961
FXAK68 PAFC 191331
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion National
Weather Service Anchorage AK 502 AM AKDT Sun May 19 2024

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

A strong and unseasonably cool upper level trough extending south
and east from the the Gulf of Anadyr to the Central Gulf of Alaska
will weaken and lift north and east today as a strong shortwave
rotating around the trough moves east through the Central Gulf of
Alaska today and over the Panhandle on Monday. Weak ridging builds
into the Western Gulf of Alaska on MOnday.

On the surface a 1001 mb low currently located approximately 50 nm
east of Kodiak City will continue to weaken this morning as it
pushes to the east into the Central Gulf today and into the Eastern
Gulf tonight. A front wrapping around the low continues to push
slowly north and is near Homer at this time. Strong southeasterly
winds ahead of the front will diminish later this morning especially
through Turnagain and Knik Arms where southeast wind gust in the 25
to 35 mph range continue early this morning. Rain has diminished
over Kodiak Island as the front passed to the north. Expect
unsettled conditions over Southcentral today with the rain over the
Eastern Kenai and Prince William Sound slowly diminishing from south
to north today as the front continues to weaken push north and east.
Copper River Basin will remain unsettled with clouds and showers
expected through the day.
Winds, clouds and precipitation will decrease late Monday and into
Tuesday as a weak ridge builds into the northern Gulf of Alaska.

A low over the Bering pushes another front into Southcentral Tuesday
morning, with rain likely overspreading much of Southcentral by late
Tuesday afternoon. A more southerly/southwesterly flow aloft as
compared to an easterly/southeasterly flow aloft with this next low
will bring a better chance of rain to the the western Kenai,
Anchorage Bowl, and MatSu areas.

-CC

&&

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

Due to good model consensus and run-to-run consistency, few changes
have been made to the forecast through Monday. By Tuesday, however,
forecast confidence diminishes as models differ on the evolution and
timing of an occluding Bering Sea low. As such, there may be shifts
in wind speed as well as precipitation timing and amounts in
subsequent forecast updates.

The negatively tilted trough and upper-level low that brought much
of yesterday`s weather will continue to move eastward into the Gulf
of Alaska through today. Shower activity over Southwest Alaska
should largely taper off through today, though the combination of
daytime heating and weak shortwaves wrapping around the low could
lead to isolated to widely scattered afternoon showers.

Out west, a series of Kamchatka lows and fronts will begin to impact
the Bering Sea and Aleutian Chain. The first frontal system is
currently over the Western and Central Bering/Aleutians spreading
rain and winds up to 25 kt as it moves to the east. The second
system, a Kamchatka low, moves across the Western Bering through
today, merging with the first system as it reaches the Pribilof
Islands. This now energized front will bring light to moderate rain
and small craft winds as it sweeps east across the Bering Sea,
reaching the coast of Southwest Alaska around midday Monday.

As the front moves into Southwest Alaska for the second half of
Monday, coastal Southwest Alaska will initially see the brunt of
precipitation. However, by late Monday night into early Tuesday
morning, an incoming stout shortwave will intensify rainfall and
progress the front eastward across Southern Alaska. Cold air aloft
moves in behind the front, keeping showers over parts of the
Bering/Aleutians and over much of Southwest Alaska through Tuesday.

-DAN/KC

&&

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

A persistent northwest to southeast oriented longwave trough will
remain over the Bering with a shortwave on the southern terminus
bending into the northern Gulf through Sunday. A second upper level
low will move from Kamchatka into the central Bering on Tuesday
followed by a third on Thursday. This series of low pressure systems
will bring gusty wind, coastal rain showers and interior cloudy and
isolated rain showers. Toward the end of next week, an area of high
pressure will push from the North Pacific into the Bering Sea and
nudge the longstanding trough eastward.


&&

.AVIATION...

PANC...VFR conditions will persist. Light northerly winds shift to
the southeast for the afternoon/evening as a weak Turnagain Arm wind
develops. There is potential for light rain showers this afternoon
as well, which could drop ceilings below 5000 ft. Southeasterly
winds will diminish through the evening hours, with ceilings rising
back above 5000 ft as any potential showers clear out.

CQ

&&


$$