Gale Warning 230, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
416 PM AKST Mon Feb 28 2022

.ANALYSIS AND UPPER LEVELS...

A weak surface low moved on shore near Cordova this morning. Light
rain continues across the Pacific facing coastal areas east of
Prince William Sound. Deeper inland, towards Valdez and the Copper
Valley, rain has changed over to light snow. Another weak low
continues to move across the southern tip of Kodiak Island. Light
and intermittent showers are seen surrounding the island and will
continue through the evening. Across the western Aleutians is the
biggest feature of note for the day. A sub 970mb low continues to
track to the north. A gale-force front approaches the western
Aleutians and will gradually sweep from west to east through mid
week. Warmer conditions and rain will accompany the front.
Otherwise, the state has moved into a quiet period to start the
workweek out.

&&

.MODEL DISCUSSION...

The latest guidance is in good agreement for the main big picture
items across our forecast area. For Southcentral, models continue
to have a good handle on smaller scale embedded shortwaves moving
overhead in the southerly flow aloft through the middle of the
week. As the low in the western Gulf continues north. Out west,
the gale force front continues east across the Central Bering Sea
and Aleutian Islands, bringing gusty winds and rain through at
least mid week. Another low is expected to form along the front
beginning tonight just south of the Central Aleutians. Some model
differences emerges, however, with the placement and strength as
the low tracks north of Atka on Tuesday.

&&

.AVIATION...

PANC...Low to moderate confidence for broken clouds at/below
5,000 feet Tuesday morning at the terminal. Otherwise, VFR
conditions and light winds will persist through the TAF package.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3/Tonight
through Thursday night)...

A rather quiet weather pattern is in place for Southcentral to
start off the workweek. An occluded front will continue to linger
over eastern Prince William Sound through tonight as an upper-
level shortwave moves northeastward across the area. Light
precipitation associated with this front is expected to last
through the overnight hours and then taper off by Tuesday morning.
Rain along the coastal areas will likely transition to a rain/snow
mix at some point throughout the night.

A weak surface low located off the southern tip of Kodiak Island
and another upper-level shortwave will work in tandem to produce
light and intermittent showers across the island and starting over
the southern Kenai Peninsula through this evening and into
tomorrow morning. The low will continue to spread weak showers
over the Kenai Peninsula and Prince William Sound as it tracks
over Southcentral through late Wednesday.

By Wednesday morning, another low and its front will reach Kodiak
Island. The front will continue to push northeastward across the
coast and Gulf of Alaska, and it will reach Southcentral around
Thursday morning. Although this system looks to be stronger than
the aforementioned system, the Anchorage Bowl and western Kenai
Peninsula are anticipated to stay relatively dry due to
downsloping from southeasterly flow running up against the Chugach
and Kenai Mountains. With the push of the frontal system toward
the coast, gusty southeasterly gap winds will ramp up through
Turnagain Arm and are expected to be strongest late Wednesday
night into early Thursday morning.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3 - Today
through Thursday)...

A weak surface low centered in Shelikof Strait is producing
scattered snow showers along the northern portions of the Alaska
Peninsula. As the low tracks eastward into the Gulf, the area of
scattered snow showers will move northeastward on Tuesday reaching
Iliamna and other locales in the northeastern portion of the
Bristol Bay zone, before exiting eastward Tuesday night.
Otherwise, a benign pattern will continue through Tuesday night,
with weak winds, mild temperatures in the 20s to 30s, and areas
of low cloud cover over interior valleys expected to persist. For
valley locations that stay relatively cloud-free tonight, patchy
fog development is possible until around sunrise Tuesday morning.
With a low stratus deck present in the Lower Kuskokwim Valley, the
most likely region for this patchy fog development will be the
interior valleys around Bristol Bay, where the cloud deck is more
broken and primarily mid-level.

Wednesday morning, a front in the eastern Bering begins to push
ashore along the Southwest Coast. The front looks to bring
primarily snow as it tracks southwest to northeast, drawing up
only a limited amount of warmer air from the North Pacific. As a
result, snow accumulations of around 1 to 2 inches are possible
through Wednesday night for Bristol Bay, with lower totals further
north. Areas near King Salmon are also likely to see less
accumulation, with temperatures in the mid 30s or higher expected
to result in limited to no accumulation of snow. By Thursday, snow
showers push off to the northeast as a shortwave ridge moves in
and brings a brief return to drier conditions for Southwest
Alaska.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3 - Today
through Thursday)...

A North Pacific tracks across the western Aleutians tonight,
bringing primarily rain along with southeasterly gale force winds
and storm force gusts. Its front sweeps eastward across the
Aleutian Chain and Bering Sea, with southeast winds and rain
advancing with the front. A triple-point low is expected to form
on the front and move north into the Bering near or just east of
Atka by Tuesday morning, then track west of the Pribilofs as it
begins to occlude Tuesday night. The main front will continue to
move north and east into the southern Alaska Peninsula and
eastern Bering through late Tuesday night. The front will send a
mix of rain and snow across the eastern Aleutians on Tuesday
night, with light snow and gusty easterly winds expected for the
Pribilof Islands. Another low approaches the Aleutians from the
North Pacific Wednesday night. The eastern Aleutians and the
southern Alaska Peninsula can expect another round of rain and
snow accompanied by southerly gale force winds on Thursday as the
low tracks into the eastern Bering.

&&

.Marine (Days 3 through 5: Thursday through Saturday)...

Gulf of Alaska: A surface low approaching the Bristol Bay area
will bring south to southeasterly winds near gale force through
the Barren Islands and Kamishak Bay along the frontal boundary
Friday morning. Winds weaken briefly before a second low moves
into the western Gulf and increasing winds as the low approaches
the coast into Saturday. Some model discrepancy exists in the
details, but winds could potentially reach well into gale force as
a barrier jet sets up along the northern Gulf coast and westerly
out of the Barrens and Kamishak Bay Saturday. Seas around 10 feet
in open waters on Thursday will build to 15 to 20 feet, with
slightly higher seas if high end gales are realized.

Bering Sea: A broad area of low pressure stretches across the
Bering for the last half of the week. Moderate confidence with the
location of this complex of low centers, one of which approaches
Bristol Bay with high end gales near the AKPen and southwestern
coast on Thursday. As the low moves north along the coast Friday,
winds will begin to weaken. Seas up to 20 to 25 feet near the
AKPen are possible with the low center approaching Bristol Bay.
Otherwise, seas are generally up to 10 to 15 feet over the Bering.

.Long Term Discussion (Days 4 through 7: Friday through Monday)...

A large area of low pressure over the Bering with a center
arriving near the Southwest coast on Friday morning will bring a
widespread area of unsettled weather across most of western
Alaska. South to southeasterly flow through Kamishak Bay will
increase gusty winds for inland Bristol Bay including Iliamna and
Koliganek areas on Friday. An elongated trough from this low
extends into the northern Gulf where coastal areas and portions of
Southcentral could expect snowfall Friday. A North Pacific low
will follow closely behind, bringing a second wave of
precipitation for Southcentral Saturday. A ridge will build across
the entirety of Southern Alaska beginning in the Central
Aleutians Friday and spread eastward through Sunday. Behind the
ridge is another complex of lows over the Aleutians that will push
from west to east and although there is some uncertainty with the
placement and orientation of these lows, a return to precipitation
is expected to arrive over the Southwest on Monday.

&&
.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Gale 155 165-179 185.
		 Heavy Freezing Spray 180.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...SS
SOUTHCENTRAL ALASKA...AF
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CQ
MARINE/LONG TERM...VR