089
FXAK68 PAFC 070142
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
442 PM AKST Wed Nov 6 2024

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

Discussion:

In advance of the next system working north out of the North
Pacific, areas along the AKPen, Kodiak Island, Cook Inlet/Western
Kenai, and portions of Prince William Sound saw partly to mostly
sunny skies at some point today...albeit briefly. Cloud cover is
once again spreading up into the western Gulf ahead of this system
with showers already ongoing across Kodiak Island and the eastern
AkPen. Showers will continue to spread north tonight with heaviest
precipitation falling over Kodiak Island and the eastern Kenai
Peninsula. Snow levels are around 1500 to 1800 feet so precipitation
is expected to remain mostly rain for lower elevations, though there
is a chance if temperatures dip down into the mid 30s that a rain-
snow mix or a brief change-over to wet snow is possible Thursday
morning. Winds are already increasing across the western Gulf with
gales to storm-force winds as the front moves through tonight.

Cross-barrier flow will lead to modest downsloping to develop over
the western Kenai up through the Mat-Su Valley and little, if any,
precipitation is anticipated to make it into these areas. Northerly,
down inlet flow will develop nearer the surface and will lead to
some wind shear concerns in this area. A strengthening gradient over
the northern Mat Valley will result in gusty north winds developing
Thursday morning and continuing through the late afternoon and
evening until the gradient begins to relax. Interior Southcentral
should remain mainly dry with showers mainly limited to the higher
elevations along the Wrangells and northern Copper Basin along
the Alaska Range.

- PP

&&


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

A 963 mb North Pacific low approaches the Alaska Peninsula (AKPEN)
this afternoon. It will draw toward itself the remnants of a low
which has lingered over Southwest Alaska for the past several
days. Colder upper level air will move in from the north to take
its place, while a new low center consolidates off the eastern
coast of Kodiak Island by early Friday, and remains in place
through Saturday morning. Most of the precipitation from this
system will be attenuated by the Kenai and Alaska Ranges, however,
periods of Gale force wind may infiltrate across Bristol Bay, and
from the Bering south across the Eastern Aleutian Chain and
AKPEN, subsiding by Thursday afternoon. With good model
agreement, a generally more settled pattern is expected for
interior areas, north of the AKPEN Friday and Saturday, with a
brief dip in weekend temperatures across Southwest.


Models are less aligned from Friday afternoon through Saturday
morning as a 970 mb, eastward moving system passes south of the
Aleutian Chain. Small craft advisory winds will be possible across
the Central Bering and Pribilof Islands, with gale force winds
through gaps and passes of the Aleutian Chain and AKPEN. The
strength of these winds will depend on the proximity of the track.
The GFS indicates the most northerly track with large areas of
gales through gaps and passes and south of the Aleutian Chain/
AKPEN, and small craft winds for Bristol Bay on Saturday
afternoon. The Canadian model, however, indicated a track 100nm
farther to the south, producing a smaller area and shorter periods
of gale force gap winds, with more widespread areas of small
craft winds, mainly south of the Pribilof Islands.

-ER

&&


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

On Sunday, a vertically stacked low pressure system in the
southern Gulf will be traversing eastward towards the panhandle.
The rain showers that had been consistent along the Gulf Coast for
the few days prior will taper off through the day, leaving dry
conditions for the majority of Southern Alaska. North to northwest
flow on the backside of the low should bring gusty gale-force
winds through bays and passes along the Alaska Peninsula, but by
Monday morning light winds will likely persist across most of the
region. At this same time, another low from the North Pacific
looks to pass just south of the Aleutian Islands, bringing with it
increased northerly winds and light to moderate precipitation.
Most models are suggesting this is a weaker system than the one
before it and will not be too impactful. Further north, some
models are picking up on a shortwave pushing a colder air mass
across the Bering on Monday, bringing the potential for a quick
shot of snow to the Kuskokwim Delta north on Monday evening, but
confidence for this is low at this time.

Looking out to Tuesday and Wednesday, there is model disagreement
between a more zonal flow pattern and a higher amplitude pattern.
The more zonal pattern would keep calmer conditions across
Southern Alaska, while the higher amplitude pattern would bring a
stronger low pressure system from the North Pacific into the
Bering Sea, bringing some potentially higher impact weather along
with it.

Throughout our long term outlook, some guidance is suggesting a
gradual trend toward cooler temperatures across Southcentral due
to cold air trying to creep down from the north, but overall
fairly mild temperatures will persist.

-TK

&&.AVIATION...

PANC...VFR conditions will persist. The gusty southeasterly winds
are expected to diminish this evening and then switch to northerly
around midnight. Winds almost will remain more southeasterly so
there may be some low level wind shear that develops overnight and
persists into Thursday.

&&


$$