Small Craft Advisory 976, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
503 AM AKDT Sat Nov 2 2024

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

A broad upper level trough encompasses the southern Mainland, but
the main weather feature for Southcentral over the weekend will be
a moderately strong surface low currently situated in the southern
Gulf. To the north of this feature, rain and upper elevation snow
continue over the Prince William Sound while the rest of the
region is now for the most part downsloped and away from upper
level forcing that could produce meaningful precipitation.
Through the day today, expect this rain to let up as the surface
low moves into the eastern Gulf.

For Sunday, a shortwave rounding the base of the longwave trough
will help lift remnants of the Gulf low into Southcentral while an
additional meso-low forms south of the Sound. As this feature
lifts north, cold air will wrap back in, allowing for a transition
from rain to snow as the feature lifts north through late Sunday
and into Monday morning. A broad one to two inches is expected to
fall for most areas, but there remains some uncertainty on timing.
This feature will quickly shift into Southeast Alaska on Monday
as ridging builds ahead of a broad and strong system moving into
the Bering. This storm will likely have widespread impacts on
Tuesday, so be sure to stay tuned to the forecast.

&&

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

Small craft gap winds will persist south of the Alaska Peninsula
and Eastern Aleutians today as a storm force low weakens and moves
into the Gulf of Alaska. A surface low in the Western Bering
remains stagnant through this weekend, producing a small area of
small craft winds across the Western/Central Aleutians. Colder air
continues to filter across Southwest Alaska today and Sunday,
keeping temperatures in the 20's to low 30's and overnight
temperatures dipping into the teens for inland areas. Snow is
expected across much of Bristol Bay and the Kuskokwim Delta,
except for areas from Iliamna south to King Salmon, who may warm
up enough to see some mixed precipitation or even periods of all
rain. Snow moves north in the lower Kuskokwim Valley by Sunday
morning. Highest snow amounts will be from Dillingham to Koliganek
with 2 to 5 inches expected, and elsewhere of up to 2 inches
possible.

The next round of active weather approaches late Sunday night
with an incoming storm force low out of the North Pacific,
remnants of typhoon Kong-Rey. There remains some light
discrepancies amongst the models regarding exact track. The GFS is
the furthest west solution, placing the low west of Nikolski late
Monday morning. The Canadian is the furthest east and slightly
slower, placing the low over Akutan Island Monday afternoon. All
three models, however, are showing a high chance for storm force
winds impacting the Central/Eastern Aleutians and southern Alaska
Peninsula by early next week. Warmer air accompanies the front,
leaving precipitation types over the Aleutians and Alaska
Peninsula as all rain Monday and Tuesday. Bristol Bay could see
temperatures pushing into the high 30's to low 40's on Tuesday,
with elsewhere across Southwest keeping to the mid-to-low 30's.

&&

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

Weather across Alaska continues an active pattern as a series of
strong lows and fronts work their way over the state through the
forecast period. A broad upper level low extends across the Bering
into Western Alaska, with the most active weather over Southern
Alaska. An ECMWF / GFS combination maintains good continuity in
the strengths and paths of the transitory systems. The first of
these lows is the remnants of the former tropical system Kong-Rey
crossing the Aleutians into Bristol Bay on Tuesday before
recurving over Southwest Alaska through Thursday. As the central
surface pressures remain around 950 mb, this system brings
widespread heavy rains from the Central Aleutians and Alaska
Peninsula into Southwest Alaska by Thursday. Gale force winds over
the Central and Eastern Bering begin to diminish late Tuesday,
with some coastal flooding possible through Wednesday. High end
gales remain over the Southern flank of the storm, affecting
Kodiak Island and the Southern end of the Kenai Peninsula, Barren
Island and Kamishak Bay before dropping off Wednesday. Storm focus
changes to Western Alaska after midweek, as winds diminish, but
rains continue to spread towards Nunivak Island through the week.
Heavier rains spread across Southcentral Alaska from the Eastern
slopes of the Alaska Range all the way to the Canadian border
through Friday. Beginning midweek, another well developed North
Pacific low and front slips Eastward just South of the Aleutians
before turning into the Western Gulf for Friday. This brings
another round of heavy rains and gusty winds along the AKPEN and
into Kodiak Island and Southcentral Alaska.

&&

.AVIATION...

PANC...VFR conditions and light northerly winds expected. There
is still a chance for IFR ceilings and visibilities this morning
as lower clouds and patches of fog linger around Anchorage Bowl.
However, observations near the terminal show that ceilings have
greatly improved overnight, lending confidence towards VFR
conditions.

&&