist southerly winds will start to bring clouds and warmer
conditions in from the pacific, ending the clear skies
everywhere. As this low moves east, it will struggle to displace
the well entrenched high pressure and will dramatically slow. By
the weekend, areas along the Gulf coast should see precipitation
return. All other inland areas will continue to remain dry,
keeping the well below normal precipitation trends intact.

&&.AVIATION...

PANC...Chance for light precipitation and MVFR conditions through
the early morning, drying out by late morning/early afternoon.
Cloud ceilings will gradually rise above 3000' through this
morning, but may hover or remain below 5000' through the
afternoon. Southerly winds 10 to 12 kts are likely this morning,
diminishing by late morning. Winds shift around to northerly by
this afternoon.

&&

Preliminary Local Storm Report
National Weather Service Anchorage AK
210 PM AKST Mon Nov 25 2024

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

0207 PM     Snow             3 W Palmer              61.62N 149.17W
11/25/2024  M3.5 Inch        Matanuska-Susitna  AK   Public

&&

Preliminary Local Storm Report
National Weather Service Anchorage AK
308 PM AKST Mon Nov 25 2024

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

0217 PM     Snow             1 SE Sutton             61.71N 148.87W
11/25/2024  M7.0 Inch        Matanuska-Susitna  AK   Public

&&