460
FXAK68 PAFC 030037
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
437 PM AKDT Tue Jul 2 2024

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: This
afternoon through Friday)...

For the rest of today and Wednesday, an upper-level low and
attendant surface low will continue to linger near the western
Gulf/North Pacific while a weak ridge of high pressure spans
across Southcentral. A couple very weak waves are setting off
areas of rain showers across the northeastern half of the Copper
Basin today, which should mostly dissipate by this evening.

Despite the developing high pressure, low level flow will remain
south to southwesterly (especially near the Cook Inlet), and this
will tamp down highs in the low to mid 60s for much of the region
this afternoon even with partial sun returning. Much of the same
is expected for Wednesday as the narrow ridge remains mostly
intact and the Gulf low moves even farther out into the Pacific.

On Thursday (July 4th), hints of a bigger pattern change will
begin to be felt by some. A series of shortwaves interacting with
a band of moisture streaming around the ridge from the Bering Sea
into the Interior will begin to encroach from the north, with a
stronger trough expected to approach the Alaska Range by the
afternoon. The main change from the previous forecast package is
that the onset of rain could happen earlier for areas farther
south, such as the Anchorage and Matanuska Valley areas. There is
greater likelihood for rain to being in the evening, however it
is possible for it to start earlier in the afternoon. The greatest
confidence remains or the northern Susitna Valley and northern
Copper River Basin, where the greatest amounts of rain can be
expected.

By Friday, a transient upper-level ridge tracks across
Southcentral and brings a brief respite in rain for most of the
region before an upper trough approaches from the west on
Saturday.

-AF/AS

&&


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

A front extending off a Kamchatka low moves into the central
Bering Sea this afternoon, bringing widespread rain showers to
Central Aleutians. High pressure ridging over Southwest Alaska
brings in some patchy fog and/or low ceilings to the Southwest
coast and Alaska Peninsula. Shortwaves riding overtop the ridge
will drop south into Southwest Alaska by Thursday morning. This
will initiate a rainy pattern which first arrives at the Kuskokwim
Delta then advances eastward across Southwest by Thursday
afternoon.

&&

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

The long range models are in more agreement today with the
pattern change mentioned in previous discussions. The areas of
high pressure that have been persistent over the Bering Sea and
the Gulf of Alaska in the early part of the period will start to
break down allowing a North Pacific low to track northward into
the Gulf. This combined with troughs of low pressure transiting
across the Bering Sea and Kuskokwim Delta will track eastward
across the region through the end of the period. As a result,
expect scattered precipitation and cooler temperatures across the
much of the forecast area. Additionally, gusty winds and possible
small craft conditions are expected in Cook Inlet and coastal
regions of the Kenai Peninsula Saturday afternoon and into Sunday.

-DD

.AVIATION...

PANC...VFR conditions and light winds persist through Wednesday
evening. Westerly winds this afternoon will shift southerly
overnight, before becoming westerly again tomorrow afternoon.

&&


$$