Brisk Wind Advisory 27, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
420 PM AKST Sun Feb 25 2024

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

With mainly clear skies and light winds, areas of patchy fog are
possible in Anchorage and the Mat-Su Valley tonight. As the gusty
northerly gap winds also continue to diminish tonight, a weak
ridge will build ahead of a robust upper level low over southwest
Alaska. The associated parent low in Bristol Bay will push its
front over Kodiak Island into the western Gulf tonight into
Monday. With warm air advection along the front, precipitation
will likely change from snow to rain quickly for much of southern
Kodiak Island. For Kodiak City, a period of snow and gusty
easterly winds are likely Monday morning before temperatures climb
into the lower to mid 30s, allowing for a rain/snow mix and
likely changeover to all rain. Around an inch of snow is possible
for Kodiak City before a changeover to rain.

Models remain in good agreement on a triple point low developing
near Kodiak and the Barren Islands Monday afternoon, but continue
to diverge in its track thereafter. The exact track of this low
and its associated front will likely determine the inland extend
of snow along the Southcentral coast through Tuesday afternoon.
The position, strength, and track of the low will also determine
precipitation type and potential for blowing snow in northern
Kodiak for late Monday into early Tuesday morning and the
potential for snow and blowing for Homer and along the Sterling
Highway south of Kenai. The current forecast package is leaning
away from the southerly GFS track and more towards a model blend
of the other relatively north solutions in regards to low track
and impacts. Regardless, areas of moderate to locally heavy snow
are expected to make a return to much of the immediate
Southcentral coast Monday afternoon through early Tuesday. A
Winter Weather Advisory is in effect for Portage, Whittier, and
Turnagain Pass from Monday afternoon through Tuesday morning where
gusty winds will create areas of blowing snow and reduced
visibilities. Gusty winds are also expected to return to the Mat
Valley Monday morning into Tuesday afternoon as the flow turns
northeasterly as the triple point low develops.

Northerly gap winds along the coast along with a reinforcing shot
of colder air will return to Southcentral late Tuesday through
the end of the forecast period as this system moves southeast and
exits the region.

-ME/TM

&&

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

A Bering Sea low will continue to deepen while traversing across
the Pribilof Islands later tonight and inland of Bristol Bay by
tomorrow evening. An occluded front extends from the low currently
240 nm west of Saint Paul, southeastward across the Eastern
Aleutians. Gusty conditions have been ongoing across the Central
Aleutians and the Pribilof Islands since this morning with
southwesterly winds gusting to 30+ knots for the Central Aleutians
and easterly winds gusting to 30+ knots through much of the day
for the Pribilof Islands. More recently, gusts to 37 knots have
been observed at Saint Paul with the combination of winds and snow
bringing visibility down to one half mile. Winds will remain
elevated the next couple of hours before steadily decreasing
through the overnight hours tonight.

The same low and front will spread eastward into Monday bringing
a round of gusty winds, snow and blowing snow to Southwest Alaska
beginning later this evening. Winter Weather Advisories remain in
effect for all three Southwest Alaska zones, including the
Kuskokwim Delta, Lower Kuskokwim Valley, and Bristol Bay. Snow and
blowing snow will bring visibility down to one half mile to the
Greater Bristol Bay area along with snow totals of 5 to 10
inches, especially for locations from Dillingham, west. Elevated
northeasterly winds gusting to as high as 45 mph will create
blowing snow and reduced visibility for the Kuskokwim Delta as
well. Meanwhile, the Lower Kuskokwim Valley is forecast to receive
snowfall amounts ranging from 4 to 8 inches with the highest
amounts near Sleetmute, though winds will be milder over the Lower
Kuskokwim Valley. These conditions will be prevalent through much
of Monday before gradually easing over the second half of the
day.

Not to be left out, winds into Unalaska, and Cold Bay as well,
are expected to be quite strong tomorrow afternoon. Gusts could
approach 70 mph through Cold Bay closer to noon, with winds
peaking across Unalaska a few hours later. Associated westerly
winds on the south and backside of the Bering Sea low Monday will
result in building seas of 20+ feet, with elevated seas
eventually spreading into the Pacific side of the AKPEN Monday
afternoon and Monday night. As the low moves inland of Bristol Bay
late Monday a triple point low is forecast to deepen over the
Gulf of Alaska. Overall surface flow across the Bering, Aleutians
and Southwest Alaska will become predominantly north or northwest
on Tuesday. The highest winds will be confined to the southern
Bering where gales should span the Eastern Aleutians and Alaska
Peninsula.

-BL

&&

.LONG TERM FORECAST (Days 4 through 7)...

The long term forecast remains unsettled with an mature low in
the Gulf Of Alaska and a Pacific low that will begin to moving
into the western Bering. By 12z Thursday, there is already some
significant divergence with the placement and the intensity of
those 2 surfaces lows. The divergence rapidly amplifies through
the forecast period. Generally expect wet and windy (gale to storm
force winds) weather across the Aleutian chain. High pressure
will build over the interior of Alaska. Strong gap flow winds most
likely will develop over portions of Southcentral. Arctic air
will filter its way into Southwest Alaska and South Central
Alaska. Portions of Southwest Alaska and the Copper River Basin
will easily reach -20F.

&&

.AVIATION...

PANC...VFR with a generally light northerly wind is expected to
prevail through the TAF period. The one big caveat is if fog
manages to redevelop across the Cook Inlet and Anchorage
overnight. Confidence in this happening is quite low, so have
only included VCFG in outgoing TAF package at this time.

-Brown

&&