Small Craft Advisory 42, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
452 PM AKST Tue Jan 13 2026

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

The short term forecast in Southcentral starts off with continued
light snowfall from the Kenai Peninsula through Anchorage and the
Mat-Su Valley. This is being caused by a low moving up the Gulf.
As the low moves onshore near Yakutat Tuesday night/Wednesday
morning, gusty winds and heavy snowfall is expected in Thompson
Pass, bringing about periods of blowing snow. Due to the threat of
visibility reductions below 1 miles, a Winter Weather Advisory has
been issued for Thompson Pass from Wednesday morning to late
Wednesday evening for blowing snow. a front will lift into the
North Gulf behind the low, bringing another round of snowfall to
Southcentral including Anchorage and the Mat- Su Valley late
Wednesday morning. This snowfall is expected to taper off by the
evening hours of Wednesday.

Thursday is the start of the big event of the week. An atmospheric
river and a low will move up into Alaska. Much warmer air will
arrive with these features. The exact track and speed of the low
is incredibly uncertain with every day showing radically
different solutions. As a result, details of the event have been
difficult to pin down. What is known is that there will be a large
warm-up across Southcentral, with temperatures likely rising to
the positive 30s and even 40s. Another detail that is known is
that heavy precipitation will arrive due to the large plume of
moisture making its way directly into the Gulf Coast. It is likely
that the moisture profile will become saturated to the point that
downsloping will be overcome, allowing for high precipitation
chances just about everywhere. Before temperatures rise above
freezing it is likely that a period of snowfall will occur. This,
in combination with the stronger winds the event may trigger
blowing snow for a time. As temperatures rise, freezing rain is
possible as higher elevations will warm faster than the surface.
Freezing rain is most likely in the Kenai Peninsula. Anchorage is
much more unclear in precipitation type. Eventually, surface
temperatures may rise above freezing at the surface, allowing for
precipitation to become either a mix of rain and snow or just
rain. The threat does not end with this as rain falling onto
frozen surfaces could create slick conditions. Due to the threat
of blowing snow/freezing rain/rain on frozen surfaces, a Winter
Storm Watch has been issued for the Kenai Peninsula and the
Portage and Girdwood areas. Again, there is much uncertainty with
this event and the forecast will continue to evolve with many
changes likely as details become more clear.

-JAR

&&

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

Key Messages:

* The arrival of clouds over much of Southwest AK today has
  allowed temperatures and wind chills to moderate. While the
  coldest conditions have passed, Cold Weather Advisories remain
  in effect for the entire region through Wednesday morning.

* A Winter Weather Advisory remains in effect for the Aleutian
  chain from Adak to Atka for snow and blowing snow Wednesday
  morning through Thursday morning.

* A major pattern shift is on the way for Thursday into Friday.
  This will bring an atmospheric river with abundant moisture and
  warmer air up to Southwest AK. There is high uncertainty in the
  track of key weather features. However, it looks increasingly
  likely that Bristol Bay and the Kuskokwim Valley will see
  significant weather impacts, including heavy snow, blowing snow,
  and freezing rain.

Discussion:

A high amplitude pattern is in place with a blocking ridge over
far eastern Russia, an upper low over the Beaufort Sea with a
trough extending southwestward across the heart of the Bering Sea,
and a downstream ridge along the west coast of CONUS and British
Columbia. Short-waved embedded within the Bering trough are
digging southward, with Arctic air once again pouring southward
across Western AK and the Bering Sea. Gusty northerly winds and
low wind chills persist across all of Southwest AK. However,
short-waves headed northward up the west side of the North
American ridge have brought clouds and light snow to the northern
Alaska Peninsula (including Pilot Point, Naknek, King Salmon) and
northward to Iliamna and up along the western Alaska Range. The
snow and clouds (which have spread further west across SW AK) have
helped moderate both air temperatures and wind chill readings. As
a result, modified Cold Weather products to raise wind chills and
move up the end time. Winds will lighten up across SW AK tonight
through Wednesday as a major pattern change ensues.

A compact surface low has developed ahead of one of the digging
short-waves in the central Bering Sea. This low is on track to
impact the central Aleutians, including Adak and Atka beginning
Wednesday morning. Model spread is fairly large on the exact
track of this low and areas most likely to see the strongest winds
and heaviest snow as the low moves through Wednesday through
Wednesday night. Made some adjustments to the wind and snow
accumulation forecast based on latest model trends. Right now it
looks like Adak will see some of the strongest winds while Atka
will see some of the heaviest snow. While confidence is high in
periods of snow and blowing snow with low visibility, confidence
in where heaviest snow and strongest winds are located at any
given time is low.

The Bering trough will dig all the way south into the North
Pacific, with multiple short-waves phasing and consolidating into
a single trough Wednesday night. Meanwhile, a ridge will rapidly
amplify to the east from the Northeast Pacific to mainland Alaska.
The consolidated trough will then lift northward up the west side
of the ridge and bring impactful weather to southern AK Thursday
through Friday. Model spread in the track of the short-wave and
associated surface low is large. Deterministic models continue to
change from run-to-run while ensemble guidance is also shifting.
As a result, confidence is the details of the forecast are low.
Based on agreement in the overall large-scale pattern, there is a
good chance that Southwest AK is impacted with heavy snow, blowing
snow, and freezing rain. Stay tuned as we continue to monitor
this pattern change and hone in on the forecast for Southwest AK.

-SEB

&&

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

The long term forecast begins with an amplified pattern over much
of Alaska. A broad trough will be in place over the central
Bering on Friday with strong southerly flow downstream of the
trough, extending from the North Pacific up into Southcentral
Alaska. Potential impacts from this atmospheric river will entail
gusty winds into the northern Gulf coast and Prince William Sound,
widespread rain showers into the coast, heavy snow at higher
elevations, and a significant warm up in temperatures across all
of Southcentral. The amplified pattern begins to break down on
Saturday with a ridge of high pressure building over the eastern
Bering and Southwest Alaska. A deepening trough west of the
Aleutians will serve to reinforce downstream ridging through the
end of the long term period early next week.

Models continue to exhibit small differences with the overall
strength and track of the low Thursday into Friday, and there is
still potential for changes to the forecast over the next 48
hours. However, overall confidence is increasing that the
strongest winds will occur offshore of the Southcentral Coast from
Kayak Island into Prince William Sound. Gales with gusts to 50+
knots are currently forecast. If the low on Thursday takes a track
further north, the potential would increase for high winds
through the Eastern Turnagain Arm lower elevations. Currently, the
highest inland winds are forecast to remain over the mountains.

One last area of concern will be across the Central Aleutians
early on Friday. A vigorous area of low pressure is progged to
lift into the region with the potential for hurricane force gusts.
This low is followed up with a large frontal system into the
western Bering and Aleutians Sunday into Monday.

-BL

&&

.AVIATION...

PANC...Snow and MVFR conditions will persist into tonight. IFR
conditions, especially IFR visibilities, are possible within
pockets of heavier snow showers Wednesday morning. North to
northeast winds around 10 kts or less will persist through much of
the TAF period before turning turning southerly Wednesday morning
as light snow continues.

&&