466
FXAK68 PAFC 281334
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
534 AM AKDT Fri Jun 28 2024

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

Discussion:

A few modest changes to the overall synoptic pattern today compared
to the last several days. The large Bering low will begin to
retrograde back to the west today as it gradually weakens. A North
Pacific low has merged with a shortwave rounding the base of the low
and sweep east along the Aleutian Chain today. The area of low
pressure south of Kodiak Island yesterday has deepened into a well-
defined closed low today over the southern Gulf. The stout ridge
that was positioned over Alaska earlier this week is now more
north/south oriented over western Canada. With the Bering low to the
west and ridge to the east, the Gulf low will quickly weaken as it
moves towards the northeastern Gulf coast over the next day or two.
With the Gulf low kind of "stuck" in the south-central Gulf today,
moisture from the system will be drawn up towards the Kenai
Peninsula and into the western interior of Southcentral Alaska. This
will result in more cloud cover today and slightly cooler
temperatures. This will also tamp down convective potential for the
Susitna Valley and the Talkeetna Mountains, though an isolated storm
or two can`t be completely ruled out, especially if we get some
breaks in the cloud cover this afternoon. Otherwise, the more
favored areas for afternoon convection both today and again tomorrow
will be for western Alaska Range and the northern half of the Copper
River Basin...including the northern Wrangells.

Looking into the weekend... The Gulf low will get nudged towards the
northeast coast as the Bering low drops south and the aforementioned
trough moving through the Aleutians and its associated front begin
lifting across the western Gulf. The ridge over Canada will start to
build back into the eastern interior of Alaska then elongate by
early next week. While precipitation in the near-term will be
primarily diurnally driven inland and light scattered showers for
Kodiak Island and the eastern Kenai, the latter half of the weekend
into the start of the workweek looks to bring more widespread
rainfall to a modest portion of Southcentral.

- PP

&&


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

A broad upper-level low over the Bering Sea will continue to
produce unsettled weather for much of the Aleutian Islands and
Southwest coast into the start of the weekend. For the interior
portions of Southwest, building high pressure will result in
warmer and drier conditions through the forecast period.
Afternoon showers are possible over the interior, including the
Western Alaska Range, eastern portions of the Lower Kuskokwim
Valley, and along the Aleutian Range in interior Bristol Bay.
However, the stable air mass from the ridge over the region will
limit the potential for thunderstorm activity through Sunday.

The Bering low will continue to drive multiple waves of
precipitation over the eastern Aleutians and Southwest coast on
Friday as it slowly moves northwestward towards the northern
Bering. A new shortwave low will start to pass along the western
Aleutians Friday morning before becoming near-stationary over the
eastern Aleutians and Alaska Peninsula by midday Saturday. The
shortwave low will again produce rounds of precipitation for much
of the eastern Bering/Aleutians and Southwest coast, lasting into
Sunday morning. The low will begin to dissipate by the afternoon
hours on Sunday as a building ridge of high pressure enters the
western Bering and pushes eastward, tapering off most remaining
precipitation behind the low as it does so.

-BS

&&
.LONG TERM FORECAST (Days 4 through 7)...

A ridge of high pressure begins to break down through the weekend
as a front crosses the AK Pen and into Southcentral.
Southeasterly to southerly flow ahead of this front will bring
above seasonal temperatures to Kodiak and portions of the Kenai
Peninsula. Ridging continues to build in the Copper River basin
through the weekend. Toward the beginning of next week, model
discrepancy increases. Most models depict the Copper River Basin
high drifting southward and the building of a ridge westward
across the Prince William Sound toward Southwest Alaska. Others
hint at a series of lows moving into the Alaska Peninsula and
northern Gulf of Alaska thus keeping the aforementioned ridge from
migrating westward.

&&

.AVIATION...

PANC...VFR conditions and light southwesterly winds will persist.

&&


$$