298
FXAK68 PAFC 101348
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
548 AM AKDT Mon Jun 10 2024

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

Some lingering gap winds are continuing for the Turnagain Arm and
Knik River Valley, but it should start to dwindle down later this
morning. Rainfall has diminished quite a bit for the Kodiak area
and while light rain may linger there, the threat for flooding has
decreased.

By late afternoon, the alignment of the longwave trough will
result in the flow both out of the surface and aloft to shift to
more of an easterly direction. In addition, weak ridging over the
interior will help support the movement of multiple easterly waves
of showers over Southcentral through the remainder of the
forecast period. Precipitation chances increase for the Copper
River Basin later tonight through tomorrow morning, then spreading
west into the Susitna Valley Tuesday afternoon and evening. There
is a chance for the western foothills of the Kenai Peninsula
mountains and the western Chugach mountains in Anchorage and the
Matanuska Valley. Rainfall is expected to greatly decrease for the
Gulf coast, Kodiak Island, and Prince William Sound. This pattern
shift will also result in more widespread cloud cover, causing
high temperatures for most locations to drop below 60 on Tuesday
and Wednesday.

The trough over the Gulf will slowly move southward towards the
North Pacific by Wednesday afternoon and slowly weaken as it does
so. As a result, precipitation chances over the Gulf coast will
slowly diminish over time, with higher chances occurring over
mainland Southcentral and persisting into the latter portions of
the week. We are keeping an eye on a potential pattern shift to
warmer temperatures and a more convective weather pattern later
this week.

-BS/rux

&&


SHORT TERM FORECAST SOUTHWEST ALASKA, THE BERING SEA AND THE
ALEUTIANS (Days 1 through 3: Today through Wednesday night)...

A large upper-level low is currently located to the southwest of
Kodiak Island, and it continues to send pinwheeling upper-level
shortwaves across all but the Western Aleutian Islands and Bering
Sea. Lingering rain showers will gradually taper off as the low
weakens and moves further south into the North Pacific, and a
ridge of high pressure builds in from the west. Gusty east-
northeasterly winds will continue across Greater Bristol Bay and
portions of the Lower Kuskokwim Valley through today before
diminishing late tonight into early Tuesday morning. Convective
showers are possible for portions of the Lower Kuskokwim Valley
today, however confidence is on the lower end. In general,
temperatures should be a bit warmer today across Southwest Alaska
due to less cloud cover and shower activity. Widespread
precipitation chances return again on Tuesday with the arrival of
an easterly wave out of interior Alaska. Most of the
precipitation with this feature can be expected across the Lower
Kuskokwim Valley and Greater Bristol Bay. Temperatures cool and
winds remain lighter for Tuesday. Additional easterly waves will
be possible into Wednesday along with subsequent shower activity
as low pressure southeast of the Alaska Peninsula finally shifts
eastward into the southern Gulf of Alaska.

For the Bering and Aleutians, northerly flow is forecast to
prevail through Tuesday while a ridge builds in from the west,
promoting drier conditions across the area. The next system
approaches the Western Aleutians from the North Pacific on
Wednesday afternoon. A front is forecast to lift northward across
the Aleutians, bringing with it steady rainfall and southeasterly
winds up to small craft.

Fenrich

&&

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

The Arctic upper level high continues to build over Mainland
Alaska and ridges into the Bering through the forecast period. A
portion of a North Pacific ridge extends towards the Alaska
Peninsula, and looks to merge with the Mainland ridge through the
period. In the Gulf of Alaska/North Pacific, the closed low
weakens and slips into the Canadian coastal waters for Sunday. Out
West, a Chukotsk upper low swings into the Russian Arctic, but a
North Pacific low moves over the Aleutians to fill in. Several
shortwave troughs rotate throughout the pattern through the
weekend. The Interior ridge should warm and dry much of the
Central portions of the state. Showers are expected along the
North Gulf Coast for the last parts of the workweek. Most of the
Aleutians and Bering should see periods of light rain through the
weekend. The model ensemble means hold good confidence through the
first half of the forecast, but become diffuse towards the ends
as models move into different strengths and tracks.

- Kutz

&&

.AVIATION...

PANC...VFR conditions persist through the TAF period. Light and
variable winds give way to another round of southeasterly
Turnagain Arm winds this afternoon, with gusts in the 20 to 30
knot range. Southeasterly winds relax through the overnight hours,
becoming light and variable once again Tuesday morning. There is a
low chance for ceilings to drop below 5000 ft (but would remain
VFR) with a weak front lifting across the terminal Monday night.

Quesada

&&


$$