311
FXAK68 PAFC 081353
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
553 AM AKDT Tue Sep 8 2026

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

Southwesterly flow has overspread Southcentral ahead of a deep
upper level trough and embedded upper level low progressing
steadily east across Southwest this morning. Much of the greater
Cook Inlet region has dried out a little faster than anticipated
this morning, namely due to a dry slot that is surging in from
the AKPen and helping to suppress rainfall. Steadier rain is still
ongoing where flow is sloping upwards into the windward side of
the various mountain ranges, particularly along and near the
Chugach Mountains and Talkeetnas. Gusty southerly gap winds are
still holding on through the Copper Basin and along parts of the
Turnagain Arm and Anchorage area, but they should trend down
quickly as the incoming trough to our west erodes the coastal
pressure gradient. Shower activity will also really flare back up
later today as cool air aloft moves in with the main upper trough
axis, supporting a more unstable atmospheric profile. In fact, an
isolated thunderstorm or two will be possible (around a 30%
chance) across parts of the northern Kenai Peninsula, Mat-Su
Valleys, and perhaps even Anchorage this afternoon.

Looking ahead, the pattern will reset once again to something more
akin to summer than to fall. By tonight, the main trough moving
past us from Southwest will dip southeast into the Gulf as a
strong ridge begins to build back into place across the Bering Sea
and Southwest. This will put Southcentral back into a zone of
brisk northwesterly flow aloft, supporting gusty offshore gap
winds out of the typical valleys and fjords along the Gulf Coast
starting late tonight into early Wednesday. Lingering showers will
clear out overnight from west to east along with some of the cloud
cover in place as drier air works in from the north. Temperatures
will rebound back into the 60s for most lower elevations for
Wednesday afternoon, especially where offshore winds and
downslope warming in the lee of the mountains continues along the
coast for spots like Whittier and Seward.

Not a whole lot of change is expected across the region for
Thursday as the longwave ridge continues to gain amplitude and
drift slightly east. A warm front associated with a very large low
pressure system moving over Siberia and the Chukchi Sea will
steadily progress north across Southcentral as it heads towards
the Interior through Thursday evening. However, this feature is
anticipated to do little beyond increase cloud cover as it passes
through, with all but areas near Broad Pass expected to stay mild
and dry throughout the day. Highs on Thursday will also be even
warmer, perhaps touching 70 near Kodiak, Seward, Whitter and
Valdez during the afternoon hours.

-AS

&&


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

Key Messages:

* Showery and breezy through tonight for most of Southwest. An
  afternoon lightning strike or two can`t be ruled out north of
  King Salmon.

* A building ridge will bring benign weather (but increasing fog
  chances) on Wednesday, then a potent front gradually tracks
  eastward across the Bering starting Wednesday morning.

* We continue to monitor the potential for minor flooding and
  coastal erosion in Kuskokwim Delta and along Kuskokwim River for
  Thursday and Friday.

Discussion:

Currently, upper level troughing extends from Southwest Alaska
down through the eastern Aleutians into the North Pacific, with
the main vertically stacked low residing over Bristol Bay. This
has brought showers across much of Southwest Alaska into the
Alaska Peninsula (AKPen) and southwesterly to westerly, small-
craft force winds across the eastern Bering and waters south of
the AKPen. To the west, a ridge is building over the western
Bering. Some small craft winds are present over the western
Aleutians near a dissipating front and patches of fog are present
throughout the Bering, otherwise the weather is mostly benign.

The vertically stacked low over Bristol Bay crosses the Alaska
Range and moves into Southcentral by this afternoon. Scattered
showers accompany the low and will persist throughout Southwest
and the AKPen today. There is a low chance for a lightning strike
or two north of King Salmon this afternoon (10-20 percent). Cold
air aloft and vorticity are the main drivers of the chance for a
lightning strike, but the lack of surface heating given the early
passage of the low this morning keeps this chance low. As winds
become more westerly late this afternoon, rainfall becomes more
concentrated along the western Alaska Range and areas in the AKPen
where winds upslope. As the low moves east tonight, winds weaken
and upper level vorticity decreases. Lingering showers along the
mountains will taper off overnight tonight, with only the northern
portions of the Alaska Range seeing showers persist into
Wednesday.

Ridging is already building in behind the low over the western
Bering and Aleutians. Some patches of fog will persist through the
Bering and Aleutians, otherwise the weather today will be mostly
benign. For weather conditions later in the week, the ridge will
be one of the key influences on how stormy the weather will be
across the Bering and Southwest Alaska in the coming days. For
Southwest, the AKPen, and the eastern Aleutians, Wednesday will be
quiet. Some showers may linger along northern portions of the
Alaska Range. Out west, a Kamchatka low will push its front into
the Western Bering (along the western periphery of the ridge)
beginning Wednesday morning. Models have generally been trending
towards a more resistant ridge, one that will be strong enough to
keep the worst winds in the Western Bering and perhaps only
clipping the northern parts of Kuskokwim Delta. With the ridge
trending stronger and the front continually being displaced north
and westwards, concern for coastal erosion and flooding for
Kuskokwim Delta is diminishing. Still, we continue to closely
monitor the behavior of this front and its ridge. Though the storm
will be weaker in this area and tides will generally be
decreasing around this time, the other factor to consider will be
an influx of water down Kuskokwim River due to recent rainfall,
which may still cause flooding issues along Kuskokwim River
itself, and especially near where the mouth of the river opens out
into Kuskokwim Bay. Stay tuned.

-PA/KC

&&


.LONG TERM FORECAST (Days 4 through 7)...

A highly amplified pattern is expected through the second half of
the week as a deep upper level Kamchatka low opens into a trough
in the western Bering while a strong upper ridge slides east
across the Mainland Friday through Saturday. Models remain
consistent on the overall upper level longwave pattern with the
biggest uncertainty continuing to be the exact timing and
placement of individual shortwaves embedded within the mid to
upper level flow. The strong surface low over eastern Russia
continues to trend farther north and west, with ensemble model
guidance steady in the general northeastward track across far
eastern Siberia and into the Arctic Ocean Friday into Saturday.
Confidence remains high on its associated gale- force front
tracking east across the Bering through mid to late this week,
bringing gusty southwesterly winds and moderate to heavy rainfall
across the Aleutians and Pribilof Islands.

The strong front similarly continues to trend farther north in
the Bering as its eastward progression stalls against the strong
high pressure stretching across the North Pacific into the
southern Mainland. The longest duration and strongest core of
winds with this system is now expected to affect the Norton Sound
and Seward Peninsula region through Friday. Despite this shift in
the storm track, a period of gusty small-craft to potentially
gale-force winds along the front is still likely to impact the
Kuskokwim Delta coast by Thursday night through Friday evening.
The long fetch of strong, southwesterly onshore winds could bring
the possibility of high surf and minor coastal flooding and
erosion along the Kuskokwim Delta coast as the front progresses
through the region. Elevated water levels in the Lower Kuskokwim
River due to preceding rainfall across the Interior, combined with
additional rainfall, could lead to minor river flooding for
communities along the river from Bethel to the Kuskokwim Bay.
Details will continue to become clearer in the coming days on the
exact timing and potential impacts of this upcoming late-week
storm.

Behind this system, weaker west-southwesterly flow continues over
the Bering and Southwest Alaska through the weekend, while the
weakening frontal system and rainfall continues east into
Southcentral and the Gulf. Broad troughing remains centered over
the Bering, with models hinting at the pattern becoming more
amplified once again as a low lifts north out of the North Pacific
early next week.

&&


.AVIATION...

PANC...Waves of rain showers will continue moving across the
terminal for the rest of the morning, with a general decrease in
coverage by midday. As such, expect MVFR visibilities and MVFR to
IFR ceilings for much of the remainder of the morning. There is
some uncertainty in how low ceilings fall this morning, especially
around the 14-18z timeframe. Also, the Turnagain Arm wind with
gusts to around 20 to 30 knots will be the case until midday, with
winds thereafter diminishing rapidly as lighter southwesterly
winds take over by this afternoon.


-AM



&&


$$