Wildfire in Alaska, August 6, 2025

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
457 AM AKDT Wed Aug 6 2025

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

The upper-level ridge continues its slow progression eastward this
morning. As it does, a surface ridge over the Gulf of Alaska is
also moving from the northern Gulf to the Alaska Panhandle. A
developing southwesterly flow in the wake of both features is
pushing low stratus and patchy fog toward the coast from southern
Cook Inlet east across Prince William Sound to Cordova. Farther
inland, skies are mostly clear with a few isolated areas of low
clouds and fog. Temperatures this morning have fallen into the
lower 40s to lower 50s across the region.

The forecast remains on track with the next big weather maker:
the now well-advertised frontal system moving from the western
Gulf Wednesday morning to the northern Gulf Thursday. The front
will lift into the Gulf and across Kodiak Island through the day
Wednesday before reaching the southern Kenai Peninsula by
Wednesday evening. With previous connections to the tropics, this
system looks particularly wet; especially for Kodiak Island where
1.5 to 2 inches of rain is likely along the eastern shores and 2
to 4 inches of rain in the mountains Wednesday morning through
Thursday morning. In addition to the steady rainfall, widespread
easterly gales are expected along the front as it lifts north
through Thursday morning. High-end gale-force winds with
occasional storm-force gusts are also expected through Kennedy
Entrance and across the Barren Islands Wednesday afternoon through
Thursday morning.

As the front moves north today, a coastal ridge will build.
Increasing pressures along the coast, coupled with a thermal
trough over the Interior, will allow southerly gap winds to
increase through the afternoon and evening hours. Hot, dry, and
windy conditions are expected for the Copper Valley with
temperatures rising into the upper 70s, relative humidities
falling into the 20 percent range, and southerly winds of 10 to 20
mph and gusts up to 30 mph. A Red Flag Warning is in effect on
Wednesday from 1 PM to 9 PM for the Central Copper River Basin as
rapid ignition, growth, and spread of fires will be possible.

As the front moves toward the Southcentral coast Thursday, rain
will overspread Cook Inlet and across the Anchorage Bowl and Mat-
Su Valleys. A persistent southeasterly cross-barrier flow aloft
will allow for some downsloping along the lee of the Kenai and
Chugach Mountains; however, weak waves embedded in the upper-
levels and moving over these areas should allow for periods of
very light rain through Thursday from Kenai north to Palmer. The
heaviest rain will along the eastern Kenai Peninsula / western
Prince William Sound as the southeasterly flow drives copious
moisture into the coastal mountains.

Steady rains continue into Friday along the immediate coast as the
front stalls and weakens. Scattered showers will remain possible
for interior locations as multiple upper-level waves continue to
lift north over the region. Models do diverge by Friday with
respect to the track of a potent upper-level shortwave rotating
around the longwave trough over the eastern Bering. The GFS drives
this feature closer to Kodiak Island and the AKPen, resulting in
prolonged shower activity and higher rainfall amounts for western
Southcentral. Other global models push this wave farther east
across the Gulf, keeping the steady and heaviest precipitation
over eastern Prince William Sound and Cordova.

-TM/JH

&&
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS
(Days 1 through 3: Today through Friday night)...

The heavy rainfall event along the south side of the Alaska
Peninsula is underway this morning as the remnants of Typhoon
Krosa are lifting across the peninsula and merging with pre-
existing low pressure in the southern Bering Sea. Since yesterday
afternoon, three quarters of an inch of rain has fallen in Cold
Bay, while nearly two inches of rain have fallen in Perryville.
An additional inch to inch and a half of rain is forecast along
the south side of the Alaska Peninsula east of Sand Point before
the front lifts north to mainland Southwest Alaska and Kodiak
Island later today. Light to moderate rain and gusty southeasterly
winds spread inland from the coast beginning this morning, though
interior areas of the Kuskokwim Delta and the Lower Kuskokwim
Valley remain dry with another day of temperatures reaching into
the 70s this afternoon/evening. Gale force winds across the
northern Alaska Peninsula into Bristol Bay diminish this afternoon
as the front lifts inland over Southwest Alaska.

Overnight, lightning activity has largely remained south of the
coastal waters. The structure of the low, with the triple point of
the cold, warm, and occluded fronts several hundred miles south
of Kodiak Island, suggests that the majority of thunderstorms are
likely to remain out of the forecast area. However, vigorous
convective activity behind the front has produced a few isolated
lightning strikes further to the north, so potential remains for
isolated thunderstorms to impinge on the areas south of the
Alaska Peninsula and west of Kodiak Island.

Cool and wet conditions push north across Southwest Alaska
Wednesday night, keeping temperatures capped in the upper 50s to
mid 60s for Thursday as the front lifts slowly northward. By
Thursday night, the front weakens and precipitation coverage
begins to diminish significantly. The Bering Sea low exits to the
North Pacific on Thursday and northerly winds overspread much of
the Bering Sea. Northerly winds will not be accompanied by any
meaningful push of cooler air initially, which will mean stratus
and fog will continue to persist across the region through late
week. Temperatures over Southwest Alaska rebound a bit on Friday
as the influence of low pressure wanes and drier, sunnier
conditions prevail. By Friday night, however, it appears that an
upper low diving from the Chukchi Sea brings much cooler air than
has been seen in the area for a while, and a cold front pushing
into the Kuskokwim Delta leads to another round of rainfall.

&&

.LONG TERM FORECAST (Days 4 through 7 Saturday through Tuesday...

Only minor changes from previous discussion... Synoptic situation
continues with a dissipating upper level low over Kodiak. It will
be absorbed into the larger upper level/deepening trough over the
central part of the State as the weekend starts. The upper level
ridge over the Eastern Gulf of Alaska will continue to migrate
eastward. A secondary, positively tilted, upper level shortwave
trough will extend from the extend from the Bering Strait and into
the western portion of the Bering Sea.

The upper level trough over the central portions of the State
will deepen and dig down the Alaskan west coast then extend down
into the North Pacific towards the end of the period. The European
and Canadian models keep it as an open trough and are more likely
the reasonable solution. GFS is in better agreement with this
system's placement, initially, but tends to keep the forward
progress slower through the period. This scenario could allow more
tropical moisture into the developing surface feature and
increase the precipitation chances along the South Central coastal
regions.

Model guidance is in better agreement with the Bering Sea upper
level trough forming its surface features along the Central
Aleutians AKPEN region early next week. However, timing and how
much potential tropical influences are still uncertain at the this
time.

DD

&&.AVIATION...

PANC...VFR conditions and light winds will persist throughout much
of the TAF period. Turnagain Arm winds will pick up late this
afternoon, becoming southerly with gusts up to 30 mph. Winds will
gradually decrease and shift back to northerly through after 10Z
tonight. Rain is expected to move over the terminal early tomorrow
morning.

&&