Gale Warning 150, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
822 PM AKST Fri Feb 2 2024

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

Clear, cold, and dry conditions generally persist this afternoon
for the Southcentral mainland. A Wind Chill Advisory remains in
effect for Thompson Pass through noon on Saturday, where wind
chills as low as 50 below zero have been observed. A change in the
pattern is underway as a front tracks over Kodiak Island today,
bringing with it light snow and warmer temperatures. A surface low
will develop just off the southern coast of Kodiak Island this
evening before moving eastward into the Gulf tonight. Another
front will follow in tow, reaching Kodiak Island early Saturday
morning, the southern Kenai Peninsula later in the morning, and
then the rest of the peninsula by Saturday afternoon. A Winter
Weather Advisory for snow and blowing snow has been issued for the
Western Kenai Peninsula from late Saturday morning through Sunday
morning. Expect the highest total snow amounts (8-10") from
Soldotna south to Anchor Point, slightly lesser snow amounts
(5-7") from Kenai north, and the lowest snow amounts (3-4") near
Homer. Northeast winds gusting from 20 to 30 mph are expected to
combine with the low-density snow to produce blowing snow and
visibility as low as one half mile or less at times.

Snow will spread north to Anchorage Saturday late afternoon and
the rest of Southcentral through Saturday night. A Winter Weather
Advisory for snow and blowing snow is also in effect for Anchorage
from Saturday afternoon through noon Sunday as northerly winds
gusting from 10 to 15 mph are expected to transport the low-
density snow and reduce visibility to one half mile or less at
times. The highest gusts and snow amounts (up to 6") are expected
across west Anchorage, while lesser snow amounts are anticipated
across the eastern part of town. Thompson Pass is another location
that can expect to see several inches of snow and blowing snow.
Thus, a Winter Weather Advisory has been issued for Thompson Pass
starting Saturday night.

By later Sunday into Monday, the system dissipates along the
Southcentral coast and snow and wind briefly taper off. Come
Monday, however, another front reaches Kodiak Island and will
likely follow a similar track to the previous front. Expect more
widespread snow and elevated winds heading into the start of the
work week.

Temperature wise...values will continue to warm over the next
several days. By Monday, daytime high temperatures will generally
reach the mid to high 20s along the coast, the teens as you move
further inland, and single digits (with very few locations still
below zero) towards the northern portion of the forecast domain.

Fenrich

&&

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

Key Points:

* A series of storms moves in through Monday, leading to active
  weather and a gradual warming trend.

* A Winter Storm Warning has been issued for blizzard conditions
  for Nunivak Island, the Kuskokwim Delta coast, and portions of
  Bristol Bay from late tonight through early Sunday morning.
  Anticipating increased winds up to 35 mph with reductions in
  visibility to one quarter to one half mile at times.

* New snowfall accumulations up to 5" for the Kuskokwim
  Delta/Nunivak Island and up to 9" for Bristol Bay.

Discussion:

Active pattern on tap for southwest Alaska through the weekend so
let's dive into it. Kicking things off is the remnants of a
dissipating FROPA draped across SW AK, which is producing light
snowfall from Nunivak Island south to Pilot Point and wind gusts
up to 30-40mph.

The storm to watch will be one currently moving towards the
Bering Sea from the North Pacific. This broad, upper level low
with multiple embedded shortwaves will spawn multiple surface lows
as it moves through the Bering Sea this weekend. The first
surface low is currently pushing its front into the Western and
Central Aleutians this afternoon. The plume of moisture
associated with this front features precipitable water values of
0.75 inches and greater. As such, the front is expected to bring
plenty of precipitation as it sweeps across the Aleutian Islands
and Southwest Alaska. Areas along the Aleutian Chain may see
precipitation amounts as high as 0.5 to 1 inch with this front.

For Southwest Alaska, the approaching front will bring the
potential for moderate/heavy snow and blowing snow by tomorrow
morning. A Winter Storm Warning for blizzard conditions has been
issued for Nunivak Island, the Kuskokwim Delta coast and the
Bristol Bay Coast. Anticipating sub-zero temperatures to support
lower density snow that's easier to loft and transport. With the
"dry" snow, sustained winds up to 25mph, and gusts up to 35mph,
anticipating periods of significant visibility reductions down to
one-quarter mile along coastal portions of SW Alaska.

By Sunday morning, this second storm system follows the path of
the first and exits towards Kamchatka Peninsula. A third low then
moves towards the Central Aleutians from the North Pacific,
bringing yet another around of active weather. By Monday, the
continued southerly flow and warm air advection associated with
these three storms will bring maximum temperatures into the teens
and 20s for Southwest Alaska and into the 30s for the Alaska
Peninsula, Aleutian Islands, and Bering Sea.

-KC/NM

&&

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

A broad upper level low center over the Bering weakens as it
becomes a broad trough extending across the Alaska Peninsula
through the forecast period. Several shortwaves of moderate
amplitude slip along its southern periphery, supporting surface
features and periods of active weather through Friday. Models are
losing their consistency with the medium to large scale features
with the transient events through the week. Dry Arctic air is
expected to remain over most of Interior Alaska with outflow into
the Bering, driving gusty, but diminishing Easterly winds across
the Northern Bering. Shortwaves pushing surface lows and fronts
along the Aleutians and AKPEN bring gusty winds, especially
through channeled terrain, and locally heavy precipitation on its
Eastward tracks. New rounds of gusty winds and snow move into
Southwest Alaska through midweek. The front splits over the
Northern AKPEN, with the Southern portions heading across the Gulf
through Thursday. A North Pacific low and its front approaches
the Eastern Aleutians Thursday, with the front extending into the
Gulf of Alaska through Friday. Rain and snow mixed or rain will
spread over the coastal portions and Prince William Sound through
the end of the forecast. Inland areas remain under periods of
snow.

Kutz

&&

.AVIATION...

PANC...Fog forming over the Knik Arm streaming down into the
terminal continues to be the primary challenge for what otherwise
will favor calm and VFR conditions. Expect fluctuations ranging
from IFR to VFR to continue through at least this evening into
tonight until tonight as areas of fog and low stratus slosh in and
out of the terminal. There is potential for areas of fog and
intermittent IFR conditions to linger until Saturday afternoon as
mid to upper cloud cover finally moves in and as winds aloft turn
southerly to southwesterly.

&&