772
FXAK68 PAFC 260000
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
400 PM AKDT Tue Jun 25 2024

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

In the upper levels, a ridge over mainland and a large low over
the Bering Sea. The Bering low with its front will push eastward,
reaching the western Gulf and Kodiak area on Wednesday and
lingering through Thursday. The trough will phase with a Pacific
low to keep southeasterly and onshore flow moving across the area.
There is lower confidence with how far north and east into
Southcentral this front will proceed as the low attempts to erode
the mainland ridge. High pressure will weaken slightly with the
additional embedded troughs pass moving through the ridge, but the
overall pattern will likely remain blocked as the ridge holds
stubbornly in place, preventing the low from progressing any
farther east.

Midlevel temperatures will remain quite warm over (10C to 14C),
especially for the Copper River Basin and northerly Susitna
Valley. Relatively cooler air (by just a few degrees) with along
the front will help promote up Cook Inlet flow. Kodiak and
portions of the southern Kenai Peninsula could be a little bit
cooler and low stratus and fog will remain possible over the next
few mornings. It is possible for cooler temperatures and low level
moisture to reach into Anchorage and northern Cook Inlet, though
confidence is much lower and primarily associated with the
location the synoptic features.

Isolated to scattered thunderstorms will remain possible for the
Copper River Basin and Susitna Valley with easterly flow
throughout the short term forecast. The midlevel temperatures will
be warmest along the eastern slopes and foothills of the
Talkeetnas and the Copper River Basin, helping to promote lift for
thunderstorm development. Thunderstorms that develop will move in
a northwesterly direction, spreading across the northern Copper
River Basin and Susitna Valley. Due to the isolated and scattered
nature of these storms, it is hard to pin point where QPF will be
located exactly. However, recent thunderstorms have produced
wetting rains and that will likely continue with any thunderstorm
development. The highest convective potential will likely be
Wednesday afternoon and evening, especially for more widespread
scattered thunderstorms in the northern Susitna Valley, including
the Alaska Range, and all the foothills surrounding the Copper
River Basin. Potential decreases after midweek, becoming more
isolated, though the eastern Alaska Range could hold onto some of
that convective potential.

rux

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA, THE BERING SEA/ALEUTIANS
(Days 1 through 3: Tonight through Friday night)...

Weak disturbances will continue tracking across interior
Southwest Alaska this evening into Wednesday. As a result,
scattered wet thunderstorms are possible this afternoon/evening
and Wednesday afternoon/evening across eastern portions of the
Middle Kuskokwim Valley and the Western Alaska Range.

Cooler and more stable conditions arrive at the coast today and
slowly work inland during the next couple of days as a result of a
strong Bering Sea low. The surface low and its upper-level
counterpart are currently centered over the southern Bering with
its front extended across much of the Bering, the eastern
Aleutians, and the AKPen. Steady rain and gale-force sustained
winds accompany the front, with gusts up to storm force occurring
through some bays and passes of the AKPen, particularly near Cold
Bay. The front will continue lifting to Southwest Alaska and is
expected the reach the coast Wednesday morning while the low
itself still expands across most of the Bering. With the front,
gale-force southeasterly winds and gusts up to 50 mph are expected
to produce high surface along the northern Kuskokwim Bay coast
(especially the communities of Kwigillingok and Kongiganak) from
Wednesday morning through early Thursday morning. Thus, a High
Surf Advisory is in effect for the northern Kuskokwim Bay coast.
Waves and surf will peak Wednesday afternoon during high tide,
with waves expected to rise 3 to 6 feet above the normal highest
tide line.

The front weakens on Thursday along the Southwest coast as the low
itself slowly drifts to the northeast into the northern Bering. The
bulk of the precipitation will be focused along the southern-
facing side of the Kuskokwim Mountains (interior Bristol Bay) as a
result of strong southeasterly cross-barrier flow, as well as the
Kuskokwim Delta coast. On Friday, as this low continues weakening
and tracking towards Russia, another system traverses the Aleutian
Chain and heads towards the AKPen.

Fenrich

&&
.LONG TERM FORECAST (Days 4 through 7)...

A ridge will remain over the area for the weekend for
Southcentral and Copper River Basin. An isolated rain shower or
thunderstorm is possible though into the beginning of next week.
In the Southwest, a series of lows progress through the Bering Sea
into the Interior Southwest bringing cooler temperatures, clouds
and frequent rain showers to the area through the early next week.

-DJ

&&
.AVIATION...

PANC... VFR conditions are forecast through the TAF period, with
ceilings at or greater than 5000 ft. Winds will remain mostly
southwesterly, with sporadic gusts as high as 20 kt in the
afternoon and evening. Southwesterly up-inlet flow is expected to
dominate southeasterly flow out of Turnagain Arm in the afternoons
and evenings, but winds could shift more southerly if these
opposing flows merge near the terminal. Otherwise, we are
monitoring the potential for fog and low stratus to move up Cook
Inlet again tomorrow, though confidence remains low.

-KC

&&


$$