948
FXAK68 PAFC 151303
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
503 AM AKDT Sat Jun 15 2024

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

The weather pattern is little changed from yesterday over
Southcentral with an unstable airmass and northeasterly flow
aloft. Some small differences revolve around temperatures and
dewpoints being quite a bit higher than yesterday morning which
may help initiate convection a little sooner today as well as help
areas not just over mountains to see showers and thunderstorms as
the day progresses. Aerial coverage of storms should be greater
today with thunderstorms expected to develop over the Kenai
Peninsula northward to the Susitna Valley as well as over the
Matanuska Valley and Copper River Basin. Closer to Anchorage,
there will probably be some thunderstorms over the Chugach
Mountains this afternoon and evening with a chance for one to
drift over the Anchorage bowl due to the northeasterly flow aloft.
One additional caveat that may influence the thunderstorm development
is that some models are showing a very weak wave at 500 mb moving
westward across the central Chugach mountains this evening and
over the Susitna Valley overnight. Normally such a weak wave would
not be worth mentioning, but in an unstable atmosphere, there is
a chance it helps to produce a more organized line of
thunderstorms this evening which last past midnight as the
propagate westward. This will be something to keep an eye on this
evening.

The northerly surface flow is also less than yesterday as the
trough along the northern Gulf coast weakens. This will allow the
seabreeze to develop again in Seward and Valdez and keep
temperatures in those areas lower than yesterday.

Sunday and Monday will both be rather similar to today, except
that the are of most likely shower and thunderstorm development
will shift farther west each day. Temperatures will also start to
cool a little on Monday, but still remain near or above normal.

&&


.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days
1 through 3)...

Mostly dry conditions with areas of fog likely along the Southwest
coast. Upper level support increases potential for convective
activity today and Sunday afternoon, expected to produce some wet
thunderstorms along the Western Alaska Range. Potential for some
isolated wet thunderstorms to develop further west into the lower
Kuskokwim Valley and south over Bristol Bay by Sunday afternoon.
The front sitting over the Central/Eastern Aleutians will
continue to bring rounds of rain showers and small craft winds to
the Western/Central Aleutians and will weaken through this
weekend.

&&

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

A very active pattern on the Alaska Weather map as an upper level
Arctic low spreads its influence across the North Slope into
Interior Alaska through Thursday. A ridge remains across the
Southern Interior, being squeezed between the Arctic low and a
broad low stretching across the Aleutians and Gulf of Alaska
through the period. This ridge is sufficient enough to support
thermal surface troughs and raises the chances for convective
activity. A number of weak perturbations are expected to slide
through the pattern across the Southern portions of the state
throughout the forecast.

Most of the concentrated weather remains in the North Pacific to
the South of the Aleutians and Alaska Peninsula. Showers and
locally breezy conditions begin in the Central and Eastern
Aleutians and the Bering up to the Pribilofs beginning Monday.
Winds taper off late Monday. Showers will occur across the
Southcentral Interior for late Monday. The Aleutians front
continues its Eastward push over the Alaska Peninsula and Kodiak
Island before spreading more rain over Southcentral, Prince
William Sound and the Copper River Valley through midweek. Showers
linger behind the front over the Aleutians and Bering.
Temperatures range from the 40s across the Aleutians warming
across the Mainland into the 70s and possible low 80s over the
Eastern Interior through the period. Thunderstorms are possible
over most of the Eastern inland areas.

- Kutz

&&

.AVIATION...

PANC... VFR conditions are expected through tomorrow. Showers are
likely to develop around the area by late afternoon though the
evening with an isolated thunderstorm possible during the evening
hours as well.

&&

$$