766
FXAK68 PAFC 301310
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
510 AM AKDT Wed Sep 30 2026

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

A shortwave trough moving over Kodiak this morning will phase with
an upper level low over the western Interior through the day and
into tomorrow. At the surface, a lee-sde trough has developed
south of the Kenai Peninsula, which will remain fairly
stationary/redevelop with the westerly flow aloft. Precipitation,
mostly in the form of showers due to widespread instability, has
begun to develop along the eastern Kenai Peninsula and will
spread inland through the day as the southern shortwave lifts into
the area. Yesterday there was some model disagreement as to the
location of the surface trough and speed of the shortwave moving
east, but generally speaking guidance has trended towards the GFS
solution, which means more precipitation for Anchorage and the
southern Mat-Su Valleys. Showers will also develop over the
eastern Sound and move over the Chugach into the southern Copper
Valley.

By Thursday morning the southern shortwave will move into the
Panhandle and Yukon Territory, while an arm of the cold upper low
moves south over the western Alaska Range and greater Bristol Bay
area. This will continue to provide lift for showers along the
Chugach and Kenai Mountains, with some precipitation possible for
Anchorage and the Mat Valley. By this time the airmass aloft will
be quite cold, dropping snow levels as low as 800 ft or so. It`s
not out of the realm of possibility for some near sea level areas
from Anchorage north to Palmer to see some snowflakes Thursday
morning if a heavier shower moves overhead. Areas along the upper
Hillside and South Fork Eagle River are likely to get a dusting up
to 3 inches depending on the elevation and intensity of the
showers. Should showers train over the higher elevation areas like
Glen Alps or South Fork tonight, up to 5" may be possible.

Moving into Thursday evening and Friday there is some uncertainty
as to when the trough axis will finally move through, thus leading
to the end of precipitation. Overall model consensus is Thursday
evening, but the GFS lingers the trough for a longer period of
time, thus leading to a longer period of potential precipitation.
By Friday morning precipitation should be out of the area, and
with clearing skies the first hard freeze with temperatures less
than 30 degrees is likely for many of the population centers.

CJ

&&

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

Key Messages:

* Chance of marine lightning (10 to 20%) across the southeast
  Bering Sea this morning.

* Sub-freezing overnight temperatures in Southwest Alaska
  throughout the week.

* A front brings rain and a corridor of gale-force winds in the
  western Bering Sea starting this afternoon for the rain and
  tonight for the stronger winds. This spreads eastward through
  Friday.

Discussion:

As the northern periphery of a low pressure system in the northern
Pacific Ocean pushes into the Aleutians, expect widespread
rainfall and generally windy conditions across the southern
Bering. A few lightning strikes are possible (10 to 20% chance)
across the southeast Bering through this morning with an unstable
airmass dropping out of the Bering. Widespread lightning over
water event is not anticipated. Aside from marine lightning
potential, expect widespread rainfall across the entirety of the
Aleutians and much of the Alaska Peninsula today through Thursday
evening.

The departure of these shortwaves in the Bering will leave
Southwest Alaska in a period of transient ridging, allowing for
relatively clearer skies, and a more notable diurnal, but
ultimately cooler, temperature range. Daytime high temperatures
will struggle to get out of the 40s with nighttime/morning lows in
the 20s. Due to cloud cover, temperatures across the AKPEN should
stay above freezing through the week.

While the low traverses the Aleutians today through Thursday,
expect diminishing winds and rainfall across the western
Aleutians as it departs. However, the area of gale-force winds
also moves east to the central Bering by this evening and Thursday
as high pressure builds across the northern Bering and Bering
Strait region. Gales become more confined to the North Pacific
south of Nikolski/Unalaska Thursday night into Friday as the
Bering Sea low transfers it energy to a new developing low in the
North Pacific by then. By Friday afternoon, a new low pressure
system enters the Western Bering, pushing a gale-force southerly
front into the western Aleutians along with widespread rainfall.
This feature will steadily advance eastward across the Aleutians
into the weekend.

-CL

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

Looking ahead toward this weekend, models are synoptically in
good agreement in the midrange forecast, featuring a low moving
toward Kodiak Island from the North Pacific and another low into
the Bering Sea from the west. Precipitation with east to southeast
winds will be more than likely for Southcentral, especially
closer to the Northern Gulf coast and Kodiak Island. By Sunday,
the front extending from the Bering Sea low reaches Southwest
Alaska and the Alaska Peninsula bringing rain, snow, and southerly
flow across the area. As the low sinks southward Monday, models
diverge on how far south the low will dip. Generally, the low
appears to pass through the Alaska Peninsula and near Kodiak
Island/Western Gulf. As this pattern sets up through the first
half of next week, cold air advection and northerly winds will
become enhanced through gaps along the Aleutians. If the low sinks
south farther east, the Alaska Peninsula would see more cold air
advection and those northerly winds. While temperatures overall
for southern Mainland are trending cooler in the short term, some
moderation of that trend is expected toward more seasonable norms,
but will remain on the cooler side.

&&

.AVIATION...

PANC...VFR ceilings are expected to lower to MVFR late this
morning as precipitation chances increase through the morning
hours. Ceilings improve back to VFR as rainfall tapers off this
evening.

&&


$$