Gale Warning 294, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
433 AM AKDT Mon Mar 18 2024

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

Widespread snow from Cook Inlet north to the Susitna Valley and
mixed rain/snow across Prince William Sound continues this
morning as a surface low south of Seward drifts across the
northern Gulf. Snow over Cook Inlet is due to a mid-level trough
extending from the parent low as well as a weak shortwave lifting
northeast from the Alaska Peninsula. A general 1-3 inches of snow
is expected from Kenai north to Talkeetna through Monday morning
as the trough slowly continues northeast to the Copper River
Basin and weakens through the day today. Up to four inches is
possible over higher elevations and where upslope flow is
favorable - Anchorage Hillside, Skwentna, and the Parks Highway
north of Talkeetna - is also possible. The surface low over the
Gulf will also weaken today as it moves east and exits the region
by early Tuesday morning.

A ridge of high pressure will build in from the western Gulf to
the northern Gulf later on Monday and remain in place through
midweek. Generally quiet weather is expected with the ridge in
place; however weak waves moving along the northern periphery of
the ridge may bring occasional cloud cover to Southcentral.

The biggest forecast challenge in the short term will be the
extent of lingering low stratus and/or fog across Cook Inlet and
the Copper River Basin overnight Monday into Tuesday morning.
There is also the potential, if low clouds and fog do linger, for
pockets of freezing drizzle from Kenai to Anchorage and Talkeetna
Tuesday morning. Forecast confidence in this scenario is low;
however, there is support for this in the latest (00z and 06z)
forecast soundings.

&&

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

A strong front is currently situated over the central/eastern
Aleutians and will continue working its way northward through
Tuesday. Warmer air behind the front will allow for a large area
of widespread snow transitioning to rain or a rain/snow mix today.
Adak has already switched to rain around 3AM; Dutch Harbor is
still currently showing snow (as of 4AM) but should transition to
rain within the next few hours. Winds have ramped up overnight
along the Aleutians and southern Alaska Peninsula and are expected
to remain gusty through at least Tuesday morning. There is a
Blizzard Warning currently in effect for the Pribilof Islands
beginning early this morning and persisting into this afternoon.
Snow has started at Saint George (as of 3AM) and is quickly
approaching Saint Paul Island. Strongest winds will be later this
morning, with another burst of gale force winds pushing over the
Pribilofs early Tuesday morning. Temperatures are expected to rise
above freezing this afternoon, diminishing the threat of blowing
snow with the second round of gales move through.

As far as precipitation along the Southwest Mainland goes, most of
it will be confined to the Kuskokwim Delta coast and along
upslope regions of western Bristol Bay. A Blizzard Warning for the
Kuskokwim Delta coast has been issued and is in effect from 6PM
this evening to 7AM Tuesday. Temperatures will warm across
Southwest As well, through at a slower rate, with temperatures
rising above freezing on Tuesday. Winds along the Southwest coast
and the Alaska Peninsula will continue to be gusty through Tuesday
afternoon, well after precipitation has diminished.

&&

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

The long term forecast remains largely unchanged. The upper level
pattern will be highly amplified, featuring deep troughing over
the Bering Sea and Aleutians and a stout ridge across much of
Mainland Alaska and the Gulf. This large scale weather pattern
will favor warmer than average temperatures across Southern
Alaska.

While drier weather and lighter winds are expected for
Southcentral Alaska under the ridge, much more active weather will
be in store for the Bering Sea, Aleutian Islands, and Southwest
Alaska as several storms move through. The biggest challenge in
the long term will be honing in on the track and evolution of
these storms, which will then inform where the strongest winds
(likely to gale force or higher) and heaviest precipitation are
expected.

Beginning early Thursday morning, a complex low with
multiple centers will slide north across the Bering Sea.
Confidence is low with the location of the embedded low centers,
but models seem to be converging on stronger winds surging across
the Eastern Aleutians, Alaska Peninsula, and Southwest coastline
through Thursday. The next storm arrives Friday from the North
Pacific, with decent agreement that surface pressure will drop to
about 970-980 mb. While the low looks to occlude as it moves into
the Bering Sea, parts of the Aleutian Islands and Bering Sea could
still see gales along the front, as well as moderate to heavy
precipitation.

Forecast confidence decreases by late Friday, with the question of
whether the aforementioned low is strong enough to completely
displace the ridge extending across much of Alaska and the Gulf.
If the low is strong enough to displace the ridge, its front will
bring stronger winds and widespread precipitation to Southcentral.
If the ridge holds strong, the front will remain west of Kodiak
and allow drier and calmer weather to persist through the weekend.

- KC

&&

.AVIATION...

PANC...VFR conditions this afternoon will gradually deteriorate
back to MVFR by late this evening and into the overnight hours as
snow begins to move back into the area. Periods of light snow
will peak Early Monday morning with a total snow accumulation of 1
to 2 inches. Expect VFR ceilings and drier conditions Monday
afternoon through the remainder of the week.

&&

Preliminary Local Storm Report
National Weather Service Anchorage AK
957 AM AKDT Mon Mar 18 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0957 AM     Snow             2 NE Sterling           60.54N 150.75W
03/18/2024  E3.5 inch        Kenai Peninsula    AK   Official NWS Obs

&&