Gale Warning 187, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
417 AM AKST Thu Feb 15 2024

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

The strong blocking ridge remains centered over the southern
Yukon and extends across most of the Gulf of Alaska and
Southcentral. This is producing mostly clear skies across
Southcentral with just a little cirrus riding over the periphery
of the ridge on the Cook Inlet area. A surface low located well
south of Kodiak Island, along with a warm occlusion extending
northward to Bristol Bay, is causing pressure gradient driven east
to southeast winds across the western Gulf of Alaska again today.
However, with winds diminished across Southcentral, there is not
the adiabatic compression occurring that created the warming that
we saw early Wednesday and through the day in some areas.
Temperatures aloft are still warm due to the inversion over the
region due to that warm ridge. This inversion is not nearly as
strong as yesterday as seen comparing the 00Z (Wednesday
afternoon) Anchorage sounding and the 12Z one from early this
morning. the 00Z sounding showed a peak temperature of 51F at 900
ft elevation, where the maximum temperatures from early this
morning are from 40F to 44F from about 1000 to 2000 ft elevation.

Kodiak Island remains along the periphery of moisture from the
Pacific storm. Kodiak City will be in and out of rain today while
steady rain will persist along the south end of Kodiak Island.

The upper level ridge will slowly shift eastward across western
Canada over the next few days. For Southcentral, there will be
very little change in weather through Friday with continued sunny
skies, windy conditions in some areas, and above normal
temperatures. Kodiak Island will see periods of rain, locally
heavy at times, as the ridge retreats and a series of lows and
upper level short- waves track northward out of the Pacific.

A change in weather will become more evident on Saturday as the
retreating ridge will bring clouds and precipitation northward
across the Gulf on Saturday. There remain some differences in
model guidance, but expect precipitation to reach the eastern
Kenai Peninsula and Gulf coast sometime on Saturday. Snow levels
will start out near 1000 feet and rise through the weekend, so
expect all rain at sea level as precipitation arrives. With
continued southeasterly low level flow, inland areas will remain
downsloped and mostly dry.

&&

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

A highly amplified pattern, with a deep longwave trough extending
across the Bering Sea into the North Pacific and a dome of high
pressure over the Yukon. On satellite imagery there is a fetch of
modified tropical moisture going over the Alaska Peninsula into
mainland Southwest Alaska this morning. There is plenty of cold
air in place and additional snow accumulations are expected. The
models ping into additional plume of moisture with origins from
the Central Pacific moving across the AKPEN into the weekend.
This set up looks to be warmer than the previous ones, so rain
may begin to mix into Bristol Bay. All the while, a Pacific low
lifts northward over the western Aleutians bringing snow and gusty
winds through Thursday and and will pivot northward. A second
Pacific low of 957 mb to 959 mb will move into the region on
Friday. There is still some uncertainty on the exact track, with
some uncertainty in potential high winds across the western
Aleutians on the south side of the low for Saturday.

&&

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

The upper level Canadian ridge extending over Mainland Alaska
briefly regains its amplitude before edging to the East through
Wednesday. A weak upper level low in the Gulf of Alaska drifts to
the Southeast through Monday, while the Bering low loops around
the Central Bering. Several significant shortwaves rotate around
this low through the end of the forecast period. Forecast
confidence is overall good, however it briefly becomes chaotically
uncertain locally as the shortwaves move along the Southern
portions. One shortwave over the Western Aleutians and Bering
brings areas of gale force winds for Sunday, diminishing.
Afterward, it helps develop a weak closed center South of the
Eastern Aleutians Tuesday that moves into the North Pacific by
Wednesday. Precipitation along the Aleutians and Alaska Peninsula
starts as snow and becomes mixed rain and snow on the Bering side
and all rain along the Pacific side through Wednesday. Another
well developed low approaches the Western Aleutians for Wednesday,
increasing winds and precipitation in the West.

The Bering shortwaves batter the Western side of the Mainland
ridge as the ridge begins its Eastward move. Surface wind flow
will boost moisture all along the Southern Coasts from the bottom
of the Alaska Peninsula and Kodiak Island into Cook Inlet, and
from the bottom of the Kenai Peninsula to the Canadian Border.
Coastal locations will see rain with the higher amounts from
Prince William Sound East as somewhat warmer than normal
temperatures continue to pump into the Interior through the
forecast period.

Kutz

&&

.AVIATION...

PANC...VFR conditions and light northerly winds will persist
through the TAF period. Light winds coupled with winds coming out
of Turnagain Arm will maintain the possibility of LLWS this
morning. LLWS should become less of a concern over the terminal by
late this afternoon/early evening.

&&

Preliminary Local Storm Report
National Weather Service Anchorage AK
1116 AM AKST Thu Feb 15 2024

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

1100 AM     Snow             Chignik                 56.29N 158.40W
02/15/2024  E24.0 inch       Lake and Peninsula AK   Local Official

            Chignik City Office estimated at least two
            feet of snow fell since the early morning
            hours of Feb 14. 9 inches of snow measured
            through 2:30 pm Feb 14. Estimated one foot
            through the day, with another foot
            overnight.

&&

Preliminary Local Storm Report
National Weather Service Anchorage AK
122 PM AKST Thu Feb 15 2024

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

0100 PM     Snow             Port Heiden             56.94N 158.63W
02/15/2024  E6.5 inch        Lake and Peninsula AK   Local Official

            Port Heiden City Office estimated 6 to 7
            inches of snow since yesterday. Storm total.

0115 PM     Snow             Sand Point              55.34N 160.49W
02/15/2024  E3.0 inch        Aleutians East     AK   Broadcast Media

            Estimated 3 inches of snow since yesterday.
            Significant snow drifts.

&&

Preliminary Local Storm Report
National Weather Service Anchorage AK
155 PM AKST Thu Feb 15 2024

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

0130 PM     Snow             Dillingham              59.04N 158.46W
02/15/2024  E12.0 inch       Dillingham         AK   Law Enforcement

            Dillingham Police estimated at least a foot
            of snow fell since it began yesterday
            morning (Feb 14). Overnight, snow changed
            over to rain. Storm total.

0145 PM     Snow             Togiak                  59.06N 160.38W
02/15/2024  E24.0 inch       Dillingham         AK   Local Official

            Togiak City Office estimated two feet of
            snow since yesterday. Storm total.

&&