217
FXAK68 PAFC 030021
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
421 PM AKDT Wed Sep 2 2026

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: This
afternoon through Saturday evening)...

Key Messages:

- Clearer skies will lead to another chilly morning tomorrow,
  though overnight lows will generally be warmer than what we`ve
  seen the past few days for all but Copper River Basin.

- Increasingly unsettled from Thursday afternoon through Friday,
  then breezy and rainy from Friday through Saturday afternoon.


Discussion:

Satellite shows mostly clear skies over Southcentral this
afternoon as we remain downstream of the ridge axis, which
currently extends from about Nunivak Island south towards Sand
Point. Though we remain under the influence of a colder air mass,
surface temperatures this afternoon are creeping into the 50s to
60s under daytime heating. Along the coast, gusty offshore winds
are also helping to promote warmer temperatures by inhibiting the
development of a sea breeze. As such, current temperatures are in
the mid to high 60s for locations such as Kodiak City, Seward, and
Valdez. With this morning`s upper level shortwave having exited
Southcentral, expect these gusty offshore winds to decline through
the overnight hours.

Light winds and mostly clear skies will lead to another chilly
night and morning, though temperatures tomorrow morning will
generally be a few degrees warmer as the air mass has moderated.
Still, morning lows will likely dip into the mid 30s to low 40s
for much of the Southcentral Mainland, with widespread
temperatures below freezing for much of Copper River Basin. While
surfaces may be a bit frosty, no precipitation is expected.

From tomorrow through Friday, expect increasingly cloudy skies as
the ridge marches eastward and warmer, moister air is transported
into Southcentral on the backside of the ridge. As the front of a
Bering Sea low pushes into Southwest Alaska, parts of Susitna
Valley could see rain spill over as early as Thursday afternoon
and evening, though there continues to be timing uncertainty with
the incoming rain. All this will likely depend on the strength of
the ridge, and whether it will be strong enough to further delay
the arrival of rain. Though there is uncertainty with the onset of
rainfall, confidence is fairly high that much of Southcentral will
see rain by late Friday night and into Saturday, as a robust
shortwave and its attendant weak surface low move up Kodiak Island
and Cook Inlet. Winds will also pick up, especially through
favored southeasterly gaps, as the pressure gradient tightens.
Overall, this will likely make for a wet and breezy end of week
and start to the Labor Day weekend, but the storm itself does not
look to be particularly strong or hazardous. As such, impacts will
likely be minor.

-KC

&&


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

Key Messages:

*A Special Weather Statement is in effect for the Kuskokwim Delta
 Coast for elevated water levels starting late tonight and lasting
 through Thursday morning. Southerly offshore winds will gust to
 40 mph, causing water levels to be 1 to 2 feet above the normal
 high tide line. Minor coastal erosion is possible.

*Strong, gusty winds continue to develop over Cold Bay through
 tonight and Thursday morning. Gusts to 65 mph Thursday morning
 are possible.


Discussion:

The forecast continues to remain on track with very little change
today. Currently, a front is lifting across Southwest Alaska,
which is producing rain showers across the region this afternoon.
Coverage in rain showers will decrease as the afternoon and
evening wears on as this system moves out of the area. However, a
much more impactful system is sitting out to the west with its
parent ~980 mb low spinning north of Shemya along with its
attendant gale force front draped from the west-central Bering
southward to across the Central Aleutians and then farther south
down across the North Pacific. The eastward progression of the
front is displacing the vertically stacked ridge that has been in
place for the last couple of days to the south and east, which has
decreased the extent of fog and low stratus coverage underneath
the ridge. The arrival and passage of this front will be the end
of 70+ degree weather that portions of the Central and Eastern
Aleutians have seen over the last few days.

Winds are already increasing across Cold Bay, as a southeasterly
wind direction aligns with the southeast to northwest gap to
enhance wind speeds. As of 3PM, Cold Bay has seen winds gust as
high as 30 mph. As the front closes in on Cold Bay late tonight,
winds will quickly ramp up further and peak Thursday morning where
gusts up to 65 mph will be possible. Although the MOS and other
models have trended slightly weaker today with winds, now is the
time to tie down or collect any loose items outside that can be
easily lofted with strong winds. Travel may be difficult as well
Thursday morning. Around the time Cold Bay sees their peak in
winds, a relatively strong fetch of southerly winds will make
their way to the Kuskokwim Delta Coast. The main area to watch
will be Kwigillingok and Kongiganak where the coastline is
perpendicular to the wind direction. These winds will last through
late Thursday evening, where gusts up to 40 mph will be expected.
While actual coastal flooding is of low concern at this time, the
focus and messaging with this system is unchanged and remains
coastal erosion coupled with high surf potential. A round of
rainfall will accompany the arrival and passage of this front,
with much of the Kuskokwim Coast and Delta on track to see up to
0.5 inch of rainfall, with higher amounts farther south along the
Western Capes.

In the wake of the front, southwesterly small crafts and low end
gales on the backside of the parent low will move across the
Western and Central Aleutians starting Thursday morning. Aloft,
the models show that the quasi-stationary, vertically stacked area
of low pressure will have shortwaves rotating around its outer
periphery. Not only will this help to enhance winds underneath the
forcing via momentum transport, but these waves will also act as
"kickers", which will help to give this low some forward momentum.
The global models are actually in great agreement heading into
Saturday morning and are picking up on the remnants of a tropical
system skirting just south of the Aleutian Chain. This system will
most likely track eastward with time across the North Pacific
waters as a larger upper level system to the north blocks any
northward progression and steers this low to the east.

-AM

&&


.LONG TERM FORECAST (Days 4 through 7: Sunday through Wednesday)...

Next week will start out with a large upper level low over the
northern Bering Sea with the upper level ridge over the
southeastern most parts of the Panhandle. A shortwave extending
out of the low and over the Alaska Peninsula  will move across
Southwest Alaska Sunday and then through Southcentral on Monday.
Uncertainty increases beyond Monday as Bering Sea low should
weaken and track eastward across the state and then result in
generally zonal flow after that. The main uncertainty arises in
how much the trough will weaken and how fast it will track across
the mainland part of the state.

How this translates into the sensible weather: The shortwave will
bring enhanced rainfall to Southwest Alaska on Sunday and then to
Southcentral Alaska Monday. Southwesterly flow aloft will keep
some showers around even after the shortwave passes through the
region. When the main upper level low moves across the area,
there will be some locally heavy rainfall, especially along the
north Gulf coast. Right now is looks like a generally wet first
half of the week next week, but should the low move through a
little faster, Wednesday (especially in Southwest Alaska) could
see some briefly drier weather.

&&


.AVIATION...

PANC...VFR conditions and light winds will persist.

&&


$$