Gale Warning 194, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
513 PM AKST Sun Feb 18 2024

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

An easterly wave of low pressure moved across Southcentral on
Sunday with numerous rain showers across Prince William Sound and
snow for Valdez up into Glennallen. Snow has begun to changeover
to rain across Valdez as temperatures have warmed into the upper
30s. Temperatures will continue to warm through Tuesday as
southeasterly flow becomes increasingly prominent across
Southcentral.

As has been advertised, gusty conditions are forecast to develop
on Monday as a North Pacific low located over the Gulf of Alaska
lifts into the ALCAN border and dissipates while a shortwave
tracks into Southwest Alaska. The resulting pressure gradient will
promote winds gusting from 40 to 60 mph across the higher
elevations of Southcentral, including the Anchorage Hillside. A
more vigorous trough then moves into Southwest Alaska on Tuesday
morning further tightening the pressure gradient already in place
across Southcentral. This will see gusts climb to above 60 mph and
potential up to as high as 75 mph. However, all is to taken with
a small grain of salt, as a fair bit of uncertainty muddies the
overall forecast. This system looks to be somewhat weaker than
last week's system which prompted a high wind warning. Regardless,
the strongest winds should occur on Tuesday morning with winds
then decreasing during the afternoon hours.

Finally, a notable change from yesterday and even this morning's
forecast is the return of cooler temperatures into Southcentral
earlier than previously forecast. Where it originally appeared
Southcentral would see warmer temperatures lingering into Thursday
before cooling again Thursday night, forecast models have now
shifted/trended to a cooler solution. As quickly as Southcentral
experiences the warm up early next week, a colder airmass will
overspread the region from the west, gradually trending
temperatures below freezing through the rest of the week.

-BL

&&

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

The active and unsettled weather will continue over mainland
Southwest Alaska through the short-term period. Two systems will
lift northward over the mainland from Bristol Bay and through the
Kuskokwim Delta and Valley Monday and Tuesday. Each system will
feature snow to start before warmer air works in and a transition
to rain or rain/snow mix occurs. A transition back to snow will
also occur as cold air works in on the backside of each system.
Light snow is possible for the Kuskokwim Delta with the system on
Monday with light accumulation. Moderate snow is possible for
portions of the northern Bristol Bay coast as well as for the
Lower Kuskokwim Valley. Special Weather Statements have been
issued to address concerns for each system for Bristol Bay,
Kuskokwim Delta, and the Lower Kuskokwim Valley. Another front
approaches coastal Southwest by Wednesday morning bringing another
chance for snow and blowing snow to coast. This front moves inland
through Wednesday spreading snow inland as it does so.

Further to the west, the parade of lows continues across the
Bering Sea. The occluded front of a central Bering low continues
moving eastward this evening over the eastern Aleutians and Alaska
Peninsula spreading precipitation eastward. The actual low itself
will continue to meander in the south-central Bering Sea through
Tuesday morning before it dissipates. A Kamchatka low sends its
front eastward towards the western Bering and western Aleutian
Chain Tuesday with another round of high winds possible for
Shemya. This front sweeps eastward across the rest of the Aleutian
Chain and makes it to the Pribilof Islands by Tuesday night. Steady
snow looks likely for the Pribilofs Tuesday night before becoming
more showery in nature for Wednesday. There will be warmer air to
the south along the Aleutian Chain where precipitation starts as
snow, goes over to rain, and transitions to snow behind the front
as colder air works in from the west.

-DAN

&&

.LONG TERM FORECAST (Days 4 through 7: Thursday through Sunday)...

The long duration upper level Bering low weakens and begins an
Easterly track through Interior Alaska, and forming a weak center
over the Gulf by the end of the forecast period. Consistent
forecast model positions, strengths and tracks will hold through
the weekend. Tightest gradients remain along the Southern
periphery, providing the axis of movement for the transient
systems supported by short waves along the Aleutians and across
Southern Alaska. Widespread gale force winds with storm force
gusts spread along the Aleutians before diminishing. Gusty winds
remain an issue across the Bering into the Gulf of Alaska through
Sunday. These transient fronts and troughs bring locally heavy
precipitation across the Aleutians, AKPEN and Southwest Alaska.
Mostly rain on the Pacific side, mixed rain and snow or all snow
on the Bering side through Friday. Colder temperatures for the
weekend expands the areas for snow through Sunday. After a
shortwave ridge moves over the Bering, another upper level low
moves out of the Russian Far East.

Longer term and locally heavy precipitation continues along the
AKPEN coast into Cook Inlet and over Kodiak Island, and expands
along the Southern Coast to the Canadian border through late
Friday, tapering off slowly afterwards. Onshore flow will be
deepest through Prince William Sound and Copper River Valley. Rain
dominates the coastal areas, with lesser amounts over higher
elevation inland. Mixed rain and snow at lower elevations across
Southcentral Alaska progressing to all snow further inland. The
above average temperatures across Southern Alaska linger before
making the turn colder through the weekend.

Kutz

&&

.AVIATION...

PANC...VFR conditions and light northerly winds will persist
through Monday evening. MVFR ceilings may briefly be realized
early Sunday night with scattered showers in the area. A light to
moderate Turnagain Arm wind is expected to move over the terminal
near the end of the TAF period as a low moves into western Alaska.

&&

SPECIAL WEATHER STATEMENT
National Weather Service ANCHORAGE AK
330 AM AKST Mon Feb 19 2024

AKZ152-155-161-200130-
Lower Kuskokwim Valley-Kuskokwim Delta-Bristol Bay-
Including the cities of Aniak, Sleetmute, Bethel, Nunivak Island,
King Salmon, Dillingham, Naknek, and Pilot Point
330 AM AKST Mon Feb 19 2024

...A SERIES OF STORMS TO BRING SNOW AND RAIN/SNOW MIX MONDAY AND
TUESDAY...

A low is pushing into Bristol Bay early this morning. Locations
of inland Bristol Bay will experience rain/snow mix while coastal
locations will remain mostly snow. Areas along the northern coast
of Bristol Bay can expect 2 to 5 inches of snow with localized
higher amounts. Inland locations, such as Koliganek and New
Stuyahok can expect 1 to 3 inches of snow with this first system.

The second system is expected to arrive later this evening and
last into Tuesday evening. This system is expected to bring warmer
air with it and help areas along the coast transition to rain for
a time Tuesday morning. Inland locations will remain warm enough
for mostly rain. Cold air will be wrapped back into the system
Tuesday mid-morning which will allow for coastal areas to turn
back to snow then. There is still some uncertainty on exactly
where the best banding and heavier precipitation will set up with
this system, especially during the day Tuesday. Expect higher
snowfall totals on the coast with lower totals inland due to the
warmer air.