Gale Warning 194, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
522 AM AKST Wed Feb 26 2025

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

A pattern shift to more active weather is underway as a strong low
pushes into the southern Gulf this morning. Though the low was
moving fairly quickly north, it will stall out in the Gulf while
slowly filling in. This will confine precipitation mostly to the
Prince William Sound, with some very light snow moving into the
surrounding mountains. A portion of the decaying upper level
energy will move into the Copper Valley later today, allowing for
chances of snow this afternoon and tomorrow. Most of the Cook
Inlet region and Mat-Su Valleys should remain dry barring a
shift in the storm track to the west, of which models have
continued to shift away from. However, a weak trough currently
associated with the ongoing snow over Bristol Bay will lift
through Southcentral tomorrow night, allowing for a chance of flurries
or a light dusting of snow for the western Kenai Peninsula, and
maybe as far north as Anchorage. There is still quite a bit of
uncertainty in the forecasted low track and shape as it nears the
Sound early Thursday morning. The primary impact will be
differences in the marine winds south of the Sound.

Starting Thursday afternoon and continuing into Friday a strong
occluded front will push north into the southern Mainland from a
broad low in the North Pacific. Expect strong winds and rain at
sea level from Kodiak Island north into the Sound by Thursday
afternoon. This pattern will hold through the start of the weekend
as the parent low slowly fills in and drifts into the eastern
Gulf. Due to the strong southeasterly winds, expect downsloping
and dry conditions from near Ninilchik north through Anchorage and
into the Mat-SU. Temperatures will be balmy throughout the
Southcentral, with highs expected to be in the low to mid 40s for
many areas due to warm air moving through the mountain gaps in
addition to our late February sun having more and more effect on
the diurnal temperature swing. However, cold air wrapping behind
the system moving into the region today will provide somewhat of a
cold/cool air dam and buffer along the coast initially, keeping
snow levels to 900 to 1500 feet throughout the storm. Therefore,
there may be times where the mountain passes throughout the Kenai
Peninsula may have accumulating, albeit wet snow on the roadways.

-CJ

&&

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

Currently, a showery pattern persists across the Bering Sea and
continues to produce some rain/snow showers across the western
Aleutians due to a broad, weak, and meandering low pressure
complex centered around 300 miles northwest of Amchitka. This
feature does not look to be going anywhere anytime soon in the
near term.

Elsewhere, a negatively tilted 500 mb trough now situated across
the central Aleutians is forecast to pivot and lift northward and
will begin to stall and stretch out over the AK Pen and Southwest
AK. However, this upper trough is broad and already working in
tandem with a weak surface trough and wave of low pressure
affecting the coastal Southwest. Radar shows that the combined
forcing has produced a band of light to moderate snow west of
King Salmon, moving right along the Bristol Bay coastline. This
axis of moisture is just far enough inland to where areas such as
Dillingham has been reporting light snow for the past 24 hours.
Model guidance suggests this snow band will progress farther north
into the Kuskokwim Delta and just west of Bethel by Wednesday
afternoon. Accumulations of 2-4" are expected to be localized to
Dillingham and points just north and west near Manokotak, Twin
Hills, and the higher terrain of the southern Kuskokwim Mountains
with lighter amounts elsewhere before the band exits early
Thursday, but snowfall should stay below advisory level.

Also by early Thursday or so, a storm-force, occluded North
Pacific low and its associated front/precip band on its northern
flank moves closer to the Aleutian Island chain. The forecast here
becomes tricky as temperature profiles initially look cold enough
Thursday afternoon to begin as snow or a rain/snow mix across
portions of the eastern Aleutians and the Bristol Bay coast.
Shortly thereafter, warm air advection starts early Friday for the
central Aleutians, AK PEN, and the Bristol Bay area that will
most likely change p-type to rain or a wintry mix from south to
north while the western Aleutians remain on the colder/drier side
with a few snow showers. By Friday afternoon, the dry conveyor
belt begins to kick in for the central Aleutians and starts to
shut off moisture behind the low from west to east while
precipitation still lingers across the AKPEN and Southwest that
lasts into the weekend.

-AM/ME

&&

.LONG TERM FORECAST (Days 4 through 7 - Saturday through Tuesday)...

The upper level Alaska Weather map is split between a broad
trough covering the Aleutians and Bering and a ridge extending
from Canada across Interior Alaska. Occasional disturbances from
the North Pacific intersect the base of the trough, adding to the
unsettled picture. A number of shortwaves are rotating through the
pattern, supporting areas of active weather on the surface.
Forecast confidence for the larger features rides on the shoulders
of an ECMWF / Canadian blend until late in the period when the
heretofore out of sync GFS joins the group. Greatest uncertainty
is in the smaller details. A well defined negatively tilted trough
will develop across the region into the Gulf of Alaska by the end
of the forecast period.

Warm air ahead of the large scale trough continues to pump over
the Southcentral coasts into the Interior, but leaving the bulk of
the precipitation along coastal zones. A well developed North
Pacific low extends a front along the North Gulf Coast. Locally
heavier rainfall from the Pacific side of the Alaska Peninsula and
Kodiak Island extends along the Eastern Kenai Peninsula into
Prince William Sound through late Sunday. Somewhat lesser amounts
spread towards the Canadian Border. This same low pushes snow or
rain and snow mixed over the Alaska Peninsula into Bristol Bay and
Southwest Alaska through Sunday. As the low loops into the
Eastern and Central Bering, the snow progresses Westward over the
Pribilofs through the rest of the period. Another North Pacific
low brings snow changing to rain across most of the Aleutians and
AKPEN Monday, pushing the snow over the Bering through Tuesday.

- Kutz

&&

.AVIATION...

PANC...VFR conditions and northerly winds will persist, though a
brief uptick in winds to around 10 kts or so can still be expected
late this morning into the early afternoon. Snow flurries could
reach the surface at the terminal late tonight into Thursday
morning, but significant visibility reductions are not expected.
Ceilings could still lower with periods of flurries or virga,
perhaps below the 5000 ft threshold at times starting late
tonight.

&&