Gale Warning 575, NWS Anchorage, AK

851 
FZAK62 PAFC 161245
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
345 AM AKST Thu Nov 16 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.

PKZ499-170200-
345 AM AKST Thu Nov 16 2017
.SYNOPSIS FOR CENTRAL BERING SEA...

A front over the Alaska Peninsula moves inland and dissipates Thu
night. A second front approaches the western Aleutians Thu 
afternoon and advances eastward across the Bering through Fri 
night.

$$

PKZ411-170200-
Bering Sea Offshore West of 180 and East of the International
Dateline-
345 AM AKST Thu Nov 16 2017

.TODAY...SW wind 10 to 25 kt. Seas 10 to 13 ft.
.TONIGHT...S wind 15 to 30 kt. Seas 9 to 13 ft. Rain.
.FRI...S wind 15 to 30 kt. Seas 10 to 14 ft. Rain.
.FRI NIGHT...W wind 15 to 30 kt. Seas 10 to 13 ft.
.SAT...W wind 25 to 40 kt. Seas 10 to 18 ft.
.SUN...SW wind 15 to 30 kt. Seas 9 to 14 ft.
.MON...S wind 15 to 25 kt. Seas 8 to 11 ft.

$$

PKZ412-170200-
Bering Sea Offshore 171W to 180 and North of 56N-
345 AM AKST Thu Nov 16 2017

.TODAY...W wind 15 to 30 kt. Seas 11 to 15 ft.
.TONIGHT...SW wind 10 to 20 kt. Seas 11 ft.
.FRI...S wind 15 to 30 kt. Seas 8 to 11 ft.
.FRI NIGHT...SW wind 15 to 25 kt. Seas 8 to 12 ft.
.SAT THROUGH SUN...NW wind 30 to 45 kt. Seas 15 to 30 ft.
.MON...S wind up to 20 kt. Seas 7 to 12 ft.

$$

PKZ413-170200-
Bering Sea Offshore 171W to 180 and South of 56N-
345 AM AKST Thu Nov 16 2017

.TODAY...W wind 15 to 25 kt. Seas 8 to 11 ft. Patchy fog.
.TONIGHT...SW wind 10 to 25 kt. Seas 9 ft. Patchy fog.
.FRI...SW wind 15 to 30 kt. Seas 7 to 11 ft.
.FRI NIGHT...SW wind 20 to 30 kt. Seas 7 to 12 ft.
.SAT THROUGH SUN...NW wind 30 to 45 kt. Seas 13 to 28 ft.
.MON...W wind 10 to 25 kt. Seas 9 to 14 ft.

$$

PKZ414-170200-
Bering Sea Offshore East of 171W-
345 AM AKST Thu Nov 16 2017

...GALE WARNING THROUGH TONIGHT...

.TODAY...NW wind 25 to 35 kt. Seas 11 to 14 ft.
.TONIGHT...NW wind 20 to 35 kt. Seas 9 to 14 ft.
.FRI...W wind 10 to 25 kt diminishing to up to 15 kt in the
afternoon. Seas 8 to 11 ft.
.FRI NIGHT...SW wind 10 to 25 kt. Seas 7 ft.
.SAT...W wind 30 to 45 kt. Seas 13 to 28 ft.
.SUN...NW wind 30 to 45 kt. Seas 17 to 32 ft.
.MON...N wind 20 to 35 kt. Seas 10 to 18 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
434 AM AKST Wed Nov 15 2017

.ANALYSIS AND UPPER LEVELS...
A subtle pattern change is underway across the southern mainland
this morning as the stout upper level ridge over the eastern
Bering Sea makes slow eastward progress, with the ridge axis
currently extending along the west coast of Alaska. The somewhat
slower progression of the ridge has allowed gusty northerly winds
to continue overnight across much of Southcentral AK and
particularly through favored gap flow areas along the Gulf coast
as dry offshore flow remains focused over the area. Winds are
finally beginning to subside early this morning over the
Cook Inlet region as the best upper level support moves off to the
east, however these winds should continue through late morning for
other locations along the Gulf coast. Mostly clear skies continue
to prevail from Bristol Bay eastward into the Copper River Basin
owing to this continued offshore flow. Meanwhile, a weak front
spreading light rain across much of the eastern Bering is
beginning to push inland over the Kuskokwim Delta accompanied by
mixed precipitation as a layer of warmer air aloft moves into the
region from the south. Surface temperatures have been warm enough
to support mostly rain along the coast, however freezing rain
remains a concern for inland areas including Bethel this morning
as the precipitation spreads east with colder air remaining in
place at the surface.

&&

.MODEL DISCUSSION...
Models remain in excellent short term agreement as the ridge
shifts eastward and the current outflow wind regime gives way to
a brief shot of snow for Southcentral with the passage of a trough
on Thursday. There are still minor differences in the timing of
this feature, but the general consensus is for a brief window of
light snow moving through Anchorage and surrounding areas Thursday
morning. Continued to utilize Hi-Res guidance for the duration of
the outflow winds today before shifting to more of a GFS based
solution for the trough passage on Thursday.

&&

.AVIATION...
PANC...Light winds and VFR conditions will persist through
Wednesday night. Light snow will spread into the terminal
beginning Thursday morning with the arrival of an upper level
trough. This will drop ceilings below 5000 ft, with a brief
period of MVFR conditions possible after 15z Thu.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2...today
and Thu)...
Pressure gradients and favorable upper support will wane this
morning and allow strong offshore flow to weaken along the North
Coast. A weather front moving moving east tonight and Thursday
will bring a snow to Southcentral beginning Thursday morning. Snow
totals should be on the light side in most areas. Although the
frontal progression has slowed some, the brunt of the snow should
end across the western Kenai Peninsula, Anchorage Bowl, and Mat-Su
Valleys by the mid afternoon hours. Cold advection behind this
front will bring another round of outflow and gap flows Thursday
night.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
The main challenges in the short range forecast are gusty winds
and precipitation as two fronts moves across the region. The first
front currently along the Kuskokwim Delta coast is expected to
slowly progress east today. Models previously projected that this
system would be fairly organized as the associated upper low was
progged to dive southeast. The most recent runs between all of the
models are now trending toward the upper level low shearing apart
as the next ridge amplifies across the central Bering. This
essentially brings a less dynamic system across the southwestern
region with an upper level shortwave accompanied by a weak surface
trough. To account for these latest trends, the front was slowed
down with the morning package and snow amounts were slightly
lowered. The front still might not progress as expected today due
to the weaker push in the upper levels, however the next disturbance
races to the southwest coast tonight which should kick the surface
front into motion.

Stronger northerly flow increases late Thursday into Friday as a
jet max noses across the Bering Strait around another ridge which
becomes highly amplified over the Central Bering. The ridge brings
a drier pattern into the weekend along with gusty northerly flow
continuing across the region.

&&

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

A front spreads rain across the eastern Bering and Alaska
Peninsula through this afternoon and then slides inland tonight.
Meanwhile, a ridge builds across the southwestern Bering this
afternoon bringing gusty zonal flow along much of the western
Bering as the pressure gradient is squeezed between this ridge
and low pressure holding to the north.

A strong disturbance rides along the western perimeter of the
ridge this afternoon and is shunted north toward Kamchatka. Strong
forcing from the disturbance around the ridge along with the
upper jet amplifying toward the Bering strait will induce very
gusty northerly flow across the eastern Bering and Alaska
Peninsula Thursday afternoon into Friday. There is still
uncertainty in the timing and location for the strongest winds and
therefore mariners should continue to monitor this system for
future updates.

&&

.LONG TERM FORECAST (Days 3 through 7)...
Yet another outflow event will develop along the North Gulf Coast
on Friday as an Eastern Gulf low intensifies and weak ridging
begins to move through the Mainland from the Bering. Just ahead of
this ridge, a shortwave will quickly push through the Southwest
coast, bringing light accumulations to many areas of Thursday,
which may also produce areas of blowing snow as gusty
northwesterly winds quickly follow it.

Certainty in the forecast then begins to quickly break down this
weekend as significant spread in the track of a rapidly deepening
low moves from the Bering into either the Gulf or North Pacific
(depending on which model guidance you look at). The EC has been
the most consistent with this low, bringing a rapidly deepening
low into the central Gulf by Sunday with widespread snow and wind
to the Southern Mainland. The GFS on the other hand was very
sporadic overnight, but is beginning to becoming more consistent
in a track much further to the south, providing only a glancing
blow of winds to the gulf and little if any precipitation to the
Southern Mainland. Due to this large spread in the low track and
expected impacts, little if any change is being made to the
extended forecast today awaiting better model consensus. This is a
system that bears watching however, as trends in either direction
will result in significant changes to the weekends forecast.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None
MARINE...Gale Warning 130 131 132 150 155 160 165 172 180 181 185

&&

SYNOPSIS AND MODEL DISCUSSION...CB
AVIATION...CB
SOUTHCENTRAL ALASKA...RMC
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KH
LONG TERM...DEK