Gale Warning 585, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
444 PM AKDT Fri Sep 20 2024

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

An upper-level trough over the Gulf of Alaska continues digging to
the east, sending its surface low into Southeast Alaska. Tonight,
expect the Cook Inlet region northward through the Mat-Su
(including Anchorage) to see skies clear out and temperatures
drop to the coldest morning temperatures so far this Autumn
season. Conditions across Southcentral and the Gulf remain
generally dry and benign until the next system enters the western
Gulf on Sunday morning. Its front will lift across the entire Gulf
and reach the north Gulf coast by Sunday evening. Steady
precipitation and sustained gale-force winds are expected to
accompany the system. The precipitation with this system should
stay confined to the Gulf coast and waters, leaving interior
Southcentral on the drier side.

&&

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

Dry and cool conditions will continue across Southwest Alaska
into Saturday while high pressure resides over the eastern Bering.
Overnight low temperatures will drop into the low to mid 30s for
much of the region. As has been advertised, active weather is
beginning to move through the Aleutians with the first of two
upper lows moving into the Central Aleutians this afternoon. Gusty
winds to 35 knots and a broader field of gales to spread across
the western Bering into tonight. A second and stronger low slides
into and replaces Friday's low across the Central Aleutians. This
low will spread a broad occluded front from west to east across
the Aleutian Chain through Sunday. Expect numerous showers and
continued gusty conditions across the Southern Bering as the front
and the low itself eventually consolidate over the Alaska
Peninsula. The main concern over the weekend will be the
consolidation of the low on Sunday and a developing pressure
gradient over the Western Alaska Range into Bristol Bay. 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
with a brief reprieve from unsettled conditions for the Bering
and Southwest Alaska.

BL

&&

.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...There is currently a weak low-level wave moving
northwestward from Prince William Sound, bringing precipitation to
parts of the Western Chugach, Kenai, and Talkeetna mountains. It
is possible these showers will briefly creep into the airport Friday
afternoon, but VFR conditions and light winds should persist. While
it is not the most favorable pattern for it, we cannot rule out
the possibility for some low-lying fog in some localized locations
Saturday morning. There is high confidence for clouds to
dissipate overnight bringing widespread sunshine across
Southcentral through Saturday.

&&