Storm Warning 126, NWS Anchorage, AK

509 
FZAK61 PAFC 231200
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
400 AM AKDT Wed Oct 23 2019

Offshore waters forecast for the Gulf of Alaska West of 144W

Wind forecasts reflect the predominant speed and direction
expected. Sea forecasts represent an average of the highest
one-third of the combined wind wave and swell height.

PKZ399-240030-
400 AM AKDT Wed Oct 23 2019
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A front associated with a 959 mb eastern Bering low remains over 
the Gulf through Fri morning. The low weakens to 981 mb Thu 
morning over the Alaska Peninsula before moving to 60N 145W at 
1003 mb Fri morning.

NOTICE: Please comment on a U.S. Coast Guard proposal to terminate
medium frequency NAVTEX broadcasts. Visit https://go.usa.gov/xVHc3
to submit comments by November 12, 2019.

$$

PKZ351-240030-
Gulf of Alaska Offshore North of 57N and West of 144W-
400 AM AKDT Wed Oct 23 2019

...GALE WARNING THROUGH THURSDAY...

.TODAY...SE to SW wind 30 to 45 kt. Seas 18 to 28 ft. Slight chance 
of thunderstorms this afternoon.
.TONIGHT...SW wind 30 to 45 kt. Seas 22 to 28 ft. Slight chance of
thunderstorms.
.THU...S wind 30 to 40 kt becoming SW 20 to 30 kt in the
afternoon.
Seas 17 to 22 ft.
.THU NIGHT...W wind 20 to 35 kt. Seas 15 to 18 ft.
.FRI...W wind 20 to 35 kt. Seas 9 to 14 ft.
.SAT...S wind 15 to 30 kt. Seas 7 ft.
.SUN...S wind 20 to 30 kt. Seas 11 to 17 ft.

$$

PKZ352-240030-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
400 AM AKDT Wed Oct 23 2019

...STORM WARNING TODAY...

.TODAY...SE to SW wind 35 to 50 kt. Seas 19 to 32 ft. Slight chance 
of thunderstorms this afternoon.
.TONIGHT...SW wind 35 to 45 kt. Seas 22 to 30 ft. Slight chance of
thunderstorms. 
.THU...SW wind 25 to 40 kt. Seas 18 to 23 ft.
.THU NIGHT...W wind 25 to 35 kt. Seas 16 to 19 ft.
.FRI...SW wind 15 to 30 kt. Seas 8 to 16 ft.
.SAT...S wind 20 to 35 kt. Seas 9 to 14 ft.
.SUN...S wind 30 kt. Seas 14 to 21 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion...CORRECTED
National Weather Service Anchorage AK
839 AM AKDT Tue Oct 22 2019

.ANALYSIS AND UPPER LEVELS...
The upper level low which has been anchored in the central Bering
is now starting to drift slowly south. Numerous shortwaves
continue to rotate around the periphery of the broad low with
several open waves pushing south through the western Bering and
over the western and central Aleutians. An upper level trough
with an associated surface low is located just to the south of
the eastern Aleutians and western Alaska Peninsula, with another
upper trough and surface low near Nunivak Island. Weak troughing
extends into the southwestern Gulf with ridging building into the
central and eastern Gulf following the low pressure system
tracking inland into British Columbia. The next incoming storm is
in the process of spinning up well to the south of the eastern
Aleutians.

&&

.MODEL DISCUSSION...
Models have come into good agreement regarding the track and
strength of the very strong low moving north towards the Alaska
Peninsula and Bristol Bay area tonight through Wednesday. This is
also the case with the rather powerful north Pacific low tracking
in from the west to the south of the Aleutians Thursday.

&&

.AVIATION...
PANC...VFR conditions are expected to prevail through Wednesday
morning. Easterly winds across the Chugach Mountains and through
Turnagain Arm will increase rapidly tonight through Wednesday
morning. While a northerly gradient down Cook Inlet is expected
to keep the stronger surface winds bent away from the terminal,
wind shear due to stronger easterly winds aloft will be a
potential concern.

&&

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

A strong low will begin to track east of the Kenai Peninsula this
evening. Easterly winds will rapidly increase Wednesday morning
across coastal areas along Prince William Sound as well as the
Whitter region and Turnagain Arm. The Turnagain Arm area is
expected to peak late Wed morning at around 60 mph with gusts
near 70 mph. Gusty northeasterly winds around 30 mph are also
likely in the Matanuska Valley at the same time. Periods of heavy
rain are expected along the associated front. However the Mat-Su
Valleys, Anchorage and the Western Kenai will be heavily
downsloped in cross barrier flow and thus precipitation will be
limited in those areas.

As the low moves onshore in SW AK Wednesday afternoon, it will
become vertically stacked and begin to slowly weaken. However,
strong southerly winds on the eastern side of the circulation will
continue to advect moisture northward into the Seward area, which
could see up to 2" of rain through early Thursday morning. Winds
will likewise diminish over the same time period. As such, areas
that were originally downsloped could begin to see light showers
by the afternoon.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...

Drying conditions and weak winds will persist through the first
half of today across the Southwest before a pattern change moves
in later this afternoon. A strengthening North Pacific low will
make its first impact to interior Bristol Bay this afternoon into
the early evening hours. Strong northeasterly winds and widespread
precipitation will accompany this system as it continues its path
northward towards the lower Kuskokwim Valley and Delta for
Wednesday. Precipitation associated with this low should fall as
rain for most locations, with the exception to locations in the
Kuskokwim Delta that may have cold enough temperatures to start
off as snow. This will quickly transition to rain once the warmer
air moves in. As the systems begins to move eastward on Thursday,
precipitation begins to taper off through the afternoon hours,
leaving only a few lingering showers across the region. Winds
will also begin to weaken, switching over to a north-northwesterly
flow as the low continues to exit the area.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...

The area of low pressure near the Pribilofs will continue to
weaken through the afternoon hours, while small craft northerly
flow remains over the central and western Bering through Wednesday.

This afternoon will see its first impacts from the North Pacific
low that is quickly deepening as it makes its way towards the
AKPEN. Gale force winds will move into areas south of the AKPEN
and into Bristol Bay starting this afternoon as the low's center
continues to move over Chignik in the overnight hours. Winds will
increase to storm-force on the south side of this low center
later tonight and through Wednesday evening. Wave heights will
quickly increase to between 25 and 30 feet in the coastal waters,
with up to nearly 40 foot seas southwest of Kodiak Island. As
the flow becomes northerly over the eastern Bering Wednesday
morning, winds will increase to gale-force for much of the day
before weakening to small crafts through Thursday morning.

The next potential storm-force low system begins to enter the
western Aleutians and Bering on Thursday morning. See the Marine
and Long Term discussions for more details on this system.

&&

.MARINE (Days 3 through 5)...
For the Gulf side, the main concern on Thursday is with the
progression of a low across the Gulf. Models vary on the track of
the low resulting in differences of northwest winds near the
Barren Islands ranging from gale force to light winds. Currently a
more northerly low track seems more favorable resulting in small
craft winds through the Barrens, but confidence is low.

The focus then shifts to a system approaching the western
Aleutians Thursday. There is high confidence with this system
being storm force into Friday. Confidence diminishes over the
weekend as the low moves into the Bering and the models diverge
with its track.

&&

.LONG TERM FORECAST (Days 3 through 7)...
The long term, beginning on Thursday, has one low exiting the
Gulf and a new low approaching the western Aleutians from the
North Pacific. The North Pacific low is bringing a long fetch of
warm air and moisture with it. As the low tracks east on Friday,
ridging will build in over the southern mainland. On Saturday the
ridge will block the progression of the low and the low will start
to track north into the Bering. Model confidence is low with how
the low will move into the Bering, however there is high
confidence of an atmospheric river setting up between the low and
the ridge. Models are also starting to converge on a more western
setup of the atmospheric river which places it closer to the
Alaska Peninsula.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Storm Warning 119 131 132 138 150 155.
		 Gale Warning 120 125 129 130 136 137 139 140 141 160 165 170
					  172 180 181 414.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...JER
SOUTHCENTRAL ALASKA...AP
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...AH
MARINE/LONG TERM...DK