Gale Warning 467, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
458 PM AKDT Mon Jun 24 2024

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

Thunderstorms and warm temperatures will continue to dominate
Southcentral weather through mid-week, though there will be a
gradual pattern change as a Bering Sea low pushes its front
towards Kodiak Island on Wednesday. Forecast confidence is about
typical, though the thunderstorm forecast (especially for
Wednesday and Thursday) will likely be updated as high-resolution
model data becomes available to use for the forecast.

Diving into the details... an upper level ridge continues to
dominate weather across the state. Weak upper level shortwaves
moving around the ridge are helping to spur areas of showers and
thunderstorms, with the most prominent convection occurring in the
Copper River Basin and along the Talkeetna Mountains today.
Further south, an upper low exiting Bristol Bay is also bringing
thunderstorms to Kodiak Island as it transits overhead. Between
Kodiak Island and the Mat-Su Valleys, an influx of clouds and
moister air is helping to keep things more stable. While a
thunderstorm or two aren't out of the question for Western Kenai
Peninsula and the Anchorage area, convection is expected to be
less robust than yesterday.

From Tuesday through Thursday, thunderstorm potential will remain
mostly limited to the Copper River Basin and Talkeetna Mountains
as surface high pressure and moist, southerly flow help to
inhibit convective activity. For Anchorage and the north Gulf
coast, the main story will be the return of breezy onshore winds,
mostly in the afternoon, as a pressure gradient sets up between
the ridge in the Gulf and the thermal trough inland. For Kodiak
Island and parts of Eastern Kenai Peninsula, the main story will
be the approaching front on Wednesday. The front will be quite
weak when it reaches Kodiak Island, with winds expected to remain
below 25 kt in coastal waters and rain remaining fairly light.
Though precipitation will be limited mostly to the Western Gulf,
increasing cloud cover will overspread much of Southern Alaska,
bringing an end to our recent spell of sunny days.

-KC

&&

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

The remnants of a Bristol Bay low continue to track south while a
ridge over the Bering Sea begins to breakdown in response to a
shortwave upper-level trough lifting up across the western
Aleutians into the southern Bering. Weak disturbances will
continue tracking across interior Southwest this evening and
tonight. As a result, scattered wet thunderstorms will persist
from the Western Alaska Range across the Kuskokwim Valley to
inland areas of the Kuskokwim Delta. By Tuesday, a cooler more
stable pattern begins to spread inland across Southwest. However,
some scattered thunderstorms are still possible along the Western
Alaska Range later Tuesday afternoon and evening.

Farther out west, a compact surface low, associated with the
aforementioned trough, approaches the Aleutian Chain and southern
Bering. The low and its front will gradually track to the
northeast and encompass much of the Bering and Aleutians through
Thursday. Steady rain and sustained winds up to gale force are
anticipated. Gusts up to storm force are likely for bays and
passes along the AKPen, particularly near Cold Bay. The front
begins to weaken as it reaches the Southwest coast on Wednesday
morning, but gusts upwards of 50 mph are still possible for
locations along the immediate coastline as the front arrives. The
bulk of the precipitation will be focused along the southern-
facing side of the Kuskokwim Mountains (interior Bristol Bay) as a
result of strong southeasterly cross-barrier flow. On Thursday,
the low itself continues to drift northeast to the northern
Bering and spreads rain to the Kuskokwim Delta. Winds gradually
diminish through Thursday.

Fenrich

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

A ridge of high pressure in the Interior will continue to dominate
through weekend resulting in an isolated rain shower or
thunderstorm. High pressure in the Gulf of Alaska will keep the
Southcentral dry into the beginning of next week. A series of
lows progress through the Bering Sea into the Interior Southwest
bringing cooler temperatures, clouds and frequent rain showers to
the area through the weekend.

-DJ

&&

.AVIATION...

PANC...Flow up Inlet and through Turnagain Arm has produced more
stable low levels compared with Sunday. In addition, storm motion
has shifted and any showers and thunderstorms which form on/along
the mountains this afternoon and evening will track from SSE to
NNW. Thus, expect the vast majority of convection to remain near
the mountains and be more isolated in nature across the northwest
Kenai Peninsula and Front Range Chugach than on Sunday. While
there could be some debris clouds and a mid level ceiling tonight,
conditions will remain VFR.

Gusty southerly winds are favored this afternoon into the overnight
hours with a combination of the up-Inlet SW winds and the SE
Turnagain winds. For Tuesday, winds up Cook Inlet will be weaker
while the Turnagain Arm jet looks a bit stronger, so expect a more
typical slightly stronger Se winds coming in mid afternoon.

&&