400
FXAK68 PAFC 290010
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
410 PM AKDT Mon Sep 28 2026

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

This afternoon has been mostly quiet across Southcentral Alaska
with mostly to partly sunny skies and seasonable temperatures.
This will be short lived, however, as a shortwave trough is
progged to dig southeastward from the Interior tonight and into
Tuesday morning. Increased cloud cover ahead of this feature will
only allow temperatures to slowly cool tonight and most valley and
lower elevation areas outside of the Copper River Basin are on
track to see low temperatures 2 to 4 degrees F warmer than what
was observed this morning. Along with precipitation chances
increasing from Anchorage to the Susitna Valley, cold air
advection working in aloft with this wave will lower snow levels
to as low as 1800 to 2000 feet for the higher terrain of the
Matanuska and Susitna Valleys, which will support a quick round of
lower elevation rain showers and higher elevation snow before the
wave lifts over the Copper River Basin. Gap winds up to small
craft continue to gust around Kodiak Island as the remnants of
Dujuan move east through the Gulf. Winds slowly diminish through
mid-week as these final remnants dissipate.

For Wednesday, a longwave trough will move over the area with a
quasi-stationary surface low developing south of Seward. Weak lift
and weak winds aloft should help to bring steady precipitation to
the Sound and the population centers from the southern Matanuska
and Susitna Valleys and southward down into the Kenai Peninsula.
Even colder air will wrap in around the low bringing 850 mb
temperatures down to a range of -2 to -5 C depending on the
model. This would yield steady snow for areas like Thompson Pass
and even South Fork Eagle River and portions of the upper
Hillside. The NAM is a significant cold outlier and drops snow as
low as 800 ft, but we will continue to watch the progression of
temperatures aloft as we get closer in time. Overall confidence is
moderate (40-60%) that some of the upper elevations of Anchorage
and Eagle River will see some snow on Wednesday. Though winds
will remain sub-small craft, they will be elevated over gap
regions around Kodiak Island as this trough passes through.

-AM/JAR

&&


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

Key Messages:

* Colder temperatures move into Southwest Alaska throughout the
  week.

* A front brings rain and small-force winds in the western
  Aleutians starting Tuesday afternoon, spreading eastward on
  Wednesday.

Discussion:

An active pattern continues across the Bering Sea and Southwest
Alaska as a series of upper-level lows and shortwaves move across
the region. A vertically stacked low is currently positioned over
the western Gulf. Cyclonic flow associated with this feature has
maintained showers across the Alaska Peninsula (AKPen), with much
of Southwest having cleared out. Some showers may linger in the
Kilbuck Mountains through this evening. Breezy northwest winds
continue in the eastern Bering and AKPen, especially through
favorable gaps. The vertically stacked low continues to move east
in the Gulf. With less support from cyclonic flow, any lingering
showers in the AKPen should taper off by tomorrow morning.

While the low in the Gulf continues to move away, another trough
digs southward across western Alaska and the Bering Sea on Tuesday.
This will allow a colder air mass to spread into Southwest
Alaska, with temperatures trending noticeable cooler compared with
recent days. Daytime temperatures will struggle to warm past the
low 40s for Southwest and the mid 40s for the AKPen, while
overnight temperatures become increasingly chilly throughout the
week, especially across the interior portions of Southwest
Alaska. Widespread low temperatures in the low 30s are expected
for Southwest tonight, dropping to the upper 20s by tomorrow
night. A weak surface low develops in the northern Bering tonight
and moves through the eastern Bering Tuesday. This looks to bring
some scattered showers across the Bering to the Pribilofs. Some
isolated showers may reach the Southwest Coast, otherwise Tuesday
looks to be dry for Southwest. This weak low moves towards the
AKPen and eastern Aleutians Tuesday evening. Chances for light
rain increase for places south of King Salmon. This system weakens
as it moves into the AKPen on Wednesday. Chances of precipitation
decrease throughout the day as showers become more isolated. The
trough with this system will allow the cooler pattern to persist
over western Alaska and the Bering, especially as more cold air is
pulled southward. Overnight lows Wednesday night look to be
cooler than earlier in the week, with high chances many locations
across Southwest drop to the upper 20s, with inland locations down
to the mid 20s. For the AKPen, cloud cover from the next Bering
system should help temperatures stay above freezing.

Farther west, the Aleutians currently sit underneath a weak ridge
which has resulted in relatively quiet conditions. A front from a
Kamchatka low moves into the western Aleutians Tuesday afternoon
and pushes this ridge east. This front looks to stall Wednesday
morning, though there is medium confidence on exact positioning
between the western Aleutian Chain and the Southwest Bering.
Nonetheless, showers and southeasterly to easterly small-craft
force winds are expected to accompany the front, especially in the
western Aleutians. The low eventually becomes elongated and
catches up to the front Wednesday night. Higher chances for
precipitation spread to the eastern Aleutians and eventually to
the Southern AKPen on Thursday as the low continues east. The area
of small- craft force winds also increases across the Aleutians
and Bering Wednesday- Thursday.

- PA

&&

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

An active weather pattern will continue as we make our way into
October. A cold upper level trough over the Interior on Friday
will begin to move out of the region for the weekend. The
departure of this low will bring a slight warming trend through
the weekend.

There are signs of slight ridging over Southcentral for Friday,
which will be the best chance to see some sun. This will be short
lived since a Gulf low is expected to bring rain and wind for the
weekend. Looking at integrated vapor transport from the GFS, the
values are low, so the low is not expected to generate a notable
amount of precipitation. Using the GEFS member spread, the pressure
gradient is nothing note worthy. No significant winds are expected
at this time Friday through Monday.

Another low from Kamchatka comes into the Bering Sea, then tracks
over the Aleutian Chain through the weekend. There is growing
model agreement of the low reaching peak intensity before going
through the Bering Sea. There is low confidence of where the
system goes after the weekend. Half of the members from the GEFS
have the centers of the low track into the Gulf, crossing over the
Alaska Peninsula. Other members have centers scattered around the
Bering.

&&

.AVIATION...

PANC...VFR conditions and light winds will persist for most of the
TAF period. There will be a potential for rain showers and lower
ceilings (possibly as low as MVFR) to return to the terminal late
Tuesday morning.

&&


$$