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000
FXAK68 PAFC 270058
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
458 PM AKDT Fri Apr 26 2024

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3:
This afternoon through Monday afternoon)...

Few changes were made to the forecast. Satellite imagery shows a
low south of the Alaska Peninsula, with its front extending across
the Kodiak Island area. The precipitation forecast remains
largely the same, with about an additional 0.75-1 inch for Eastern
Kodiak Island and up to another 0.5 inches of precipitation for
Western Kodiak Island.

With the low pivoting southwards from this evening through
tomorrow morning, expect clearing skies and light winds in its
wake, with precipitation tapering off for Kodiak Island through
tomorrow. Clear skies and abundant daytime heating could lead to
afternoon/evening convective showers along mountain slopes,
especially as weak shortwaves move through the area. Showers look
to be limited to interior Copper River Basin tomorrow afternoon,
but they could become a bit more widespread by Sunday afternoon as
a lobe of vorticity dives southwards from the Alaska Interior.
Westerly steering flow aloft of about 10-20 kt would favor showers
developing along west-facing mountain slopes. The location and
intensity of these showers will be the biggest forecast question
as we head into early next week. Aside from that, the weather
looks to be fairly quiet, providing a great opportunity to get out
and enjoy the sunshine this weekend.

-KC

&&


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

Low pressure over the Bering has since moved into the western
Gulf of Alaska, and with it calmer conditions are gradually
setting in across the region. Diminished winds and minimal
precipitation are forecast from the Aleutians into Southwest
Alaska both Saturday and Sunday with highs in the 40s and 50s. The
one question mark entails cloud cover as the presence of low
pressure in the western Gulf of Alaska could send moisture and
clouds into Greater Bristol Bay and also the Kuskokwim Delta and
Lower Kuskokwim Valley. In similar fashion northerly flow through
the Bering may bring scattered clouds into the Aleutians. The next
weather system moves into the Western Aleutians on Monday in the
form of a broad front. Increasing rain showers and gusty
conditions associated with the front are anticipated early next
week. Interestingly enough, models are showing colder temperatures
move in behind the front, which may support initial rain showers
transitioning to a mix of rain and snow for the Western Aleutians
by Monday night.


&&


.LONG TERM FORECAST (Days 4 through 7: Mon through Thu)...

An upper level trough will be situated over the southern Alaska
Peninsula by Tuesday morning, crossing into the southwestern Gulf
of Alaska, and a new upper level trough entering the western
Bering Sea behind it. A building ridge is expected to remain
situated over Southcentral Alaska. Through Tuesday, the ridge
will likely extend from Southcentral into Southwest Alaska
following the departure of the AKPen trough, while the western
Bering system pushes a front across the Aleutians, likely reaching
Unalaska by late Tuesday. The front is expected to generally
weaken as it approaches Southwest and the resident ridge, but the
parental low pressure system behind the front will likely move
over the Western and Central Aleutians through Wednesday.

By Wednesday afternoon, the ridge over southern Alaska may begin
to weaken as the upper-level support shows signs of shifting out
of the area. This may allow for influence from the Bering low to
move into Southwest Alaska and even Southcentral Alaska as the
system approaches by late Thursday. Gauging impacts from this
low in Southwest and Southcentral is still precarious given the
uncertainty regarding the ridge movement, as well as the
location/progression of the low itself. Model agreement regarding
the progression and potency of these systems is not good, leading
to a general uncertainty regarding timing the several fronts and
lows to enter the Bering and move through the area. However,
given the prolonged shift towards warmer weather over the next
week expected, impacts from this system will likely not be winter
weather. Although the overall synoptic setup is in fair agreement
for the extended period, the details could mean bigger differences
in the QPF and wind fields across the Bering and Southwest
Alaska.

-CL

$$



.AVIATION...

PANC...The Anchorage area will remain on the north side of a low
rotating about in the Gulf of Alaska. Wind will remain weak and
clouds will be limited and primarily in the form of high-based
fair weather cumulus.

-Brown

&&


$$