Storm Warning 42, NWS Juneau, AK

884 
FZAK67 PAJK 080036
OFFAJK

Offshore Waters Forecast
National Weather Service Juneau AK
336 PM AKST Fri Dec 7 2018

Offshore waters forecast for Gulf of Alaska east of 144W

Wind forecasts reflect the predominant speed and direction
expected. Sea forecasts represent the average of the highest
one-third of the combined windwave and swell height.

PKZ398-081845-
336 PM AKST Fri Dec 7 2018
.SYNOPSIS FOR THE EASTERN GULF OF ALASKA...
A storm force low will track north across the Gulf of Alaska
Friday night to be near Prince William Sound by early Saturday 
morning. Another storm force low will follow a similar track on 
Saturday and arrive near Prince William Sound late Saturday night.
High seas will range from 15 to 25 feet across the eastern Gulf 
through Saturday night. 

$$

PKZ310-081845-
Gulf of Alaska North of 55 Degrees North and East of 144 Degrees
West-
336 PM AKST Fri Dec 7 2018

...STORM WARNING THROUGH THIS EVENING AND SATURDAY...

.TONIGHT...SE wind 50 kt becoming S 30 kt late. Seas 22 ft. Rain 
in the evening, then rain...heavy at times late. 
.SAT...SE wind 35 kt increasing to 50 kt in the morning. Seas 20 
ft. Rain showers.
.SAT NIGHT...S gale to 35 kt becoming W 25 kt late. Seas
19 ft. 
.SUN...W wind 25 kt. Seas 15 ft. S swell. 
.SUN NIGHT...SW wind 25 kt. Seas 11 ft. S swell. Showers in
the evening, then rain late. 
.MON...SW gale to 35 kt. Seas 16 ft. 
.TUE...SW gale to 35 kt. Seas 20 ft. 
.WED...S wind 25 kt. Seas 22 ft. 

$$

865 
FZAK67 PAJK 080155 AAA
OFFAJK

Offshore Waters Forecast...UPDATED
National Weather Service Juneau AK
455 PM AKST Fri Dec 7 2018

Offshore waters forecast for Gulf of Alaska east of 144W

Wind forecasts reflect the predominant speed and direction
expected. Sea forecasts represent the average of the highest
one-third of the combined windwave and swell height.

PKZ398-082000-
455 PM AKST Fri Dec 7 2018
.SYNOPSIS FOR THE EASTERN GULF OF ALASKA...
A storm force low will track north across the Gulf of Alaska
Friday night to be near Prince William Sound by early Saturday 
morning. Another storm force low will follow a similar track on 
Saturday and arrive near Prince William Sound late Saturday night.
High seas will range from 15 to 25 feet across the eastern Gulf 
through Saturday night. 

$$

PKZ310-082000-
Gulf of Alaska North of 55 Degrees North and East of 144 Degrees
West-
455 PM AKST Fri Dec 7 2018

UPDATED

...STORM WARNING THROUGH SATURDAY...

.TONIGHT...E wind 50 kt becoming S. Seas 30 ft. Rain.
.SAT...SE wind 50 kt. Seas 20 ft. Rain showers. 
.SAT NIGHT...S gale to 35 kt becoming W 25 kt late. Seas
19 ft. 
.SUN...W wind 25 kt. Seas 15 ft. S swell. 
.SUN NIGHT...SW wind 25 kt. Seas 11 ft. S swell. Showers in
the evening, then rain late. 
.MON...SW gale to 35 kt. Seas 16 ft. 
.TUE...SW gale to 35 kt. Seas 20 ft. 
.WED...S wind 25 kt. Seas 22 ft. 

$$

859 
FZAK67 PAJK 081200
OFFAJK

Offshore Waters Forecast
National Weather Service Juneau AK
300 AM AKST Sat Dec 8 2018

Offshore waters forecast for Gulf of Alaska east of 144W

Wind forecasts reflect the predominant speed and direction
expected. Sea forecasts represent the average of the highest
one-third of the combined windwave and swell height.

PKZ398-090600-
300 AM AKST Sat Dec 8 2018
.SYNOPSIS FOR THE EASTERN GULF OF ALASKA...
A storm force low nears Prince William Sound early Saturday
morning while weakening. Another storm force low will track
north over the AK gulf on Saturday and arrive near Prince
William Sound late Saturday night. High seas will range from
15 to 25 feet across the eastern Gulf through Saturday night.  

$$

PKZ310-090600-
Gulf of Alaska North of 55 Degrees North and East of 144 Degrees
West-
300 AM AKST Sat Dec 8 2018

...STORM WARNING TODAY...

.TODAY...S wind 40 kt increasing to 50 kt in the afternoon. Seas
21 ft. Rain...heavy at times. Slight chance of thunderstorms in 
the afternoon. 
.TONIGHT...S wind 30 kt becoming W 25 kt late. Seas 19 ft. Slight
chance of thunderstorms in the evening. 
.SUN...W wind 25 kt. Seas 16 ft. SE swell. 
.SUN NIGHT...S gale to 35 kt. Seas 16 ft. Showers in the
evening, then rain late. 
.MON...S gale to 35 kt. Seas 18 ft. 
.TUE...W gale to 35 kt. Seas 25 ft. 
.WED...S wind 30 kt. Seas 22 ft. 

$$

054 
FZAK67 PAJK 090026
OFFAJK

Offshore Waters Forecast
National Weather Service Juneau AK
326 PM AKST Sat Dec 8 2018

Offshore waters forecast for Gulf of Alaska east of 144W

Wind forecasts reflect the predominant speed and direction
expected. Sea forecasts represent the average of the highest
one-third of the combined windwave and swell height.

PKZ398-091830-
326 PM AKST Sat Dec 8 2018
.SYNOPSIS FOR THE EASTERN GULF OF ALASKA...
A storm force weather front over the eastern gulf will push 
inland this evening. A low pressure system will rapidly develop 
and track inland near Cape Decision Sunday morning. Outlook. 
Another strong front will enter the gulf from the west Monday. 

$$

PKZ310-091830-
Gulf of Alaska North of 55 Degrees North and East of 144 Degrees
West-
326 PM AKST Sat Dec 8 2018

...GALE WARNING THROUGH THIS EVENING...

.TONIGHT...S wind 40 kt diminishing to 30 kt in the evening, then
becoming W 25 kt late. Seas 20 ft. Rain early in the evening.
Slight chance of thunderstorms in the evening. 
.SUN...W wind 25 kt. Seas 16 ft. SE swell. 
.SUN NIGHT...S gale to 35 kt. Seas 16 ft. Rain.
.MON...S gale to 45 kt. Seas 16 ft. Rain.
.MON NIGHT...W gale to 35 kt. Seas 20 ft. Showers in the
evening, then rain late. 
.TUE...W gale to 35 kt. Seas 25 ft. 
.WED...S wind 30 kt. Seas 22 ft. 
.THU...SW wind 30 kt. Seas 22 ft. 

$$

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
247 PM AKST Thu Dec 6 2018

.SYNOPSIS...The shift into a wet, windy, and active, but still
seasonably warm weather pattern will occur over the next day. This
new weather regime will persist through next week.

&&

.SHORT TERM...A return to an active weather pattern will occur
over the next 24 hours. Current satellite imagery shows a surface
low pressure system just south of Kodiak, as well as a large area
of energy over the northern Pacific. This energy will organize
into a surface low pressure system over the next day and push
northward across the gulf of Alaska. A band of storm force winds
will accompany this low as it tracks north over the gulf.
Additionally, seas will build to 20 to 30 feet over the vast
majority of the gulf by Friday night. For land areas and the inner
channels, expect the strongest winds to be along the outer coast
as the low tracks north and for the East-West orientated channels
specifically Sumner Strait and Cross Sound. While some strong
gusts are possible out of the system along the coast, high winds
are not expected due to low level atmospheric stability acting to
keep the strongest low level jet winds from mixing down to the
surface. That being said, if the low takes on a slightly more
easterly track, Yakutat could see a very brief southerly high
wind on the back side of the system early Saturday morning. As far
as precipitation impacts, the biggest area of concern will be the
Haines and Klondike Highways where precipitation looks to fall as
snow, but with the front significantly weakening by the time it
reaches these locations, significant accumulations are not
expected.

This active pattern continues into Saturday as another strong low
pressure system tracks north over the gulf. While the surface low
center takes a more westerly track than the Friday system, strong
gale and some storm force winds are expected again over the
eastern gulf waters. Precipitation will be more impactful out of
this storm as well, with periods of heavy rain expected for much
of the Panhandle Saturday. Along the Haines and Klondike Highways
some significant snowfall is possible; however, with lower
confidence in the ultimate timing and track of this storm, no
watches are currently in effect.

Overall little to no changes were made regarding the Friday low.
The intensity of Saturday's low was increased to bring strong
gales and some storm force winds into the forecast; however,
confidence is lower for Saturday's storm as a fair amount of
spread still exists. The 12 GFS was favored to adjust Saturday as
needed; however, this portion of the forecast could still see some
refining by future shifts.

.LONG TERM.../Saturday through Wednesday/Upper trough will be
deepening and taking on a negative tilt over the Gulf by Saturday.
Low level frontal zone will remain draped over the Panhandle or
perhaps just offshore in the eastern Gulf into Sunday. Models are
struggling greatly with timing and strength of individual pieces
of energy ejecting out of the base of the trough towards SE AK on
Saturday into Sunday. Diffluent upper jet will provide ample upper
support to tighten the low level front late Saturday into Sunday,
as evidenced by the presence of 70-80kt at 850 mb in many of the
models along the frontal zone. This could lead to strong gales or
storm conditions over the eastern Gulf with the potential for high
wind gusts for parts of the coastal and southern Panhandle at some
point late in the weekend. Still too much uncertainty to pin down
strength and location, so later shifts will need to monitor.

Heavy precipitation will likely occur as well Saturday into Sunday,
again dependent on the exact track and strength of any surface
waves. Thermal profiles along the Haines and Klondike highways
initially will support snow, with the potential for enough warming
to change the Haines road over to rain by Saturday night. Should
the precipitation remain all snow, significant accumulations will
be possible for the higher elevations of the highways through
Sunday. Elsewhere, only rain is expected near sea level.

For early to mid next week, most ensemble guidance continues to
call for a very strong and active zonal Pacific jet to develop and
nose into the western Gulf. This will set the stage for yet
another significant storm to enter the Gulf by late
Monday/Tuesday, bringing another round of heavy precipitation and
strong winds. Temperatures begin to cool by mid week as modified
arctic air begins to drawn into the Gulf from the Bering Sea,
however no significant snowfall near sea level is expected through
mid week at this time.

&&

.AVIATION...Biggest aviation concern will be the threat of
significant low level wind shear beginning late tomorrow morning
for the southern Panhandle and tracking north with the low through
the day evening and overnight hours. A significant low level jet
will develop northeast of the of the low center with around 50 to
60 kts of wind around 2000 ft. sliding northward along the
coastline.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...None.
MARINE...Gale Warning for PKZ043-051-052.
     Small Craft Advisory for PKZ022-041-042.
     Small Craft Advisory due to Seas for PKZ053.

&&

JB/DEL

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