Small Craft Advisory 636, NWS Juneau, AK

787 
FZAK52 PAJK 210019
CWFAEG

Coastal Waters Forecast for Southeast Alaska
National Weather Service Juneau AK
319 PM AKST Mon Dec 20 2021

Southeast Alaska Coastal Waters from Dixon Entrance to
Cape Suckling out 100 NM

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

PKZ099-211830-
319 PM AKST Mon Dec 20 2021
.SYNOPSIS FOR OUTSIDE WATERS...
A gale-force low will develop in the northern gulf Mon night and 
track SE along the outer coast through Tue night. Outlook. A 
trough over the panhandle returns late Tue evening. 

$$

PKZ041-211830-
Dixon Entrance to Cape Decision-
319 PM AKST Mon Dec 20 2021

...SMALL CRAFT ADVISORY TUESDAY...

.TONIGHT...W wind 15 kt. Seas 6 ft. 
.TUE...SW wind 30 kt. Seas 13 ft building to 18 ft in the
afternoon. Rain.
.TUE NIGHT...N gale to 35 kt. Seas 21 ft. 
.WED...N wind 30 kt. Seas 17 ft. 
.WED NIGHT...N wind 30 kt. Seas 14 ft. 
.THU...NE wind 20 kt becoming N 30 kt. Seas 11 ft. 
.FRI...N wind 25 kt. Seas 12 ft. 
.SAT...NE wind 15 kt. Seas 9 ft. 

$$

PKZ042-211830-
Cape Decision to Cape Edgecumbe-
319 PM AKST Mon Dec 20 2021

...GALE WARNING TUESDAY...

.TONIGHT...W wind 10 kt increasing to 25 kt late. Seas 6 ft. Rain
late. 
.TUE...SW wind 30 kt becoming W 40 kt in the afternoon. Seas
14 ft building to 20 ft in the afternoon. Rain in the morning. 
.TUE NIGHT...N gale to 35 kt. Seas 19 ft. 
.WED...N gale to 35 kt. Seas 16 ft. 
.WED NIGHT...N wind 30 kt. Seas 13 ft. 
.THU...N wind 20 kt increasing to 30 kt. Seas 8 ft building
to 12 ft. 
.FRI...N wind 25 kt. Seas 12 ft. 
.SAT...SE wind 10 kt. Seas 9 ft. 

$$

PKZ043-211830-
Cape Edgecumbe to Cape Fairweather-
319 PM AKST Mon Dec 20 2021

...GALE WARNING TUESDAY...

.TONIGHT...W wind 15 kt increasing to 25 kt late. Seas 6 ft. Snow
in the evening. Rain late. 
.TUE...W wind 35 kt becoming N in the afternoon. Seas 14 ft
building to 18 ft in the afternoon. Rain in the morning. 
.TUE NIGHT...N gale to 40 kt. Seas 17 ft. 
.WED...NE wind 30 kt. Seas 13 ft. 
.WED NIGHT...NE wind 25 kt. Seas 10 ft. 
.THU...NE wind 20 kt. Seas 6 ft building to 11 ft. 
.FRI...NE wind 25 kt becoming E 15 kt. Seas 12 ft. 
.SAT...E wind 15 kt. Seas 10 ft subsiding to 6 ft. 

$$

PKZ051-211830-
Cape Fairweather to Icy Cape-
319 PM AKST Mon Dec 20 2021

...GALE WARNING TUESDAY...

.TONIGHT...SW wind 15 kt. Seas 6 ft. Rain and snow. 
.TUE...N wind 35 kt. Seas 12 ft. 
.TUE NIGHT...N gale to 35 kt becoming NE 25 kt late. Seas
13 ft. 
.WED...NE wind 20 kt. Seas 9 ft. 
.WED NIGHT...E wind 15 kt. Seas 7 ft. 
.THU...NE wind 15 kt. Seas 8 ft. 
.FRI...E wind 10 kt. Seas 10 ft. 
.SAT...E wind 10 kt. Seas 7 ft. 

$$

PKZ052-211830-
Icy Cape to Cape Suckling-
319 PM AKST Mon Dec 20 2021

...GALE WARNING TUESDAY...

.TONIGHT...W wind 10 kt becoming E 20 kt late. Seas 6 ft. Rain in
the evening. Snow.
.TUE...N wind 35 kt. Seas 12 ft building to 16 ft in the
afternoon. 
.TUE NIGHT...N gale to 35 kt becoming NW 25 kt late. Seas
14 ft. 
.WED...N wind 25 kt. Seas 10 ft. 
.WED NIGHT...N wind 20 kt. Seas 6 ft. 
.THU...N wind 30 kt. Seas 10 ft. 
.FRI...N wind 20 kt becoming E. Seas 8 ft. 
.SAT...E wind 10 kt becoming light. Seas 6 ft. 

$$

356 
FZAK52 PAJK 211242
CWFAEG

Coastal Waters Forecast for Southeast Alaska
National Weather Service Juneau AK
342 AM AKST Tue Dec 21 2021

Southeast Alaska Coastal Waters from Dixon Entrance to
Cape Suckling out 100 NM

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

PKZ099-220645-
342 AM AKST Tue Dec 21 2021
.SYNOPSIS FOR OUTSIDE WATERS...
A gale-force low in the northern gulf is tracking SE  along the
outer coast through Tuesday night. A trough over the  panhandle
returns late Tuesday evening. Outlook. A second gale- force low
enters the northern gulf and tracks SE along the outer  coast
late Wednesday.  

$$

PKZ041-220645-
Dixon Entrance to Cape Decision-
342 AM AKST Tue Dec 21 2021

...GALE WARNING THIS EVENING...

.TODAY...W wind 20 kt becoming SW 30 kt. Seas 7 ft building to
18 ft. Rain.
.TONIGHT...N wind 35 kt. Seas 21 ft. 
.WED...N wind 30 kt. Seas 17 ft. 
.WED NIGHT...N wind 25 kt. Seas 14 ft. 
.THU...NE wind 30 kt. Seas 11 ft. 
.FRI...N wind 25 kt. Seas 12 ft. 
.SAT...NE wind 15 kt. Seas 9 ft. 

$$

PKZ042-220645-
Cape Decision to Cape Edgecumbe-
342 AM AKST Tue Dec 21 2021

...GALE WARNING THIS AFTERNOON THROUGH THIS EVENING...

.TODAY...SW wind 25 kt becoming W 40 kt in the afternoon. Seas
8 ft building to 20 ft. Rain early in the morning. 
.TONIGHT...N wind 35 kt. Seas 19 ft. 
.WED...N 30 kt. Seas 16 ft. 
.WED NIGHT...N wind 20 kt. Seas 12 ft. 
.THU...N wind 30 kt. Seas 12 ft. 
.FRI...N wind 25 kt. Seas 12 ft. 
.SAT...SE wind 10 kt. Seas 9 ft. 

$$

PKZ043-220645-
Cape Edgecumbe to Cape Fairweather-
342 AM AKST Tue Dec 21 2021

...GALE WARNING THIS MORNING THROUGH LATE TONIGHT...

.TODAY...W wind 25 kt increasing to 35 kt in the morning, then
becoming N in the afternoon. Seas 9 ft building to 18 ft. Rain
early in the morning. 
.TONIGHT...N wind 40 kt. Seas 17 ft. 
.WED...NE wind 30 kt decreasing to 15 kt. Seas 13 ft. 
.WED NIGHT...W wind 15 kt. Seas 10 ft. 
.THU...NE wind 20 kt. Seas 12 ft. 
.FRI...NE wind 25 kt becoming E 15 kt. Seas 12 ft. 
.SAT...E wind 15 kt. Seas 10 ft subsiding to 6 ft. 

$$

PKZ051-220645-
Cape Fairweather to Icy Cape-
342 AM AKST Tue Dec 21 2021

...GALE WARNING THIS AFTERNOON THROUGH THIS EVENING...

.TODAY...SE wind 20 kt becoming N 35 kt. Seas 9 ft building to
14 ft in the afternoon. Rain early in the morning. 
.TONIGHT...N wind 35 kt becoming NE 25 kt late. Seas 13 ft. 
.WED...E wind 20 kt. Seas 9 ft. 
.WED NIGHT...E wind 15 kt. Seas 6 ft. 
.THU...NE wind 15 kt. Seas 11 ft. 
.FRI...E wind 10 kt. Seas 10 ft. 
.SAT...E wind 10 kt. Seas 7 ft. 

$$

PKZ052-220645-
Icy Cape to Cape Suckling-
342 AM AKST Tue Dec 21 2021

...GALE WARNING THIS MORNING THROUGH THIS EVENING...

.TODAY...E wind 20 kt becoming N 35 kt. Seas 8 ft building to
14 ft. 
.TONIGHT...N wind 35 kt becoming NW 25 kt late. Seas 15 ft
subsiding to 11 ft late. 
.WED...NW wind 20 kt. Seas 9 ft. 
.WED NIGHT...E wind 20 kt. Seas 7 ft. 
.THU...NW wind 30 kt. Seas 14 ft. 
.FRI...N wind 20 kt. Seas 8 ft. 
.SAT...E wind 10 kt. Seas 6 ft. 

$$

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
418 PM AKST Sun Dec 19 2021

.SHORT TERM.../Through Tuesday night/ As a new week begins, the
next weather system to impact the region develops in the northern
gulf. The main story in the short term will be the threat for
accumulating snow across the Panhandle.

Currently, a very dry airmass remains over the region with a large
upper ridge over Alaska and a surface high pressure system over
Canada. As the high pushes east, the ridge collapses and the exit
region of a 150 kt upper jet noses into the Northern Gulf,
inducing a leeside surface low just SE of Yakutat. This low will
be pushed SE down the Outer Coast as a ridge reforms over much of
Alaska. This quick hitting system is expected to bring
accumulating snow to many areas across the region. Due to such a
dry airmass in place, it may take a while for the entire column to
saturate, delaying the onset of precipitation. Expect
precipitation to begin along the NE Gulf Coast Monday afternoon,
then spread southeast through Tuesday. Bufkit soundings do
indicate the possibility of precipitation starting as a brief
period of freezing drizzle Monday afternoon and evening across the
northern half of SE Alaska. Once the Dendritic Growth Zone (DGZ)
fully saturates, any freezing drizzle should transition over to
snow. Expect the heaviest snow accumulations south of Upper Lynn
Canal, through the Icy Strait Corridor, and down the Coast
Mountains; therefore a Winter Storm Watch has been issued for
amounts around 3 to 8 inches. Due to westerly flow aloft, expect
Upper Lynn Canal to be rain shadowed for much of the event;
however confidence was not high enough to completely remove PoP
from there. With the coldest air locked in place closer to the
Coast Mountains, areas from Juneau to Petersburg to Hyder should
remain all snow and have the highest snow amounts. With southerly
flow at the surface, the Outer Coast is expected to change to
rain Tuesday morning, keeping snow amounts on the lower side. Went
ahead and issued a Winter Weather Advisory for the Southern Inner
Channels including Prince of Wales Island as a quick 2 to 4
inches of snow is possible (especially at higher elevations on the
road system) before a change to rain Tuesday.

Winds ahead of this system turn southerly Monday evening and
remain out of the south until the low passes by. Expect 15 to 20
kt southerlies ahead of the system through the Inner Channels.
Impactful marine conditions develop as this low departs Tuesday
night. Very strong northerly outflow develops behind the low as
high pressure settles back into NW Canada. Expect Gales to form
through Lynn Canal and small craft conditions through much of the
Inner Channels. Northerly winds gusting over 45 kt possible out
of Taku Inlet and other interior passes as well beginning Tuesday
night. Will have to watch for High Wind potential for Skagway as
the northerly pressure gradient really tightens.

Confidence in the short term forecast is only marginal. Lower
confidence regarding the north and eastward extent of the
rain/snow line along the Outer Coast and Southern Panhandle.
Models still have some discrepancies in how close the low will
track down the Outer Coast, which could greatly effect snow
amounts.

.LONG TERM.../Wednesday through Friday/...As the previous low
continues to move southeastward away from the Panhandle, we will
be under the influence of a strong ridge of high pressure centered
over the Yukon region of Canada, which will generally dominate
our weather through the end of the forecast period.

Once again, we will continue to have strong outflow winds from
the tight pressure gradient between the aforementioned strong high
and the relatively lower pressure over the eastern Gulf and
Panhandle. This will produce strong outflow winds over the north-
south oriented Inner Channels and stronger winds and gusts out of
adjacent interior passes. Lynn Canal looks to have Gales for
Wednesday potentially stretching into Thursday. Adjacent inner
channels and around ocean entrances look to have up to Small Craft
winds for Wednesday into Thursday.

According to forecast model guidance, ensembles, and 850mb model
forecast Cold Air Advection, temperatures will cool with some
far northern areas from the Icy Strait Corridor and Mendenhall
Valley, northward, dipping down into the single digits below zero
for low temperatures through the end of the long-term forecast
period. 850mb temperatures aloft of between -20 and -30 Celsius
look to advect toward the northern Panhandle through the period
from the high pressure center poised to the north. These
temperatures translate into the aforementioned low temperatures.
White Pass may not even get above zero for their high temperatures
as we head toward next weekend. Use extra caution if you must be
out and about in the cold temperatures and wind for a prolonged
period of time as wind chills may become dangerously cold and you
run the risk of acquiring frostbite. Additionally, temperatures
this cold for any prolonged period may cause pipes to freeze.

As for moisture and cloud cover, as is typical for outflow
events, Southeast Alaska looks to remain dry with many breaks in
cloud cover through the end of the long-term forecast period.
This is due to the strong offshore component, the anticyclonic
nature of the surface wind, and sinking air from the orientation
of the 300mb Jet.

Forecast confidence is generally average to above average due to
good weather forecast model consensus.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Storm Watch from Monday evening through Tuesday morning
     for AKZ020-021-025-026.
     Winter Weather Advisory from 3 AM to 3 PM AKST Tuesday for
     AKZ027-028.
     Winter Storm Watch from late Monday night through Tuesday
     evening for AKZ029.
MARINE...Small Craft Advisory for PKZ012-013-031.

&&

CM/JLC

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