279
FXAK68 PAFC 190137
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
437 PM AKST Tue Nov 18 2025

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

Generally speaking, the pattern this afternoon remains similar to
what we saw yesterday. Southcentral continues to sit within a
zone of southwesterly flow between a weakening low moving up the
western Alaska coast and an upper ridge focused over British
Columbia and Southeast. Relatively mild conditions in the 20s and
30s near the surface contrasting with much colder temperatures in
the mid to upper levels is continuing to support an unstable air
mass along with several areas of convective showers drifting north
from the Gulf into much of the Gulf Coast. A low-amplitude
shortwave trough progressing northeast from near Kodiak Island
into the Kenai Peninsula is helping to support more aggravated
shower activity near the Barren Islands and along the southern
coast of the Kenai Peninsula. Some of this activity will likely
shift north towards the eastern Chugach Mountains, Anchorage and
the Mat-Su Valleys this evening as the trough progresses towards
the Talkeetnas overnight.

While the exact track of individual shower clusters over the next
several hours is uncertain, no single location across the Mat-Su,
Anchorage and western Kenai Peninsula is expected to see much
accumulation tonight. The observed Anchorage sounding from this
morning also showed a dry layer from about 1000 to 5000 ft, and
this dry air prevented much of the snow that moved past the
Anchorage Bowl last evening from reaching the ground. It would
not be surprising to see this dry layer act as a spoiler for
heavier snow showers that try to move inland up towards Anchorage
and Palmer again tonight.

Looking to Wednesday and beyond, clarity is still rather lacking
for the evolution of a complex and much more active pattern taking
shape across the region. A shortwave trough with numerous smaller
embedded waves is expected to round the base of the longwave
trough sitting out over the Bering Sea between Wednesday and
Thursday, with the bulk of the energy expected to lift northeast
towards the AKPen. Several differing scenarios remain on the table
for how this system ultimately evolves, though the bigger picture
impacts to Southcentral will not differ too much overall in spite
of the poor model agreement. Guidance continues to struggle with
the location and track of a surface low expected to spin up ahead
of the incoming shortwave. The general consensus is now that the
surface low will initially form close to the southern end of the
AKPen on Wednesday evening, but solutions quickly diverge from
there, bringing the center somewhere between Bristol Bay and the
northern Gulf on Thursday.

In terms of the impacts from this system to Southcentral, there
are really still two but similar scenarios for how this plays
out. If the low takes the more northerly track into Bristol Bay
and the southern Cook Inlet, this would generally favor more warm
air making it into interior valleys, with more of a Chinook
pattern that could result in temperatures across much of the Kenai
Peninsula, Anchorage and Mat Valley warming a few degrees above
freezing on Thursday. This would also be more favorable for more
intense southeast winds to develop along the Turnagain Arm and
much of the Kenai Mountains. If the low skirts more south into
Kodiak Island and the Barrens, this would keep inland temperatures
cooler and snow levels lower across the Kenai and Chugach
Mountains. Either way, heavy precipitation enhanced by upslope
flow with increasing southeasterlies ahead of the low and its
front is expected along the coast from the southern Kenai
Peninsula out to Prince William Sound late Wednesday into
Thursday. There will also be a threat for periods of light
freezing rain/sprinkles to make it into parts of the western Kenai
Peninsula, Anchorage and the Mat Valley as a warm nose aloft
develops overtop a layer sitting at/below freezing close to the
surface on Thursday. Fortunately, it looks like anything that does
"spill over" from the mountains will stay fairly light, albeit it
does not take much freezing rain to create treacherously slick
surfaces.

From late Thursday into Friday, there is a loose consensus that
the low and supporting trough will continue to shift northeast
to somewhere in the vicinity of Prince William Sound. This could
entail a band of rain switching over to snow moving up into
western parts of the outlook area as a cooler air mass begins to
work in from the west. However, this will depend on how the system
evolves on Thursday and how quickly it shifts northeast, so the
details are still very difficult to pin down at this point.

-AS

&&


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

Onshore flow in the wake of the low that brought active weather
across the area the last couple of days continues to bring showers
across Southwest Alaska this afternoon. Light rain showers across
Bristol Bay are beginning to diminish as the low continues to
pull off to the north into the Bering Strait, while snow showers
persistently continue across the Kuskokwim Delta. A more intense
band of snowfall for this afternoon and evening that model runs
have been depicting the past day or so has come to fruition, with
its axis of heaviest snowfall currently setting up from roughly
the mouth of the Kuskokwim River up through Kalskag. This band of
snow will slowly drift north across the Kuskokwim Delta and Lower
Kuskokwim Valley through this evening into tonight before it falls
apart ahead of an approaching front in the eastern Bering early
Wednesday morning. Based on current radar returns and
observations, areas within the heaviest axis of snow could see a
quick couple inches of wet, heavy snow accumulation through this
evening.

Further west, the front tracking across the Bering bringing gusty
southerly winds and rain has reached the Central Aleutians. The
front makes it to the Eastern Aleutians and Pribilof Islands by
late this evening, at which point a triple point low spins up
along the front just west of the Pribilof Islands. This will help
lead to a modest enhancement of rain and winds across the islands
overnight as the low tracks to between Nunivak Island and St
Matthew Island Wednesday morning. Colder air currently in place
over Southwest Alaska will retreat to the north through Wednesday
morning as a strong push of southerly flow will accompany the
front as it reaches the Southwest coast. Precipitation will first
begin to spread inland across Nunivak Island and the Kuskokwim
Delta by early Wednesday morning. Precipitation for these areas
likely begins as snow before the southerly flow erodes away the
colder air in place enough for a transition to a rain/snow mix
along the coast by mid to late morning. Most precipitation
associated with this front along the Bristol Bay coast also likely
falls as a rain/snow mix.

The pattern amplifies further on Wednesday night as the broad
upper-level trough complex across the Bering digs into the North
Pacific. A robust shortwave and associated strong surface low
pressure system will lift from the North Pacific to the Alaska
Peninsula (AKPEN) Wednesday evening. Strong gusty gale-force
southeasterly winds as well as heavy rain are likely along the
AKPEN starting Wednesday afternoon. While confidence for strong
winds and heavy rain is greatest along the AKPEN, there are still
questions about the exact track of this system. Confidence for
precipitation-type and precipitation intensity along Bristol Bay
and the Kuskokwim Delta/Kuskokwim Delta Coast for Wednesday night
and Thursday remains low at this time until there is more
confidence in storm track. Behind this low, a colder airmass will
spread across the Bering for Thursday night and Friday with
instability- driven showers likely across the Aleutian Chain,
Pribilof Islands, and southern AKPEN as mainland Southwest will
contend with wrap around moisture from the low that looks to be in
Cook Inlet or along the Kenai Peninsula early Friday morning.
Stay tuned for forecast updates as details on the exact track of
this low will hopefully become clearer with time.

&&


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

Only minor changes from previous discussion. Forecast confidence
remains generally low as the weekend starts and into early next
week. Generally expect stormy weather as a low impacts Southern
Alaska on Friday, followed by a brief break before the next storm
moves into the Bering Sea from the west.

Broad upper level troughing will be present over the Bering Sea
by the start of the long term forecast period. A robust shortwave
curving up from the North Pacific will spur the development of a
surface low near the Alaska Peninsula. However, model solutions
remain very divergent, which makes forecast details and potential
impacts difficult to pinpoint. Among the deterministic solutions,
low tracks range from the low curving up the Southwest Alaska
coastline, to the low moving onshore in Bristol Bay, to the low
curving up the Gulf coast towards Prince William Sound. Given the
strength of this low (minimum MSLP as low as 970-980 mb), gales
are possible, with sustained storm force winds likely. All told,
this will be a potentially impactful storm, and one to watch as
forecast confidence gradually improves.

As the aforementioned low gradually weakens and exits out of the
Southern Mainland, a ridge will move in, followed by the front
from a strong low that moves in by late Saturday. Winds to storm
force are possible with this front, impacting the Western and
Central Bering/Aleutians. As the front approaches the Mainland by
Monday and Tuesday, secondary lows developing along the front will
lead to stormy weather along the Bering Sea, though uncertainty
with low tracks will once again lead to difficulty pinpointing
exact details. Overall, a low-confidence long-term forecast.

KC/DD

&&

.AVIATION...

PANC...Generally, VFR conditions are expected. However, skies
will clear tonight, which may lead to MVFR to IFR conditions
with fog and stratus possibly developing in the Inlet.

&&

$$