Gale Warning 591, NWS Anchorage, AK

978 
FZAK61 PAFC 291231
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
331 AM AKST Wed Nov 29 2017

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.

PKZ399-300200-
331 AM AKST Wed Nov 29 2017
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A strong front along the North Gulf Coast will move inland this
morning. A 954 mb Bering low will cross the Akpen today and enter
the Gulf near 54N 153W at 983 mb Thu morning. The low will then 
continue to weaken to 1000 mb as it moves into the northeast 
Pacific by early Fri morning.

$$

PKZ351-300200-
Gulf of Alaska Offshore North of 57N and West of 144W-
331 AM AKST Wed Nov 29 2017

...GALE WARNING TODAY...

.TODAY...S wind 25 to 35 kt diminishing to 15 to 25 kt in the
afternoon. Seas 15 to 21 ft.
.TONIGHT...S wind 15 to 25 kt. Seas 15 to 21 ft.
.THU...S wind 20 kt becoming SE up to 15 kt in the afternoon. 
Seas 12 to 18 ft.
.THU NIGHT...N wind up to 15 kt. Seas 10 to 15 ft.
.FRI THROUGH SAT...SW wind 10 to 25 kt. Seas 7 to 12 ft.
.SUN...SE wind 15 to 25 kt. Seas 9 to 14 ft.

$$

PKZ352-300200-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
331 AM AKST Wed Nov 29 2017

...GALE WARNING TODAY...

.TODAY...S wind 25 to 35 kt. Seas 19 to 26 ft.
.TONIGHT...SW wind 20 to 30 kt. Seas 19 to 23 ft.
.THU...SE wind 10 to 25 kt. Seas 17 to 22 ft.
.THU NIGHT...NE wind 15 kt. Seas 12 to 18 ft.
.FRI THROUGH SAT...SW wind 10 to 25 kt. Seas 8 to 13 ft.
.SUN...S wind 20 to 30 kt. Seas 11 to 19 ft.

$$

096 
FZAK61 PAFC 300017
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
317 PM AKST Wed Nov 29 2017

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.

PKZ399-301400-
317 PM AKST Wed Nov 29 2017
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 967 mb low at 55N 161W moves to 55N 150W at 990 mb Thu
afternoon. The weakening low then moves to the southeast and 
exits the Gulf Fri afternoon. A front enters the western Gulf Fri 
afternoon.

$$

PKZ351-301400-
Gulf of Alaska Offshore North of 57N and West of 144W-
317 PM AKST Wed Nov 29 2017

.TONIGHT...S wind 15 to 25 kt. Seas 14 to 21 ft. Rain showers.
.THU...S wind 10 to 20 kt. Seas 13 to 19 ft.
.THU NIGHT...SE wind up to 10 kt becoming NW after midnight. Seas
9 to 16 ft.
.FRI...W wind up to 15 kt. Seas 7 to 11 ft.
.FRI NIGHT...SW wind 10 to 25 kt. Seas 6 to 9 ft.
.SAT THROUGH SUN...SE wind 15 to 25 kt. Seas 8 to 13 ft.
.MON...S wind 25 kt. Seas 20 to 26 ft.

$$

PKZ352-301400-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
317 PM AKST Wed Nov 29 2017

.TONIGHT...SW wind 20 to 30 kt. Seas 20 to 24 ft.
.THU...SE wind 10 to 25 kt. Seas 17 to 23 ft.
.THU NIGHT...NE wind 10 to 20 kt. Seas 11 to 19 ft.
.FRI...W wind up to 20 kt. Seas 8 to 13 ft.
.FRI NIGHT...S wind 15 to 30 kt. Seas 8 ft.
.SAT...SW wind 15 to 25 kt. Seas 7 to 12 ft.
.SUN...S wind 20 to 30 kt. Seas 11 to 19 ft.
.MON...S wind 20 to 30 kt. Seas 19 to 28 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
437 AM AKST Tue Nov 28 2017

.ANALYSIS AND UPPER LEVELS...
An active pattern continues over the region this morning as one
low dissipates over the western Gulf of Alaska and a new dominant
system nears peak intensity over the East-Central Aleutian chain.
An occluded front arcs around this low center from east of Atka
up through the Pribilof Islands and across the Alaska Peninsula,
bringing wet snow to the Pribilofs and rain to portions of the
Akpen. Strong winds are present across the Central Aleutians near
the bent-back occlusion on the backside of the system, although
these winds have remained below hurricane force thus far
overnight. Meanwhile, a compact disturbance is moving into the
Prince William Sound region accompanied by localized gale force
winds over the coastal waters and light snow along the coast from
Whittier to Cordova. Inland locations including Anchorage remain
under quieter conditions owing largely to downslope flow in the
lee of the coastal mountain ranges.

&&

.MODEL DISCUSSION...
Guidance remains in reasonable synoptic agreement for the next few
days as the strong Bering low makes slow eastward progress into
the southwestern Gulf by Thursday morning. Despite the general
large scale agreement, models are still struggling with some
specific details. This includes the evolution of a strong North
Pacific disturbance rounding the base of the longwave Bering
trough and moving up towards the Akpen later today. How this
feature interacts with the current Bering low will have large
implications on the placement of the low and associated wind
fields over the next 24-48 hrs, as well as the timing of the next
front moving into the Gulf. Recent runs of the GFS have failed to
adequately resolve this developing feature, and thus the GFS
solution has largely been discarded in favor of the NAM for the
morning package.

&&

.AVIATION...
PANC...VFR conditions and light north winds will persist through
this evening before winds begin to increase somewhat around 06z as
a result of a tightening pressure gradient ahead of an approaching
low. Chances for precipitation will increase at the terminal after
15z Wednesday as a front moves over the north Gulf coast, with
cigs lowering to 5000 ft or lower.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
An active pattern will remain in place over the next couple days
with the bulk of impacts from precipitation and winds remaining
along the coast and over Kodiak Island and the Gulf of Alaska.
Each feature that moves through brings warmer air with it, so
temperatures will continue to rise, with a transition to more and
more rain along the coast.

An upper level low moving inland across Prince William Sound this
morning will rapidly fall apart as it heads inland today. Focus
will shift to a Gale force front south of Alaska Peninsula, which
will swing northward across the Gulf today through tonight, then
move rapidly onshore early Wednesday thanks to broad southerly
steering flow aloft. Easterly winds will quickly increase along
the north Gulf coast, Prince William Sound and through Passage
Canal and Turnagain Arm out ahead of the front This evening, then
peak during the overnight hours. Winds will rapidly fall off early
Wednesday as the front moves onshore and falls apart in the
mountains. The windy conditions will contribute to vertical mixing
and warming temperatures. Thus, once temperatures warm up near sea
level today, expect precipitation to remain all rain through
Wednesday.

In the upper levels a series of short-waves will head inland on
Wednesday. Though low level flow will weaken, the prevailing wind
direction will remain southeasterly and maintain some level of
downslope flow in the lee of the Kenai and Chugach Mountains.
However, cooling temperatures aloft will increase instability and
may allow brief periods of precipitation to move through. For now,
have mostly stuck with chance PoPs inland for Wednesday through
Wednesday night, with the exception of upslope areas along the
Alaska Range. Meanwhile, a steady supply of showers will continue
across Kodiak and the Gulf coast as the Bering low transitions
into the Gulf and a plethora of upper level waves out ahead of it
march northward across the Gulf.

&&

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

Another strong 950 mb low continues to spin just northwest of
Dutch Harbor early this morning, with a secondary low near equal
strength rotating northward towards Sand Point as it gets absorbed
by the first low. These systems will send an occluding front
northward through the morning, before stalling as it stretches out
from the southern Bering, through Bristol bay, towards Ports
Alsworth.

Along this front, fairly widespread precipitation is expected,
with rain being the dominant mode of precipitation to its south.
Right along and immediately ahead of the front, enough warm air
will ride over the front aloft while surface temperatures are
slightly below freezing to produce a narrow swath of light
freezing rain. Further north, precipitation will become more
scattered in coverage in the form of light snow or snow showers.

As the lows depart the area to the southeast Wednesday, a drying
trend will commence although skies will generally remain cloudy. A
short-wave ridge will build across the region later Wednesday into
thursday, allowing skies to clear some while continuing the dry
weather. However, a low moving across eastern Siberia will send
another front into southwest Alaska on Friday. Widespread
precipitation will once again develop, with snow on the leading
edge changing to rain as warmer air pushes inland. The exception
to this will be the interior, but where this transition line sets
up remains to be seen.

&&

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

As monotoned above, today's low continues to spin in the just
north of the central Aleutians. This low ended up being a little
weaker and further south than what was expected yesterday, with
the colder air displaced more westward where an isolated
thunderstorm developed about 100 miles south of Atka. This
displacement allowed winds to remain below warning criteria given
not as much of a downward push due to the tropopause heights higher
than forecast. Thus, the warning was cancelled with the morning
forecast package.

Otherwise, the associated surface front currently lies just west
of Dutch Harbor as of 4 am. This front will sweep eastward with
widespread rainfall along it, and more showery precipitation
behind it. The cold air will maintain strong wind gusts through
the day, helping add a little chill to the air. As the low slides
into the Gulf of Alaska Wednesday night, a transitory ridge will
shift from west to east across the chain, reaching the central
Aleutians by midday Thursday, before continuing eastward through
the night. This ridge will bring a period of decreasing winds,
drier weather, and decreasing cloud cover. However, a strong front
will be quickly on its heels as it sweeps eastward, with strong
winds and widespread precipitation returning to the region.

&&

.LONG TERM FORECAST (Days 3 through 7)...
Beginning late Wednesday, the weather over most of the South
Mainland will become much quieter as the low over the Eastern
Bering cross the AK pen and dissipates over the North Pacific,
leaving generally cold and clear conditions. Guidance has also
trended much further south with this low on Thursday, meaning that
without a strong pressure or thermal gradient along the North Gulf
Coast, the persistent outflow winds that have blown through the
area recently are not expected to develop again. Over the Western
Bering, a gale force front entering the area late Wednesday will
slowly spread through the area bringing rain/snow and gusty
southerly winds that will be weaker than the high wind events
that moved through the Aleutians since the Thanksgiving holiday.

This front will then enter the Southwest Mainland late Friday,
bringing snow to that area before creating a triple point low in
the Gulf sometime on Saturday. The models continue to struggle
with the timing and intensity of this development, however they
all create a triple point sometime on Saturday which will track
into the North Gulf. The exact details of the impacts of this low
will need to be determined as model agreement improves, but at
this point it appears that there will be increasing chances of
snow along the North Gulf coast and Southcentral this weekend,
along with the potential for gap winds through the usual areas
such as Turnagain Arm the Matanuska Valley. Afterwards model
agreement begins to break down with the track/intensity of what
looks to be a very active pattern for the Gulf late this
weekend/early next week as a blocking ridge sets up over the
Pacific NW, leaving the Gulf exposed to a deep southerly jet. The
general impact of this pattern change will be to shift the most
active weather further east into the Gulf region for early next
week.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None
MARINE...Storm Warning 170 172 173 174 175 176 177 413
		 Gale Warning 119 125 130 131 132 137 138 139 150 155
					  160 165 171 178 180 181 185 411 412 414

&&

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