Blizzard Warning 4, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
536 AM AKST Fri Mar 7 2025

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

A low in the Gulf of Alaska is centered southeast of Kodiak
Island early this morning. There had been some uncertainty with
this low and whether it would remain more to the southwest in the
Gulf or track farther northeast and closer to the Cordova area.
The low definitely is more in the southwest Gulf, but its
occluded front is elongated toward the northeast and the
uncertainty in the forecast model guidance most likely came from
a jet streak intersecting the front south of Cordova as seen on
satellite imagery early this morning. The jet streak was not able
to give enough upper level support for a true secondary low to
develop, but enough to stretch out and elongate the front. What
this means is that while there will still be some stiff northerly
winds at elevation along the coastal mountains, the farther south
location of the low center and stretching out of the front will
keep those winds from getting quite as strong as looked possible
yesterday. The biggest question with the winds for today revolve
around whether they will get strong enough to cause any
significant blowing snow in Thompson Pass due to the snow that
fell there Wednesday into Thursday.

This front is moving from east-to-west as it sweeps the north Gulf
coast today, but looks to mainly just bring some mid to high level
clouds to most of Southcentral today. Where some uncertainty
remains is tonight as a short wave, which will be moving from
east-to-west along the north Gulf coast, is able to bring some
precipitation to the Gulf coast or even some inland areas
overnight tonight. Some of the higher resolution models are giving
a shot at some snow along the coast and as far west as some flurries
in Anchorage, the GFS and some other models are keeping
precipitation all to the east of Anchorage. Either way, it will
not be anything of note for Anchorage, the mountains around Prince
William Sound could see a few inches snow of accumulation through
tonight.

For the weekend, there should be some short-term clearing after
this low moves away from the area and before the next front
approaches from the west. This next front will be weakening as it
crosses the Aleutian Range and into the Gulf of Alaska. A triple
point low could develop along it in the lee of the mountains, but
most of the precipitation with this front is expected to remain
along the Gulf coast and southern Cook Inlet.

&&

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

A low pressure in the eastern Bering Sea continues to weaken this
morning as it moves south. Snow showers across the Kuskokwim
Delta will begin to taper off later this morning into the
afternoon. The same goes for precipitation across the Bristol Bay
coast. However, cold northerly flow off the Bering will continue
across the Eastern Aleutians and southern Alaska Peninsula (AKPEN)
today which will bring more snow showers to the those areas.

The next big weather-maker for the area is beginning to make its
presence felt across the Western Aleutians with gusty
southeasterly winds. This is a strengthening low pressure system
in the North Pacific between southern Kamchatka and the Western
Aleutians. The storm-force front will sweep eastward across the
Aleutian Chain today through Saturday and make it to the coast of
mainland Southwest Alaska Saturday evening as the low pressure
occludes by then.

As the front makes it to the Pribilof Islands, there will be
enough cold air in place for the precipitation to start off as
snow. Falling snow combined with strong gusty southeast winds,
along with snow already on the ground previously, will promote
significantly reduced visibility across the area. This is
especially true for early Saturday morning through the mid-morning
hours before temperatures begin to warm up. With that, the Winter
Storm Watch has been replaced with a Winter Weather Advisory to
highlight the threat of visibilities dropping to one- half mile or
less at times Saturday morning.

Across the Aleutian Chain, rain should be the dominant
precipitation-type as the front moves eastward through Saturday.
Colder air will work in behind the front through Saturday evening
with off and on snow showers becoming likely across the Chain
Saturday afternoon through the rest of the weekend and into the
new work week.

Snow and blowing snow become a concern across the northern
Bristol Bay coast and Kuskokwim Delta coast Saturday evening.
Precipitation looks to remain mostly snow, despite the southerly
winds, due to the storm occluding and warmer air being shunted to
the south over the AKPEN. The front continues to push inland of
Southwest through Sunday as it weakens. Light snow is likely for
Sunday across the Lower Kuskokwim Valley. There could be some
enhancement to the snow across interior Bristol Bay for Sunday
into Monday as a triple- point low tries to spin up near Kodiak
Island.

&&
.LONG TERM FORECAST (Days 4 through 7 - Monday through Thursday)...

An extensive upper level trough stretches from the Russian Far
East across the Bering and continues its Eastward push over
Interior Alaska into Northern Canada through the forecast period.
A low center separates from this trough at the Alaska Peninsula
and moves across the Gulf of Alaska before exiting to the
Southeast for Wednesday. A weak ridge moving over the Aleutians
flattens out by Thursday. An ECMWF / GFS and Canadian blended
cluster continues to handle features consistently well through the
period. Greatest uncertainty rests with the smaller details
supported by shortwaves rotating through the pattern.

A well developed surface low and front over the Central Bering
weakens and dissipates as it approaches Western Alaska by Tuesday.
Widespread snow and gale force winds over the Bering subsides by
late Tuesday. Meanwhile a low that formed on the front near Kodiak
Island pushes snow over the inland areas of Southcentral Alaska,
the Alaska Peninsula into Southwest Alaska, and areas of rain
along the coastal zones in Southcentral and over the Gulf,
diminishing late Tuesday. A strong North Pacific low and front
bears down on the Western and Central Aleutians late Tuesday
through Thursday. Locally heavy rains and gale force winds move
over the Aleutians, diminishing Thursday.

- Kutz

&&

.AVIATION...

PANC...VFR will prevail through the TAF period in wake of a frontal
system. Winds will become northerly this evening, becoming gusty
overnight before abating on Friday. Snow flurries or isolated rain
showers are possible late Friday evening / early Saturday
morning as a short wave moves inland from the Gulf of Alaska.

&&

SPECIAL WEATHER STATEMENT
National Weather Service ANCHORAGE AK
527 AM AKST Fri Mar 7 2025

AKZ103-126-081600-
East Turnagain Arm-Western Prince William Sound-
Including the cities of Girdwood, Portage, Whittier, Seward,
and Moose Pass
527 AM AKST Fri Mar 7 2025

The following message is transmitted at the request of the
Chugach National Forest Avalanche Center.

...THE CHUGACH NATIONAL FOREST AVALANCHE INFORMATION CENTER HAS
ISSUED A SPECIAL AVALANCHE STATEMENT FOR THE FOLLOWING AREAS:
GIRDWOOD, PORTAGE, TURNAGAIN PASS, LOST LAKE, AND SEWARD FROM
FRIDAY MARCH 7 AT 7:00 AM TO SATURDAY MARCH 8 AT 7:00 AM...

* WHAT...Due to recent snowfall on an unstable snowpack,
  dangerous avalanche conditions exist, avalanche danger is
  CONSIDERABLE in the backcountry.

* WHERE...For the Western Chugach and Kenai Mountains in and
  around Girdwood, Portage Valley, Turnagain Pass, Lost Lake, and
  Seward.

* WHEN...In effect from Friday 7:00 AM AKST through Saturday 7:00
  AM AKST.

* IMPACTS...Large human-triggered avalanches are likely. Despite
  a lack of new snowfall today, the snowpack is very unstable and
  dangerous avalanches can be easily triggered by people. It is
  likely avalanches can be triggered remotely, from flat terrain
  below steeper slopes.

* PRECAUTIONARY / PREPAREDNESS ACTIONS... If deciding to recreate
  in the backcountry, choose slopes that are low angle or less
  than 30 degrees in steepness, with nothing steeper above you.
  Cautious route-finding and conservative decision-making skills
  will be necessary to identify and avoid slopes that could
  avalanche.

Similar avalanche danger may exist at locations outside the
coverage area of this or any avalanche center.

For more information visit cnfaic.org.