256
FXAK68 PAFC 310006
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
406 PM AKDT Thu May 30 2024

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

A weakening surface front will continue to dissipate this
afternoon while a strengthening area of low pressure moves from
the North Pacific into the Western Gulf overnight. This low will
be the main feature through the end of the week as it deepens
into a gale-force low over the central Gulf, bringing continued
widespread rain for Kodiak, and portions of the north Gulf coast.

The low slowly moves to the northwest for Saturday with some
uncertainty as to how far north and west the occluded front
tracks. An upper-level ridge extending across the western half
of Southcentral will either remain in place or retreat to the
west as an easterly wave moves into the Copper River Basin from
the Yukon. If this easterly wave helps to break down the ridge,
scattered showers will return to interior Southcentral on Saturday.

&&


SHORT TERM FORECAST SOUTHWEST ALASKA, THE BERING SEA AND THE
ALEUTIANS (Days 1 through 3: Tonight through Sunday)...

Two main features are now acting as the main weather-makers across
the Bering Sea and Southwest this afternoon. The first of these is
a very decayed, weakening low drifting over the eastern Bering Sea
close to Bristol Bay. This first low is helping to focus areas of
light rain showers along the AKPen and across parts of Bristol Bay
this afternoon. Gusty winds forced through Kamishak Gap should
gradually decrease as this low weakens through early Friday.
Farther to the west, a much stronger, gale force low is now
approaching the far western Aleutians as it prepares to move from
the North Pacific into the southwest Bering. Rain and gusty winds
also extend along the low`s front already moving out into the
southern Bering Sea, and this corridor of small craft to low-end
gale force winds and rain will shift quickly out towards the
eastern Aleutians and Pribilofs as the parent low reaches Shemya
by tomorrow morning.

From Friday to Saturday, the main player over the Bering will
continue to be the stronger low which gradually moves north of
the Aleutian Chain and weakens/fills with time. Areas of showers
and light rain will continue to drift around this system, but
heavy rainfall amounts are not expected. Much calmer conditions
will return to the Bering and Aleutians as the remnants of the low
move south of the AKPen and become absorbed by a separate system
moving over the Gulf. Meanwhile, a short stint of dry, warm and
sunny conditions over parts of Southwest on Friday will quickly
transition back to a cloudier and somewhat wetter pattern over the
weekend as the Gulf low shifts northwest close to Kodiak Island
and begins to draw moisture and multiple easterly waves across the
Alaska Range into Southwest. There is still a decent amount of
uncertainty for the track of these smaller shortwaves, but the
best potential for measurable rain will be focused over the Lower
Kuskokwim Valley Saturday afternoon and evening, shifting towards
northern Bristol Bay and the Kilbucks on Sunday as a stronger wave
rotates across from northeast to southwest. At this time, it appears
instability will be too weak and shallow to support significant
thunderstorm potential with this activity as is spreads southwest
over the weekend.

-AS

&&

.LONG TERM FORECAST (Days 4 through 7) Monday through Thursday...

The Alaskan upper level map opens with a closed low to the South
of the Alaska Peninsula beginning its track around the Gulf of
Alaska. It draws closest to Southcentral through Wednesday before
curving past Kodiak Island into its exit for the end of the
forecast period. A second low center tracks out of the Arctic
along the West Coast late Tuesday before swirling out and stalling
in the Central Bering by Thursday. Several surface troughs rotate
over the Western Bering through Thursday. Jet stream support has
pushed further South. A weak upper level ridge holds over the
Central and Northern Mainland, and looks to support surface
thermal troughs, especially across the Central Interior.

Gusty Northerly winds are expected over the Eastern Bering as the
Arctic low moves through, diminishing late Tuesday. Showers
spread over the Bering, Southwest Alaska, AKPEN and the Aleutians.
Easterly to Southeasterly airflow over the Southcentral Alaska
spreads moisture as far North as the Alaska Range, and from the
Canadian Border across Prince William Sound and the Kenai Peninsula.
Locally heavy showers will come with each Easterly wave, otherwise
periods of light rain are expected. Potentially larger amounts of
rain over the Copper River Basin associated with more convective
events are expected.

-Kutz

&&

.AVIATION...

PANC...VFR conditions will persist. Gusty southeasterly Turnagain
winds will affect the terminal again this aft/eve with a coastal
ridge in place ahead of a diminishing front in the Gulf. Equally
important, some sunshine and a well-mixed boundary layer will
promote stronger winds mixing down to the surface from aloft.
Winds will taper off 06Z-09Z as winds begin to head down Cook
Inlet in response to a deep low moving into the Gulf. The surface
ridge will be pushed inland Friday, so largely expect light sea
breezes. There could still be a some weak gusts out of the
Southeast Friday evening due to lots of sun and warmth inland.

&&


$$