040
FXAK68 PAFC 211239
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
439 AM AKDT Sat Sep 21 2024

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

This morning`s weather map has that persistent upper level trough
still extending out of the Interior and over the Talkeetna
Mountains and southward to Prince WIlliam Sound, not unlike where
it was yesterday morning. A difference today is that other are no
other waves around to kick off any light showers. Lower elevations
have mostly cleared out overnight, but this pesky trough is just
enough to keep some mid-level clouds over the Talkeetna Mountains
and packed up bear the Chugach and Kenai Mountains as well. This
has limited the cooling overnight and kept Anchorage and the
Matanuska Valley in particular warmer. Still expect these clouds
to mostly dissipate today as that trough moves eastward and weak
ridging move in from the west. All this should combine for a
rather nice day for Southcentral.

That starts to change Sunday as the next low plows toward the Gulf
and brings rain into Kodiak by early Sunday morning and increases
winds around the Gulf. While most of the marine winds around the
Gulf should remain at Gale force, there is a chance for storm
force winds in barrier jets right along the north Gulf coastline
Sunday evening and Sunday night. This low will then rapidly weaken
on Monday as it moves int the northwest part Gulf. It then remain
there as the upper level trough from the Arctic starts to phase
up with this low and solidify Southern Alaska in yet another upper
level trough that wants to remain seemingly forever.

&&


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

Dry and cool conditions will continue across much of Southwest
Alaska through the weekend. Some light rain is expected to work
its way up the Alaska Peninsula and into the southern portions of
Bristol Bay on Sunday with the next front. Precipitation should
clear out by Sunday night as the front tracks into the Gulf of
Alaska. Some wrap around precipitation may spill over the Western
Alaska Range, however, mostly dry and cool conditions will roll
over into early next week. Overnight low temperatures will drop
into the low to mid 30s for much of the region through early next
week, with daytime temperatures in the mid 40`s.

As has been advertised, active weather is beginning to move
through the Aleutians with the first of two upper lows moved into
the Central Aleutians yesterday afternoon and has spent the night
fizzling into an open wave. A second and stronger low absorbs
yesterdays system and slides over the Central Aleutians before
tracking east towards the AKPen. Gale force winds will pick up
across the AKPen and southeastern Bering Sea by Sunday morning.
Gusty winds will wrap around the backside and pushing near gale
force gusts over the Eastern Aleutians by Sunday afternoon.

The consolidation of the low on Sunday and a developing pressure
gradient over the Western Alaska Range into Bristol Bay will
result in gusty gap winds. Gusty easterly winds of 35 to 45 mph
are forecast to spill through the Kamishak Gap into portions of
Greater Bristol Bay while 35 to 45 knot gusts are expected to
encompass much of the Alaska Peninsula into Sunday night. Low
pressure departs the region early next week.

&&

.LONG TERM FORECAST (Days 4 through 7: Tuesday through
Friday)...

Long wave upper level low pressure system over much of the State
continues to be the main focus in the extended outlook. Models are
in fairly good agreement with a well defined surface low and
upper level troughing across most of the southern portion of the
State, Aleutians Islands and and Gulf waters early in the period.
Models differ somewhat on intensity of shortwave troughs
developing across the southern portion of the Bering Sea, Aleutian
Islands and coastal Gulf of Alaska throughout the period. The
long wave trough axis will remain fairly entrenched across the
interior of the state, allowing for quickly moving shortwaves to
bring strong coastal winds and moderate precipitation across the
eastern portion of the Aleutians, the Alaskan Peninsula and
coastal Gulf waters through Friday.

High pressure will ridge in behind the long wave trough late
Thursday and into Friday ahead of another North Pacific Low that
will approach the Western Aleutians Friday evening.

&&

.AVIATION...

PANC...VFR conditions and Light winds are expected to persist. The
is a slight chance for some fog to develop near the airport early this
morning if the mid-level clouds clear out before mid-morning.

&&

$$