746
FXAK68 PAFC 171341
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
541 AM AKDT Mon Jun 17 2024

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

Low marine stratus has engulfed the entire Gulf of Alaska and
pushed up Cook Inlet and fairly far inland up the Susitna River
valley this morning. The is the most challenging aspect of the
forecast for today and maybe tomorrow: how far inland these low
clouds will be able to make it inland and how much of the stratus
all dissipate during the day? If this was any other time of the
year except in the middle of summer, this stratus would likely
persist for days as the region remains under high pressure with
southwesterly surface flow. However, with the long daylight
hours, it is likely much of the stratus over land will dissipate.
Over the Gulf and along the north Gulf coast (Seward and Cordova
especially) there is a good chance it just stay socked in with
that southwest surface flow. Stratus moving in and out of the
Prince William Sound area and Cook Inlet may be a factor to deal
with the next few days.

Inland, the airmass remains unstable, but not nearly as much as a
few days ago. Most of the showers and thunderstorms this
afternoon and evening are expected to be over elevated terrain.

&&


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

Southwest Alaska: Afternoon and evening rain showers and
thunderstorms in the Kuskokwim Valley and parts of the Alaska
Range will return later today.  The precipitation will start in
the Alaska Range during the mid to late afternoon hours and
migrate into the Kuskokwim Valley for the evening hours. The
greatest chance of thunderstorms today stretches from Stony River
west to Lower Kalskag. The main threats from the thunderstorms
will be frequent lightning and small hail. Tuesday, late afternoon
and evening isolated thunderstorms in the Alaska Range and
scattered rain showers elsewhere can be expected. More widespread
rain showers arrive Wednesday as Gulf Low brings mainly southerly
to southwesterly flow to the area.


The Bering Sea and the Aleutians: A low south of Dutch Harbor
will move eastward through the first part of this week. As its
front along the southern Aleutian chain moves north an eastward
through the day today, continued rain showers from the Central
Aleutians to the AK Pen are expected. Also, persistent southerly
to southeasterly winds will result in gap winds ranging from 20 to
30 kts for most of today in the Eastern Aleutians. Tomorrow, the
rain showers shift eastward as the low moves toward the Eastern
Aleutians; still staying south of the Aleutians though. Southerly
to southeasterly flow remains from the Central Aleutians to the AK
Peninsula. The chances of rain diminish in the ALeutians and the
Alaska Peninsula Wednesday as this low dissipates.

-DJ

&&
.LONG TERM FORECAST (Days 4 through 7: Thursday through Sunday)...

Model agreement is pretty good through the forecast period. The
upper level high covers the Northern two- thirds of the Mainland
before shifting to cover the Eastern half through the weekend.
This ridge supports surface thermal trough, maintaining the
chances for convection. Coming from the Chukchi Sea through the
Bering Strait, an upper level closed low weakens as it drifts into
the Central Bering by Sunday. A trough moving over the Alaska
Peninsula Thursday becomes a low center near the Southwest Gulf of
Alaska Friday before meandering around the Gulf and the Eastern
North Pacific through the end of the forecast period. While the
main storm track is out in the North Pacific, weak troughs
continues to slide along the Aleutians and AKPEN, continuing
around the Gulf through the period.

Showers and possible thunderstorms are expected mostly in the
Eastern Interior. Morning fog and stratus yields to afternoon
showers across the Western Alaska coast and Pribilofs with the
Bering low`s movement. The upper low over the AKPEN brings locally
heavy showers across Southwest Alaska and Kodiak Island starting
Thursday. Weak fronts bring rain across the Aleutians and AKPEN,
spreading into Southwest and Southcentral Alaska for late
Saturday. Generally mild conditions spread across Southcentral
through late Friday with scattered afternoon and evening showers
and isolated thunderstorms developing through Sunday and clearing
up/drying out afterwards.


- Kutz

&&

.AVIATION...

PANC...The big question for the airport has to do with
southwesterly flow up Cook Inlet has brought in low stratus
clouds and fog from the Gulf over much of Cook Inlet. At this time
it looks like these low clouds will remain west of the airport,
but this will certainly bear watching today, tonight and in coming
days with the persistent southwesterly flow.

&&
$$