Mill Bay, Alaska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

522
FXAK68 PAFC 061337
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
537 AM AKDT Tue Oct 6 2026

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

A low centered just a little south of Seward early this morning
will slowly drift toward Middleton Island over the next day. This
low is vertically stacked, fully occluded, and cut off from upper
level jet stream support. In short, it is just spinning and
weakening is place. As it does this, it continues to produce
widespread showers activity with the heaviest showers moving
through the Prince William Sound area. The showers are less from
Anchorage northward, but the residual moisture from rain the past
few days paired with stronger inversions near the surface is
producing areas of fog and some low clouds over these areas.

The showers activity should decrease in coverage and intensity
through Wednesday as the low weakens. However, there is a shortwave
trough that will approach the area from the northwest tonight
into Wednesday. This shortwave has the potential to bring
additional showery activity to the northern Susitna Valley. Since
temperatures aloft will also begin to cool with this shortwave the
chance for light snow at higher elevations will increase. The
most likely place for snow to reach road level tonight into
Wednesday will be north of Chulitna toward Windy Pass. Conditions
become drier from late Wednesday into early Thursday as weak
ridging behind the shortwave will move into the area.

&&

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

Key Messages:

* A strong storm system will impact the Bering Sea, Aleutian
  Islands, and Southwest Alaska from this afternoon through the
  end of the week.

* For the Bering Sea and Aleutian Islands: Winds pick up today,
  but the strongest winds will be from Wednesday afternoon through
  Thursday afternoon. High Wind Watches are in effect from Shemya
  east to Atka, and for the Pribilof Islands.

* For Southwest Alaska and Alaska Peninsula: Timing of stormiest
  conditions will be Thursday into the weekend. Max gusts
  approaching 40-50 mph. Coastal flooding unlikely, but there is
  still a potential for high surf along Kuskokwim Delta coast due
  to sustained onshore winds.


Discussion:

Not much has changed since the previous forecast package. A Gulf
of Alaska low will continue to bring breezy and showery conditions
to the Eastern Bering and Alaska Peninsula through tomorrow, with
a cooling trend for Southwest Alaska through Wednesday night.

Farther west in the Bering, the main focus will be on a
sprawling, strong storm system that will result from the
interaction of a Kamchatka low and the remnants of ex-Typhoon
Choi-wan. The Kamchatka low will be the first to bring impacts to
the area; its gale-force front will sweep into the Western Bering
beginning this afternoon. Choi-wan will arrive Wednesday
afternoon/evening, bringing with it strong winds and abundant
moisture.

Confidence remains fairly high that Choi-wan will bring sustained
storm force winds and hurricane force gusts somewhere in our
forecast area, though the exact location will depend on the track
of Choi-wan. High Wind Watches are in effect where the strongest
winds will likely occur. Current thinking is that there will be
about a 50-70% chance of Shemya and Adak seeing gusts 75 mph or
greater, while Atka and the Pribilof Islands will see about a
40-60% chance of gusts 75 mph or greater. These probabilities may
change as confidence increases in the low track. In addition to
strong winds, large portions of the Bering Sea will see wave
heights 20 ft or greater, with wave heights as high as 30 to 35 ft
in the far western Bering.

For areas east of the Pribilof Islands (including Unalaska, Alaska
Peninsula, and Southwest Alaska), this storm will still pack a
punch when it arrives late this week, but it will be weakening as
it tracks east across the Bering Sea. As such, gusts will very
likely remain below 75 mph, and will likely top out in the range
of 40-50 mph. Still, we continue to monitor the potential for high
surf along Kuskokwim Delta coast, especially for south-facing
communities like Kwigillingok and Kongiganak. While wind speeds
won`t be excessively strong, a long duration of southerly winds in
combination with a long fetch could lead to high surf.

-KC

&&

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

The long term begins with a broad and deep upper low (former
typhoon Choi-Wan) over the Gulf of Anadyr and a fairly high
amplitude ridge over the southern mainland. Through the weekend
the pattern will amplify rapidly, pushing a strong jet streak over
Southwest on Saturday and Southcentral on Sunday. This jet streak
will bring at atmospheric river to the AOR, particularly over
Southcentral. A strong shortwave will move south to north through
the jet into Southcentral overnight Saturday into Sunday. This
will increase winds along the north Gulf coast and produce heavy
rain throughout the Sound and potentially inland areas of
Southcentral. The east/west positioning of this feature remains
uncertain and will be important for the focused area of heavy
rainfall. Forecast uncertainty increases significantly on Monday,
with a large divergence in the two main models EC/GFS. On the GFS
the upper trough takes on a negative tilt, which would focus the
AR back onto Southcentral (and potentially Southwest), while the
EC keeps the primary jet more towards Yakutat and Southeast.
Another round of moderate rain is likely Monday regardless, but
the farther west shift would mean another focused period of heavy
rain.

&&

.AVIATION...

PANC...LIFR ceilings are over the terminal early this morning as
persistent rain showers have saturated the surface airmass and
winds have gone calm. The showers are tracking just south of the
airport, with LIFR ceilings and occasional reduced visibility in
mist. The stable airmass producing the low stratus and fog may
suggest that these showers will, for the most part, remain to the
south of the airport. How long will it last is now the question.
With widespread low ceilings over the Anchorage Bowl with just
patchy fog, the low ceilings will be more likely to persist
through the morning hours with visibility returning to
predominantly VFR by mid morning. Ceilings might remain no better
than MVFR into the afternoon, but should improve as some light
southeasterly winds move over the area this evening.

&&

$$