Gale Warning 448, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
509 AM AKDT Tue Aug 5 2025

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3:
Tuesday through Thursday evening)...

An upper-level ridge sits over Southcentral Alaska this morning
with partly cloudy to mostly clear skies over much of the region.
The exception is a area of cloud cover lingering over the Copper
River Basin, the result of mid-level moisture remaining in the
wake of a shortwave trough that moved through yesterday evening.
Cyclonic flow around high pressure over the Gulf and weak onshore
flow is blanketing some areas along the immediate coast in cloud
cover as well, with the bulk of the clouds extending from Prince
William Sound to Cordova and around the entrance to Cook Inlet.

With the ridge remaining in place today, another warm and
generally sunny day is on tap of much of Southcentral. Daytime
highs will again reach into the upper 60s to mid 70s over interior
locations. Temperatures along the coast will be slightly cooler as
gusty sea breezes once again develop this afternoon. Another
shortwave trough moving across the Alaska Range this afternoon
will again bring a chance for an isolated shower across higher
elevations surrounding the Copper River Basin.

The forecast remains on track with the next big weather maker: a
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 2.5 inches of rain is
likely 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 to Storm-force gusts are also possible across the Barren
Islands Wednesday afternoon through Thursday morning.

As the front moves north on Wednesday, 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. With
temperatures well into the 70s and min RH values falling into the
20 percent range, the gusty winds could bring hot, dry, and windy
conditions to the Copper Valley for Wednesday.

As the front moves toward the Southcentral coast Thursday, rain
will also 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.

-TM

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

Broad low pressure in the Bering Sea is beginning to draw north
tropical moisture associated with the remnants of former Typhoon
Krosa. While the bulk of the moisture and precipitation arrives
this afternoon to the south side of the Alaska Peninsula, the
broader upper-level energy associated with the former typhoon is
already beginning to spread across the eastern Aleutians into the
Bering Sea this morning. This will lead to intermittent rain
showers across the eastern Bering Sea/Aleutians and Alaska
Peninsula today. For the Southwest mainland, a front weakening
along the coast will continue to bring rain showers to Bristol
Bay, particularly focused in the upslope regions of the Kilbuck
and Ahklun Mountains. Inland areas of Southwest Alaska remain
warmer and drier, with high temperatures again in the 70s for the
Lower Kuskokwim Valley, but cloud cover overspreads all but the
Western Alaska Range today. Precipitation in the Bristol Bay
region diminishes this evening.

Heavy rain is expected for the Alaska Peninsula with the arrival
of the main front from the remnants of Krosa this evening through
Wednesday. Much of the southern Alaska Peninsula is forecast to
see around, or in excess of 2 inches of rainfall as a result. The
communities of Perryville and Chignik (east of Sand Point along
the Alaska Peninsula) are expected to see rainfall totals of 2 to
4 inches, with the majority of that falling in a 24 hour period
beginning this afternoon. Gale force winds are also forecast
across the northern Alaska Peninsula into Bristol Bay as the
remnants of Krosa merge with the pre-existing Bering low. As the
front sweeps into the area, increased instability will also bring
the threat of marine thunderstorms. This occurs primarily south of
the Alaska Peninsula, but there is potential for thunderstorm
activity to impact portions of the central Alaska Peninsula as
well tonight through Wednesday. The front then lifts north across
Kodiak Island and mainland Southwest Alaska Wednesday evening,
pushing lighter rain and gusty winds across the Bristol Bay and
Lake Iliamna regions.

Cool and wet conditions continue for Southwest Alaska Wednesday
night into 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, which will mean stratus and fog
will continue to persist across the region through late week.

&&

.LONG TERM FORECAST (Days 4 through 7 Friday through Monday...

Synoptic situation starts with a a dissipating upper level low
over Kodiak. It gets 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. This 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 lessor agreement with the Bering Sea surface
features with the GFS forming a surface low and fronts in the
central bearing sea with the Canadian and European models allowing
the surface low and fronts to form south of the Central Aleutians
and AKPEN region early next week. The reasonable solution would
favor the latter scenario.

DD

&&.AVIATION...

PANC...VFR and light winds are expected to persist through the
TAF period.

&&