019
FXAK68 PAFC 060049
AFDAFC

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

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

An upper-level ridge continuing to sit over Southcentral Alaska
again promotes clear skies and warm temperatures this afternoon
and evening across much of the area. Satellite imagery this
afternoon shows cumulus development in the northern Copper River
Basin and surrounding higher terrain as a shortwave trough moving
across the Alaska Range and very modest instability brings a
chance for an isolated shower through this evening.

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 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. Hot, dry, and
windy conditions are expected for the Copper Valley Wednesday
with temperatures rising into the upper 70s, relative humidities
falling into the 20 percent range, and southerly winds of 10 to 20
mph with 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.

-JH/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. Rainfall associated with this system has initiated across
the eastern Aleutians and the southern Alaska Peninsula this
afternoon and will continue through tonight. Expect intermittent
rain showers across the eastern Bering Sea/Aleutians and Alaska
Peninsula this afternoon, intensifying later tonight. 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, but will return with the arrival of the
front Wednesday morning.

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.

-CQ/CL

&&


.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 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. Gusty SE winds out of the Turnagain Arm
may bend into ANC by late afternoon Wednesday.

&&


$$