518
FXAK68 PAFC 151333
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
533 AM AKDT Wed Oct 15 2025

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

A transient upper-level ridge is quickly exiting the region this
morning as a potent upper-level trough and occluding surface front
drive into the western Gulf ahead of a strong surface low situated
over the eastern half of the Aleutian Islands. Clouds are quickly
on the increase across the region as these features move east and
the ridge departs. Areas of fog have developed across portions of
the Copper River Valley overnight, but are expected to scour out
by mid morning. Temperatures there were falling through the 30s
for many locations but have stabilized as the increasing cloud
cover hampers any further radiational cooling.

The aforementioned front will move over Kodiak Island later this
morning, then into the northern Gulf by the afternoon hours. A
corridor of gale force winds will intensify to storm force as the
front approaches both Kennedy Entrance and the northern Gulf
coast as a barrier jet forms ahead of the boundary. These strong
easterlies will affect the Barren Islands briefly on Wednesday
afternoon before the front continues to the north. A secondary
corridor of storm force winds will move south of Prince William
Sound Wednesday afternoon into Wednesday night before winds
rapidly weaken as the front moves onshore.

Aside from the marine impacts, strong easterly winds are also
expected to move up into the Kenai Mountains and Turnagain Arm,
but a sharp down-inlet gradient developing ahead of the front
will prevent strong winds from coming into Anchorage. However,
fairly strong winds gusting up to 40 mph will still pick up across
the Mat Valley out of the northeast Wednesday afternoon through
Wednesday night thanks to the same northeast to southwest pressure
gradient picking up ahead of the front. In terms of rainfall,
the heaviest rain will shift from Kodiak on Wednesday morning into
the eastern Kenai Peninsula and Prince William Sound Wednesday
afternoon, with storm total accumulations from Cordova to
Whittier and Portage on the order of 2 to 3 inches or rain. Most
areas in the lee of the mountains will stay relatively dry
through Wednesday night due to the strong cross-barrier flow
moving in ahead of the front; however, rain showers will
eventually make it to these locations by late Wednesday night or
Thursday morning as both the surface front and flow aloft weaken.
Higher elevations such as Thompson Pass and Tahneta Pass/Eureka
will likely see some accumulating snow, around 1 to 3 inches,
before a changeover to a rain/snow mix or all rain by Wednesday
night.

By early Thursday, the parent low currently moving over the
Aleutians will drift northeast into the Gulf and move south of
Prince William Sound by Thursday evening. Winds along the
coastline will mostly subside as winds up to gale force south of
the low shift from southerly to westerly over the open Gulf
waters. Steadier periods of rain will give way to scattered
showers as multiple weak waves rotating around the low pinwheel
into Southcentral. Unsettled and showery conditions will persist
into Friday as the low continues to degrade over the northern Gulf
and as a cooler air mass begins to filter in from the west across
the Alaska Range.

-AS/TM

&&


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

Morning satellite imagery reveals a large and mature ~965 mb
occluded low located just south of Akutan and Unalaska. Overlaid
surface analysis shows surface troughing/its front situated just
east of the Pribilof Islands, stretching southeastward across the
Alaska Peninsula, and farther southward into the North Pacific.
According to surface observations, winds have been sustained at
gale force and gusting upwards of 35-45+ kts through favored bays
and passes of the Alaska Peninsula and northwestward across
Bristol Bay. Saint Paul has also seen wind gusts over 40 kts this
morning, which is evidence that this low is over-performing wind
wise as models are not really capturing/initializing its
associated winds that well, though the NAM/GFS LAMP MOS seems
closer to the ballpark of what is being observed. Also of note, a
sting jet is present on the back side of the low with drier air
and colder air advecting into the circulation. This has resulted
in gale force northwesterly winds moving across the Central
Aleutians in the wake of the low.

Short range model guidance shows that the front will take little
time traversing this region, with the front pivoting inland across
the coastal Southwest Alaska zones this morning. The front looks
to also reorient itself more east-west, which means that easterly
Kamishak gap winds will become more favorable and begin to pick up
in intensity later this morning. Near-term QPF amounts look to be
on the order of 0.5-1" for the Eastern Aleutians/Alaska Peninsula
(with locally higher amounts of 2"+ for the windward slopes of the
southern Alaska Peninsula due to orographic lift), up to 0.25"
across the Kuskokwim Valley, and 0.5-1" seeming likely for the
immediate coastal Southwest areas, including the Kuskokwim Delta
region. Easterly to east-southeasterly winds are really not a
great setup to see coastal flooding for this region just hit very
hard by the previous storm. However, we could see elevated water
levels during higher tide cycles.

Behind this storm system, 850 mb temperature anomalies from the
global models are signaling an unseasonably cool airmass moving
across much of the Bering and Aleutians through the end of the
week, with a near freezing to subfreezing airmass in place for
Southwest Alaska by Thursday/Friday. Aloft, the synoptic pattern
continues to remain unsettled through the short term and beyond,
with the upper level low associated with the aforementioned
occluded low moving out of the region and into the Gulf Wednesday
afternoon. The upstream 500 mb dynamic pattern has a couple of
shortwaves rotating over the Bering, with a more robust wave
located south of the Western Aleutians Thursday morning. Models
agree that this upper level support will favor weak cyclogenesis
at the surface south of the Aleutian chain heading into Thursday
afternoon. Looking forward to Day 4 (Saturday), most of the global
models are in loose agreement of another gale force low making
its way from the North Pacific and generally northeastward towards
the Aleutian Chain, but differ on placement, timing, and
strength. All said, confidence remains lower than average for a
potential storm system for this weekend.

-AM

&&


.LONG TERM FORECAST (Days 4 through 7/Saturday through Tuesday)...

Starting with this weekend, all guidance points toward a continued
stormy pattern, with a highly amplified and strong subtropical jet
stream. However, there is a huge spread in operational model
guidance and poor run-to-run continuity with the handling of
individual storm systems. The hemispheric flow does look
progressive and favors a west to east storm track across the
southern tier of Alaska from the Aleutians and southern Bering Sea
to Bristol Bay and the Alaska Peninsula to the Gulf of Alaska and
north Gulf coast/Prince William Sound. These regions would be
favored for strong winds and heavy precipitation. Areas further
north would see lesser impacts from wind and precipitation.

By early next week, models indicate the jet stream becoming more
zonal and the center of the long-wave trough shifting just a bit
eastward (with some ridging indicated upstream over the Asian
continent). This could bring an end to this period of intense
storms that we have been experiencing over the past week.

-SEB

&&

.AVIATION...

PANC...Light northerly winds intensify through the day with the
approach of a strong front and low pressure system. Ceilings begin
VFR above 5000 ft. Low level wind shear is possible as winds will
be southeasterly aloft through the morning. By this afternoon,
down inlet pressure gradients intensify enough for wind shear to
abate below 2000 ft. Winds could gust as high as 25 kt this
afternoon out of the north to northeast. Late this evening, the
front lifts across the terminal, allowing winds to diminish and
potentially bringing ceilings below 5000 ft with light rain
showers. However, there is only a low probability for MVFR
ceilings. Light rain shower potential continues into Thursday
morning with light northerly winds.

Quesada

&&


$$