694
FXAK68 PAFC 180435
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
835 PM AKDT Mon Aug 17 2026

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

Key message:

* Flood Advisory in effect for the Yetna River near Lake Creek
  until 4 PM Wednesday. A flood watch remains in effect for the
  Susitna Valley for areas upstream of Lake Creek and the Yetna
  River until 4 PM tomorrow.

Discussion:

The large low that has been tracking through the Bering Sea is
now in Southwest Alaska. The main front associated with it has
swept through Southcentral and is in the Interior of the state.
The result is that there are strong pressure rises behind this
front that are spurring gusty southerly winds up Cook Inlet and
also though the Copper River Basin gap areas. Southcentral is also
in the showery sector of the low with multiple shortwaves kicking
off periods of showers. Both winds and shower activity should
diminish throughout tonight into tomorrow morning, with some gusty
winds persisting in the Copper River Basin. The Susitna Valley is
the one region that will likely really hold onto the rainfall as
the south-to- southwest flow aloft is favorable for upsloping
along the Alaska Range and Talkeetna Mountains. In addition, the
Susitna Valley is closer to the upper low center which is keeping
it more unstable as well. This is a major reason there is a Flood
Watch in effect for some portions of the Susitna Valley. This low
center moves slowly from Southwest to the interior on Tuesday as
it weakens, fully dissipating late Tuesday night. The northern
Gulf Coast and high elevations will also see lingering showers on
Tuesday, with lower elevations seeing less of a chance.

As is the case in August, large longwave troughing persists
across the Bering Sea with another upper low embedded at the base
of the trough over the Aleutians. This low will move eastward
throughout the week, crossing the AKPen Wednesday night and moving
into the northern Gulf on Thursday. With southerly flow ahead of
the low pulling in more moisture, another round of widespread
precipitation is expected for for Southcentral Wednesday and
Thursday, starting with Kodiak Island early Wednesday morning and
the rest of Southcentral Wednesday afternoon. Ahead of the upper
level low, a surface low develops in the North Pacific Tuesday
night and moves into the Gulf on Wednesday. With a coastal ridge
building in, winds will strengthen to small- craft levels offshore
the northern Gulf Coast Wednesday evening into early Thursday
morning as the low moves onshore and quickly weakens.

Widespread precipitation will continue across Southcentral on
Thursday as the upper low slowly moves into the northern Gulf. The
heaviest precipitation Wednesday-Thursday will be along the
northern Gulf Coast and around Prince William Sound.

- PA

&&


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

An active pattern continues across Southwest Alaska, the Bering
Sea and Aleutians through the middle of the week as a series of
upper-level lows track across the region.

This afternoon, windy conditions persist across Bristol Bay as a
low lingers over the Kuskokwim river delta. This low weakens as
it lifts north along the western mainland coast overnight, and
leaves more settled winds Tuesday morning.

Rain continues, however, as a compact upper-level low near Adak
lifts to the northeast, reaching Bristol Bay Tuesday afternoon.
This low and its associated front will bring additional rain
before winds further weaken Wednesday morning. While weak ridging
builds across the Bering Wednesday behind the low, light rain is
expected to linger across Southwest mainland through Thursday
morning as the compact low continues northeast across King Salmon
and along the Alaska Range.



&&


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

The long term begins with a strong zonal jet between Kamchatka
and western Alaska that will amplify into a broad trough over the
state on Saturday and Sunday. The jet streak over the Bering will
help to generate a fairly strong and broad low pressure system
that will impact southwest Alaska starting early Friday. Depending
on the track and timing of this system, which has a fairly large
spread, there are concerns regarding the potential for coastal
flooding, high surf, and/or erosion. It`s difficult to pinpoint
where this may occur at this time with guidance highlighting a
broad area of concern from the northern Alaska Peninsula all the
way to the Y-K Delta.

The other aspect to this system is significant rainfall. Although
there isn`t a deep connection to the pacific and tropical
moisture, a decent slug of warm, moist air will accompany the
system. Models are indicating 1-2 inches of rain may fall on
Southwest Friday and Saturday. The storm will pass into
Southcentral and then the Gulf over the weekend, with a widespread
1-3 inches of rain possible. Given the wet environment,
particularly in the Susitna where flooding is currently occurring,
flood concerns will rise once again. Winds look strong through
the Bering, Southwest, and Gulf of Alaska/Kodiak Island.

&&


.AVIATION...

PANC...VFR conditions are expected to remain through the TAF
period, with ceilings hovering around 5000 ft. Gusty southerly
winds will persist through the day and start to diminish tomorrow
morning. As the surface winds and winds aloft are both from the
south, low level wind shear is no longer expected.

&&


$$