Wildfire in Alaska, June 21, 2025

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
522 AM AKDT Sat Jun 21 2025

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

Discussion:

The primary weather concern today will be elevated fire weather
conditions across portions of the Copper River Basin this afternoon
and evening. The upper level ridge axis has shifted over the ALCAN
border this morning. While slightly cooler temperatures will be felt
across the western half of Southcentral...the Copper Basin will see
one more day with temperatures rising into the upper 70s to lower
80s before the slight cool-off. In addition to the continued warm
temperatures, surface ridging over the northern Gulf will increase
the gradient over the coastal mountains leading to downsloping winds
into the Basin. Winds will start to increase by early this
afternoon, helping to keep the boundary layer well mixed. Dewpoints
will fall into the 30s and 40s resulting in relative humidity values
to drop down to the 20-30 percent range by late afternoon. The
combination of these hot, dry, and gusty conditions will allow for
increased fire weather concerns. As such, a Red Flag Warning remains
in effect from noon today through 10 pm tonight. Conditions will
improve overnight as relative humidities recover under cooling
temperatures and decreasing winds.

The last several days have seen quite a bit of convection for
portions of the Susitna Valley and Cooper River Basin. Today's
convective chances will shift north with much of the convection to
stay north of the Wrangells near the eastern Alaska Range and
northwards into the interior. However, an isolated thunderstorm
can't be ruled out elsewhere in the Copper Basin.

A front is still slowly working north across the Gulf today. The
front has pushed north of Kodiak Island this morning and while the
more steady rainfall has ended, the island may still see some
lingering light showers through early afternoon. Showers have moved
into the southern Kenai Peninsula, but easterly flow will help to
keep the bulk of the precipitation on the Gulf side. The front will
continue to weaken with showers mostly dissipating before working
too far up the Kenai Peninsula. A secondary front may bring better
precipitation chances to inland Southcentral Sunday night into
Monday.

- PP

&&

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

A large upper-level low continues to sit nearly stationary across
the Central Aleutians this morning while the surface low remains
just west of the Pribilof Islands. Rainy and misty conditions
will continue across the Pribilofs through the weekend as the low
remains nearby and continues to weaken.

Scattered showers will continue across the mainland Southwest
Alaska through the weekend with the majority of rain occurring at
the coast. However, a few showers may try to push inland to the
Kuskokwim Valley this morning, especially the western portion of
the Valley around Aniak. Chances for wetting rain (0.1 inches in a
12 hour period) remain low. Regardless, temperatures will remain
on the cooler side across Southwest in the presence of cloud cover
and southerly flow off of the Bering Sea. Southeast winds through
Kamishak Gap into Interior Bristol Bay and the Kuskokwim Valley
will begin to diminish early this evening into the overnight
hours. A warming trend will begin into the new work week as low-
level to mid-level flow becomes more southeasterly Monday and into
Tuesday. Clouds and showers will linger with upper-level
shortwaves lifting across the area from the North Pacific and
Bering Sea.

Further west, gusty southeast winds continue across the southern
Alaska Peninsula (AKPEN), especially through Cold Bay, through
Sunday evening before winds slowly come down then. Gusts should
peak up to 45 mph during the day today. Showery conditions will
also persist through the weekend and into the new work week across
the southern AKPEN with low cloud ceilings and off and on showers
across the Eastern Aleutians. A stronger front works eastward
from Kamchatka Sunday morning to over the western Bering and
Western Aleutians by Sunday evening. Southerly gale-force winds
are expected to accompany this front across the Western Aleutians
and weaken back to high- end small craft as it reaches the Central
Aleutians for Monday and the Eastern Aleutians, Pribilof Islands,
and southern AKPEN for Tuesday. The heaviest rain is expected to
be confined across the western Bering and Western Aleutians Sunday
evening with light to moderate rain across the Central Aleutians
Monday and light rain across the Eastern Aleutians, Pribilofs
Islands, and southern AKPEN for Tuesday.

&&

.LONG TERM FORECAST (Days 4 through 7: Tuesday through Friday)...

The overall weather pattern continues with an elongated upper
level trough stretched from Siberia across the Bering into the
Gulf of Alaska. One main low center in the West Central Bering
meanders around the Bering through the forecast period. A second
low center slips across the Alaska Peninsula into the Gulf
through the week. The trough sets up across the Central Gulf by
Friday. The upper ridge weakens and moves from the Interior to
the Beaufort Sea just North of the Canadian border through
Friday. The GFS / ECMWF and Canadian ensemble models maintain
better agreement on the large scale features.

Warmer temperatures over Interior Alaska slowly subside through
Friday, with warmest temperatures remaining in the Eastern
portions. Scattered areas of convection continue across the
Interior portions of the state. The highest possibilities for
thunderstorms are are expected in the Eastern Interior. A
weakening front over the AKPEN and Kodiak Island spreads along
Southcentral Alaskan coastal zones through Friday. A better
developed Central Aleutians front Tuesday brings rain and breezy
conditions into Southwest Alaska, AKPEN and Kodiak Island for
Thursday and reinforces rainfall along the Southcentral coast on
Friday. The Pacific side of the AKPEN, Kodiak Island and parts
of the Kenai Peninsula will see moderate to locally heavy rain
Thursday into Friday. A developing North Pacific low and front
approaches the Western Aleutians on Friday.

- Kutz

&&

.AVIATION...

PANC...VFR conditions expected to persist. Southerly winds will
back to more southeasterly as Turnagain Arm wind increases this
afternoon and evening. Turnagain Arm winds may bend towards the
terminal at times with wind gusts of 15-25 kt possible from about
00Z Sunday through 10Z.

&&