Gale Warning 758, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
424 PM AKDT Sat Nov 2 2024

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

An area of low pressure over the Gulf continues to weaken as it
approaches the southeast coast of Alaska this evening. Much of the
Gulf remains under a thick blanket of clouds with small craft
easterly winds and areas of scattered showers stretching from
Yakutat to the Kenai Peninsula. Inland of the coast, generally
"pleasant" conditions are ongoing with drier weather noted across
the region. Daytime temperatures for all of Southcentral,
excluding the Copper River Basin, have warmed to above freezing
with widespread upper 30s and even some low to mid 40s down
through the Kenai Peninsula and Prince William Sound.

Looking to Sunday, and beyond. the weakening area of low pressure
over the Gulf is forecast to become absorbed by a pair of
troughs, one lifting northward across the Gulf, and a second
tracking eastward through Southwest Alaska. What this means for
Southcentral is continued rain for the Gulf coast and Prince
William Sound areas while potential light snow moves across the
Western Kenai Peninsula and Mat-Su Valleys Sunday into Sunday
night. The warmer temperatures will negate any accumulations for
areas that do see snow.

Southcentral will remain in an active pattern into early next
week as the remnants of Typhoon Kong-Rey, now extratropical, move
into the Bering on Monday. Ahead of the sub 960 mb low, a storm
force front is progged to lift across Kodiak Island Monday night
and into Southcentral by Midday Tuesday. This front will bring
widespread impacts to the region, including storm force winds,
widespread precipitation, and the potential for snow and blowing
snow across the Eastern Turnagain Arm and Portage area. Much of
the forecast depends on the development of a triple point low
along the front, which will determine when and where the
strongest winds occur, as well as the heaviest areas of
precipitation. The finer details will continue to be ironed out
over the next couple of days. Keep an eye on weather.gov/afc for
the latest.

&&

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

Light snow remains ongoing this afternoon across Southwest Alaska as
troughing lingers over the area amid relatively weak isentropic
lift. The upper level low over the eastern Bering will become more
defined as it elongates northwards and tilts back to the west later
tonight as a front pushes across the eastern Bering. Should see some
enhancement of snow across the Southwest, from Bristol Bay area to
the Kuskokwim Delta, with the band lifting north into the interior
through Sunday afternoon/evening. Overall, not expecting much in the
way of additional snowfall. areas from about Iliamna south to King
Salmon should see mostly rain or a rain/snow mix this afternoon
before transitioning over to light snow overnight as colder air
begins to work in. By Sunday afternoon and evening, most areas over
the Southwest should see snow coming to an end, however, there may
still be some lingering flurries or a passing snow shower through
early Monday morning.

Attention then turns towards a potent storm-force low approaching
the Central and Eastern Aleutians late Sunday night from the North
Pacific. Models still have some discrepancies on the placement of
the low track, but have switched it up a bit with the NAM and
Canadian becoming the western solutions and the GFS and ECMWF the
eastern solutions. While this will have an impact on where the
strongest winds occur, almost model solutions agree with the
strongest winds lifting up across the Aleutians between about
Nikolski to Cold Bay Monday morning. Right now, it looks like south
to southeasterly winds will stay below High Wind criteria, but windy
conditions should be expected for the Central/Eastern Aleutians over
to the southern AKPen on Monday. Strong north to northwesterly winds
will also develop on the backside of the system on Tuesday as the
system tracks along the north side of the eastern Aleutians before
lifting north towards Cape Newenham. This system will pull moisture
northwards, as well as warmer temperatures and the southern side of
the Aleutians and especially the southern AKPen should see decent
rainfall as the front lifts through. As the precipitation pushes
north towards Bristol Bay, cold air already in place will allow
precipitation to start out as snow before transitioning over to a
rain/snow mix and then all rain as warmer air moves in. Further
north towards Kuskokwim Bay is a little more nebulous, but will
likely see a transition to a rain/snow mix to all rain for at least
areas along the coast. The western Aleutians will see snow or a
rain/snow mix as colder air works in behind the system.

- PP

&&

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

A broad upper level low stretches across the Bering into the
Interior of Alaska through the forecast period. The very active
weather pattern will occur across the Aleutians and Southern
Bering, Alaska Peninsula, Kodiak Island and the Southcentral
Coastal zones into the weekend. The ECMWF / GFS blend continues to
handle strengths and tracks of the systems through most of the
forecast, with model means picking up the slack by Saturday.
Opening the surface weather forecast is the remnants of the former
tropical system Kong-Rey moving over the Eastern Bering and
Western Alaska coastal zones. Precipitation will start as snow
across Southwest Alaska before a short period of mixed rain and
snow or freezing rain slips inland around Bristol Bay. Chances of
coastal flooding are highest along the Bristol Bay coast through
Wednesday. Gusty winds less than gale force spread along the AKPEN
coast, Kodiak Island and across the Southcentral coasts. Areas of
gusty winds move across the Bering through Thursday. Locally
heavy rains are expected all the way over to the Canadian Border,
with snow likely at higher elevations and further inland.

A second well developed low and frontal system glide along South
of the Aleutians before curving towards the AKPEN and Kodiak
Island and Southcentral zones on Thursday. Gale force winds move
into the Kodiak Island Waters late on Wednesday, the Barren
Islands and Kamishak Bay, and the Eastern Kenai Peninsula and
Prince William Sound Thursday before diminishing to widespread
less than gale force on Friday. In the Far West, a third
developing low approaches the Western Aleutians late Thursday, and
closes in on the Western and Central Aleutians through Saturday.
Gale force winds and another round of locally heavy rains spread
into the AKPEN for Saturday.

&&

.AVIATION...

PANC...VFR conditions and light winds will persist through at
least 12Z Sunday morning. Light snow will then approach from the
south and east, most likely reaching the terminal between 19Z and
22Z. Ceiling and vis will rapidly lower with the commencement of
snow. There is a chance of mixed precipitation right at the start,
but forecast soundings show it should quickly go to all snow as
the low levels are saturated. Snow will then persist through much
of the day, tapering off mid to late evening (05-08Z). Snow
intensity will be light for the entire event, suggesting MVFR
to IFR conditions will prevail.

&&