Gale Warning 773, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
548 AM AKST Sat Dec 30 2023

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

Fog has improved overnight for the Anchorage area overall. There
is still some lingering fog though around the area, but it is
becoming more patchy and should continue to improve as the upper
level low begins to shift north. Winds are still quite gusty this
morning through the gaps along the Gulf coast. It will take
sometime for the cold air to funnel through as flow begins to
shift southerly with an active pattern returning to Southcentral
Alaska. Low pressure pushing up the SE Panhandle this morning will
bring light precipitation to McCarthy and the Wrangell Mountains
this morning.

Flow will gradually shift southerly throughout the day as a
transient ridge moves through and a trough following behind lifts
through Kodiak into the Gulf through Sunday morning. Models have
continued to trend a little slower with the progression of the
pattern shift, but overall the expectation is on track. Moist
southerly flow will bring increased precipitation chances to
Kodiak Island by this afternoon, spreading to the Kenai Peninsula
Gulf Coast this afternoon into tonight and along the rest of the
Gulf Coast midnight through Sunday. Precipitation is expected to
begin as snow and gradually transition to rain for Saturday night
in Kodiak. A second, more energetic low will move in behind the
trough through Kodiak Sunday. The position of this low has been
more challenging and will play a factor in where precipitation
will ultimately set up from Kodiak and the western Gulf and to the
Kenai Peninsula and Cook Inlet. The Gulf Coast is certain to get
plenty of precipitation.

As the low moves toward the Kenai Peninsula Sunday, a band of
snow could develop along Cook Inlet affecting Kenai up to the
Susitna Valley. Snowfall cannot be ruled out for Anchorage either.
For now though, not anticipating widespread snowfall for
Anchorage, with the best chances expected along the Alaska Gulf
coast as easterly downsloping winds should keep areas further
inland dry. Expect snow to linger for higher elevations though as
far inland as the Alaska Range. While snow will linger for the
northwestern Gulf coast, most areas across Southcentral will have
snow potential ease a bit with a passing ridge Sunday night. Then
for Monday morning, a repeat returns with yet another trough
moving along the same path as the previous, reaching Kodiak early
and spreading north in the afternoon.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3:
Today through Monday night)...

A very slow moving front associated with a large low stalled out
over the Bering Sea is now draped between Bristol Bay and the
Kuskokwim Delta Coast this morning. Farther inland, cold
temperatures as low as -20 to -30 are holding in place this
morning where an upper level ridge is retreating north farther
into the western interior. Steady light snow is now pushing into
much of the coastal portions of the Kuskokwim Delta along the
front. More light snow is showing up on the King Salmon radar as
of this writing, and is likely to reach the northern Bristol Bay
coast over the next few hours. The front will lose most of its
definition as it moves farther inland through tonight, giving way
to scattered snow showers that will spread across Southwest from
south to north.

By early Sunday, a very negatively-tilted shortwave trough will
lift north from the the AKPen swiftly across Bristol Bay and then
up into the Lower Kuskokwim Valley. This is looking increasingly
likely to bring a quick-hitting round of snow to parts of this
corridor, mainly close to the Alaska Range, including near
Sleetmute and Iliamna. Later on Sunday, a much stronger system
will come into the picture, as a strong North Pacific low runs up
against a strong upper ridge building over the Gulf and into the
southern Mainland. This will set up a very strong northeast
southwest pressure gradient as the low slowly approaches the
southern Alaska Peninsula through Monday. Strong, gusty east winds
will steadily develop late on Sunday and persist well into Monday,
particularly along the Alaska Peninsula and up across much of
Bristol Bay. This progression of this low has slowed down
compared to earlier expectations, and the low is looking more
likely to weaken quickly as it finally reaches the Alaska
Peninsula late on Monday night. Even so, widespread wind gusts
between 35 and 50 mph are still expected to develop late on Sunday
across all but the Lower Kuskokwim Valley starting Sunday
afternoon and lasting well into Monday night. Any precipitation
with this system will remain light and intermittent, with warming
temperatures likely to change any snow over to rain for much of
Bristol Bay by Monday.

-AS

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3:
Today through Monday night)...

An active pattern is set to continue with multiple strong low
pressure systems expected to affect parts of the Bering Sea region
in the coming days. This morning, a stacked and weakening low
continues to spin in place over the western Bering Sea as a sea of
snow and rain showers continues to rotate around it into much of
the Aleutian Chain and Pribilofs at times. This low will continue
to meander nearly aimlessly as it slowly fills through Sunday,
but will retain enough strength to keep prolonged westerly gales
in place over the western Aleutians until Sunday afternoon. Late
on Sunday, a North Pacific low will lift slowly north and closer
to the AKPen as it runs into a strong ridge developing to its
north. This will help support a strong wind field to the north of
the center, and sustained gales will develop out towards the
easternmost parts of the Bering Sea and continue through Monday as
the low then quickly weakens before it crosses the Alaska
Peninsula. At the same time, another potent low will lift east-
northeast into the central to eastern Aleutian Chain, effectively
absorbing the remnants of the low crossing into the eastern Bering
by Monday night. Uncertainty for the exact track of this third
system is still quite high at this time, but continued strong
winds in gale to storm force range are likely to impact the
central and eastern parts of the Aleutians as this system moves in
from Monday to Monday night.

-AS

&&

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

Continued unsettled weather into the New Year for most of
Southern Alaska. Forecast models begin well, but diverge in
strengths and tracks of individual systems through the end of the
week. The longwave trough that extends from the Russian Far East
through Bristol Bay into the Gulf of Alaska will move to the North
and undergo some reorientation as several significant shortwaves
work around the center through the forecast period. With well
developed surface lows and frontal systems moving across the
region, widespread precipitation and gusty winds will affect the
Aleutians and Alaska Peninsula into Southwest Alaska through
Friday. Snow prevails across the Northern portions, while mixed
rain and snow or rain push over the Aleutians and AKPEN into
Southwest Alaska through the period. High end gale force winds
with local areas of storm force gusts spreads across the Aleutians
and Bering into the AKPEN and Southwest Alaska up to Nunivak
Island. A significant shortwave repeats the process over the
Central Aleutians for Wednesday and Thursday.

The active weather continues its Eastward track, as strong
surface lows bring heavy rains to parts of Alaska Peninsula and
Kodiak Island starting New Year's Day, and spreading to the
Eastern Kenai Peninsula and Southcentral coasts through midweek.
Gale force gap winds spread along the AKPEN, across Kodiak Island
and through the Barren Islands and Kamishak Bay, diminishing late
Wednesday.

Kutz

&&

.AVIATION...

PANC...Mostly similar conditions through early this morning as we
have seen over the past couple of days. Low stratus and/or fog is
likely over the airport and should lift through late morning/early
afternoon. Winds will be overall light and northerly. There is a
chance for a quick shot of snow later tonight with cloud ceilings
dropping below 5000'. Winds will remain northerly but pick up to
around 10 knots early (~16Z) Sunday morning.

KM

&&