Gale Warning 138, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
333 PM AKST Tue Feb 4 2025

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

Not much of a shift in the pattern in expected over the next
couple of days. There is a shortwave dropping south across
Southcentral that is expected to increase gap winds through
typical areas, including Seward/Resurrection Bay, Whittier/Passage
Canal, the Valdez Narrows and Copper River Delta. Another round
of fog is expected for the Anchorage/Knik Arm area tonight into
tomorrow morning.

&&

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

Currently, a large ridge is set up over much of mainland Alaska,
allowing for mostly calm and clear conditions with some notable
exceptions. These exceptions are fog and low stratus, which have
been the prevailing weather in much of the Kuskokwim Delta
including Bethel and Bristol Bay including Dillingham, King
Salmon, and Iliamna. The Pribilofs are also experiencing fog and
low stratus. However, due to increased daylight hours and a higher
sun angle, the fog and stratus, at least in the mainland, have
been allowed to diminish in coverage during the day. As a result,
locations such as Bethel, Dillingham, King Iliamna, and King
Salmon are currently experiencing only periods of low visibility.
The fog and low stratus is likely to thicken in the nighttime
hours as light and variable flow and temperature inversions from a
warmer air mass allow it to continue. A frontal wave will move
into the Kuskokwim Delta by Wednesday afternoon, bringing an end
to the fog for that region as well as a bit of light snowfall to
Bethel north. There is some uncertainty if the wave will be south
enough to have any effect on the fog in Bristol Bay.

The Bering is a bit of a different story. A frontal system is
moving through the Bering, allowing for precipitation and breezy
winds to affect the central and western Aleutians. The eastern
Aleutians, however, remain under the influence of the ridge and
are drier and calmer. Come Wednesday, a north Pacific low will
rise up from the south and will begin affecting the Bering.
Precipitation will continue to impact the central and western
Aleutians and will slowly spread eastward as a second low center
swings around the first, finally reaching the Cold Bay area by
Friday afternoon. Warm air advection will take place due to this
north Pacific low, so the precipitation will mostly be in the form
of rain. Wind speeds will be another concern with this low. Gale
force winds will begin impacting the central Aleutians by
Thursday morning, spreading to much of the Bering including the
Pribilofs and Eastern Aleutians by Friday afternoon. There is a
potential for the gale force winds to impact the Kuskokwim coast
after the forecast period. Coastal flooding is on the radar, but
this outcome is uncertain as of now. As for the rest of the
mainland, the ridge will remain in place through the end of the
period, so calm, mostly clear, and cool weather will remain.

-JAR

&&

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

An elongated trough across the Aleutians and Bering weakens
somewhat as several shortwaves rotate through the pattern. This
trough abuts a narrow but well developed ridge extending from the
Gulf of Alaska over Southwest Alaska into the Russian Far East.
The shortwaves help reorient the ridge to a more North-South
direction, and broadens it a bit over Mainland Alaska through the
forecast period. The ridge is keeping most of the active weather
in the West through the weekend. A deterministic blend of GFS /
ECMWF / Canadian and UKMET supports the larger features quite
well, but significant uncertainty rides with the changes
accompanying the active weather producers. An ensemble blend picks
up the forecast through the end of the period.

One impulse after another brings active weather across Southern
Alaska. A strong low over the Western Aleutians opens widespread
area of snow changing to rain and gusty winds across the Bering
into Bristol Bay and the Alaska Peninsula Saturday. Areas of gale
force winds West of St Lawrence and St Matthew Islands move into
the Western Bering through Sunday. Locally heavy rains and strong
winds will spread over the Central and Eastern Aleutians and the
Southern AKPEN on Saturday, before pushing into Southwest Alaska,
Kodiak Island and Southcentral Alaska through Tuesday. A second,
more developed low and front bring another round of locally heavy
rains and gusty winds across the Aleutians and over the Bering
late Sunday through Tuesday. A third developed low driving into
the Gulf of Alaska Monday through Tuesday brings heavy rains and
gusty winds over Kodiak Island and the AKPEN, with lighter
precipitation over the remainder of the Southcentral coasts.

- KZ

&&

.AVIATION...

PANC...Fog and stratus will likely persist into Wednesday. While
there may be some breaks this evening, very light winds and a
strong inversion look to keep this fog and stratus around.

&&