Gale Warning 44, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
420 PM AKST Mon Jan 9 2023

.ANALYSIS AND UPPER LEVELS...

A moderate-strength low is southwest of Kodiak Island early this
afternoon and weakening as it tracks toward the Alaska Peninsula.
There is not so much a well-defined front, but an inverted trough
associated with this low that is moving from east-to-west across
the Bristol Bay region this afternoon. This is the source of the
snow and blustery north winds across Southwest mainland Alaska.
High pressure is building into Southcentral Alaska from the east
behind this inverted trough.

Over the western Aleutians, there is a small polar low which is
cranking up some intense snow showers out toward Attu which
dropped some visibilities down to 1/4 mile in the snow earlier
today.

&&

.MODEL DISCUSSION...

The model agreement is much better than it was just a few days
ago as stronger, more consolidated lows have replaced the diffuse,
complex lows in the Bering Sea and Gulf of Alaska. An area in
question is for northern Cook Inlet where some of the higher
resolution models are indicating a little bit of snow is possible
Tuesday night or Wednesday morning while the more course
resolution models keep the region completely in the downslope
hole. Heading toward the weekend, the models really do start to
break down over the Aleutians with some striking disparity in
placement and strength of the low or lows over there at that time.

&&

.AVIATION...

PANC...VFR conditions and light winds will persist.

&&

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

A low pressure system from the western Gulf is lifting
northwestward into the Bering Sea. The strong easterly winds are
expected to subside tonight, but widespread rain over Kodiak
Island will likely linger until Tuesday morning. The front will
slowly move north and east, bringing snow accumulations along the
Kenai Mountains and Turnagain Arm areas through Tuesday, and into
the eastern Chugach on Wednesday. The rest of the Southcentral
mainland meanwhile remains relatively dry due to downsloping
easterly flow.

An upper level shortwave tracks northward across the Gulf from
Tuesday afternoon to Wednesday. Another round of precipitation
spreads across the eastern Kenai Peninsula, with the heaviest
along Prince William Sound overnight Tuesday. Precipitation type
is expected to remain snow throughout the Tue afternoon to
Wednesday period for most elevated areas, with rain likely for the
low- lying regions. Although confidence is low, there is a
slight chance for some light snow farther inland for the western
Kenai Peninsula, Anchorage Bowl, and the Mat-Su Valleys between
Wednesday afternoon and early Thursday.

&&

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

A moderately strong low will cross the Alaska Peninsula (AKPen)
tonight and move into Bristol Bay Tuesday. This will continue the
light snow observed throughout the area today. A narrow band of
heavier snow will set up from Dillingham north into the Wood River
Mountains through Tuesday evening before letting up as the low
tracks into the interior and weakens rapidly. Up to 6 inches of
snow accumulation is possible in this area, while elsewhere will
likely see 1 to 2 inches.

The other side to the coin of this storm is the wind. Strong
offshore winds in response to the low this evening will weaken
slowly from south to north as they transition to onshore flow by
Wednesday morning. Blowing snow is likely to persist through at
least Tuesday morning for the Kuskokwim delta, though no
significant reduction in visibility is expected due to the low
snowfall accumulation and availability, or lack there of, of
transportable snow. Weather on Wednesday and Thursday should quiet
down significantly, as the low moves inland. Some light snow
showers, overcast skies and above normal temperatures are
expected.

&&

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

Much of the Bering will remain quiet through Wednesday morning as
the area for the most part is surrounded by, but not impacted by,
storm systems. A strong front with storm force winds and snow
transitioning to rain will reach the Western Aleutians early
Wednesday morning and the Central Aleutians Wednesday afternoon.
Winds should dissipate to ~25 kt by the time the front reaches the
Eastern Aleutians and Pribilof Islands Thursday as the system
occludes. Conditions will then be slow to change as the low
occludes in place.

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

A building ridge in eastern mainland Alaska will promote a stable
environment for Southcentral. Out west, a longwave trough will
make its way through the region, with several shortwaves and North
Pacific lows approaching the Bering. A shortwave trough
approaching coastal Southcentral Friday looks to promote
precipitation along the coast, but lacks the strength and
orientation to push inland. A drier pattern seems to emerge for
Southcentral and Southwest this weekend as shortwave passages drop
out and upper-level ridging builds. In the Bering, a low complex
in the Western Bering/North Pacific will draw multiple fronts and
low pressure systems into the Aleutians through the Weekend into
Monday. A low formed at the triple point of one such front looks
to approach the Southwestern Gulf of Alaska Monday morning.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Gale Warning 130 138 150 178.
		 Heavy Freezing Spray Warning 139 180 185 414.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...EZ
SOUTHCENTRAL ALASKA...MF
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CJ
LONG TERM...CL