Storm Warning 150, NWS Anchorage, AK

056 
FZAK62 PAFC 030016
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
316 PM AKST Sun Dec 2 2018

Offshore Waters Forecast for the Bering Sea

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.

PKZ499-031400-
316 PM AKST Sun Dec 2 2018
.SYNOPSIS FOR CENTRAL BERING SEA...
A 962 mb low at 46N 179E moves to 51N 172W at 974 mb by Tue 
afternoon. Its front wraps over the Aleutians and Bering into the
Southern Alaska Peninsula for Tue afternoon.

$$

PKZ411-031400-
Bering Sea Offshore West of 180 and East of the International
Dateline-
316 PM AKST Sun Dec 2 2018

...STORM WARNING THROUGH MONDAY NIGHT...

.TONIGHT...NE wind 20 to 35 kt increasing to 35 to 50 kt after
midnight. Seas 8 to 13 ft. Rain.
.MON...NE wind 35 to 50 kt. Seas 15 to 23 ft. Rain and snow.
.MON NIGHT...NE wind 40 to 50 kt. Seas 21 to 29 ft. Rain and snow.
.TUE...N wind 35 to 50 kt. Seas 24 to 29 ft.
.TUE NIGHT...N wind 30 to 45 kt. Seas 18 to 28 ft.
.WED...N wind 15 to 30 kt. Seas 12 to 20 ft.
.THU THROUGH FRI...W wind 15 to 30 kt. Seas 13 to 21 ft.

$$

PKZ412-031400-
Bering Sea Offshore 171W to 180 and North of 56N-
316 PM AKST Sun Dec 2 2018

...STORM WARNING MONDAY AND MONDAY NIGHT...

.TONIGHT...SE wind up to 20 kt becoming E 25 to 40 kt after
midnight. Seas 8 to 11 ft.
.MON...E wind 30 to 45 kt increasing to 40 to 50 kt in the
afternoon. Seas 15 to 23 ft. Rain and snow.
.MON NIGHT...NE wind 35 to 50 kt. Seas 20 to 28 ft. Rain.
.TUE...NE wind 35 to 50 kt. Seas 14 to 29 ft.
.TUE NIGHT...NE wind 30 to 45 kt. Seas 13 to 28 ft.
.WED...NE wind 20 to 35 kt. Seas 10 to 18 ft.
.THU...W wind up to 15 kt. Seas 7 to 12 ft.
.FRI...NW wind 25 kt. Seas 16 to 21 ft.

$$

PKZ413-031400-
Bering Sea Offshore 171W to 180 and South of 56N-
316 PM AKST Sun Dec 2 2018

...STORM WARNING THROUGH MONDAY...

.TONIGHT...E wind 30 to 45 kt increasing to 40 to 55 kt after
midnight. Seas 11 to 19 ft. Rain and snow.
.MON...E wind 40 to 55 kt. Seas 18 to 30 ft building to 24 to 29
ft in the afternoon. Rain.
.MON NIGHT...NE wind 30 to 45 kt. Seas 19 to 27 ft. Rain.
.TUE...NE wind 30 to 45 kt. Seas 15 to 23 ft.
.TUE NIGHT...N wind 30 to 45 kt. Seas 15 to 23 ft.
.WED...NW wind 15 to 30 kt. Seas 10 to 18 ft.
.THU...W wind 15 to 25 kt. Seas 12 to 15 ft.
.FRI...W wind 30 kt. Seas 20 ft.

$$

PKZ414-031400-
Bering Sea Offshore East of 171W-
316 PM AKST Sun Dec 2 2018

...STORM WARNING MONDAY AND MONDAY NIGHT...

.TONIGHT...S wind 10 to 25 kt becoming SE 25 to 40 kt after
midnight. Seas 8 to 12 ft.
.MON...E wind 40 to 55 kt. Seas 12 to 20 ft.
.MON NIGHT...E wind 35 to 50 kt. Seas 14 to 22 ft.
.TUE...SE wind 20 to 35 kt. Seas 11 to 16 ft.
.TUE NIGHT...SE wind 20 to 35 kt. Seas 9 to 15 ft.
.WED...SE wind 10 to 25 kt. Seas 5 to 10 ft.
.THU...SW wind up to 15 kt. Seas 5 to 10 ft.
.FRI...NW wind 15 to 30 kt. Seas 13 to 20 ft.

$$

074 
FZAK62 PAFC 031300
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
400 AM AKST Mon Dec 3 2018

Offshore Waters Forecast for the Bering Sea

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.

PKZ499-040145-
400 AM AKST Mon Dec 3 2018
.SYNOPSIS FOR CENTRAL BERING SEA...

A 961 mb low at 49N 178W Mon morning moves to 52N 174W at 968 mb by 
Tue morning and then moves to 53N 171W at 985 mb by Wed morning.

$$

PKZ411-040145-
Bering Sea Offshore West of 180 and East of the International
Dateline-
400 AM AKST Mon Dec 3 2018

...STORM WARNING THROUGH TONIGHT...

.TODAY...NE wind increasing to 35 to 50 kt. Seas 14 to 22 ft. Rain 
with snow.
.TONIGHT...NE wind 35 to 50 kt. Seas 20 to 27 ft. Rain with snow.
.TUE...N wind 30 to 45 kt. Seas 23 to 27 ft.
.TUE NIGHT...N wind 25 to 40 kt. Seas 18 to 27 ft.
.WED...NE wind 15 to 30 kt. Seas 11 to 19 ft.
.THU THROUGH FRI...NW wind 10 to 25 kt. Seas 9 to 14 ft.

$$

PKZ412-040145-
Bering Sea Offshore 171W to 180 and North of 56N-
400 AM AKST Mon Dec 3 2018

...STORM WARNING THROUGH TONIGHT...

.TODAY...E wind 30 to 45 kt increasing to 40 to 50 kt in the
afternoon. Seas 9 to 17 ft building to 15 to 23 ft in the
afternoon. Rain with snow.
.TONIGHT...NE wind 35 to 50 kt. Seas 19 to 27 ft. Rain.
.TUE...NE wind 30 to 45 kt. Seas 14 to 26 ft. Rain and snow.
.TUE NIGHT...NE wind 30 to 45 kt. Seas 15 to 23 ft.
.WED...NE wind 20 to 35 kt. Seas 13 to 21 ft.
.THU THROUGH FRI...N wind 10 to 20 kt. Seas 8 to 13 ft.

$$

PKZ413-040145-
Bering Sea Offshore 171W to 180 and South of 56N-
400 AM AKST Mon Dec 3 2018

...STORM WARNING TODAY...

.TODAY...E wind 45 to 55 kt diminishing to 35 to 50 kt in the
afternoon. Seas 13 to 27 ft. Rain.
.TONIGHT...E wind 35 to 45 kt becoming NE 25 to 35 kt after
midnight. Seas 17 to 26 ft. Rain.
.TUE...NE wind 25 to 40 kt. Seas 15 to 23 ft.
.TUE NIGHT...N wind 25 to 40 kt. Seas 14 to 22 ft.
.WED...N wind 15 to 30 kt. Seas 13 to 21 ft.
.THU THROUGH FRI...NW wind 15 to 30 kt. Seas 8 to 13 ft.

$$

PKZ414-040145-
Bering Sea Offshore East of 171W-
400 AM AKST Mon Dec 3 2018

...STORM WARNING THROUGH TONIGHT...

.TODAY...E wind increasing to 35 to 50 kt. Seas 11 to 19 ft.
.TONIGHT...E wind 35 to 50 kt. Seas 10 to 20 ft.
.TUE...SE wind 20 to 35 kt. Seas 10 to 16 ft.
.TUE NIGHT...SE wind 15 to 30 kt. Seas 9 to 13 ft.
.WED...E wind 10 to 25 kt. Seas 5 to 10 ft.
.THU THROUGH FRI...N wind 15 to 30 kt. Seas 6 to 11 ft.

$$

449 
FZAK62 PAFC 040026
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
326 PM AKST Mon Dec 3 2018

Offshore Waters Forecast for the Bering Sea

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.

PKZ499-041415-
326 PM AKST Mon Dec 3 2018
.SYNOPSIS FOR CENTRAL BERING SEA...
A 962 mb low at 51n 175W moves to 52N 168W at 990 mb by Wed
afternoon. Its front arches over the Aleutians and Bering and
pushes into the Gulf of Alaska for Wed afternoon. A 984 mb
Kamchatka low extends a front across the Western Aleutians through
Wed afternoon.

$$

PKZ411-041415-
Bering Sea Offshore West of 180 and East of the International
Dateline-
326 PM AKST Mon Dec 3 2018

...STORM WARNING TONIGHT...

.TONIGHT...NE wind 35 to 50 kt. Seas 20 to 27 ft. Rain and snow.
.TUE...N wind 30 to 45 kt. Seas 23 to 27 ft. Rain and snow.
.TUE NIGHT...N wind 30 to 45 kt diminishing to 20 to 35 kt after
midnight. Seas 18 to 27 ft.
.WED...NE wind 15 to 30 kt. Seas 13 to 21 ft.
.WED NIGHT...E wind up to 20 kt. Seas 9 to 15 ft.
.THU THROUGH FRI...NW wind 10 to 25 kt. Seas 9 to 14 ft.
.SAT...SE wind 15 to 25 kt. Seas 7 to 12 ft.

$$

PKZ412-041415-
Bering Sea Offshore 171W to 180 and North of 56N-
326 PM AKST Mon Dec 3 2018

...STORM WARNING TONIGHT...

.TONIGHT...NE wind 35 to 50 kt. Seas 20 to 29 ft. Rain and snow.
.TUE...NE wind 30 to 45 kt. Seas 14 to 26 ft. Snow with rain
showers.
.TUE NIGHT...NE wind 30 to 45 kt. Seas 15 to 25 ft. Snow showers.
.WED...NE wind 20 to 35 kt. Seas 13 to 21 ft.
.WED NIGHT...N wind 10 to 25 kt. Seas 10 to 15 ft.
.THU THROUGH FRI...N wind 10 to 20 kt. Seas 8 to 13 ft.
.SAT...E wind 10 to 20 kt. Seas 6 to 11 ft.

$$

PKZ413-041415-
Bering Sea Offshore 171W to 180 and South of 56N-
326 PM AKST Mon Dec 3 2018

...GALE WARNING THROUGH TUESDAY NIGHT...

.TONIGHT...E wind 35 to 45 kt becoming NE 25 to 35 kt after
midnight. Seas 18 to 29 ft. Rain showers.
.TUE...NE wind 20 to 35 kt increasing to 30 to 45 kt in the
afternoon. Seas 15 to 25 ft. Rain showers.
.TUE NIGHT...N wind 25 to 40 kt. Seas 14 to 22 ft.
.WED...N wind 15 to 30 kt. Seas 13 to 21 ft.
.WED NIGHT...N wind up to 20 kt. Seas 11 to 16 ft.
.THU THROUGH FRI...NW wind 15 to 30 kt. Seas 8 to 13 ft.
.SAT...S wind up to 20 kt. Seas 6 to 11 ft.

$$

PKZ414-041415-
Bering Sea Offshore East of 171W-
326 PM AKST Mon Dec 3 2018

...STORM WARNING TONIGHT...

.TONIGHT...E wind 35 to 50 kt. Seas 13 to 24 ft. Rain.
.TUE...SE wind 20 to 35 kt. Seas 10 to 17 ft. Rain.
.TUE NIGHT...SE wind 15 to 30 kt. Seas 10 to 13 ft.
.WED...E wind 10 to 25 kt. Seas 7 to 11 ft.
.WED NIGHT...E wind up to 20 kt. Seas 4 to 9 ft.
.THU THROUGH SAT...NW wind 15 to 30 kt. Seas 6 to 11 ft.

$$

138 
FZAK62 PAFC 041256
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
356 AM AKST Tue Dec 4 2018

Offshore Waters Forecast for the Bering Sea

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.

PKZ499-050130-
356 AM AKST Tue Dec 4 2018
.SYNOPSIS FOR CENTRAL BERING SEA...

A 970 mb low at 52N 174W Tue morning moves to 52N 171W at 985 mb by 
Wed morning and then moves to 53N 154W at 989 mb by Thu morning. 

$$

PKZ411-050130-
Bering Sea Offshore West of 180 and East of the International
Dateline-
356 AM AKST Tue Dec 4 2018

...GALE WARNING THROUGH TONIGHT...

.TODAY...N wind 30 to 45 kt. Seas 24 to 27 ft. Rain and snow.
.TONIGHT...N wind 25 to 40 kt. Seas 18 to 27 ft.
.WED...NE wind 15 to 30 kt. Seas 14 to 21 ft.
.WED NIGHT...E wind 10 to 20 kt. Seas 10 to 14 ft.
.THU THROUGH FRI...N wind 10 to 25 kt. Seas 9 to 14 ft.
.SAT...SE wind 15 to 25 kt. Seas 7 to 12 ft.

$$

PKZ412-050130-
Bering Sea Offshore 171W to 180 and North of 56N-
356 AM AKST Tue Dec 4 2018

...GALE WARNING THROUGH WEDNESDAY...

.TODAY...NE wind 30 to 45 kt. Seas 15 to 26 ft. Snow with rain
showers.
.TONIGHT...NE wind 30 to 45 kt. Seas 15 to 23 ft. Snow showers.
.WED...N wind 20 to 35 kt. Seas 14 to 22 ft.
.WED NIGHT...N wind 15 to 30 kt. Seas 10 to 16 ft.
.THU THROUGH FRI...N wind 10 to 25 kt. Seas 8 to 13 ft.
.SAT...E wind up to 20 kt. Seas 6 to 11 ft.

$$

PKZ413-050130-
Bering Sea Offshore 171W to 180 and South of 56N-
356 AM AKST Tue Dec 4 2018

...GALE WARNING THROUGH TONIGHT...

.TODAY...NE wind 20 to 30 kt increasing to 25 to 40 kt in the
afternoon. Seas 13 to 21 ft. Rain showers.
.TONIGHT...N wind 25 to 40 kt. Seas 14 to 22 ft.
.WED...N wind 15 to 30 kt. Seas 12 to 20 ft.
.WED NIGHT...N wind up to 20 kt. Seas 11 to 16 ft.
.THU THROUGH FRI...NW wind 15 to 30 kt. Seas 8 to 13 ft.
.SAT...S wind up to 20 kt. Seas 6 to 11 ft.

$$

PKZ414-050130-
Bering Sea Offshore East of 171W-
356 AM AKST Tue Dec 4 2018

.TODAY...SE wind 20 to 30 kt. Seas 10 to 16 ft. Rain.
.TONIGHT...SE wind 15 to 30 kt. Seas 9 to 13 ft.
.WED...E wind 10 to 25 kt. Seas 7 to 10 ft.
.WED NIGHT...NE wind up to 20 kt. Seas 4 to 9 ft.
.THU THROUGH SAT...NW wind 10 to 25 kt. Seas 7 to 12 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
447 PM AKST Sat Dec 1 2018

.ANALYSIS AND UPPER LEVELS...
A look at the large scale flow shows a long-wave trough
encompassing the Bering Sea and western Alaska, with a
downstream ridge over the Northeast Pacific extending northward
across the Gulf and the eastern part of Alaska. A seasonably
strong and undulating upper level jet stream supports multiple
storm systems tracking quickly from the North Pacific to mainland
Alaska.

As for specifics, a surface low is tracking inland across Southwest
Alaska with a robust negatively tilted trough aloft. Temperatures
are warm enough for rain from Bristol Bay to the Kuskokwim Valley.
Meanwhile, over Southcentral isentropic lift and upslope flow are
leading to areas of precipitation, mainly along the Gulf coast,
Cook Inlet, and up the Susitna Valley. Precipitation is falling as
mainly rain along the coast with snow inland. The tail end of the
upper level short-wave over Southwest Alaska is headed for Cook
Inlet, which will help intensify precipitation. Tight east-west
pressure gradients are leading to gusty gap winds, particularly
through Turnagain Arm. Gale force winds are also being observed
across the western Gulf waters as a cold front approaches from the
west. As the low over Southwest Alaska continues northward this
afternoon, southerly winds will spread inland across Southcentral.

The next system in line is a mature, compact gale force low in
the vicinity of the Eastern Aleutians. This low is on a more
westerly track than the one over Southwest, headed north-northeast
into the Bering Sea and toward the Kuskokwim Delta coast. A third
large and deep low is well south of the Aleutian chain, but
tracking northward as the upper trough digs across the North
Pacific and amplifies the upper level flow. Weather across the
remainder of the bering Sea and Aleutians is showery with gusty
winds.

&&

.MODEL DISCUSSION...
Model guidance is in good agreement with these fast moving systems,
with just some minor timing differences (3 to 6 hours). The biggest
forecast challenge will be precipitation type, particularly for
Southcentral.

&&

.AVIATION...
PANC...Strong southeasterly Turnagain winds will shift to more
southerly late this evening as the current storm exits across
Interior Alaska. Pressure gradients will then rapidly diminish
after about 09Z, so winds should die down quickly. There is a
shot of precipitation between 00Z and 06Z, but with some cross
barrier flow think VFR conditions will prevail. There could be a
very brief period of MVFR as flow shifts around to southerly. The
well mixed boundary layer will support mostly rain as this passes
through. Looks like good clearing behind this, but short-lived as
the next round of precipitation approaches late Sunday afternoon.
Forecast soundings indicate precipitation will likely start as
rain, but as it intensifies Sunday evening, would expect a change
to snow.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)...
Colder air advecting into Southcentral behind a cold front will
allow increased precipitation coverage for the region with snow
showers continuing. North of Talkeetna, increased lift via
orographics will keep the snow going through early morning,
before a brief lull develops. Then in the afternoon, widespread
snow will develop from west to east through the Sunday
night/Monday morning time frame.

For the Matanuska Valley and Anchorage metro, the 12z hi-res
models and Canadian Regional increased precipitation amounts
compared to previous runs, with the 18z run of the keeping pace
for the most part. The operational NAM decreased precip amounts
some and is more in line with the other models, as is the GFS. The
main issue looks to be how quickly the Turnagain winds shuts down
and how quickly the colder air rushes in as another storm affects
the region Sunday night. Significant snowfall is expected from
Sunday afternoon through Sunday night for Anchorage through the
Matanuska and Susitna valleys.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3)...
An active weather pattern is underway as one low exits Southwest
this evening, leaving isolated to scattered rain showers (with
some snow showers over the Lower Kuskokwim Valley). The next low
is currently moving over Dutch Harbor and will move inland late
tonight and Sunday. This will bring another shot of rain and snow
with light accumulations mainly over the Kuskokwim Delta area. The
low is rather fast moving and compact, but there will be
potential blowing snow over the Delta where strong west southwest
winds will develop behind the low. Otherwise, this low exits
Sunday night and high pressure aloft builds in through Monday
night before a warm front and southeast flow develops and moves
into Southwest on Tuesday, bringing strong southeast winds and
more rain/snow chances.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3)...
Two compact gale force lows inhabit the Bering/Aleutians this
evening, with the main impactful low currently over Dutch Harbor
moving northeast towards Bristol Bay. This low will move inland
tonight with attention turning to a large developing storm force
low which will move into the southwest Bering Sea Sunday afternoon
and evening. Expect gusts to near 60-70 MPH along the Aleutian
Chain from Atka westward with low end storm force gusts from Dutch
Harbor east. The low will eventually drift north and fill the
entire Bering Sea through Tuesday as the front moves inland.

&&

.LONG TERM FORECAST (Days 3 through 7)...
The forecast period commences with a longwave trough spanning
from the Central Bering to the North Pacific and a high amplitude
ridge over the Gulf Of Alaska extending into the Yukon Territory.
The GFS/ECMWF and Canadian all ping into several potent shortwaves
embedded in the upper level trough. At the surface, there is a
deep mature low near the central Aleutians, however the GFS has
the surface low south of Nikolski at 12Z Wednesday and the ECMWF
has the surface low near St. Paul at 12Z Wednesday. Additionally,
to the west, the same models are out of sync with the cyclone over
the Sea Of Okhotsk. As time elapses, expect this eastern low to
rapidly decay. The GFS continues to keep the remnants south of the
chain and the ECMWF keeps it quasi-stationary over the Bering.
With the cyclone near Russia, the GFS is more bullish bringing it
into the Bering. By late Thursday/Friday the next round of
cyclogenesis is well under way in the vicinity of the Gulf Of
Alaska. The intensity and the track of this new low is present on
both the GFS and ECMWF but the timing is slightly off. Generally
expecting a progressive and active pattern.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Storm Warning 172>178.
 Gale Warning 155 160 165 170 171 180.

&&

SYNOPSIS AND MODEL DISCUSSION...SB
SOUTHCENTRAL ALASKA...PD
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JA
LONG TERM...PJS