Small Craft Advisory 371, NWS Juneau, AK

884 
FZAK52 PAJK 202331
CWFAEG

Coastal Waters Forecast for Southeast Alaska
National Weather Service Juneau AK
331 PM AKDT Fri Aug 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.

PKZ099-211745-
331 PM AKDT Fri Aug 20 2021
.SYNOPSIS FOR OUTSIDE WATERS...
A ridge remains anchored over the eastern gulf and the
panhandle. A weak system will move along the eastern edge of the
ridge through Saturday.  

$$

PKZ041-211745-
Dixon Entrance to Cape Decision-
331 PM AKDT Fri Aug 20 2021

.TONIGHT...NW wind 20 kt, lighter winds near the coast. Seas 7 
ft.
.SAT...NW wind 20 kt. Seas 7 ft. 
.SAT NIGHT...NW wind 25 kt. Seas 8 ft. 
.SUN...NW wind 20 kt. Seas 8 ft. 
.SUN NIGHT...NW wind 20 kt. Seas 7 ft. 
.MON...W wind 10 kt becoming S. Seas 6 ft. 
.TUE...S wind 15 kt. Seas 6 ft. 
.WED...SW wind 15 kt. Seas 5 ft. 

$$

PKZ042-211745-
Cape Decision to Cape Edgecumbe-
331 PM AKDT Fri Aug 20 2021

.TONIGHT...NW wind 20 kt, lighter winds near the coast. Seas 7 
ft.
.SAT...NW wind 20 kt. Seas 7 ft. 
.SAT NIGHT...NW wind 20 kt. Seas 8 ft. 
.SUN...NW wind 20 kt. Seas 7 ft. 
.SUN NIGHT...NW wind 15 kt. Seas 6 ft. 
.MON...S wind 20 kt. Seas 6 ft. 
.TUE...S wind 20 kt. Seas 6 ft. 
.WED...S wind 15 kt. Seas 5 ft. 

$$

PKZ043-211745-
Cape Edgecumbe to Cape Fairweather-
331 PM AKDT Fri Aug 20 2021

.TONIGHT...W wind 20 kt, lighter winds near the coast. Seas 6 ft.
.SAT...NW wind 20 kt. Seas 7 ft. 
.SAT NIGHT...NW wind 15 kt. Seas 7 ft. 
.SUN...NW wind 15 kt. Seas 6 ft. 
.SUN NIGHT...W wind 15 kt. Seas 5 ft. 
.MON...S wind 20 kt. Seas 6 ft. 
.TUE...S wind 20 kt. Seas 6 ft. 
.WED...S wind 10 kt. Seas 5 ft. 

$$

PKZ051-211745-
Cape Fairweather to Icy Cape-
331 PM AKDT Fri Aug 20 2021

.TONIGHT...W wind 15 kt. Seas 7 ft. 
.SAT...NW wind 15 kt. Seas 7 ft. 
.SAT NIGHT...NW wind 15 kt. Seas 6 ft. 
.SUN...NW wind 10 kt. Seas 5 ft. 
.SUN NIGHT...S wind 10 kt. Seas 4 ft. 
.MON...SE wind 25 kt. Seas 5 ft. 
.TUE...SE wind 20 kt. Seas 6 ft. 
.WED...SE wind 10 kt. Seas 5 ft. 

$$

PKZ052-211745-
Icy Cape to Cape Suckling-
331 PM AKDT Fri Aug 20 2021

.TONIGHT...NW wind 15 kt. Seas 7 ft. 
.SAT...NW wind 20 kt. Seas 6 ft. 
.SAT NIGHT...NW wind 15 kt. Seas 5 ft. 
.SUN...W wind 10 kt. Seas 4 ft. 
.SUN NIGHT...SE wind 15 kt. Seas 5 ft. 
.MON...E wind 30 kt. Seas 6 ft. 
.TUE...SE wind 20 kt. Seas 6 ft. 
.WED...SE wind 15 kt. Seas 5 ft. 

$$

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
253 PM AKDT Thu Aug 19 2021

.SHORT TERM...Widespread stratocumulus still lurks across our
skies signifying a persistently saturated boundary layer. Light
gradients at the surface and the only transiting feature of note--
a weak short-wave largely passing to our south--should do little
to introduce a new air mass, or even to change our existing one.
Therefore, we once expect lower clouds to once again re-form this
evening. Passing disturbances aloft may indeed induce sufficient
lift in the low levels to promote some patchy drizzle across the
area. When some of these disturbances encounter the higher terrain
of Baranof, Chichagof, Prince of Wales, and Admiralty Islands,
some bona fide scattered to isolated light rain showers will
develop. As ridging becomes stronger overnight in the lee of the
short-wave, lift should diminish and thus showers will fade. Yet
drizzle and lower clouds will still persist into Saturday morning.

Models have been optimistic with cloud cover, but their skill
level is dubious regarding moist boundary layer interactions with
terrain features. It is true that some breaks have formed near
Gustavus and over some of our fjords. But this will likely spark
more rapid cooling in spots to help promote earlier fog
development. We chilled temperatures by a couple of degrees Friday
morning. This in itself should help in fog/low cloud development.
Weak northerly flow develops through the channels when the
shortwave enhances lower pressure across the south. But this
should not result in meaningful offshore flow that would
significantly mix out the boundary layer.

Friday, still looks like a stellar day across the south with some
sun and only partly cloudy skies. Temperatures should eclipse 70
in Hyder with the rest of the south at least in the mid to upper
60s. Meanwhile to the north, a front bringing in cooler air from
the Alaska Interior southeast into the Panhandle, will spread
scattered showers from north to south through Saturday. Snow
levels will once again fall to less than 6K feet. Thus, the north
should experience cooler temperatures and cloudier skies than the
south. Lower pressure progged to develop with the front's approach
on Friday from the northwest will enhance southerlies Friday
afternoon through Skagway and Lynn Canal. But overall winds will
be on the lighter side and begin to turn northerly from south to
north through Saturday. Likewise, scattered showers by the
afternoon will be exiting the north on their way southward.
Saturday, temperatures across the south will be significantly
cooler while the north will barely feel the difference between
Friday and Saturday. As this front originates across the Alaska
Interior, we are more confident that it will clean the boundary
layer of low level moisture and allow some sun to peak through the
clouds Saturday afternoon for a sunnier evening walk across most
areas of the Panhandle. All of this--clearer skies for efficient
radiational cooling, a front from the north at summer's tail end,
and lower freezing levels--sets us up for a hint of autumn Sunday
morning.

.LONG TERM.../Sunday through Wednesday/...As of 10pm Wednesday.
Saturday night an inverted trough over the inner channels and a
ridge of high pressure will strengthen, causing N-NW winds. This
flow pattern is a dry one and should aid in decreasing clouds into
Sunday. Overnight Saturday into Sunday the northerly winds will
peak around 15kt through the northern inner channels while the
southern inner channels should see that peak during the day along
with a tip jet around the southern tip of Baranof Island and Cape
Decision. Due to the northerly pressure gradient, sea breezes will
be weaker or non- existent around the northern inner channels, so
kept temps above or on the high end of guidance with 65-70F.

Monday will see the next low pressure system and assoc front moving
into the gulf from the west. Rain will gradually spread into the
area through Monday night, making for a wet Tuesday. Models are in
relatively good agreement on this system, so POP is pretty high
considering how for in the future it is. Rainfall could be moderate
to heavy at times with this system, namely for Yakutat to Pelican.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...None.

&&

JWA/Ferrin

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