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FXAK68 PAFC 080159
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
559 PM AKDT Sun Jul 7 2024

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

Unsettled weather will continue over Southcentral through at least
midweek as moist southwesterly flow aloft is aiding in showery
conditions across the region. An upper level trough over
southwest Alaska is aiding in this process and will remain
situated through early Tuesday morning. Starting midday Tuesday,
a strong shortwave low over the Bering Sea and an upper level low
in the Gulf of Alaska will begin to move towards Southcentral.
The shortwave is expected to produce considerable rainfall for
most of southwest Alaska, with areas east of the Alaska Range
expected to get some spillover precipitation into Wednesday. The
shortwave will begin to stall and weaken over southwest Alaska
Wednesday morning as its parent upper low in the Bering Strait
begins to dive southward towards the eastern Bering.

As for the upper low in the Gulf of Alaska, it will send a front
fronts towards the gulf coastline up into Prince William Sound and
parts of the Kenai Peninsula Tuesday afternoon. The front will
become stationary over the area as a ridge in western Canada
begins to build in over the interior. In turn, the uniform
southeasterly flow over the gulf will carry sufficient moisture
over the coastal portions of Southcentral, resulting in a long-
duration rainfall event that is expected to continue into
Wednesday night. Lastly, a new shortwave will form on Wednesday south
of the Bering low near Kodiak Island that is currently expected to
swing towards Southcentral later in the week. Current model
guidance is struggling on the placement and timing of the
shortwave, but this system appears to the next opportunity for
widespread rainfall for the interior portions of the forecast
area.

-BS

&&


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

In the Western Aleutians, satellite images show clouds from both
a North Pacific High and a Kamchatka Low over the area. The
Kamchatka Low currently northeast of Shemya will continue to
slowly drift southward along the northern side of the Western
Aleutians through tomorrow afternoon. As the North Pacific High
moves southwest and its ridge over the Aleutians flattens,
shortwaves moving across the area from the Kamchatka Low will
bring intermittent periods of rain showers and fog in Shemya and
Adak into this evening. These conditions will persist as the low
moves toward, and then over, Adak tomorrow morning. The warm front
from this low will bring period of rain, low clouds and foggy
conditions to the Central Aleutians through tomorrow afternoon. In
the low`s wake, northerly winds will bring continued cloudy
conditions through Tuesday evening to the area.

Currently, patchy fog exists on the Pribilof Islands and the Cape
Newenham coast with cool and isolated rain showers elsewhere
across the Southwest, Alaska Peninsula and Eastern Aleutians.
Satellite images and surface observations show continued variable
winds over the area, too. Patchy fog will return overnight across
the region through tomorrow morning. Afterward, a weak wave will
move through the YK Delta resulting in increased cloud cover and
isolated rain showers through the evening hours. These will become
more scattered and widespread across the area Tuesday as a low in
the northern Bering Sea moves southward through the day toward
Bristol Bay.


-DJ

&&

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

The upper level Alaska Weather map opens with a closed low over
the Northwest Bering that will shift towards the Western Alaska
coast by the end of the forecast period. A weakening low near
Kodiak Island is absorbed into this low, and results in a broad
low that stretches from the Russian Far East into the Western
Alaska Mainland by Sunday. A weak ridge holds across the Eastern
Interior of the state, supporting surface thermal troughs and
local convection through the weekend. Forecast model spread is
reduced through the period. Southcentral Alaska is sustained with
considerable moisture and areas of rain from the Alaska Range
South. Some areas may experience briefly heavier rains through
Sunday. A well developed surface frontal system brings locally
heavy rains over the Aleutians and Bering through Saturday. An
increasing area of heavier rains sets up from Nunivak Island and
the West Coast Late Friday, and spreads inland and across the
Alaska Peninsula by Saturday. Heavier rains move over Kodiak
Island and the Southern Kenai Peninsula late Saturday and Sunday.
This area of heavier rains continues across the Southcentral
Coastal zones beyond the end of forecast period.

- Kutz

.AVIATION...

PANC...MVFR ceilings near or just below 3000 ft will persist
through this afternoon and into tonight with scattered light
showers in the area. South to southeast winds will persist this
evening and diminish late tonight.

CC

&&


$$