Gale Warning 348, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
545 AM AKDT Sat May 3 2025

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

At 4 AM this morning, an occluded 996 mb surface low is situated
northwest of Middleton Island. A surface trough is wrapping around
this low as it continues to fill and weaken as it moves north
toward Prince William Sound. A distinct band of rain is associated
with the trough along with widespread showers behind the trough
and wrapping around the center of circulation.

Farther inland, conditions are rather tranquil, with partly
cloudy to mostly clear skies and temperatures in the low to mid
30s for much of interior Southcentral. It is a touch warmer in
locations where light winds have persisted overnight.

The surface low and attendant upper level trough will both lift
over the coastal mountains by late this morning. Lingering
instability over the western Kenai, Anchorage Bowl, Mat-Su, and
Copper River Basin will allow for a redevelopment of showers and
isolated thunderstorms. Like yesterday, the best chance for any
thunderstorms will be the northwestern corner of the Kenai
Peninsula, the foothills of the Chugach around Eagle River, and
from Wasilla and Big Lake north to Talkeetna and Skwentna.
Southeasterly gap winds will also increase again in the typical
locations this afternoon as the trough lifts north.

The shower activity and winds over interior Southcentral will
diminish overnight Saturday; however, showers will continue along
the coast as the flow turns easterly out ahead of a potent frontal
system moving into the western Gulf for Sunday.

On Sunday, that front, attached to a low over the AK PEN, drives
into the Southcentral coast, forcing heavy precipitation and a
barrier jet along the coastline. Inland areas will be sheltered
from most precipitation due to downsloping and will see lower
precipitation chances. Once again, higher elevations generally
above 2500 ft could see snowfall, especially at night. Winds will
be enhanced as well from this front. By Sunday afternoon, winds
will increase to storm force along the front near the Barren
Islands with high end gale force winds over the northern Gulf
increasing to storm-force winds as a barrier jet ahead of the
front develops south of Prince William Sound. The front drives
into Prince William Sound by early Monday with high-end gales and
strong winds continuing for Whittier and Portage. With the front
over Prince William Sound, steady rain will persist for the
Southcentral coast and eastern Kenai Peninsula.

-TM/AM

&&

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

A low in the Gulf of Alaska extends a weak front over interior
Southwest Alaska this morning, producing a broken band of light
rain showers along a line from Aniak to Iliamna. A second cluster
of related showers is ongoing near the mouth of the Kvichak River.
High resolution guidance suggests scattered rain showers build
over interior Bristol Bay this morning as the main band of rain
shifts slowly east and dissipates. By this afternoon, fairly
robust rain showers are scattered to numerous in coverage from
Bristol Bay northward into the Lower Kuskokwim Valley. Instability
appears insufficient for the development of thunderstorms, with
mid-levels warmer than over Southcentral (where some thunderstorms
occurred yesterday) and a bit warmer compared to yesterday based
on the 12z King Salmon sounding. Though covered in low stratus
this morning, this is expected to burn off through the day and the
Kuskokwim Delta is likely to see temperatures warm into the mid to
upper 40s.

Tonight, a low south of the Alaska Peninsula pushes its front into
Bristol Bay, with increasing winds out of Kamishak Gap. With
easterly flow aloft, precipitation begins on Sunday with a focus
over northern Bristol Bay. Downsloping keeps areas closer to the
Alaska/Aleutian Range drier, though periods of rain are still
possible. The Kuskokwim Delta and Lower Kuskokwim Valley remain
mostly dry, with breaks of sun, which will allow high temperatures
to reach into the low to mid 50s on Sunday. The low moves slowly
near Kodiak Island through Monday, which will keep the best
precipitation chances in Bristol Bay, though by Monday moisture
may be able to work north into the Kuskokwim region and bring some
light rain to the area.

&&

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

A gale force North Pacific low south of the eastern Aleutians this
morning will bring light rain to the islands and the southern
Alaska Peninsula today. Snow will begin to mix in as cooler air
filters in from the north tonight. Accumulation is expected to be
little to none near sea level, with temperatures remaining at or
above freezing, though higher elevations of the islands may see
several inches of snow. The low slowly tracks toward Kodiak Island
for Sunday, intensifying as well. Cold air wrapping around the
back side of the low will help to intensify winds and gales will
begin to spread across the eastern Bering/Aleutians and southern
Alaska Peninsula by Sunday night. As the low shifts slowly east,
precipitation becomes more showery and more likely to be snow over
time, with colder air moving in across the Bering Sea. The western
Bering Sea sees high pressure build in this week with relatively
light winds. A front pushes into the western Aleutians by Monday
night, bringing rain.

&&

.LONG TERM FORECAST (Days 4 through 7/Tuesday through Friday)...

At the start of the extended period on Tuesday, a deep vertically
stacked low will be positioned in the southern Gulf with a
dissipating occluded front wrapped around the Gulf coast. With a
high amplitude ridge sitting downstream, the upper level low will
linger over the southern Gulf through at least Friday. Short-waves
rotating around the low center will likely lead to development of
multiple additional surface lows, but all of them will ultimately
end up tracking to the position of the upper center. The bulk of
impacts will will be along the Gulf coast and Kodiak Island, with
occasional rain or rain showers. At this point, none of the
surface lows look particularly strong, so winds for the Gulf
coastal waters look to remain at Small Craft Advisory levels or
lower. For Southcentral and Southwest AK, this pattern will bring
a mix of sun and clouds, with some weak ridging at times but also
the likelihood of upper level short-waves rotating through with
some clouds and showers. This type of pattern is typical for
spring and the details of amount of sunshine (or clouds) and
specific temperatures for each day will have to be worked out as
we get closer and time.

Meanwhile, out west, a deep low will track into the far western
Bering Sea Monday night through Tuesday, with a leading frontal
system progressing eastward across the Bering and Aleutians. This
storm system will rapidly weaken Tuesday night through Wednesday
as the downstream ridge gets flattened out and upper jet support
weakens. A remnant weak low will exit to the Pacific late
Thursday. Bottom line, expect low impact weather for the Bering
and Aleutians next week.

-SEB

&&

.AVIATION...

PANC...VFR conditions will persist through the TAF period. Light
south winds, generally 10 kts or less, will continue this morning
and become more gusty from the southeast into the afternoon and
evening hours. Gusts up to 25 to 30 kts will be common this
afternoon and evening. Flow becomes down-inlet dominant Sunday
morning and the core of southeast winds should remain over
Turnagain Arm with light and variable winds returning across the
terminal.

&&