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FXAK68 PAFC 170110
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
510 PM AKDT Sun Jun 16 2024

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

High pressure remains over Southcentral this evening with a
compact upper low spinning over Kodiak Island. Despite strong
daytime heating contributing to numerous areas of cumulus clouds
over the Copper River Basin, high pressure is expected to limit
the overall threat for wet thunderstorms this afternoon and
evening. Temperatures have been warmer across the Copper River
Basin beneath the ridge of high pressure, with Chistochina and
Chitina reaching 80 degrees and Gulkana just below at 79 degrees.
Across the Mat-Su Valleys and Anchorage Bowl temperatures are
warm, but not as warm as Saturday`s high temperatures. The
greatest threat for thunderstorms will extend from along the
Talkeetnas westward into the Susitna Valley. Satellite imagery
shows a few lightning strikes have occurred northeast of
Chickaloon and southeast of Talkeetna. Through the evening hours
isolated lightning will remain possible. Further south, into the
Kenai Peninsula, up-inlet flow has brought areas of fog and low
stratus along the coast, helping to moderate temperatures. Kenai
remains in the low 50s while Soldotna sits in the low 60s.

High pressure over the Bering has resulted in widespread low
stratus and areas of fog on Sunday. Tonight some of this marine
layer will advect northward into Prince William Sound and up Cook
Inlet. Expect reduced visibility down or less than 1 mile at
times across the Kenai area as well as across Cordova.

The weather pattern changes over the next couple of days with the
low over Kodiak Island to lift northward across the Western
Alaska Range and high pressure over Southcentral to shift eastward
over the ALCAN border through Tuesday. This will see a subtle but
noticeable cooling trend as well as reduced thunderstorm activity
across Southcentral. By Tuesday south to southeast flow moves
into the Gulf Coast which should see increased cloud cover over
Southcentral and even cooler temperatures over the region.

&&

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

Upper level ridging shifts northward as a series of shortwaves
move through Southwest Alaska over the next few days.
Thunderstorms across the western Aleutian Range and interior
Bristol Bay area will drift westward through this evening, with
activity possibly lasting overnight into the Kuskokwim Delta area
with modest upper level support. On Monday, a potent vort max
swings in from the east over Southwest Alaska with scattered
thunderstorms capable of producing frequent lightning and small
hail expected once again. Storms will initiate over the western
Alaska Range and Middle Kuskokwim Valley in the late afternoon and
slowly drift north and west through the evening. While
instability will be lower near the Kuskokwim Delta, scattered
shower activity is still expected, and an isolated lightning
strike or two cannot be ruled out.

A front over the central Aleutians will continue to slide
eastward through the eastern Aleutians bringing periods of rain
through Monday night. Southerly/southeasterly gap winds near small
craft criteria will continue across the eastern Aleutians and
Alaska Peninsula through at least Tuesday. Scattered rain showers
are expected to continue over the rest of the Aleutian Chain over
the next few days as an upper low meanders over the area.

-ME

&&

.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...VFR conditions and light winds will persist. Expect isolated
thunderstorms to form on the Front Range Chugach this afternoon/evening
and possibly again Monday. However, storm motion is much lighter
than on Saturday and is from southeast to northwest (opposite of
Saturday). Thus, anything that does form will remain well away
from the terminal. Meanwhile, southerly flow in Cook Inlet has
brought in some low stratus clouds (and potentially fog) from the
Gulf. At this point, do not think this will make it as far north
as Anchorage. More likely, it will hover over the southern and
western Inlet. Still, this will bear watching tonight and in
coming days with persistent southerly flow.

&&

$$