591
FXAK68 PAFC 111406
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
506 AM AKST Tue Nov 11 2025

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

Satellite imagery this morning reveals a mature, weakening low in
the eastern Gulf of Alaska analyzed at 987mb and drifting north
toward Yakutat. On the western flank of this low exists a broad
shield of higher-level clouds draped across the eastern Copper
River Basin from the Wrangells through the eastern Chugach.
Elsewhere, clear skies have prevailed across much of Southcentral
AK outside of some additional cirrus from the Kenai west. The
clear skies paired with high pressure have allowed temperatures to
drop into the lower teens and single digits across much of the
area, with below zero temperatures currently observed across much
of the Copper River Basin. VIIRS nighttime microphysics imagery
shows fog has developed in some spots such as in the Knik Valley
and Turnagain Pass, along with a few other isolated locations.
Latest trends don`t suggest much spatial growth in the fog, likely
due to significant dry air just above the surface as observed in
the 12z PAFC RAOB. In fact, the webcam at the Palmer Airport shows
the patchy fog layer to be quite shallow, suppressed by this dry
air and strong inversion. Wouldn`t rule out some additional growth
this morning, but this may be limited to land adjacent to open
bodies of water.

A tight pressure gradient (nearly 20mb between the low and the
Denali Highway) between this weakening Gulf low and a building
interior ridge continues to support strong offshore gap winds in all
the usual places - Seward/Resurrection Bay, Whittier/Passage
Canal, Copper River delta, etc with gusts as high as 45 mph being
observed thus far overnight.

The observed weather analyzed above will be what we see through
the day. The low will continue to weaken as it drifts inland, thus
reducing the pressure gradient and the outflow winds with this.
However, this will be quite gradual over the course of the day and
most of the gap locations will continue to see gusty winds until
Wednesday. Temperatures will continue to be colder - colder than
climatological average - with the coldest day of the season
expected for most locations around the area.

A stronger shortwave trough will eject into the Gulf of Alaska on
Wednesday. Renewed onshore flow coincident with the remnant moisture
from the previous low will allow the develop of rain/snow across the
Prince William Sound with showers advecting into the adjacent
mountains and possibly into the coastal towns such as Whittier. At
this time, any accumulation looks to be on the lighter side.

Elsewhere across Southcentral, mostly clear, calm, and
meteorologically-quiescent conditions should prevail through
Wednesday. Cloud cover spreads across the area Thursday with a
decaying front, but shouldn`t really impact Southcentral outside
of the standard dose of winter gray.

-Brown

&&


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

As of this morning, a well defined 500 mb shortwave trough is
digging southeastward across the Yukon-Kuskokwim Delta region. As
a result, this upper level energy has allowed a small, compact
area of low pressure to form at the surface, which can be seen on
satellite situated northwest of the Bethel area. Areas of fog, low
stratus, and scattered snow flurries/showers are the main impacts
this morning. Nighttime microphysics satellite imagery paints low
stratus and fog across most of Southwest Alaska, the Eastern
Bering, and Bristol Bay locations. The global models as well as
the high resolution guidance has done a good job initializing this
feature of interest. All of the guidance this morning wants to
dissipate the surface low through this afternoon, though it will
still keep relatively unsettled weather in the forecast through
this evening and early Wednesday morning for Southwest Alaska.

Meanwhile, across the Western and Central Aleutians, a northwest
to southeast oriented gale force front has pushed its way across
the Western Aleutians, and is poised to move eastward through this
evening. The models show this front weakening as it progresses
eastward, with small craft sustained winds in store for the
Pribilof Islands as the front itself begins to pivot and elongate.
The front nears the Kuskokwim Delta Coast and Bristol Bay areas
Wednesday afternoon. Models diverge on the exact setup as the
front nears the coast, with some of the guidance still showing a
loosely defined trough/front, with others pinching off a small
area of low pressure embedded within the trough axis. These small
differences are important because as precipitation works its way
inland across Southwest Alaska Wednesday afternoon, thermal
profiles will be cold enough to support snow, which coupled with
gusty winds, increases the chance of blowing snow. Due to the
guidance showing some agreement on the front/trough making little
progress inland, this should keep blowing snow potential mostly
confined to coastal areas.

Looking forward to Thursday evening, the global models bring a
strong gale force low northward from the North Pacific and into
the Alaska Peninsula. Models do differ on intensity and placement
of this low, and the ECMWF seems to be the outlier as of now
bringing the low north of the Alaska Peninsula and into the
southern Bering. A much larger and stronger baroclinic low
pressure system, not associated with the remnants of Typhoon Fung-
Wong, moves somewhere in the vicinity of the Western
Aleutians/Western Bering this weekend. There are a lot of details
to iron out with this system and overall forecaster confidence is
lower than average at this time. Please stay tuned and monitor the
forecast for this upcoming system.

-AM

&&


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

A vertically stacked low over the Eastern Aleutians and Alaska
Peninsula for the second half of this week slides east into the
Gulf of Alaska by Saturday. Gusty westerly to northwesterly winds
ranging from small craft to gales along with diminishing
precipitation are anticipated on the back side of this system for
the Eastern Aleutians and AKPen. For Southwest and much of
Southcentral Alaska, seasonably cool temperatures and relatively
quiet weather is expected Friday into Saturday, with the greatest
chances for periods of precipitation remaining mainly along the
northern Gulf coast and Kodiak Island as the low tracks towards
Southeast Alaska.

The bigger story continues to be a much stronger storm lifting
out of the North Pacific towards the Central Aleutians this
weekend. Deterministic models and ensemble guidance are loosely in
agreement for a sub 950 mb low reaching the Aleutian Chain
sometime Saturday into Sunday as it merges with an upper level
trough in the western Bering Sea. Confidence is currently high
that as the storm arrives, the Aleutian Chain is likely to see
moderate to heavy rain and sustained high end gale to storm force
winds through the weekend. As we head further into the weekend and
into early next week, there remains a high degree of uncertainty
with regards to the track and intensification of the low as it
tracks across the Aleutians and into the southern Bering as model
spread significantly increases by this point. While most guidance
generally favors the storm remaining over the southern Bering, the
GFS continues to depict the storm deepening to a sub 940 mb low
and tracking north into the central Bering. If this scenario were
to play out, impacts such as heavy rain, a prolonged period of
strong south-southeasterly winds, and high seas would affect much
more of the region including the Pribilof Islands as well as the
Kuskokwim Delta coast through the early part of next week. The
impacts from this storm will be highly dependent on the storm
track, and we continue to closely monitor and update the forecast
as confidence in the strength and track of the storm increases.

-JH

&&

.AVIATION...

PANC...Clear skies and light winds this morning will bring a
returning threat for fog and low stratus to develop along the Knik
Arm. This could lead to a return to IFR conditions or lower if it
manages to move south near the terminal at any point from this
morning into tonight, although this potential for fog to extend
into west Anchorage remains highly uncertain. Otherwise, light
winds and VFR conditions will persist through the TAF period if
fog and low stratus fail to form.

-AS

&&
$$