953
FXAK68 PAFC 110042
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
442 PM AKDT Fri May 10 2024

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

A large vertically stacked low situated over the southern Alaska
Peninsula looks to push towards southern Alaska over the next
couple of days. The storm system will be slow moving, with the
low drifting into the western Gulf Saturday afternoon. A series
of short-waves rounding the low will provide plenty of lift and
produce some hefty precipitation totals for Kodiak Island and the
coastal zone of Southcentral. Drier conditions for interior
Southcentral as well as Anchorage and western Kenai Peninsula. Snow
is still possible at higher elevations.

Marginally warmer temperatures are expected across much of
Southcentral Saturday and Sunday, with values reaching into the
mid-50`s for interior Southcentral. Gusty winds will continue
across the Kenai Peninsula and eastern Turnagain Arm through
Saturday. Southeasterly gap winds will slowly diminish through
tonight for the Copper River and Knik River Valley.

The low weakens by Sunday and the upper level trough will lift
northwards across Southcentral. Steady moderate to heavy
precipitation will fade to lighter rain showers, primarily around
Prince William Sound and the north Gulf coast.

&&


.SHORT TERM FORECAST SOUTHWEST ALASKA, THE BERING SEA AND THE
ALEUTIANS (Days 1 through 3)...

The weakening vertically stacked low over the Alaska Peninsula
continues to move eastward. Moisture from the Gulf of Alaska
will be carried in with the persistent southerly flow, providing
rain and wet snow for much of Southwest. This will continue to
occur through Sunday morning before the low further dissipates and
moves into the gulf. Some breaks in the clouds and shift to
southerly flow will help bring temperatures back up closer to
normal for this time of year. Highs should be up closer to the 50s
inland with coastal areas getting into the 40s. The increased
temperatures will support increased instability which could result
in showers to occur in the late afternoon hours tomorrow and
Sunday. Gusty conditions on the north and west side of the low
over the Bering will continue as well, producing gale force gusts
between the Pribilofs and AKPen.

Over the Aleutians, another low currently located south of Shemya
will brush by the central Aleutians through Sunday morning. Much
of the impacts will remain either over the Aleutians or for the
North Pacific, with small craft winds and gale force gusts
forecast. Precipitation in the form of a rain/snow mix or all rain
is expected as the low moves eastward, with high temperatures
getting into the upper 30s or low 40s. The track of the low
continues to move slightly south over the last few model runs,
bus some impacts over the Aleutian are still likely. The next
system will start to enter the western Bering midday Monday, with
widespread precipitation and gustier winds possible as the front
of the low moves eastward.

-BS

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

The Alaska weather map opens with an elongated and somewhat
fragmented positively tilted trough extending from the Arctic over
the Eastern Mainland. The trough then curves back to the South of
the Alaska Peninsula. The Northern portions drifts into the
Canadian Provinces through Wednesday, while the Southern portion
links up with a second system moving out of the Russian Far East.
The trough becomes negatively for Thursday, with an increasing
negative tilt through Friday. A ridge builds over the ALCAN border
through Friday. Model agreement is good through midweek, but
falls apart afterwards, as the flow pattern across the region
weakens.

The extended forecast opens somewhat quietly as North Pacific low
moves the active weather into Southeast Alaska. Locally heavy
rain over Prince William Sound and the Copper River Basin
dissipates Tuesday. In the far West, the Northern Kamchatka low
and front brings gusty winds and precipitation starting as snow,
but quickly changing to rain across the Aleutians and Bering. The
front brings locally heavy precipitation over the Central and
Eastern Aleutians, AKPEN and Western Alaska. Some of this will be
mixed precipitation over Western Alaska into the Interior, and
trailing through Wednesday before diminishing over the AKPEN
Thursday. Locally heavy rainfall moves moves over Kodiak Island
and Southcentral Alaska for Thursday and across Prince William
Sound and Copper River Delta through Friday. Lesser amounts of
rainfall from the South reaches the Alaska Range for Friday.


- Kutz

&&

.AVIATION...

PANC...VFR conditions will persist through the TAF period.
Southeast winds out of Turnagain Arm will continue out ahead of a
frontal system in the southwestern Gulf of Alaska. Winds peak
later this this evening coincident with the greatest amount of
instability present. Southeast winds may gust as high as 30 mph
before the down inlet flow strengthens by the evening hours and
persists into Saturday. This will help to keep the southeast winds
over Turnagain Arm and out of the terminal with northerly winds
prevailing this evening through Saturday. LLWS will likely develop
later this evening as the winds over Turnagain Arm and the
Anchorage Hillside remain southeasterly. The majority of
precipitation will remain along the coast and the eastern facing
slopes of the coastal mountain ranges due to the downslope drying
effects of the southeasterly flow.

-CC

&&


$$