Storm Warning 27, NWS Anchorage, AK

928 
FZAK62 PAFC 180028
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
328 PM AKST Sat Feb 17 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.

PKZ499-181345-
328 PM AKST Sat Feb 17 2018
.SYNOPSIS FOR CENTRAL BERING SEA...
A 997 mb low at 57N 179W moves to the Chukchi Sea at 994 mb Sun 
night. The associated front pushes over Northwest Alaska with the
trailing front over the Eastern Aleutians through Mon afternoon. 
A 962 mb North Pacific moves to 59N 175E at 967 mb by Mon 
afternoon.

$$

PKZ411-181345-
Bering Sea Offshore West of 180 and East of the International
Dateline-
328 PM AKST Sat Feb 17 2018

...GALE WARNING SUNDAY AND SUNDAY NIGHT...

.TONIGHT...SW wind 20 kt. Seas 9 to 14 ft.
.SUN...SE wind 15 to 30 kt becoming E 25 to 40 kt in the
afternoon. Seas 8 to 11 ft building to 9 to 17 ft in the afternoon. 
Snow and rain.
.SUN NIGHT...SE wind 25 to 35 kt. Seas 16 to 20 ft. Rain.
.MON...SW wind 30 to 45 kt. Seas 17 to 31 ft.
.MON NIGHT...SW wind 35 to 50 kt. Seas 19 to 34 ft.
.TUE...SW wind 20 to 35 kt. Seas 13 to 21 ft.
.WED...S wind up to 20 kt. Seas 6 to 10 ft.
.THU...S wind 25 kt. Seas 9 to 16 ft.

$$

PKZ412-181345-
Bering Sea Offshore 171W to 180 and North of 56N-
328 PM AKST Sat Feb 17 2018

...GALE WARNING SUNDAY AND SUNDAY NIGHT...

.TONIGHT...SW wind 15 to 25 kt. Seas 11 to 16 ft. Rain.
.SUN...SW wind 15 to 25 kt becoming SE 25 to 40 kt in the
afternoon. Seas 10 to 14 ft. Snow and rain.
.SUN NIGHT...SE wind 30 to 45 kt. Seas 13 to 20 ft building 
to 19 to 25 ft after midnight. Rain.
.MON...S wind 30 to 45 kt. Seas 22 to 32 ft.
.MON NIGHT...SW wind 30 to 45 kt. Seas 25 to 35 ft.
.TUE...SW wind 25 to 40 kt. Seas 13 to 28 ft.
.WED THROUGH THU...S wind 10 to 20 kt. Seas 7 to 12 ft.

$$

PKZ413-181345-
Bering Sea Offshore 171W to 180 and South of 56N-
328 PM AKST Sat Feb 17 2018

...GALE WARNING SUNDAY AND SUNDAY NIGHT...

.TONIGHT...SW wind 15 to 25 kt. Seas 9 to 13 ft.
.SUN...SE wind 20 to 35 kt increasing to 30 to 45 kt in 
the afternoon. Seas 11 to 19 ft. Rain.
.SUN NIGHT...S wind 35 to 45 kt. Seas 19 to 25 ft. Rain.
.MON...SW wind 30 to 45 kt. Seas 20 to 30 ft.
.MON NIGHT...SW wind 25 to 40 kt. Seas 16 to 31 ft.
.TUE...SE wind 10 to 25 kt. Seas 10 to 18 ft.
.WED THROUGH THU...S wind 10 to 25 kt. Seas 6 to 11 ft.

$$

PKZ414-181345-
Bering Sea Offshore East of 171W-
328 PM AKST Sat Feb 17 2018

...GALE WARNING THROUGH SUNDAY NIGHT...

.TONIGHT...S wind 30 to 45 kt becoming SW 20 to 30 kt after
midnight. Seas 11 to 19 ft.
.SUN...SW wind 15 to 25 kt becoming S 20 to 35 kt in the
afternoon. Seas 10 to 14 ft.
.SUN NIGHT...SE wind 30 to 45 kt. Seas 12 to 20 ft. Rain.
.MON...S wind 30 to 40 kt. Seas 15 to 23 ft.
.MON NIGHT...SW wind 20 to 35 kt. Seas 12 to 20 ft.
.TUE...S wind 15 to 30 kt. Seas 10 to 18 ft.
.WED THROUGH THU...S wind 10 to 20 kt. Seas 5 to 8 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
453 AM AKST Sat Feb 17 2018

.ANALYSIS AND UPPER LEVELS...
A high amplitude long wave ridge is currently over the western
third of the mainland and moving east over southcentral bringing
rather tranquil weather to the southern half of the state.
Clearing skies and rather weak offshore winds have lead to the
development of low stratus and fog over the Knik Arm and Anchorage
Bowl early this morning. Further west, satellite imagery shows a
broad cirrus shield advecting north and east over the top of the
ridge out ahead of a longwave trough which is located over the
western Bering Sea. A strong southerly jet is currently moving
over the central and eastern Aleutians supporting a surface low in
the Bering. A front out ahead of the low is sweeping east across
the island chain bringing storm force winds and heavy rain to
places like Dutch Harbor and Akutan.

&&

.MODEL DISCUSSION...
Models remain in good agreement through the mid-term as a front
moves across SW Alaska Sunday morning then falls apart as it
reaches southcentral by Sunday night. All models have now come
into agreement that as the front reaches southcentral the main
lobe of energy will split off from the trough and form a weak
surface low in the Gulf, keeping most of the precipitation well
south of southcentral.

&&

.AVIATION...
PANC...Clear skies and weak flow have led to the re-development
of low stratus over the Knik Arm early this morning, which has
advected into the Anchorage Bowl, staying mostly over south and
west Anchorage so far. Webcams show the stratus to be patchy in
nature so only expect intermittent LIFR conditions over the
terminal this morning before clearing up by noon.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
An upper level ridge will slowly move eastward across southern
Alaska through tonight. The low level flow is fairly weak inland,
and some fog is expected, especially near Cook Inlet. On Sunday
an upper level trough will move through the ridge. This will bring
rain to Kodiak Island beginning around noon and ending some time
in the evening. Precipitation chances are less further north, but
there is at least a slight chance Sunday evening for the Cook
inlet area through the Susitna Valley. This system will rapidly
move east, exiting into Canada Monday morning.

&&

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

A high amplitude upper level pattern is in the midst of developing
this morning as ridging aloft builds over Southwest Alaska. Dry
offshore flow will be dominant today and this evening before the
warm front over the Bering Sea moves inland tonight and moves
eastward through Sunday. Enough cold air will be in place for at
least some snow across most of Southwest Alaska although rain will
likely mix in, especially along the immediate coast line and in
the lee of the large mountain ranges. The heaviest snow
accumulations will be from Dillingham north and west where 2 to 5
inches of snowfall is possible. The front clears the Alaska Range
Sunday evening with dry conditions remaining through the daytime
Monday.

&&

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

The storm track will remain over the Bering Sea for the
foreseeable future as a strong gale force front this morning moves
east toward the Southwest Alaska coast. Gusts along the Eastern
Aleutians will reach into the low 60 MPH range, especially in
favored gaps with southerly winds.

A large gale force low (with some storm force winds mixed in)
over the Western Aleutians will move into the Bering Sunday and
will remain over the Bering Sea through Monday as it slowly tracks
northward toward the Bering Strait. Long fetch southwest winds
behind the low will support sea states as high as 30-35 feet on
Monday and Monday evening over the Bering Sea outer waters.

&&

.LONG TERM FORECAST (Days 3 through 7)...

Long term period starts off with increased uncertainty due to
models suddenly diverging with the movement of the low across
Southcentral Alaska and the Gulf of Alaska. Most reasonable
approach to Sunday night through Monday is to nudge precipitation
chances down over most of Southcentral Alaska and increase them
some in the Gulf. The Bering Sea storm at that same time frame
seems to still be on track with a deep low in the western Bering
Sea and general south to southwest flow over most of the Bering
Sea into Southwest mainland Alaska. After Monday, there is still a
high likelihood that there will be a general progressive pattern
over that region with a high amplitude upper level ridge building
over the mainland part of the state which will usher in warmer
temperatures. This ridge looks to get displaced later in the week
by a trough and hence the progressive pattern. The big
uncertainty remains the timing of these features as models have
not been consistent with one another or even with themselves on a
run-to-run basis. So what does all this mean for the sensible
weather next week? A warm up for the middle of the week with a
chance of precipitation. Precipitation type may be mixed for
inland areas in both Southwest and Southcentral Alaska mid-week so
that will be something to keep an eye on.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Storms: 173 175
Gales: 150 155 160 165 170 171 172 174 176-181 185 411-414 .

&&

SYNOPSIS AND MODEL DISCUSSION...KVP
SOUTHCENTRAL ALASKA...BL
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JA
LONG TERM...EZ