470
FXAK68 PAFC 190059
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
459 PM AKDT Tue Aug 18 2026

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

A complex longwave trough continues to drift over much of the
greater Alaska region this afternoon, with several embedded
smaller troughs slowly moving northeast along an axis between the
Aleutians and the northern Yukon. With the leading trough well
into the Yukon, gap winds are beginning to trend down as the
north-south pressure gradient slowly relaxes, and this weakening
trend should continue tonight. A smaller shortwave currently over
Southcentral has brought some shower redevelopment this afternoon,
especially over the Talkeetna Mountains. This shortwave will move
to the Copper Basin late tonight, shifting any lingering shower
activity to there while the rest of Southcentral briefly dries
out. Some higher elevations may maintain showers overnight
tonight. By tomorrow morning, this shortwave will move into the
Yukon.

Right on the heels of the system currently overhead, an upper
level low moves from the Aleutians to the AKPen late tonight. At
the surface, an occluded front moves into the Gulf. This will send
renewed bands of rain quickly northeast, reaching Kodiak Island
by tomorrow morning, then shifting to up the Cook Inlet to the
MatSu and to Prince William Sound by tomorrow afternoon. With
proper timing of a shortwave, some light precipitation may spill
over into the Copper River Basin Wednesday evening. Models hint at
the development of a weak triple-point low in the Gulf southeast
of Kodiak Island Wednesday afternoon. As this low forms, the front
will sharpen somewhat Wednesday evening into Thursday morning as
it approaches the northern Gulf Coast. With a bit of a coastal
ridge, the sharper pressure gradient will result in a weak barrier
jet, bringing some easterly small-craft winds offshore the
northern Gulf Coast Wednesday night into Thursday morning.

Southerly flow ahead of the slow moving upper low over the AKPen
will continue to stream moisture northwards into Southcentral.
This maintains widespread chances of showers Thursday through
Friday. Thursday appears to be the wetter day with better
orientation of upper level flow pulling moisture northward. The
heaviest precipitation will be along the northern Gulf Coast,
especially at and east of Prince William Sound due to the occluded
front moving onshore. Steady precipitation looks to spill into the
Wrangell Mountains as well, with more showery and lighter rain for
the rest of Southcentral. The low passes over Kodiak Island
Thursday evening into Friday, which should limit precipitation
there during that timeframe. Though the low eventually points the
most favorable moisture towards the AKPen, chances for showers
continue across Southcentral on Friday, with the steadiest rain
again along the northern Gulf Coast east of Prince William Sound.
In summary, overcast, cool, and showery conditions will continue
for Southcentral through Friday.

- PA

&&


.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS
(Days 1 through 3: This afternoon through Friday evening)...

The active, but non-impactful weather pattern continues across
the Bering Sea, Alaska Peninsula (AKPEN), and Southwest Mainland
through Thursday. Satellite imagery shows a vertically stacked low
pressure system track along the Eastern Aleutians and moving
slowly eastward with time. Isolated showers across Southwest will
become more widespread beginning tonight and last through
Thursday as the weak low along the Eastern Aleutians moves into
Bristol Bay by Wednesday evening. Waves of rain will lift into
Southwest and the AKPEN out ahead of it. The low in Bristol Bay
Wednesday night and Thursday will slowly move southeastward to the
southwest Gulf of Alaska by early Friday morning as showers
continue along the Southwest Interior.

Farther to the west, an upper-level trough will dive
southeastward out of the Arctic, across Siberia, and into the
northern Bering Sea by Thursday afternoon. A surface low will spin
up in the northern Bering as well Thursday afternoon. As the low
digs southeast to around Saint Matthew Island Friday morning, rain
will overspread Mainland Southwest from the Bering through the
day on Friday. Expect southerly small-craft winds with gale-force
gusts stretching from the Bering all the way to the Kuskokwim
Delta Coast Friday.

Coastal flooding is of low concern currently (less than a 10
percent chance) as the tidal influence will be low, and the fact
that this storm has trended weaker in today`s guidance than in
previous days. Regardless of storm strength, this looks to be
quite a wet system with moderate to heavy rain across the Pribilof
Islands to Coastal Southwest through Friday. Rain tapers off
across the Pribilof Islands beginning Friday afternoon as it picks
up intensity across Southwest by then. Back behind this system, a
ridge builds in across the western Bering and Western Aleutians
Friday afternoon and evening. Stay tuned for forecast updates
regarding this late week storm.

&&


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

The long term period begins with an amplified upper-level pattern
across Alaska as a deep trough and embedded upper low move across
the Bering and toward Southwest Alaska through the weekend. Strong
southwesterly flow ahead of the trough will connote to transport
moisture northward, supporting periods of rain across Southwest
Alaska and the Alaska Peninsula (AKPEN) Saturday. The trough
gradually shifts east into mainland Alaska Sunday into Monday,
allowing steadier precipitation to spread into portions of
Southcentral while becoming more showery farther west.

By Monday, the upper low becomes centered over mainland Alaska as
the associated trough encompasses much of the state. This will
maintain cooler and unsettled conditions with scattered showers
across much of southern Alaska. Guidance then shows the trough
continuing eastward into Canada Tuesday while heights begin to
rise from the west. This should allow conditions to gradually
improve across Southwest Alaska and the Bering, though lingering
cyclonic flow may keep showers around portions of Southcentral.

Model agreement remains reasonable with the overall evolution of
the upper-level pattern, though differences increase early next
week regarding the exact position and progression of the upper
low. These differences will ultimately influence the placement of
heavier precipitation and stronger winds. overall, an unsettled
and relatively cool pattern begins to shift eastward Tuesday as
heights gradually rise over the western Bering.


LM


&&


.AVIATION...

PANC...VFR conditions are expected to remain through the TAF
period, though periods of showers may causing ceilings to dip to
MVFR at times. Gusty southerly to southeasterly winds will persist
through the day, though will gradually diminish this afternoon.


&&

$$