Gale Warning 270, NWS Juneau, AK

058 
FZAK67 PAJK 111234
OFFAJK

Offshore Waters Forecast
National Weather Service Juneau AK
334 AM AKST Tue Dec 11 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.

PKZ398-120645-
334 AM AKST Tue Dec 11 2018
.SYNOPSIS FOR THE EASTERN GULF OF ALASKA...
A gale force front will slide E across the gulf Tue and move into
the panhandle Tue evening. Another strong gale force low will 
move across the gulf Wed into Thu. 

$$

PKZ310-120645-
Gulf of Alaska North of 55 Degrees North and East of 144 Degrees
West-
334 AM AKST Tue Dec 11 2018

...GALE WARNING TODAY THROUGH TONIGHT...

.TODAY...SW wind 30 kt becoming W 40 kt in the afternoon. Seas
building to 20 ft. Slight chance of thunderstorms. 
.TONIGHT...W wind 35 kt becoming S 20 late. Seas 24 ft. Slight
chance of thunderstorms in the evening. 
.WED...SE gale to 40 kt becoming S 30 kt in the afternoon.
Seas 23 ft. Rain showers. 
.WED NIGHT...W gale to 40 kt. Seas 26 ft. Showers.
.THU...W gale to 35 kt. Seas 22 ft. 
.FRI...SE gale to 40 kt. Seas 16 ft. 
.SAT...SE gale to 40 kt. Seas 22 ft. 

$$

021 
FZAK67 PAJK 120053
OFFAJK

Offshore Waters Forecast
National Weather Service Juneau AK
353 PM AKST Tue Dec 11 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.

PKZ398-121900-
353 PM AKST Tue Dec 11 2018
.SYNOPSIS FOR THE EASTERN GULF OF ALASKA...
A strong gale force low will move into the central gulf Wednesday
with the front stretching over to the southern outer coast. The 
low will move east making landfall north of Sitka early Thursday 
morning. 

$$

PKZ310-121900-
Gulf of Alaska North of 55 Degrees North and East of 144 Degrees
West-
353 PM AKST Tue Dec 11 2018

...GALE WARNING TONIGHT AND WEDNESDAY...

.TONIGHT...W wind 40 kt diminishing to 30 kt in the evening, then
becoming S late. Seas 24 ft. Isolated thunderstorms. 
.WED...SE wind 40 kt becoming S 30 kt in the afternoon.
Seas 23 ft. Snow showers in the morning. Rain showers. 
.WED NIGHT...W gale to 40 kt. Seas 26 ft. Rain showers in
the evening. 
.THU...W gale to 35 kt. Seas 24 ft. 
.THU NIGHT...SW wind 30 kt. Seas 21 ft subsiding to 14 ft
late. 
.FRI...SE gale to 40 kt. Seas 16 ft. 
.SAT...SE gale to 40 kt. Seas 22 ft. 
.SUN...S wind 30 kt. Seas 25 ft. 

$$

486 
FZAK67 PAJK 121252
OFFAJK

Offshore Waters Forecast
National Weather Service Juneau AK
352 AM AKST Wed Dec 12 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.

PKZ398-130700-
352 AM AKST Wed Dec 12 2018
.SYNOPSIS FOR THE EASTERN GULF OF ALASKA...
A storm force low will move into the south central gulf Wednesday
pushing a front into the southern outer coast. This low will 
weaken as it moves ENE across the gulf before moving inland north 
of Sitka early Thursday morning. 

$$

PKZ310-130700-
Gulf of Alaska North of 55 Degrees North and East of 144 Degrees
West-
352 AM AKST Wed Dec 12 2018

...GALE WARNING TODAY THROUGH TONIGHT...

.TODAY...S wind 20 kt becoming SE wind 35 kt late in the morning.
Seas 20 ft. Rain and snow showers.
.TONIGHT...NW wind 45 kt. Seas 20 ft. Rain showers in the
evening. 
.THU...W gale to 35 kt. Seas 18 ft. 
.THU NIGHT...SW wind 25 kt. Seas 16 ft. W swell. 
.FRI...SE gale to 40 kt. Seas 16 ft. 
.SAT...SE gale to 40 kt. Seas 22 ft. 
.SUN...S wind 30 kt. Seas 19 ft. 

$$

886 
FZAK67 PAJK 130048
OFFAJK

Offshore Waters Forecast
National Weather Service Juneau AK
348 PM AKST Wed Dec 12 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.

PKZ398-131900-
348 PM AKST Wed Dec 12 2018
.SYNOPSIS FOR THE EASTERN GULF OF ALASKA...
A storm force low in the eastern gulf Wednesday night will cross 
the outer coast south of Sitka early Thursday morning. 

$$

PKZ310-131900-
Gulf of Alaska North of 55 Degrees North and East of 144 Degrees
West-
348 PM AKST Wed Dec 12 2018

...STORM WARNING TONIGHT...

.TONIGHT...N wind 50 kt becoming NW 45 kt late. Seas 19 ft. Rain 
showers in the evening. 
.THU...NW wind 30 kt. Seas 17 ft. 
.THU NIGHT...SW wind 25 kt. Seas 15 ft. W swell. 
.FRI...S wind 25 kt. Seas 12 ft. W swell. 
.FRI NIGHT...SE gale to 40 kt. Seas 14 ft building to 19 ft
late. Showers late. 
.SAT...SE gale to 40 kt. Seas 22 ft. 
.SUN...S wind 30 kt. Seas 19 ft. 
.MON...SE wind 20 kt. Seas 16 ft. 

$$

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
253 PM AKST Mon Dec 10 2018

.SYNOPSIS...A storm force front offshore of Southeast Alaska will
push into the Panhandle Mon night and weaken. A gale force front
will then slide E across the gulf Tue and move into the Panhandle
Tue evening. Outlook. A strong low will move into the central gulf
Wed.

&&

.SHORT TERM...Yet another storm force front is giving Southeast
Alaska its best punch. Windy conditions are reported across
Southeast Alaska, except abnormally Skagway, where a parallel
gradient has neutralized the winds farther to the south. These
winds come with gusts of 40 to 55 mph, driving rain, and high
elevation heavy snow. Most areas have received rain rates of less
than a tenth of an inch per hour, but occasional moderate and
heavy rates are embedded. Lastly, this morning AK DOT reported up
to 4 inches of snow had already fallen at White Pass, and we are
looking for up to 17 inches storm total by the end of tonight. The
winter storm warning remains in effect through 5 AM tomorrow
morning.

A wave is forming well south of Prince of Wales Island and is
forecast to move north-northeast to the southern Panhandle
tonight. We considered a short order High Wind Warning, but given
strong stability with the front moving in aloft, we elected to
raise wind gusts to 55 mph but keep them below 60 mph. We also
elevated Clarence Strait to storm force 50 kt, which coordinates
very well with the 50-60 kt in Hecate Strait forecast by our
Canadian neighbors. Our winds will gradually relax from west to
east through tonight with most of the strongest winds occurring
late this afternoon and this evening.

Looking over the gulf behind the front, more unstable air will
bring a slight threat of thunderstorms beginning tonight and
spread to our beaches including Sitka and Ketchikan by Tuesday.
This air will spread inland of the Panhandle with stronger cold
air advection in the low levels Tuesday night. Unstable conditions
with a much cooler column could result in some snow showers late
Tuesday night with a mix getting into most all of the Panhandle.
We have indicated some light accumulations, but confidence is not
high, as convective regimes are usually more difficult to
forecast.

Little changes were made to the forecast Tuesday
night/Wednesday/Wednesday night other than the lowering snow
levels. Wednesday does bring a very strong low somewhere in the
central gulf. Where it tracks and how it evolves may affect are
wind and precipitation forecast mid-week. Thus, we see no reason
to change the forecast at this time.

Lastly we mention to subjects of poor confidence. The lighter
winds in Skagway are perilously close to busting through south
gust 40 mph. But we will allow them to steadily ramp up to more
confident levels Tuesday night as a ridge replaces the front. The
other item is Hyder. Temperatures have risen to 34 degrees and
snow changed over to rain. We foresee light winds tonight. It is
possible for a change back with some ramifications on snow
accumulation, but our current forecast supports no change at the
moment, so we go with rain.

We used NAM/GFS/NAMnest for changes to wind Monday night/Tuesday
and for changes to POP/QPF through Wednesday.

.LONG TERM/Wednesday through the weekend/...The long range
forecast remains very active with multiple strong low pressure
systems expected to enter the gulf.

Wednesday begins with a strong upper level trough pushing
northeast over the northern Pacific. A well developed surface low
pressure system will be present as well, and continue to
intensify as it pushes northeast into the south central gulf of
Alaska Wednesday. While the low intensifies, a substantial low
level just will develop on the south side of the low, with some
hints of nearly 100 knot winds in the lowest 2000 ft of the
atmosphere. There is potential for winds to develop to hurricane
force strength at the surface; however, with the uncertainty in
the track and ultimate intensity winds remain limited to strong
gales. These will likely see increases as the final path and
strength of the low becomes more certain. The current forecast
carries this low toward northern Baranof and Chichagof Island by
late Wednesday night. Additionally this storm may support snow
across the northern Panhandle and heavy precipitation rates will
accompany the low due to its convective nature.

Another strong upper level low pressure system will push across
the Pacific later this week and bring another strong low pressure
system into the gulf Saturday. This low looks to be yet another
strong one with a band of storm force winds likely to accompany
it.

Favored the 00Z NAM and 18Z GFS to handle the low development on
Wednesday. While not incorporated into the decision making
process, the 00Z GFS remained in good agreement with its 18Z run
and 00Z ECMWF trended toward the stronger solutions held within
the NAM and GFS. For Friday through the rest of the period the
forecast remained unchanged with newest WPC guidance remaining in
good agreement with the existing forecast. Overall forecast
confidence is average in the long term.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind until midnight AKST tonight for AKZ025>027.
     Strong Wind until 9 PM AKST this evening for AKZ019>021-023-024.
     Strong Wind until 3 PM AKST this afternoon for AKZ022.
     Strong Wind through late tonight for AKZ028.
     Winter Storm Warning until 5 AM AKST Tuesday for AKZ018.
     Strong Wind until 6 PM AKST this evening for AKZ017.
MARINE...Storm Warning for PKZ036-041-042.
     Gale Warning for PKZ013-021-022-031>035-043-051-052.
     Small Craft Advisory for PKZ011-012-053.

&&

JWA/JB

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