Gale Warning 690, NWS Anchorage, AK

014 
FZAK62 PAFC 230029
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
329 PM AKST Fri Dec 22 2017

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.

PKZ499-231330-
329 PM AKST Fri Dec 22 2017
.SYNOPSIS FOR CENTRAL BERING SEA...
A 978 mb low at 61N 178W moves to the Gulf of Anadyr tonight. A 
second low enters the southeastern Bering tonight at 988 mb near 
57N 165W and moves to 63N 169W Sun afternoon at 1001 mb. A front 
remains nearly stationary along the eastern Bering through the 
forecast period. Another low approaches the western Aleutians Sun 
afternoon at 1007 mb. 

$$

PKZ411-231330-
Bering Sea Offshore West of 180 and East of the International
Dateline-
329 PM AKST Fri Dec 22 2017

.TONIGHT...W wind 15 to 30 kt. Seas 8 to 13 ft. Freezing spray.
.SAT...SW wind 10 to 25 kt. Seas 7 to 12 ft. Freezing spray.
.SAT NIGHT...W wind 15 to 30 kt. Seas 8 to 13 ft. Freezing spray.
.SUN...NW wind 15 to 30 kt. Seas 8 to 13 ft.
.SUN NIGHT...NW wind 15 to 30 kt. Seas 8 to 13 ft.
.MON...N wind 15 to 30 kt. Seas 7 to 12 ft.
.TUE...SE wind 20 to 35 kt. Seas 8 to 13 ft.
.WED...SE wind 25 to 35 kt. Seas 12 to 20 ft.

$$

PKZ412-231330-
Bering Sea Offshore 171W to 180 and North of 56N-
329 PM AKST Fri Dec 22 2017

...GALE WARNING TONIGHT...

.TONIGHT...W wind 20 to 35 kt. Seas 12 to 19 ft. Freezing spray.
.SAT...NW wind 15 to 30 kt. Seas 8 to 13 ft.
.SAT NIGHT...NE wind 10 to 25 kt. Seas 6 to 11 ft.
.SUN...SW wind 10 to 25 kt. Seas 7 to 12 ft.
.SUN NIGHT...SW wind 10 to 25 kt. Seas 8 to 12 ft.
.MON...NW wind 15 to 30 kt. Seas 7 to 12 ft.
.TUE THROUGH WED...E wind 10 to 25 kt. Seas 4 to 8 ft.

$$

PKZ413-231330-
Bering Sea Offshore 171W to 180 and South of 56N-
329 PM AKST Fri Dec 22 2017

.TONIGHT...W wind 15 to 30 kt. Seas 10 to 18 ft.
.SAT...W wind 10 to 25 kt. Seas 7 to 12 ft.
.SAT NIGHT...W wind 10 to 25 kt. Seas 6 to 11 ft.
.SUN...NW wind 15 to 30 kt. Seas 7 to 12 ft.
.SUN NIGHT...NW wind 15 to 30 kt. Seas 10 ft.
.MON...N wind 15 to 30 kt. Seas 8 to 11 ft.
.TUE THROUGH WED...E wind 10 to 25 kt. Seas 6 to 11 ft.

$$

PKZ414-231330-
Bering Sea Offshore East of 171W-
329 PM AKST Fri Dec 22 2017

...GALE WARNING THROUGH SATURDAY NIGHT...

.TONIGHT...NW wind 20 to 35 kt. Seas 9 to 17 ft. Rain and snow.
.SAT...NW wind 25 to 40 kt. Seas 11 to 17 ft. Snow with rain.
.SAT NIGHT...NW wind 25 to 40 kt. Seas 9 to 17 ft.
.SUN...NW wind 15 to 30 kt. Seas 6 to 11 ft.
.SUN NIGHT...NW wind up to 15 kt. Seas 7 ft.
.MON...S wind 10 to 25 kt. Seas 5 to 9 ft.
.TUE THROUGH WED...NE wind up to 20 kt. Seas 3 to 8 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion...CORRECTED
National Weather Service Anchorage AK
935 PM AKST Thu Dec 21 2017

.ANALYSIS AND UPPER LEVELS...
A broad negatively tilted upper trough extends from eastern Russia
southeast to over the northeast Pacific. To its east a relatively
warm upper ridge extends northwest across the Gulf of Alaska to
over the mainland. At the surface, a series of lows, associated the
with upper trough, extend from the western Bering Sea to south of
the Alaska Peninsula. The most significant of the surface
features is a 980s low heading north toward the Alaska Peninsula
and associated leading front. Strong easterly winds ahead of these
features extend from the Gulf and Ak Pen to the eastern
Bering/Bristol Bay. Rain was evident across the AK Pen and was
approaching Kodiak Island and the north Bristol Bay coast.
Satellite imagery shows a broad Cirrus shield associated with
mountain wave turbulence and warm advection extending to the lee
of the Ak Pen and Aleutian Range. Elsewhere, strong and gusty
winds with showers were evident across the central and western
Aleutians/Bering Sea.

&&

.MODEL DISCUSSION...
Guidance continues to have a good handle on the synoptics of the
pattern, but struggle a bit with phasing of the Pacific system
into the Bering Sea trough. All guidance phases the system, but
how much and exactly where the resultant surface low sets up are
still in question.

&&

.AVIATION...
PANC...Generally VFR conditions and light surface winds will
persist. Cross barrier flow will increase tonight and bring in
potential for LLWS across the airport complex.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
"Dirty" upper level ridging is building over Southcentral ahead
of a rather impressive warm front which will track across
Southwest Alaska tonight and tomorrow. A very dense cirrus cloud
shield has formed in association with a elongated mountain wave
along the Alaska Peninsula and Eastern Aleutians, with the cirrus
wrapping anticyclonically over Southcentral (hence the "dirty"
upper ridging as that is more commonly associated with more clear
weather). There is also extensive low status and fog over the
Copper River Basin associated with a strong surface high and
stagnant air. The main weather feature of interest the next two
days will be a strong storm force front moving into the Gulf of
Alaska. This will bring 3-6" of rainfall for Kodiak Island along
with strong easterly winds. Beyond this, interior weather will be
rather banal given the dry offshore flow and moderate inversions.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
There are two storms west of southwest Alaska and their cloud
shields have already merged on satellite imagery resulting in a
broad shield from the interior into the North Pacific. The High
Wind Warning remains in effect as there is good confidence that
the low will bring high wind gusts to the downslope and gap wind
prone areas along the Aleutian Range as well as portions north of
Dillingham. Warm air advection will accompany this event,
although some places may get a wet snow. Another low is expected
to move into the area Saturday keeping the unsettled conditions in
place.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
There is a broad area of troughing from northeast Russia to the
North Pacific. There are several distinct circulations at the
surface, one over Attu Island, one near the Pribilofs, and another
south of the AK Pen. To the east, there is a dome of high
pressure over the interior. With high pressure in place, expect
the lows to follow the path of least resistance. Sensible weather-wise,
expect more gradient winds over the Eastern Aleutians. As this
unsettled pattern evolves, the storm from the North Pacific will
become entrained in the synoptic flow and get pulled northward
keeping the gusty winds in place over the Eastern Aleutians this
forecast period. Given the source region for this storm, expect
warm air to advect into the region. All the while, another low
will trek from Attu directly over the chain with the models
spinning up another low in its wake. Overall, its a very dynamic
pattern with plenty of opportunities for gusty winds and rough
seas.

&&

.LONG TERM FORECAST (Days 3 through 7)...
The long-term forecast beginning Saturday evening will start off
with ongoing wet and windy conditions stretching from the northern
Gulf area through the southwest Mainland, and into the
eastern/central Aleutians and Bering as a north Pacific low
begins to track into the Alaska Peninsula. There remains some
model differences regarding the timing of the frontal winds and
precipitation, and how far the system will push into the northern
Gulf coast and Cook Inlet region by Sunday. Currently the middle
ground GFS solution was preferred, bringing the rain over Kodiak
Island northward into the Kenai Peninsula by Saturday evening,
then into the northern Gulf coast by Sunday morning. The low then
begins to track north along the western coast Sunday afternoon,
switching the southeasterly flow over the southern Mainland to
southwesterly flow, which will bring colder onshore flow and
showery conditions over the southwest mainland Sunday night into
Monday morning. This will also bring a slight chance of some
light snow to fall over the Cook Inlet region overnight Sunday
into Monday morning.

On the western periphery of this low pressure system, some strong
cold air advection will persist over the Pribilofs and Eastern
Aleutians through the weekend and into the early part of next
week. This will likely bring snow showers and the potential for
blowing snow over these areas Saturday evening through Sunday
morning. A ridge will build in over the western Aleutians/Bering
Monday morning, and quickly push eastward over the central
Bering/Aleutians by the middle of the week. This ridge will be
short lived as the next trough moves over the area Tuesday. This
system could bring another round of wet and windy weather to the
western and central Bering/Aleutians Tuesday afternoon through
the later part of the week. However, previous runs have shown
significantly different solutions, so confidence in the forecast
from Monday through the end of next week remains low.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...High Wind Warning 161.
MARINE...Storm Warning 130 131 132 150 155 160 165 180.
 Gale Warning 119 120 136-138 141 170 172-176 181 185.

&&

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