968
FXAK68 PAFC 290033
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
433 PM AKDT Tue May 28 2024

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

A Prince William Sound low continues to rotate offshore this
afternoon. This resulted in the upper level trough to migrate
westward continuing to bring north to northeasterly winds into
the Copper River Basin and Prince William Sound coastline. An
area of precipitation continues to move through Prince William
Sound this afternoon. Rainfall amounts from this area of
precipitation range from a trace to a few tenths of an inch
through 400pm today. The precipitation will continue to migrate
southwestward through late this evening.

A mix of sun and clouds was today`s theme in the Mat-Su,
Anchorage and Kenai Peninsula areas today. The aforementioned
trough migrating westward will bring an end to the dry conditions.
Overnight, clouds will increase and rain showers become more
numerous throughout the region as the area of precipitation moves
westward from Prince William Sound.

Tomorrow, a front from a low presure system crossing the Bristol
Bay will push northward over Kodiak Island and the Kenai Peninsula.
This will result in a return of cloudy, rainy and windy conditions
for coastal locations. Ahead of the front, moderate easterly
winds are expected in Kodiak Island and the Kenai Peninsula
overnight through tomorrow afternoon and in Cook Inlet, Passage
Canal and Turnagain Arm will increase tomorrow afternoon and
evening. Strong gap winds are expected too as the front moves
northward through the day. Scattered rain showers are likely in
Anchorage and the Mat-Su Valley tomorrow as well. Looking ahead,
a Gulf low could bring continued rain to the Gulf coast and
Prince William Sound Friday, though there is some uncertainty
in how far north this low will make it in the Gulf.

-DJ

&&

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

Unsettled weather continues through the remainder of the work
week as two lows move across the forecast area. The most notable
weather will be the chance for thunderstorms across Southwest
Alaska this afternoon and evening, then winds to gale force and
steady rain for the Western and Central Bering/Aleutians from
Wednesday afternoon through Friday afternoon.

Diving into the details...a weakening 997 mb low is currently
located north of Nikolski, where it is bringing showers and breezy
conditions across the Eastern Aleutians and much of Southwest
Alaska. Multiple upper level shortwaves rotating around the low
will lead to spells of more active weather until the low itself
exits the area on Wednesday. Of note is the slight chance for
thunderstorms in Southwest Alaska today as a wave emanating from
this low merges with another shortwave moving in from the east;
the combination of thermal instability from daytime highs in the
60s and weak synoptic lift from these waves provide decent support
for convection. With southeasterly steering flow, the expectation
is for showers (and any thunderstorms that develop) to move
northwestward through the evening.

The Western and Central Aleutians/Bering Sea will stay relatively
quiet, but cloudy, through around midday Wednesday as a transient
ridge builds between storm systems. The next system, a 964-970 mb
low, begins to push its gale force front into the Western Aleutians
by Wednesday afternoon. The low begins occluding on Thursday,
with southwest small craft speed winds wrapping around the low.
Forecast confidence is decently high with this system. The primary
challenges are minor differences in low track and timing, as well
as the potential for precipitation along the Eastern Aleutians
and Alaska Peninsula to be a higher than currently forecast as a
North Pacific shortwave directs moisture towards these areas on
Thursday.

-KC

&&

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

An elongated area of upper level troughing continues across the
Bering into the Gulf of Alaska. The Gulf low weakens and becomes
absorbed by a second center moving across the Southern Bering and
Alaska Peninsula by Sunday. The jet stream energy maintains its
track to the South of the Aleutians through the beginning of the
week. A deterministic model blend hold good confidence through the
weekend before an ensemble blend takes over. Weak ridging sets up
over the Central and Northern Mainland, as well as over Siberia,
which will allow for lower level thermal troughs to form across
the Central Interior beginning in the new week.

Sustained Easterly to Southeasterly airflow over the Southcentral
areas spreads increased moisture as far North as the Alaska
Range, and brings showers with each Easterly wave. Potentially
larger amounts of rain over the Copper River Basin associated with
more convective events are expected. Transient lows, fronts and
troughs spread their precipitation over the Aleutians and Bering,
and into Southwest Alaska, and the AKPEN and Kodiak Island.

-Kutz

&&

.AVIATION...

PANC...VFR conditions and light westerly winds will persist
through late Tuesday evening. Overnight, the winds will give way
to southeasterly Turnagain winds. Forecast conditions remain
unchanged, with sustained 15-20 mph winds and 25-30 mph gusts,
before weakening into the Wednesday morning. Rain showers will
develop late overnight and last into the morning hours as well.
Occasional MVFR conditions are possible with any shower activity.

&&

$$