Small Craft Advisory 570, NWS Juneau, AK

307 
FZAK52 PAJK 231239
CWFAEG

Coastal Waters Forecast for Southeast Alaska
National Weather Service Juneau AK
339 AM AKST Tue Nov 23 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.

PKZ099-240645-
339 AM AKST Tue Nov 23 2021
.SYNOPSIS FOR OUTSIDE WATERS...
A weak front passes over the panhandle this morning. A gale-force
system enters the gulf and moves toward the panhandle Tuesday 
night. 

$$

PKZ041-240645-
Dixon Entrance to Cape Decision-
339 AM AKST Tue Nov 23 2021

...GALE WARNING LATE TONIGHT...

.TODAY...SW wind 20 kt. Seas 11 ft. 
.TONIGHT...S wind 30 kt increasing to 40 kt late. Seas 11 ft
building to 20 ft late. Rain showers late. 
.WED...SE gale to 40 kt becoming S 30 kt in the afternoon.
Seas 21 ft. Rain.
.WED NIGHT...S wind 30 kt. Seas 18 ft. Rain.
.THU...W wind 30 kt. Seas 18 ft. 
.FRI...W wind 25 kt becoming S. Seas 14 ft. 
.SAT...SE wind 25 kt. Seas 9 ft. 

$$

PKZ042-240645-
Cape Decision to Cape Edgecumbe-
339 AM AKST Tue Nov 23 2021

...GALE WARNING LATE TONIGHT...

.TODAY...W wind 15 kt. Seas 11 ft. 
.TONIGHT...S wind 30 kt becoming SE 40 kt late. Seas 10 ft
building to 20 ft late. Rain showers late. 
.WED...E wind 30 kt. Seas 19 ft. Rain in the morning. 
.WED NIGHT...S wind 30 kt. Seas 17 ft. Rain.
.THU...W wind 30 kt. Seas 17 ft. 
.FRI...SW wind 20 kt. Seas 14 ft. 
.SAT...E wind 20 kt. Seas 9 ft. 

$$

PKZ043-240645-
Cape Edgecumbe to Cape Fairweather-
339 AM AKST Tue Nov 23 2021

...GALE WARNING LATE TONIGHT...

.TODAY...SW wind 15 kt. Seas 10 ft. 
.TONIGHT...SE wind 30 kt becoming E 40 kt late. Seas 10 ft
building to 18 ft late. Rain showers late. 
.WED...SE gale to 35 kt. Seas 20 ft subsiding to 15 ft in
the afternoon. Rain in the morning. 
.WED NIGHT...NW wind 25 kt. Seas 14 ft. S swell. 
.THU...W wind 30 kt. Seas 14 ft. 
.FRI...SW wind 25 kt. Seas 14 ft. 
.SAT...E wind 15 kt. Seas 9 ft. 

$$

PKZ051-240645-
Cape Fairweather to Icy Cape-
339 AM AKST Tue Nov 23 2021

...GALE WARNING LATE TONIGHT...

.TODAY...SW wind 10 kt. Seas 9 ft. Snow showers early in the
morning. 
.TONIGHT...SE wind 25 kt becoming E 35 kt late. Seas 8 ft
building to 13 ft late. Rain and snow showers. 
.WED...SE wind 30 kt. Seas 16 ft. Rain in the morning. 
.WED NIGHT...W wind 20 kt. Seas 12 ft. SE swell. 
.THU...W wind 25 kt. Seas 13 ft. 
.FRI...SW wind 20 kt. Seas 13 ft. 
.SAT...E wind 10 kt. Seas 8 ft. 

$$

PKZ052-240645-
Icy Cape to Cape Suckling-
339 AM AKST Tue Nov 23 2021

...SMALL CRAFT ADVISORY TODAY AND TONIGHT...

.TODAY...SW wind 15 kt becoming S. Seas 9 ft. 
.TONIGHT...SE wind 20 kt becoming E 30 kt late. Seas 7 ft
building to 11 ft late. Rain and snow showers late. 
.WED...E wind 30 kt diminishing to 20 kt in the afternoon.
Seas 13 ft. Rain in the morning. 
.WED NIGHT...SW wind 20 kt. Seas 11 ft. SE swell. 
.THU...SW wind 20 kt. Seas 12 ft. 
.FRI...SW wind 25 kt. Seas 12 ft. 
.SAT...SW wind 10 kt. Seas 8 ft. 

$$

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
646 AM AKST Mon Nov 22 2021

.SHORT TERM...A low passing over the S panhandle has brought with
it windy conditions and renewed precipitation for much of the
area. Ketchikan in particular experienced high wind during the
overnight hours. As the western half of the low has moved over
various areas, snow has been introduced into places like Klawock
and Petersburg. Think that these areas could see some minor snow
accumulations before the precipitation intensity diminishes
through the morning hours. In the N half of the panhandle, many
areas have seen temperatures at or near freezing which has
encouraged a rain snow mix in some locations. Think that some
minor snow accumulations may be possible across the N as well,
particularly in cooler areas.

SW flow arrives for much of the S and Central panhandle in the
wake of the low through the day on Monday, though suspect that
winds in Lynn Canal will try to stay N thanks to pressure gradient
induced outflow. This SW flow, along with a decaying low over the
N gulf, will ensure continued showers across the area. A
shortwave will race up from the SW gulf and arrive early Tuesday
morning This system doesn't look particularly impressive, and
aside from more widespread coverage for precip, do not expect
significant impacts from it at this time.

A powerful system will arrive late Tuesday into Wednesday. For
further details on this system, see the long term discussion
below. Winter Storm Watches are out for much of the N panhandle in
association with it. Overall, forecaster confidence is average.

.LONG TERM.../Tuesday through Friday/ Very active and uncertain
winter weather pattern for southeast Alaska through the week
including potentially impactful weather for holiday travel. A
series of fronts and deeper lows track into the AK Gulf
bringing ample moisture which along with initially cold
temperatures that could produce more heavy snow for the central
and northern panhandle before a transition to rain. Meanwhile the
southern panhandle will change over the rain much sooner with
limited snow accumulation, however these areas will be impacted by
heavy rainfall.

Remnants of the low over the Northern Gulf Coast will keep shower
activity over most of the panhandle Tuesday into Tuesday night.
Precipitation amounts including snow expected to be minor, a
couple of inches. Temperatures north of Frederick Sound should be
cold enough for mostly snow with some mix of rain while
temperatures for the southern areas will start to warm with snow
initially then mainly rain. Then Wednesday is where the weather
takes a turn.

We've been tracking the development of a low which is now
projected to move northeast into the AK Gulf from the N Pacific
starting late Tuesday night. Along the front at the triple point
is another developing circulation. Similar to the system that
brought heavy snow to the panhandle over the weekend this system
also has defined warm and cold sectors v an occluded front. Also
the previous northerly gradient and cold air advection sets up for
an over running event. Question is while we've got the long fetch
of tropical moisture for heavy precip concern is warming and when
will the transition snow to rain occur. While increased precip
rates will have snow melt cooling, hence more snow, we don't have
a solid cold air mass in place. In addition the track of this
triple point low has shown large variation run to run, so not
confident resulting weather. MOS guidance has been variable on
snow totals, and while ensemble snow totals are high enough to
warrant the winter weather watch being issued, getting 850 temps
warming rapidly and winds mixing down and warming surface temps
right when the higher QPF values correspond to the higher snow
totals. So in a word, uncertainty with this system on precip type.
What expected: Heavy precip is expected, increased winds are
expected, but snow totals and where/when snow will start and stop
are the issue. Beyond Thursday with an upper low in place for most
of the long range will continue to see more low pressure systems
move into the AK Gulf from the southwest. Overall looking like a
warm and rainy pattern.

Went with a blend of ECMWF/GFS to get the Wednesday system into
the grids. New WPC picked up on this new low but then had little
change beyond Thursday afternoon. Forecast confidence is below
average.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Storm Watch from late Tuesday night through Thursday
     morning for AKZ017>021-025.
     High Wind Warning until 6 AM AKST early this morning for AKZ028.
MARINE...Gale Warning for PKZ036-041.
     Small Craft Advisory for PKZ022-042-043-051>053.

&&

GFS/PRB

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