824
FXAK68 PAFC 011235
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
435 AM AKDT Mon Jul 1 2024

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

A slowly weakening, stacked low continues to slowly wander east
and into the far western Gulf near Kodiak Island this morning.
This low`s ill-defined and occluded front now extends to the north
and east into the southern Kenai Peninsula and out across the
northern Gulf, where a few bands of showers continue to stream
northwest into western portions of the Gulf Coast. A shortwave
trough that helped usher a quick shot of rain across parts of the
Kenai Peninsula yesterday has since rotated off into Southwest,
although gusty gap winds in the wake of this feature have
stubbornly persisted this morning along namely the Turnagain Arm.
These southeast winds bending into west Anchorage should abate
later this evening as the weakening frontal wave over the Kenai
Peninsula shifts north and weakens the coastal gradient in place
around Prince William Sound. Otherwise, expect a somewhat cooler
and cloudier day in most places compared to the past few days.
Onshore flow, higher cloud cover and cooler low level
temperatures will allow a much more stable atmospheric profile to
prevail today, and no thunderstorms are expected across any part
of Southcentral as a result of this switch over to a more
statically stable and cooler regime. Still, a few showers will be
possible over mainly higher terrain through this evening.

Looking towards Tuesday and beyond, a slight shift in the pattern
will begin to take shape once again. The western Gulf low will
begin to shift farther south between Tuesday and Wednesday while a
narrow west-east oriented ridge begins to develop to the north
across the southern Mainland. Prevailing upper flow will turn more
easterly and become quite weak, and there will likely be some
clearing over at least interior parts of Southcentral, with some
slight rebound in temperatures possible by Wednesday as the
elongated ridge builds overhead. One exception may be parts of the
Copper River Basin, where a weak easterly wave could move around
the ridge from the Yukon into the Wrangells during the day on
Tuesday. This could help focus the best chance for measurable
rainfall across the outlook area through at least Tuesday
afternoon, especially close the the Alaska Range between Mentasta
Lake and Paxson.

AS

&&


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

Weakening low pressure centered over the Alaska Peninsula will
continue to cycle weak shortwaves over Southwest Alaska. Light
scattered rain showers will continue today, becoming most isolated
by Tuesday. Partly cloudy skies will persist through at least
mid-week. High pressure will build over the Bering Sea and will
push eastward over the next few days. Widespread areas of fog set
up under the ridge, encompassing much of the Bering and Aleutians
and pushing into Southwest by early Tuesday morning.


&&


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

A pattern change is looking to be underway, but pinpointing what
will happen is proving to be difficult beyond day 5 (the end of
the workweek). What we do know is that by Thursday, low pressure
that has been working across the AKPEN through the week, will
continue to track deeper south into the Pacific. Strong ridging
will build in across the western Alaska, nosing in across the
Alaska Range and western Anchorage. This ridge will slowly drift
south into the weekend. What that means is that the nice weather
at the start of the week will likely shift to more of a cooler,
cloudier and potentially wetter one. Long range ensemble guidance
helps to clue us in on how things will shake out, but there are
wild differences between the ensemble and operational guidance
after day 6. What we are seeing is the first `wet` system moving
in from the Bering around the holiday timeframe. The second into
the middle of the weekend. Details should (hopefully) become
clearer as the week pushes on.

&&

.AVIATION...

PANC...VFR conditions to persist through the period. Southerly
Turnagain Arm winds should be milder this afternoon and evening
with gusts not exceeding 25 knots. The biggest question mark
entails rain chances with yet another trough lifting across the
Kenai Peninsula today. At this time, however, it appears the bulk
of precipitation will remain south of the terminal.

BL

&&


$$