Gale Warning 671, NWS Anchorage, AK

922 
FZAK61 PAFC 051251
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
351 AM AKST Tue Dec 5 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.

PKZ399-060145-
351 AM AKST Tue Dec 5 2017
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 1003 mb low at 55N 145W moves to 59N 147W at 1004 mb Tue afternoon
and then moves inland. Another 996 mb low at 52N 148W Tue night 
moves to 59N 149W at 995 mb Wed afternoon and then moves inland Wed 
night. A strong front remains nearly stationary in the eastern Gulf 
throughout the forecast period.

$$

PKZ351-060145-
Gulf of Alaska Offshore North of 57N and West of 144W-
351 AM AKST Tue Dec 5 2017

...GALE WARNING TONIGHT AND WEDNESDAY...

.TODAY...S wind 15 to 30 kt. Seas 9 to 14 ft.
.TONIGHT...E wind 20 to 35 kt. Seas 11 to 19 ft. Rain.
.WED...SE wind 25 to 40 kt. Seas 14 to 22 ft. Rain.
.WED NIGHT...SE wind 15 to 30 kt. Seas 14 to 20 ft.
.THU THROUGH SAT...SE wind 15 to 30 kt. Seas 10 to 18 ft.

$$

PKZ352-060145-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
351 AM AKST Tue Dec 5 2017

...GALE WARNING TONIGHT AND WEDNESDAY...

.TODAY...S wind 10 to 25 kt becoming 15 kt in the afternoon. Seas
8 to 16 ft.
.TONIGHT...NE wind 25 to 40 kt. Seas 11 to 19 ft. Rain.
.WED...E wind 20 to 35 kt becoming W 15 to 30 kt in the afternoon.
Seas 13 to 21 ft.
.WED NIGHT...SE wind 10 to 25 kt. Seas 12 to 18 ft.
.THU THROUGH FRI...SE wind 15 to 30 kt. Seas 9 to 17 ft.
.SAT...SE wind 15 to 25 kt. Seas 14 to 18 ft.

$$

632 
FZAK61 PAFC 060027
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
327 PM AKST Tue Dec 5 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.

PKZ399-061330-
327 PM AKST Tue Dec 5 2017
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...
A 999 mb low in the North Pacific Wed afternoon moves to 60N 146W 
at 1001 mb and then moves inland Thu afternoon. A strong front 
remains nearly stationary in the eastern Gulf through Thu afternoon.

$$

PKZ351-061330-
Gulf of Alaska Offshore North of 57N and West of 144W-
327 PM AKST Tue Dec 5 2017

...GALE WARNING THROUGH WEDNESDAY...

.TONIGHT...S wind 15 to 30 kt becoming E 20 to 35 kt after
midnight. West of 146 W...Variable wind less than 10 kt. 
Seas 10 to 13 ft building to 11 to 19 ft after midnight. Rain.
.WED...SE wind 20 to 35 kt. West of 146 W...NE wind 15 kt. 
Seas 12 to 20 ft. Rain.
.WED NIGHT...SE wind up to 15 kt increasing to 20 kt after
midnight. Seas 11 to 17 ft.
.THU...SE wind 10 to 25 kt. Seas 11 to 14 ft.
.THU NIGHT...SE wind 15 to 30 kt. Seas 10 to 18 ft.
.FRI THROUGH SUN...SE wind 15 to 30 kt. Seas 11 to 18 ft.

$$

PKZ352-061330-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
327 PM AKST Tue Dec 5 2017

...GALE WARNING TONIGHT...

.TONIGHT...NE wind 20 to 35 kt. West of 146 W...NE wind 10 kt. 
Seas 10 to 18 ft. Rain.
.WED...SE wind 20 to 30 kt. West of 146 W...NE wind 15 kt. 
Seas 11 to 19 ft.
.WED NIGHT...E wind 10 to 25 kt becoming SE after midnight. 
Seas 11 to 18 ft.
.THU...SE wind 10 to 25 kt. Seas 10 to 14 ft.
.THU NIGHT...SE wind 15 to 30 kt. Seas 9 to 14 ft.
.FRI THROUGH SUN...SE wind 15 to 30 kt. Seas 10 to 18 ft.

$$

575 
FZAK61 PAFC 061218
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
318 AM AKST Wed Dec 6 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.

PKZ399-070145-
318 AM AKST Wed Dec 6 2017
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 988 mb North Pacific low moves to 55N 155W tonight at 986 mb. 
The low then moves inland Thu afternoon. A 982 mb low at 49N 168W 
Wed night moves to 49N 159W Thu night at 980 mb. A strong front 
remains nearly stationary in the eastern Gulf through Thu 
night.

$$

PKZ351-070145-
Gulf of Alaska Offshore North of 57N and West of 144W-
318 AM AKST Wed Dec 6 2017

...GALE WARNING THURSDAY...

.TODAY...NE wind 15 to 30 kt. Seas 12 to 20 ft. Rain.
.TONIGHT...SE wind 10 to 25 kt. Seas 13 to 17 ft.
.THU...SE wind 15 to 25 kt increasing to 20 to 35 kt in the
afternoon. Seas 12 to 16 ft. Rain.
.THU NIGHT...S wind 15 to 30 kt. Seas 11 to 18 ft.
.FRI THROUGH SUN...SE wind 15 to 30 kt. Seas 11 to 19 ft.

$$

PKZ352-070145-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
318 AM AKST Wed Dec 6 2017

.TODAY...NE wind 15 to 30 kt. Seas 11 to 19 ft.
.TONIGHT...SE wind 15 to 30 kt. Seas 12 to 18 ft.
.THU...SE wind 15 to 30 kt. Seas 11 to 15 ft. Rain.
.THU NIGHT...S wind 15 to 30 kt. Seas 10 to 16 ft.
.FRI THROUGH SUN...SE wind 15 to 30 kt. Seas 10 to 18 ft.

$$

027 
FZAK61 PAFC 070048
OFFAER

Offshore Waters Forecast
National Weather Service Anchorage AK
348 PM AKST Wed Dec 6 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.

PKZ399-071400-
348 PM AKST Wed Dec 6 2017
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 988 mb North Pacific low moves to 55N 158W Thu afternoon and
moves inland and dissipates Thu night.  A strong front remains 
nearly stationary in the eastern Gulf through Fri afternoon.

$$

PKZ351-071400-
Gulf of Alaska Offshore North of 57N and West of 144W-
348 PM AKST Wed Dec 6 2017


.TONIGHT...SE wind 10 to 25 kt. Seas 13 to 17 ft.
.THU...SE wind 15 to 25 kt increasing to 20 to 30 kt in the 
afternoon. Seas 12 to 17 ft. Rain.
.THU NIGHT...S wind 15 to 30 kt. Seas 11 to 18 ft.
.FRI...SE wind 10 to 20 kt. Seas 12 to 15 ft.
.FRI NIGHT...SE wind 15 to 25 kt. Seas 10 to 13 ft.
.SAT THROUGH SUN...SE wind 25 to 35 kt. Seas 10 to 16 ft.
.MON...S wind 15 to 25 kt. Seas 15 to 20 ft.

$$

PKZ352-071400-
Gulf of Alaska Offshore South of 57N North of 55N and West of
144W-
348 PM AKST Wed Dec 6 2017

.TONIGHT...SE wind 15 to 30 kt. Seas 12 to 18 ft.
.THU...SE wind 15 to 30 kt. Seas 11 to 16 ft. Rain.
.THU NIGHT...S wind 15 to 30 kt diminishing to 10 to 20 kt after 
midnight. Seas 10 to 17 ft.
.FRI...SE wind 10 to 25 kt. Seas 10 to 14 ft.
.FRI NIGHT...SE wind 15 to 25 kt. Seas 11 to 14 ft.
.SAT THROUGH MON...S wind 20 to 35 kt. Seas 11 to 18 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
436 AM AKST Mon Dec 4 2017

.ANALYSIS AND UPPER LEVELS...

A complex weather pattern is set up across Southern Alaska this
morning. By far the highlight of it is a strong vertically stacked
low centered near Bristol Bay. Over Southwest Alaska, it's
producing areas of rain and snow with strong winds over the
Kuskokwim Delta. Over the Gulf of Alaska and Southcentral, strong
southerly winds over the Gulf become easterly as they're forced
through the gaps of the coastal Chugach Range. As a result,
Turnagain Arm and the Matanuska and Knik Valleys are all seeing
strong winds. Meanwhile at the coast, the surge of mass into the
mountains has developed a storm force barrier jet, with the latest
ASCAT pass picking up several areas of 50 kt winds south of the
Copper River Delta.

Conditions are comparatively tranquil over the central and western
Bering, where much cooler air lies. There, the atmosphere is quite
unstable, as evidenced by the large cumulus field over much of the
area, with the cold air streaming southeastward out of Siberia.
While the cold air exists under broad, weak troughing over the
Bering, further east across Southcentral, strong southerly flow is
pumping in unseasonably warm air over the area. Most notable are
temperatures over the Matanuska Valley, where many areas are
currently in the mid 40s under strong southeast winds out of the
Knik Valley. Meanwhile most everywhere else with the exception of
the Copper Basin and the far northern Susitna Valley are above
freezing.

&&

.MODEL DISCUSSION...

Models remain in good agreement on the track of the storm moving
across the Aleutian Range into Southwest Alaska, and have come
into better agreement on a much smaller, weaker low forecast to
also track near Kodiak Island Monday night into Tuesday. A third
weak low is also becoming better resolved by the models to take a
track northward through the central Gulf and to near Prince
William Sound by Tuesday afternoon. Beyond that the model
agreement breaks down considerably on the strength, intensity, and
even existence of another potentially strong low moving through
the western Gulf Tuesday night into Wednesday. Where the models
are in somewhat better agreement is that east of there, very
strong southerly winds tapping deep subtropical moisture will
create an "atmospheric river", bringing prodigious amounts of rain
and mountain snow to some portion of the north Gulf Coast. Though
where that sets up is anyone's guess at this point due to large
model disagreements.

Even in the short term, potentially significant differences in the
models exist regarding local scale weather phenomena, namely the
strong winds gusting down Turnagain Arm, if and when they get into
Anchorage, and the ever-present large forecast question, how much
rain or snow gets into town. Thus, forecast confidence is
generally low across the board, though higher pertaining to the
broad aspects of the present weather pattern.

&&

.AVIATION...
PANC...VFR to occasionally MVFR conditions will persist. Winds
will increase out of the south to southeast later this morning as
a front moves into the coast, increasing the Turnagain Arm winds.
As the low moves north, up-Inlet flow will bring the winds through
the airport. Low level wind shear will also persist through the
morning, then increasing winds at the surface will diminish the
shear threat. The 1,500-2,000 foot level winds will continue
blowing at 40-55 kt through the day.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
The strong low near Kodiak Island early this morning is
continuing to bring strong winds to a good portion of the area.
One thing that will be a little different in this system as
opposed to some other ones in the amount of southerly winds that
will move up Cook Inlet later this morning through early evening.
Winds on the Kenai Peninsula near the Inlet may gust up to 50 mph
which does not happen nearly as frequently as the strong southeast
winds over the region. Strong downslope will keep out the
majority of rain out of Anchorage and the Matanuska Valley this
morning but by late morning the cross-barrier flow will decrease
bringing in some rain to those areas. This will be accompanied by
southeast winds which will push temperatures near or above 40
degrees. The stronger downsloping returns again tomorrow which
should keep Anchorage and Mat Valley mostly dry again, but due to
the location of the storm track there is a chance that there could
be some more steady precipitation on Wednesday.

This very active weather pattern will keep Southcentral Alaska
prone to rapid changes in the weather the next few days.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
The frontal system associated with the strong low in the western
Gulf stretches from the Kuskokwim Delta coast south-southeast to
the Alaska Peninsula early this morning bringing snow and windy
conditions to the Kuskokwim Delta. Currently easterly flow and
downsloping are keeping portions of the Bristol Bay area and
western slopes of the Alaska and Aleutian Range warmer,
particularly those areas downwind of gaps and mountain passes.
However, as the entire frontal system including the low in the
western Gulf and a secondary low forming in Bristol Bay lift
north, cold air aloft on the south side of the system will spread
over Southwest Alaska changing precipitation over to all snow as
southwesterly flow pushes inland this afternoon and evening.

Continued upper level troughing over the eastern Bering, a
persistently cold air mass aloft and a series of weak shortwaves
rotating through the southwesterly flow will keep isolated to
scattered snow showers in the forecast through at least Tuesday
and Wednesday.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
The upper level pattern of a large trough with multiple smaller
lows and troughs rotating around it will continue to persist over
the Bering through Tuesday while a strong westerly jet remains
centered along and to the south of the western and central
Aleutians. The next more organized low pressure system will
approach the western Aleutians Tuesday night and then track east
through central Aleutians Wednesday and Wednesday night, arriving
south of the western Aleutians Thursday.

&&

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

For the long term forecast, inconsistency grows through the day 8
forecast as a strong ridge begins to build over the west coast of
the lower 48. This pattern looks to be very active, especially
for the Gulf and South Mainland which will be under the influence
of a strong southerly jet with the potential for a series of fast
moving systems through the Gulf through the upcoming work week.
As has been the case for the past few days, the models are struggling
with placement of these lows leading to ensembles being the choice
guidance. The one area where there is some agreement is with a
potentially sub 960 mb low moving toward the Western Aleutians on
Saturday. However, the potential track of this low after Saturday
varies wildly.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Storm Warning: 132 351.
Gale Warning: 119 120 125 130 131 138 139 140 141 150 155 160 165
180 352

&&

SYNOPSIS AND MODEL DISCUSSION...JPW
SOUTHCENTRAL ALASKA...EZ
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JR
LONG TERM...DK

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
202 PM AKST MON DEC 04 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0800 AM     SNOW             THOMPSON PASS           61.14N 145.75W
12/04/2017  M20.0 INCH                          AK   DEPT OF HIGHWAYS

&&

DK