Gale Warning 115, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
534 AM AKST Mon Jan 27 2025

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through
3/Today through Wednesday Night)...

Here is an update on the Warning, Watches, and Advisories that
have been issued throughout this storm:

* Winter Storm Warning for Thompson Pass in effect until 5 PM
  Monday. Heavy snow and blowing snow with additional snow
  accumulation of 6-12 inches for Thompson Pass and 2-6 inches
  for Valdez to Keystone Canyon.

* Flood Warning for the Anchor River near Anchor Point Road
  downstream of the Sterling Highway and the Anchor River State
  Recreation Area, with additional flooding along the Sterling
  Highway near mile marker 160 and 161 (Blackwater Bend).

* High Surf Advisory for the Homer Spit where strong southwesterly
  winds with gusts to 50 kt could bring large crashing waves to
  the Homer Spit.

The front that brought a myriad of active weather to Southcentral
over the past 24 hours has now weakened as it continues to push
inland and across the Al-Can border. In its wake, the widespread
precipitation has become showery in nature as colder air begins to
wrap in from the south and west around the parent low moving into
interior Southwest Alaska. A vorticity lobe riding along the
southwesterly flow ahead of the longwave trough is lifting into
Cook Inlet this morning. This feature, combined with increased
instability from the cold air advection, is producing bands of
showers moving across Western Kenai Peninsula and into the
southern Susitna Valley. Temperatures are dropping rapidly with
these bands, falling from the upper 30s and lower 40s down to the
lower and mid 30s, resulting in a quick transition to snow.

The challenge in the near term will be how these multiple waves
rotate around the upper-level trough as it continues to lift into
the Interior. The southwesterly flow will likely allow snow
showers to persist along upslope areas of the Chugach, Kenai, and
Talkeetna Mountains through at Tuesday. Isolated to scattered
showers are also likely for lower elevations.

A reinforcing shot of colder air will also begin to work in on
Tuesday as a more potent shortwave moves east from the Alaska
Peninsula. This feature will likely help initiate northerly and
westerly gap winds for places like Seward and Whittier as
temperatures elsewhere fall to more seasonal for this time of
year. By Wednesday, the entire upper-level low may drop over
Southcentral, bring yet more cold air across the region and
stronger northerly gap winds to the mountain passes and
Southcentral coast.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA AND THE BERING
SEA/ALEUTIANS (Days 1 through 3: Tonight through Wednesday)...

Key messages:

 - A strong low pressure system moving up into Interior Alaska
   will continue to cause multiple hazards across parts of the
   outlook area ranging from strong winds, snow and blowing snow
   and heavy freezing spray through this afternoon.

 - Winter weather headlines continue into this morning for the
   Lower Kuskokwim Valley and Kuskokwim Delta.

 - The Blizzard Warning for the southern AKPen and Winter weather
   Advisory for Bristol Bay continues into this afternoon.

A very large low pressure system supported by a strong upper
trough will continue to weaken today as it moves northeastward
into Interior Alaska. Periods of blizzard conditions are still
being observed this morning for the Southern Alaska Peninsula,
particularly near False Pass and Cold Bay. Further north and east,
much of the northern AKPen, Bristol Bay, and Kuskokwim Delta saw
steady snow overnight that will continue to become more showery in
nature as the low moves out of the area and the very cold airmass
on the back side of the low continues to fill in over Southwest
Alaska. Conditions will improve across the board throughout today
for the outlook area as snowfall and winds diminish. Temperatures
across Southwest Alaska will continue to fall today, reaching
single digits and sub-zero temperatures by Tuesday morning and
persisting through at least mid-week with wind chills dipping into
the negative 30s for the coldest interior locations. Meanwhile,
heavy to extreme freezing spray rates will continue to affect
waters close to the ice edge across the northern Bering until
winds begin to weaken throughout this afternoon.

A small, compact low will quickly dive southeastward across the
Bering Sea towards the AKPen this afternoon into Tuesday morning.
A compact core of gale-force winds may brush the Pribilof Islands
before reaching the AKPen by Tuesday morning. Enhanced snow
showers accompanying the small area of gusty winds will
potentially lead to a brief period of snow and blowing snow for
the Pribilof Islands with the low passage, while the AKPen can
expect snow showers through Tuesday night. By Wednesday, a frontal
system will move up into the central and western Aleutians and
bring southerly to easterly gale force winds into western and
central parts of the Chain. A mix of rain and snow will
transition to mainly rain as the front moves north throughout the
day. Snow and gusty winds could approach the eastern Aleutians and
Pribilof Islands by Wednesday evening.

-JH/AS

&&

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

A series of lows move through the northern Gulf of Alaska
through the end of this week causing coastal rain and mountain
snow to Prince William Sound inland to Copper River Basin. Cooler
air will filter from the Interior to the Kenai Peninsula, Kodiak
Island, Anchorage and Mat-Su Valleys bringing the return of more
seasonable late January temperatures. Precipitation during this
time is favoring a rain/snow mix later this week with the chance
for snow for the weekend.

Northwest winds bring cooler air into the Southwest and AK Pen
through the end of this week as a trough moves across the Bering.
Winds on the Pacific side of the Eastern Aleutians and AK Pen
could be strong mid-week. Locations in the Southwest turn warm
this weekend as a front moves across the region reaching the
Southwest by the weekend. This will push cooler end-of-week air
eastward.

-DJ

&&

.AVIATION...

PANC...Gusty southeast winds will give way to gusty up-inlet
south-southwest winds this morning as cold air continues to advect
into the area from the south. A couple weak upper disturbances
will pass over the terminal this morning and bring some light
snow showers over the area. With this activity, potential MVFR
ceilings and visibilities are possible within heavier snow
showers. The snow shower activity begins to diminish late this
morning into the afternoon with VFR conditions dominating through
the rest of the TAF period. Gusty southerly to south-southwesterly
winds will also begin to diminish Tuesday morning.

&&

Preliminary Local Storm Report
National Weather Service Anchorage AK
218 PM AKST Mon Jan 27 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1140 AM     Snow             Palmer                  61.69N 149.21W
01/27/2025  M2.5 Inch        Matanuska-Susitna  AK   Trained Spotter

            Snow started at 7 AM. 37F with peak winds at
            10 mph. By 11:40 AM, light snow, 27F, and
            light winds.

&&

JAR

Preliminary Local Storm Report
National Weather Service Anchorage AK
226 PM AKST Mon Jan 27 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1214 PM     Snow             Anchorage (Rabbit Creek 61.07N 149.77W
01/27/2025  M1.6 Inch        Anchorage          AK   Trained Spotter

            1.6 inches of snow from driveway at 7:30 AM.
            Graupel for a short period before
            transitioning to snow. Blowing snow.

&&

JAR

Preliminary Local Storm Report
National Weather Service Anchorage AK
229 PM AKST Mon Jan 27 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1243 PM     Snow             Sutton                  61.71N 148.87W
01/27/2025  E5.0 Inch        Matanuska-Susitna  AK   Trained Spotter

            5 inches of snow as of 12:45 PM. Heavy snow
            and sideways snow. Gusty winds. 28F at 12:45
            PM from 40F at 7 AM.

&&

JAR

Preliminary Local Storm Report
National Weather Service Anchorage AK
233 PM AKST Mon Jan 27 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0220 PM     Snow             8 SE Eagle River        61.23N 149.44W
01/27/2025  M9.4 Inch        Anchorage          AK   NWS Employee

            9.4 inches of new snow since 8 AM. Snow
            still falling as of 2:20 PM.

&&

JAR