Small Craft Advisory 862, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
453 PM AKDT Sat Sep 28 2024

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

Key Messages:

- Unsettled weather for areas along the western Gulf coast this
  weekend with periods of rain and/or showers.

- A storm force low moves into the Gulf of Alaska offshore waters
  Monday, bringing Storm force winds with potential for Hurricane
  Force wind gusts and wave heights of 30 feet or higher Monday
  night into Tuesday.

- Models are coming into better agreement with the track of
  Monday's low, which is trending further south and east. Thus,
  the strongest winds and highest waves will remain well offshore,
  with most coastal areas maxing out at 25 to 40 kt winds and 8 to
  15 ft seas.

Discussion:

Much of Southcentral enjoyed another day of cloudy but dry conditions
on Saturday as weak high pressure remains over the region. Afternoon
satellite imagery shows areas of clearing across the Copper River
Basin with temperatures ranging from the 40s to lower 50s. Further
south, a near-stationary front extends southeastward from Kodiak
Island into the North Pacific. A recent ASCAT pass revealed a
narrow axis of southeasterly Small Craft Advisory level winds
along the front, with additional Small Craft winds interspersed
across the Barren Islands. The front is forecast to gradually
dissipate through tonight.

For tomorrow, a trough moves into the western Gulf, which should
keep areas of scattered showers in the forecast from Kodiak to
Prince William Sound. The bigger story remains the upcoming low
into the Gulf on Monday. Models have come into much better
agreement with the track of the low, which has trended further
south and east. This is good news for Southcentral's coastal
regions, which should be spared the strongest winds. Instead,
storm force winds and potential hurricane force gusts are expected
to remain across the offshore zones. Significant seas will still
have the potential to build to above 30 feet Monday into Tuesday.
The low departs into Southeast Alaska Tuesday afternoon with
conditions across the Gulf steadily improving.

Ending the discussion on a positive note, the more southerly
track of the low will result in offshore flow across Southcentral.
This will lead to dry conditions for the first half of the week
along with a good amount of sunshine. Temperatures will be right
around or slightly below normals for this time of year.

- BL

&&

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

An elongating, negatively-tilted trough continues to slowly
progress eastward over Southwest Alaska, with a band of steady
rain associated with a front oriented across Bristol Bay into
the Kuskokwim Valley near Aniak. The front pushes further inland
tonight, bringing rain showers to the Middle Kuskokwim Valley
where rain chances will continue into Sunday. Sunday night, the
front begins to fracture and precipitation will trend lighter and
more showery.

Out over the Bering Sea, a gale force low continues to track
southward across the Pribilof Islands today, bringing steady
rainfall today and gusty winds through tonight. Across the
Bering/Aleutians, generally expect isolated to scattered rain
showers through the weekend, punctuated by the low dropping south
across the Bering Sea. The low weakens and tracks into the eastern
Bering and along the Alaska Peninsula for Sunday as winds fall
below gale force and precipitation becomes showery yet again.

Heading into next week, a large but weaker low tracks into the
western Bering Sea on Monday, bringing southerly gale force winds
and a band of rainfall along a front that looks to sweep to the
eastern Aleutians by Tuesday morning.

-ME/Quesada

&&

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

The Alaska Weather map continues with a progressive pattern into
the weekend. An upper level low center South of the Alaska
Peninsula weakens as it drifts across the Gulf of Alaska towards
Queen Victoria Island dissipating by Friday. Locally moderate rain
and gusty winds accompany this surface low over the AKPEN and
Kodiak Island, diminishing from North to South as the low moves
East to Southeast. Over the Canadian Provinces, a blocking ridge
sets up through the week. ECMWF and GFS have handling the larger
scale features well, but uncertainty increases with local weather.
A strongly developing low exiting the Russian Far East becomes a
major weather producer in the Western Bering Thursday. Periods of
heavy rain and gusty winds increasing to gale force extend over
the Western Aleutians and Bering for Thursday. Friday brings areas
of heavy rain and more gales spreading into the Central and
Eastern Aleutians and Bering, with areas of storm force gusts
swinging into the Western Bering behind the low. Heavy rains moves
over Southwest Alaska through Saturday. Areal wind coverage
decreases somewhat, with higher end gales and local storm force
lingering over the Western and Central Aleutians and Bering into
the weekend.

&&

.AVIATION...

PANC...VFR conditions are expected through the period. A weak
Turnagain jet will be in place this afternoon/evening and again
Sunday afternoon/evening. However, it will remain over the
northern Inlet. The terminal may see a short duration of
southeasterly winds, but expect them to remain less than 10 kts.

&&