Small Craft Advisory 978, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
453 AM AKST Thu Dec 8 2022

.ANALYSIS AND UPPER LEVELS...

An upper level wave and associated surface low is tracking
southward into the eastern Gulf. Light snow continues in the
Copper River Basin under weak cyclonic flow aloft. Meanwhile, cold
air advection along with tightening pressure gradients as the low
exits across the Gulf and high pressure builds in from the north
and west is promoting strong gusty gap winds through area mountain
ranges. This is also allowing widespread strong winds across the
Gulf waters. Some of the strongest winds are being reported
through coastal bays, including Resurrection Bay, Passage Canal,
and the Valdez Narrows and Arm. Quieter weather with northwesterly
flow prevails across Southwest Alaska under a ridge of high
pressure building from the eastern Bering Sea. Further west, a low
is bringing wind and precipitation along the Aleutian Chain.

&&

.MODEL DISCUSSION...

The latest operational model runs are in decent agreement with
the placement and intensity of synoptic scale features at both the
surface and in the upper levels. The aforementioned Aleutian low
will continue to track along the Chain before shifting south and
weakening over the North Pacific later today.

&&

.AVIATION...

PANC...VFR conditions and light winds will persist.

&&

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

Clouds will gradually clear across the western portion of
Southcentral today as the vertically stacked low over the Gulf
tracks toward Southeast Alaska. Surface temperatures have been
slow to drop thus far despite much colder air aloft. As skies
clear temperature falls will begin to accelerate. A short-wave
trough will dig southeastward across the Kenai Peninsula this
morning and into the northern Gulf this afternoon. This will
maintain cyclonic flow and areas of light snow across the Copper
River Basin. Also expect a weak low to form somewhere in the
vicinity of Cape Suckling, which could throw a few snow showers
onshore near Cordova this afternoon and evening.

Aside from drier and colder conditions settling over Southcentral
for the next few days, the big story will be persistent deep
northerly flow through Saturday morning. This will maintain strong
winds across much of the Gulf and Kodiak Island, along ridge tops
of area mountains, and through bays and passes. There will be
multiple fluctuations in the strength of winds as various upper
level short-waves and associated cold air advection pass through.
Most noteworthy, a series of weak upper level short-waves will
cross the Alaska Peninsula and western Gulf on the leading edge
of an amplifying ridge Thursday night/Friday, leading to an uptick
in winds for Shelikof Strait and Kodiak Island. As the upper ridge
approaches Southcentral Friday/Friday night, a series of short-
waves will drop from the Arctic southward across the eastern
mainland of Alaska. This will advect even colder air into
Southcentral and strengthen winds along the north Gulf coast and
Prince William Sound. This will be particularly favorable for
strong winds in Valdez and vicinity as well as through the Copper
River Delta. Winds will quickly diminish from west to east on
Saturday as the ridge moves overhead. Temperatures will steadily
fall each day, with the coldest temperatures likely Saturday
morning.

The upper level ridge will quickly flatten out Saturday/Saturday
night as a strong storm system drives over top of it up to the
Bering Strait. This will allow an associated frontal system to
progress eastward to Kodiak Island Saturday afternoon and into
Southcentral Saturday night. With such a cold air mass in place
out ahead of the front, precipitation will be all snow for
Southcentral with snow changing to rain for Kodiak Island.

&&

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

Cool, calm weather continues across Southwest Alaska through the
end of the week. The next frontal system moves towards the
Southwest coast Saturday morning. With it, comes increased winds
and snowfall. There is a chance for some blowing snow potential
along the immediate coast, spanning both the Kuskokwim Delta coast
and the Bristol Bay coast on Saturday morning. The bulk of the
precipitation will likely be snow, however, there is a bit of
warmer air that may increase temperatures along the immediate
coast above freezing. Thus, there is a chance for mixed
precipitation or rain Saturday afternoon for that area.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...

Agreement continues to improve amongst the models for the next
couple of systems set to track across the Bering Sea. The first of
which moves over the Central/Eastern Aleutians today. There is a
small area of gale force winds expected along the front, as well
as periods of rain/snow showers today. The next system pushes
across the Bering through Saturday morning. Anticipate widespread
gale force winds with periods of storm force gusts, as well as
widespread precipitation along the front.

&&

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

An active weather pattern will continue over the latter half of
the weekend into next week across Alaska. Models continue to
advertise a North Pacific low lifting into the Gulf of Alaska
Sunday into Monday while a broader trough lifts from the Northern
Bering into the Chukchi Sea. Colder temperatures are anticipated
over the Bering as northwesterly flow follows in the wake of the
departing low into the Chukchi Sea. Enhanced westerly flow into
the coast of Southwest Alaska is a possibility on Sunday with
potential storm force winds for a short period.

Meanwhile, an impressive plume of moisture is forecast to
accompany the North Pacific low as it pushes into the Gulf Coast
through Monday. Models are advertising impressive 24 hour QPF
amounts of 2 to 4 inches as the low tracks from near Kodiak, to
Prince William Sound and into Southeast Alaska. As temperatures
are expected to remain cold, this could produce some significant
snowfall for Southcentral. However, more run to run consistency in
model output would be ideal to increase confidence levels.
Regardless, operational models such as the GFS, is splashing
precipitation across all of southern Alaska Sunday night and
Monday morning with the highest amounts over the coastal regions.
Gap winds may also become a concern for parts of the Eastern
Aleutians and Alaska Peninsula on Monday and Tuesday with cold air
advection helping to spill enhanced drainage winds into the Gulf
of Alaska.

Attention then turns back to the Aleutians with the next upper
trough tracking just south of the Aleutian Chain Tuesday into
Wednesday. Some models want to close off this low south of the
Central Aleutians, effectively stopping its eastward progress
before diving it southward into the North Pacific. A threat for
rain and snow may exist ahead of the low with strong southerly
flow and warm air advection lifting into the Southern Bering
Tuesday into Wednesday of next week.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Gales 119-121 127-132 136-138 150 170 172-179 351 352
411-414. FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...MF
SOUTHCENTRAL ALASKA...SEB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KM
LONG TERM...BL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
932 AM AKST THU DEC 8 2022

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

0400 PM     SNOW             8 SSE ANCHORAGE         61.10N 149.82W
12/07/2022  M22.0 INCH       ANCHORAGE          AK   NWS EMPLOYEE

&&

BL

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1148 AM AKST THU DEC 8 2022

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

0957 AM     SNOW             10 SE EAGLE RIVER       61.26N 149.31W
12/07/2022  M14.8 INCH       ANCHORAGE          AK   NWS EMPLOYEE

            MODERATE TO OCCASIONALLY HEAVY SNOW OVER THE
            PAST HOUR.

&&

BL