Gale Warning 293, NWS Anchorage, AK

409 
FZAK61 PAFC 232344
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
344 PM AKDT Mon Apr 23 2018

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.

PKZ399-241315-
344 PM AKDT Mon Apr 23 2018
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...
A weak trough in the northern Gulf moves inland Tue morning. A 
strong front enters the western Gulf and reaches the central Gulf 
by Tue afternoon. The front moves to the eastern Gulf by Wed 
afternoon.

$$

PKZ351-241315-
Gulf of Alaska Offshore North of 57N and West of 144W-
344 PM AKDT Mon Apr 23 2018

...GALE WARNING TUESDAY...

.TONIGHT...S wind 10 to 25 kt. Seas 9 to 12 ft.
.TUE...S wind 20 to 35 kt. Seas 10 to 17 ft. Rain.
.TUE NIGHT...SW wind 15 to 30 kt. Seas 16 ft.
.WED...SW wind 10 to 20 kt. Seas 11 to 14 ft.
.WED NIGHT...SW wind 10 to 20 kt. Seas 11 ft.
.THU THROUGH SAT...W wind 10 to 20 kt. Seas 6 to 11 ft.

$$

PKZ352-241315-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
344 PM AKDT Mon Apr 23 2018

...GALE WARNING TUESDAY...

.TONIGHT...SW wind 25 kt becoming S after midnight. Seas 10 to
14 ft. Rain.
.TUE...S wind 25 to 40 kt. Seas 11 to 18 ft. Rain.
.TUE NIGHT...SW wind 15 to 30 kt. Seas 17 ft.
.WED...SW wind 10 to 25 kt. Seas 11 to 15 ft.
.WED NIGHT...SW wind 10 to 20 kt. Seas 11 to 14 ft.
.THU...SW wind up to 20 kt. Seas 8 to 13 ft.
.FRI THROUGH SAT...NW wind up to 10 kt. Seas 5 to 8 ft.

$$

612 
FZAK61 PAFC 241153
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
353 AM AKDT Tue Apr 24 2018

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.

PKZ399-250100-
353 AM AKDT Tue Apr 24 2018
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...
A strong front in the western Gulf of Alaska will weaken as it moves
into the eastern Gulf Tue night. A second front over the western 
Gulf Wed morning will stall and weaken through Thu morning.

$$

PKZ351-250100-
Gulf of Alaska Offshore North of 57N and West of 144W-
353 AM AKDT Tue Apr 24 2018

...GALE WARNING TODAY...

.TODAY...S wind 20 to 35 kt. Seas 10 to 17 ft. Rain.
.TONIGHT...SW wind 15 to 30 kt. Seas 16 ft.
.WED...SW wind 10 to 20 kt. Seas 13 ft.
.WED NIGHT...SW wind 10 to 20 kt. Seas 11 ft.
.THU THROUGH SAT...W wind 15 kt. Seas 6 to 10 ft.

$$

PKZ352-250100-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
353 AM AKDT Tue Apr 24 2018

...GALE WARNING TODAY...

.TODAY...S wind 25 to 40 kt. Seas 11 to 19 ft. Rain.
.TONIGHT...SW wind 15 to 30 kt. Seas 17 ft.
.WED...SW wind 10 to 25 kt. Seas 12 to 15 ft.
.WED NIGHT...SW wind 10 to 20 kt. Seas 10 to 14 ft.
.THU THROUGH SAT...W wind up to 20 kt. Seas 6 to 11 ft.

$$

405 
FZAK61 PAFC 242342
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
342 PM AKDT Tue Apr 24 2018

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.

PKZ399-251315-
342 PM AKDT Tue Apr 24 2018
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...
A strong front in the western Gulf of Alaska will weaken as it
moves into the eastern Gulf Tue night. Southwest flow will prevail
across the Gulf through Thursday afternoon.

$$

PKZ351-251315-
Gulf of Alaska Offshore North of 57N and West of 144W-
342 PM AKDT Tue Apr 24 2018

.TONIGHT...SW wind 15 to 30 kt. Seas 16 ft.
.WED...SW wind 10 to 20 kt. Seas 13 ft.
.WED NIGHT...SW wind 10 to 20 kt. Seas 11 ft.
.THU...SW wind 15 kt. Seas 7 to 10 ft.
.THU NIGHT...SW wind up to 15 kt. Seas 6 to 9 ft.
.FRI THROUGH SUN...W wind 10 to 20 kt. Seas 6 to 10 ft.

$$

PKZ352-251315-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
342 PM AKDT Tue Apr 24 2018

.TONIGHT...SW wind 15 to 30 kt. Seas 17 ft.
.WED...SW wind 10 to 25 kt. Seas 14 ft.
.WED NIGHT...SW wind 10 to 20 kt. Seas 10 to 13 ft.
.THU...SW wind up to 20 kt. Seas 9 to 12 ft.
.THU NIGHT...W wind up to 15 kt. Seas 9 ft.
.FRI THROUGH SUN...W wind up to 20 kt. Seas 6 to 10 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
444 PM AKDT Sun Apr 22 2018

.ANALYSIS AND UPPER LEVELS...
Upper lows over the eastern Bering Sea and western Aleutians and
a strong zonal jet south of the western Aleutians are the main
upper level features. At the surface, series of lows were evident
from the eastern Bering Sea to south of the Alaska Peninsula. A
970s low and its associated frontal system over the western Bering
Sea produced widespread rain and east-southeast gales across the
Aleutians and western Bering. A weakening frontal system along
with showers extended across Southwest Alaska. Cold advection on
the back side of the eastern Bering low produced widespread snow
showers across the eastern Bering Sea and Pribilof Islands. A
secondary gale force front over the northern Gulf was moving
rapidly north. Rain associated with this feature was fairly
widespread along the coast coast. Downslope drying, due to
easterly flow across the Chugach Mountains, mitigated
precipitation inland.

&&

.MODEL DISCUSSION...
Models are reasonable and in good synoptic agreement. The GFS was
used overall out west. The NAMNEST was used across Southcentral
to better capture mesoscale affects.

&&

.AVIATION...
PANC...VFR conditions will continue. Ceilings will likely lower
a bit during the day Monday as upper level flow shifts to south-
southwest, but low level southeasterly flow will keep them in
the VFR category. The Turnagain wind will bend into the airport
tomorrow afternoon and strengthen into the evening hours. In fact,
with pressure gradients rapidly tightening ahead of the next
system, the southeasterly winds may just continue to strengthen
all the way through Tuesday afternoon.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
Even as the gale force front slowly weakens as it makes landfall
over the North Gulf Coast this evening, an active weather pattern
for the Gulf and the South Mainland looks to continue into mid-
week. This first front will bring continued rain to much of the
North Gulf Coast and Prince William Sound into Monday before
slowly dissipating, while gusty winds through Turnagain Arm and
down Cook Inlet will diminish this evening. This will only provide
a brief respite in gusty winds along Turnagain Arm however as
these winds will begin to increase again during the afternoon.
This will occur as a developing trough of low pressure moves up
the West Coast, providing a strong pressure gradient along the
Chugach that will strengthen into Tuesday. This will bring strong
winds not only through Turnagain Arm, but also through the Knik
and Copper River Valleys. Gusty southeasterly winds also look to
develop in the Anchorage Bowl and Matanuska Valley for Tuesday as
the down inlet flow weakens. There is also a chance this gradient
will be strong enough to bring warning level gusts through
Turnagain Arm on Tuesday, which will need to continue to be
monitored as new model runs come in. Another change in this next
system will be for a greater risk of precipitation (mostly in the
form of rain) into interior Southcentral as the flow shifts to
southwesterly and conditions become more convective late Tuesday.
If enough cold air moves into the lower elevations of the Northern-
Western Susitna Valley, there could also be accumulating snow,
which could be significant as temperatures cool during the evening.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
The remnants of the Arctic trough will eject negatively tilted
energy towards Kuskokwim Bay and Bristol Bay. The radar for King
Salmon has been pretty active this afternoon with showers near
Pilot Point, Egegik and Dillingham. More precipitation is
anticipated tonight as that short-wave lifts northward. There
will be a very short break between storms, then the next Bering
system will be at the doorstep of Western and Southwest Alaska.
This storm will bring moderate to heavy rain along the coast.
Additional impacts include a fetch of southeast winds across
Bristol Bay and Hooper Bay resulting in enhanced waves and
potentially rough surf on Tuesday and Wednesday.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
At the onset of the forecast period there is a closed low over
the Eastern Bering and a second closed low near Attu Island. The
models continue to advertise gale force winds and rough seas for
much of the Bering due to these features. The remnants of the
Arctic trough/Eastern Bering disturbance will eject negatively
tilted energy toward Southwest Alaska tonight. Looking upstream,
the occluded system continues to march across the Western and
Central Aleutians. The surface low anchoring the occlusion will
push eastward on the Bering side of the Aleutians and then curve
northeastward late Tuesday. All the models imply that the gale
force winds are really associated with the cold sector of this
second system. In the wake of this frontal passage, the models
are currently building a ridge over the Western Aleutians.

&&

.LONG TERM FORECAST (Days 3 through 7)...
The long range forecast beginning Tuesday night will be in an
active pattern as a broad Bering low spins multiple shortwaves
around its perimeter which spans across the state and surrounding
waters. Onshore flow supplies abundant moisture for showers to
develop with the embedded shortwaves as they move around the low
center which brings higher precipitation chances for the southern
mainland through mid week.

Late Thursday, the Bering low is kicked eastward as the next low
races up from the North Pacific to the western Bering. Models are
in good agreement on the timing of this storm reaching the
central Aleutians early Friday morning; however, they diverge on
the timing and track of the system thereafter. The main challenge
for models is resolving a ridge that builds into the southern
Gulf ahead of the next approaching low. The ECMWF had the best
run to run consistency and also had good continuity between its
operational and ensemble solutions for the extended range
forecasts. Overall, only minor updates were made for second half
of the forecast as there is low confidence concerning the track
of the Bering low.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Gale warning 119 130 150 170 172 173 174 175 176 177 178
185.

&&

SYNOPSIS AND MODEL DISCUSSION...BC
SOUTHCENTRAL ALASKA...DEK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PS
LONG TERM...DK