Gale Warning 227, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
401 PM AKST Sat Mar 8 2025

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3:
Saturday afternoon through Tuesday afternoon)...

Quieter weather today becomes much more active by tonight as a
strong front pushes into Southcentral Alaska from the Bering Sea.
Most of the impacts will be felt along Kodiak Island and the
north Gulf coast, with Western Kenai Peninsula, Mat-Su Valleys,
and Copper River Basin remaining mostly dry. Good synoptic model
agreement has led to higher overall forecast confidence. However,
snow amounts for Eastern Turnagain Arm and Eastern Kenai
Peninsula remain highly uncertain as temperatures hover just above
freezing. If you'll be in or traveling through these areas between
early tomorrow morning and Monday afternoon, please exercise
caution as potentially heavy snow, reduced visibilities, and slick
roads could lead to difficult travel conditions.

Diving into the details... mostly clear skies across much of
Southcentral this afternoon, with the exception of showers moving
across Eastern Kenai Peninsula as a shortwave rotates around an
occluded low in the southeastern Gulf. These showers will
reinvigorate late tonight as another shortwave sweeps in ahead of
the arriving front. The front itself is already visible on
satellite as it approaches Kodiak Island. Model agreement has
improved significantly with this front, leading to higher forecast
confidence at the synoptic scale. Models have trended slower and
more southerly with this feature, keeping precipitation amounts a
bit lower across Eastern Prince William Sound than previously
forecast.

Overall, the main focus with this feature continues to
be Eastern Kenai Peninsula and Turnagain Arm, where persistent
easterly flow will lead to upsloping and enhanced precipitation
amounts from early tomorrow through about midday Monday. As
mentioned in the previous forecast discussion, the main question
will be where the rain/snow line sits. With pretty good confidence
that daytime temperatures will climb into the mid-30s for areas
like Girdwood, Portage Valley, and Whittier, the question will be
(a) how much snow can accumulate before melting, and (b) will
heavier showers drop temperatures just enough to facilitate higher
surface accumulations? With colder air aloft, surface
temperatures will be the pivotal piece of the puzzle. Generally,
we're expecting any snow that falls to be wet and heavy, with the
potential to mix with rain. The likelihood of snow accumulation
will be highest overnight from Sunday into Monday, when
temperatures will drop from their daytime highs. The envelope of
possibilities is very wide with snow amounts in this area - our
forecast is on the lower end of the spectrum as we anticipate
above-freezing surface temperatures. As such, if temperatures
stay low enough, there could be more snow than what's currently in
the forecast, potentially in the double digits. Regardless of
snow amounts, expect poorer weather and travel conditions with
this storm.

-Chen

&&

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

The strong front associated with the low pressure system centered
between the Kamchatka Peninsula and the Western Aleutians is
currently pushing across the Eastern Bering Sea. Cold air wrapping
back in behind the front will promote favorable conditions for
heavy, more sporadic snow showers across much of the Bering Sea
and Aleutian Chain for the next couple of days. Strong westerly
winds will traverse the Aleutians through Tuesday.

The front will begin to occlude as it hits the mainland coast
this evening. Winter Weather Advisories have been issued for both
the Kuskokwim Delta Coast, including Nunivak Island, and the
Bristol Bay region from Dillingham north and west from 7PM this
evening to 7AM tomorrow morning. Forecasted total snow
accumulations range from 2 to 5 inches with even higher magnitudes
expected over elevated terrain around the Wood River Mountains.
Winds gusting up to 40 mph could cause visibilities to drop to
one- half mile at times; especially this evening and overnight.
Nunivak Island has the best chance for visibility to briefly drop
to one-quarter mile overnight with heavy snow and 45+ mph wind
gusts. Conditions look to improve through Sunday morning as winds
begin to diminish and steady snow tapers to snow showers.

A triple point low will form near Kodiak Island on Sunday,
helping to enhance snow showers from Lake Iliamna north across
interior Southwest through Monday afternoon. The weakening parent
low in the Bering will push into mainland Alaska on Monday,
bringing a round of light precip to coastal communities. This
system will continue to weaken before getting absorbed by a low in
the Gulf of Alaska Tuesday afternoon. By this time, the Aleutians
will begin to see the impacts of a front associated with a low in
the North Pacific. Moderate precipitation and gusty winds are
likely with this system as well.

&&

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

An upper level area of low pressure occupies the western Bering
Sea and extends into the North Pacific. A smaller scale ridge
slides across the Aleutians and Gulf of Alaska ahead of the low
through Thursday. Several shortwaves ride through the pattern
through the week.

A Western Bering surface low brings areas of mostly snow and gale
force winds across the Central and Eastern Bering, diminishing
Thursday. Rain continues to spread into the Alaska Peninsula,
Kodiak Island and across the Southcentral coasts through Friday.

&&

.AVIATION...

PANC...VFR conditions and light northerly winds will persist. A
front and developing low will move into the eastern Gulf tonight.
This will induce easterly winds over the mountains, which may
cause some LLWS on Sunday; however, at this time the strong
easterlies appear to be above the 3000 ft threshold.

&&