Gale Warning 756, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
420 PM AKST Fri Nov 25 2022

.ANALYSIS AND UPPER LEVELS...

A broad trough currently encompasses much of mainland Alaska.
Despite this, much of the state remains partly cloudy as drier air
builds in from the north ahead of a ridge. The only precipitation
remains near the trough axis along Prince William Sound. The
ridge centered over the central Bering is bringing very quiet
conditions to the Bering with only scattered cloud cover.

&&

.MODEL DISCUSSION...

Models show good agreement with regards to the longwave pattern.
GFS never aligned with other models and still indicates a surface
low farther west in the Gulf, lingering the associated precipitation
longer near Prince William Sound. In any case, it will depart the
area by Saturday morning. While there remain some slight
discrepancies, all models show Southcentral Alaska remaining
between an upper low over western Canada and a ridge moving across
the Bering. This pattern will lead to cooler temperatures and
mostly sunny skies. Agreement is generally good as well for a
front tracking across the Bering this weekend. Precipitation looks
to reach southwest Alaska by Sunday evening. Confidence is
moderate.

&&

.AVIATION...

PANC...Light winds will persist. Areas of low stratus (less than
1,000 ft AGL) will likely linger across northern Cook Inlet
through the evening and overnight hours, occasionally moving
across the terminal. Expect ceilings to fluctuate between VFR and
IFR through early Saturday morning. There is a chance that this
cloud deck lowers overnight, allowing for the development of fog.
Confidence is this solution, however, is low at this time.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3:
Tonight through Monday night)...

Snow continues to fall across eastern Prince William Sound and
the Copper River Basin this afternoon as a surface low exits into
Southeast Alaska. The snow will taper off during the overnight
hours tonight and into early Saturday morning with the low's
departure. A pattern shift unfolds following the low as an upper-
level shortwave and Bering ridge push east to Southcentral,
bringing colder, drier, and clearer conditions to the region.
Gusty northerly offshore winds are also starting to develop along
the north Gulf coast this afternoon and will continue to
strengthen through Saturday. Winds will be especially gusty
through areas of channeled terrain such as Thompson Pass and the
Valdez area. On Sunday, offshore flow beings to relax while the
cold, clear, and dry conditions persist into Monday. There is
moderate confidence for Kodiak Island and the southern tip of the
Kenai Peninsula to see some precipitation again by Monday
afternoon and Monday evening, respectively, as a surface low
tracks from the eastern Bering into the western Gulf.

&&

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

Some disorganized shortwaves, onshore flow and cold air advection
aloft will continue light to moderate snow showers this evening
before things transition to solely upslope flow on Sunday. High
pressure moving in from the west will lead to areas of clear skies
and cooling temperatures through Sunday. For coastal areas this
will be fairly short lived as a front tries to push it's way into
Southwest Sunday afternoon and Monday. There is quite a bit of
uncertainty in the progression of the upper level shortwave
and where a triple point low will develop along the front on
Monday. Solutions vary considerably, with northern solutions
taking the low into the Kuskokwim Delta and southern solutions
moving it into Bristol Bay. This will have considerable
implications for precipitation type across Bristol Bay with the
northern solutions favoring rain along the coast and southern
solutions favoring snow.

&&

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

A gale to storm force front will move east across the Bering over
the weekend. A general transition of snow to rain is expected
along the Alaska Peninsula and the Pribilof Islands, where winds
will also be elevated. Blowing snow is likely over the Pribilof
Islands as the front moves in, but temperatures should remain too
warm to reduce visibility considerably. After the front passes,
expect rain showers to develop.

&&

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

There is high confidence in deterministic and ensemble guidance
that a high amplitude ridge will continue to establish itself over
the central to western Bering. Overall quiet weather is expected
across the southern Mainland and majority of the Bering Sea with
the ridge overhead. Starting off on Tuesday, a shortwave dropping
southeast from Bristol Bay will move over Kodiak Island, bringing
rain and snow. The other feature that may bring active weather to
western Alaska later in the week are shortwaves riding over the
ridge axis, attempting to break it down. The north/south deviation
in these waves remains highly uncertain, but it will dictate where
precipitation falls late Wednesday into Thursday. Given the strong
ridging, the thermodynamic profile will favor freezing rain or
rain. Otherwise, expect a mild week overall, with the exception of
the Copper River Basin, where temps will drop into the negative
teens to twenties.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Storm Warning 412.
		 Gale Warning 120 125 130-132 170-179 185 351 352 411 413
					  414.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...AP
SOUTHCENTRAL ALASKA...AF
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CJ
LONG TERM...CJ