Alert archive / Alaska / Small Craft Advisories in 2021

Small Craft Advisory 235, NWS Juneau, AK

April 20, 2021

NWS Juneau, AK issued this small craft advisory at Apr 20, 2021, 10:00 PM AKDT. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued
Apr 20, 2021, 10:00 PM AKDT (06:00 UTC)
Expired
Apr 21, 2021, 3:34 AM AKDT
In force
6 hr
Issued by
NWS Juneau, AK

The text

As transmitted.

549 
FZAK51 PAJK 210600 AAB
CWFAJK

Coastal Waters Forecast for Southeast Alaska
National Weather Service Juneau AK
1000 PM AKDT Tue Apr 20 2021

Southeast Alaska Inside Waters from Dixon Entrance to Skagway

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.

PKZ098-211615-
1000 PM AKDT Tue Apr 20 2021
.SYNOPSIS FOR SOUTHEAST ALASKA INNER CHANNELS COASTAL WATERS...
A ridge of high pressure will remain over the eastern Gulf of
Alaska tonight. High pressure from the interior will build
southeast across the Yukon through Wednesday and create a strong
northerly pressure gradient over the far northern inner
channels. 

$$

PKZ011-211615-
Glacier Bay-
1000 PM AKDT Tue Apr 20 2021

.TONIGHT...SE wind 10 kt becoming NW. Seas 2 ft or less.
.WED...NW wind increasing to 15 kt in the morning. Seas building
to 3 ft. Patchy fog in the morning.
.WED NIGHT...N wind 10 kt. Seas 2 ft or less.
.THU...N wind 10 kt. Seas 2 ft or less. 
.THU NIGHT...N wind 15 kt. Seas 3 ft. 
.FRI...N wind 15 kt. Seas 3 ft. 
.SAT...N wind 10 kt. Seas 2 ft or less. 
.SUN...N wind 10 kt. Seas 2 ft or less. 

$$

PKZ012-211615-
Northern Lynn Canal-
1000 PM AKDT Tue Apr 20 2021

...SMALL CRAFT ADVISORY WEDNESDAY...

.TONIGHT...SE wind 20 kt becoming N late. Seas 4 ft. 
.WED...N wind increasing to 25 kt in the morning. Seas building to 5
ft.
.WED NIGHT...N wind 20 kt. Seas 4 ft. 
.THU...N wind 20 kt. Seas 4 ft. 
.THU NIGHT...N wind increasing to 25 kt. Seas building to 5 ft. 
.FRI...N wind 25 kt diminishing to 10 kt. Seas 5 ft subsiding to 2
ft or less.
.SAT...N wind 10 kt. Seas 2 ft or less. 
.SUN...N wind 15 kt. Seas 3 ft. 

$$

PKZ013-211615-
Southern Lynn Canal-
1000 PM AKDT Tue Apr 20 2021

...SMALL CRAFT ADVISORY WEDNESDAY...

.TONIGHT...S wind 15 kt becoming N late. Seas 3 ft. 
.WED...N wind increasing to 30 kt in the morning then diminishing
to 20 kt in the afternoon. Seas building to 6 ft then subsiding to
4 ft in the afternoon.
.WED NIGHT...N wind 20 kt. Seas 4 ft. 
.THU...N wind 20 kt. Seas 4 ft. 
.THU NIGHT...N wind 25 kt. Seas 5 ft. 
.FRI...N wind 25 kt diminishing to 10 kt. Seas 5 ft then 2 ft
or less. 
.SAT...N wind 10 kt. Seas 2 ft or less. 
.SUN...NE wind 10 kt. Seas 2 ft or less. 

$$

PKZ021-211615-
Icy Strait-
1000 PM AKDT Tue Apr 20 2021

.TONIGHT...NW wind 20 kt diminishing to 10 kt late. Strongest
winds W of Point Adolphus. Seas 4 ft in the evening then 2 ft or 
less. Patchy fog late.
.WED...NW wind 10 kt. Seas 2 ft or less. Patchy fog in the
morning. 
.WED NIGHT...NW wind 15 kt. Strongest winds near Couverden. Seas 
building to 3 ft late.
.THU...W wind 15 kt. Seas 3 ft. 
.THU NIGHT...W wind 15 kt. Seas 3 ft. 
.FRI...NE wind 15 kt. Seas 3 ft. 
.SAT...NE wind 10 kt. Seas 2 ft or less. 
.SUN...N wind 10 kt becoming E. Seas 2 ft or less. 

$$

PKZ022-211615-
Cross Sound-
1000 PM AKDT Tue Apr 20 2021

...SMALL CRAFT ADVISORY TONIGHT...

.TONIGHT...W wind 25 kt becoming light late. Seas 7 ft. SW swell 
early in the evening. Patchy fog late. 
.WED...NE wind 15 kt. Seas 5 ft. Patchy fog in the morning.
.WED NIGHT...Light winds becoming E 10 kt late. Seas 5 ft. 
.THU...NE wind 15 kt. Seas 6 ft. 
.THU NIGHT...NE wind 15 kt. Seas 6 ft. 
.FRI...NE wind 20 kt. Seas 6 ft. 
.SAT...NE wind 15 kt. Seas 5 ft. 
.SUN...NE wind 15 kt. Seas 4 ft. 

$$

PKZ031-211615-
Stephens Passage-
1000 PM AKDT Tue Apr 20 2021

...SMALL CRAFT ADVISORY WEDNESDAY...

.TONIGHT...NW wind 10 kt except 20 kt near Young Bay. Seas 2 ft 
or less except 4 ft near Young Bay.
.WED...N wind 25 kt. Seas 5 ft. 
.WED NIGHT...N wind 20 kt. Seas 4 ft. 
.THU...N wind 15 kt. Seas 3 ft. 
.THU NIGHT...N wind 20 kt. Seas 4 ft. 
.FRI...N wind 20 kt becoming light. Seas 4 ft then 2 ft or
less. 
.SAT...Light winds. Seas 2 ft or less. 
.SUN...N wind 10 kt. Seas 2 ft or less. 

$$

PKZ032-211615-
Northern Chatham Strait-
1000 PM AKDT Tue Apr 20 2021

.TONIGHT...NW wind 15 kt. Seas 3 ft. 
.WED...N wind 20 kt. Seas 4 ft. 
.WED NIGHT...N wind 20 kt. Seas 4 ft. 
.THU...N wind 10 kt. Seas 2 ft or less. 
.THU NIGHT...N wind 15 kt. Seas 3 ft. 
.FRI...N wind 15 kt becoming light. Seas 3 ft. 
.SAT...Light winds. Seas 2 ft or less. 
.SUN...Light winds. Seas 2 ft or less. 

$$

PKZ033-211615-
Southern Chatham Strait-
1000 PM AKDT Tue Apr 20 2021

...SMALL CRAFT ADVISORY WEDNESDAY...

.TONIGHT...NW wind 15 kt diminishing to 10 kt late. Seas 3 ft in 
the evening then 2 ft or less. Near ocean entrances, seas 7 ft. 
.WED...N wind increasing to 25 kt in the afternoon. Seas building
to 5 ft.
.WED NIGHT...N wind 20 kt. Seas 4 ft. 
.THU...N wind 15 kt. Seas 3 ft, except 6 ft near ocean
entrances. 
.THU NIGHT...N wind 10 kt. Seas 2 ft or less, except 6 ft near 
ocean entrances. 
.FRI...N wind 15 kt becoming light. Seas 3 ft then 2 ft or less. 
.SAT...Light winds. Seas 2 ft or less. 
.SUN...Light winds. Seas 2 ft or less. 

$$

PKZ034-211615-
Frederick Sound-
1000 PM AKDT Tue Apr 20 2021

.TONIGHT...NW wind 15 kt. Seas 3 ft. 
.WED...NW wind 15 kt. Seas 3 ft. 
.WED NIGHT...N wind 15 kt. Seas 3 ft. 
.THU...N wind 10 kt. Seas 2 ft or less. 
.THU NIGHT...NE wind 20 kt. Seas 4 ft. 
.FRI...E wind 20 kt becoming light. Seas 4 ft then 2 ft or
less. 
.SAT...Light winds. Seas 2 ft or less. 
.SUN...NE wind 10 kt. Seas 2 ft or less. 

$$

PKZ035-211615-
Sumner Strait-
1000 PM AKDT Tue Apr 20 2021

.TONIGHT...NW wind 15 kt. Seas 3 ft. 
.WED...NW wind 15 kt. Seas 3 ft. 
.WED NIGHT...N wind 10 kt. Seas 2 ft or less. 
.THU...NE wind 10 kt. Seas 2 ft or less. 
.THU NIGHT...E wind 15 kt. Seas 3 ft. 
.FRI...E wind 20 kt becoming light. Seas 4 ft then 2 ft or
less. 
.SAT...Light winds. Seas 2 ft or less. 
.SUN...Light winds. Seas 2 ft or less. 

$$

PKZ036-211615-
Clarence Strait-
1000 PM AKDT Tue Apr 20 2021

.TONIGHT...NW wind 15 kt. Seas 3 ft. 
.WED...NW wind 20 kt. Seas 4 ft. 
.WED NIGHT...NW wind 20 kt. Seas 4 ft. 
.THU...NW wind 10 kt. Seas 2 ft or less. 
.THU NIGHT...NW wind 10 kt. Seas 2 ft or less. 
.FRI...NW wind 10 kt. Seas 2 ft or less. 
.SAT...NW wind 10 kt. Seas 2 ft or less. 
.SUN...SE wind 10 kt. Seas 2 ft or less. 

$$
2 follow-up statements
214 
FZAK51 PAJK 210848 AAC
CWFAJK

Coastal Waters Forecast for Southeast Alaska...UPDATED
National Weather Service Juneau AK
1248 AM AKDT Wed Apr 21 2021

Southeast Alaska Inside Waters from Dixon Entrance to Skagway

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.

PKZ098-211430-
1248 AM AKDT Wed Apr 21 2021
.SYNOPSIS FOR SOUTHEAST ALASKA INNER CHANNELS COASTAL WATERS...
A ridge of high pressure will remain over the eastern Gulf of
Alaska tonight. High pressure from the interior will build
southeast across the Yukon through Wednesday and create a strong
northerly pressure gradient over the far northern inner
channels. 

$$

PKZ011-211430-
Glacier Bay-
1248 AM AKDT Wed Apr 21 2021

UPDATED

.EARLY THIS MORNING...NW wind 15 kt. Seas 3 ft. 
.WED...NW wind increasing to 15 kt in the morning. Seas building
to 3 ft. Patchy fog in the morning.
.WED NIGHT...N wind 10 kt. Seas 2 ft or less.
.THU...N wind 10 kt. Seas 2 ft or less. 
.THU NIGHT...N wind 15 kt. Seas 3 ft. 
.FRI...N wind 15 kt. Seas 3 ft. 
.SAT...N wind 10 kt. Seas 2 ft or less. 
.SUN...N wind 10 kt. Seas 2 ft or less. 



$$

PKZ012-211430-
Northern Lynn Canal-
1248 AM AKDT Wed Apr 21 2021

UPDATED

...SMALL CRAFT ADVISORY LATE THIS MORNING THROUGH THIS AFTERNOON...

.EARLY THIS MORNING...S wind 15 kt becoming N late. Seas 4 ft. 
.WED...N wind increasing to 25 kt in the morning. Seas building to 5
ft.
.WED NIGHT...N wind 20 kt. Seas 4 ft. 
.THU...N wind 20 kt. Seas 4 ft. 
.THU NIGHT...N wind increasing to 25 kt. Seas building to 5 ft. 
.FRI...N wind 25 kt diminishing to 10 kt. Seas 5 ft subsiding to 2
ft or less.
.SAT...N wind 10 kt. Seas 2 ft or less. 
.SUN...N wind 15 kt. Seas 3 ft. 



$$

PKZ013-211430-
Southern Lynn Canal-
1248 AM AKDT Wed Apr 21 2021

UPDATED

...SMALL CRAFT ADVISORY LATE THIS MORNING THROUGH THIS AFTERNOON...

.EARLY THIS MORNING...S wind 15 kt becoming N late. Seas 3 ft. 
.WED...N wind increasing to 30 kt in the morning then diminishing
to 20 kt in the afternoon. Seas building to 6 ft then subsiding to
4 ft in the afternoon.
.WED NIGHT...N wind 20 kt. Seas 4 ft. 
.THU...N wind 20 kt. Seas 4 ft. 
.THU NIGHT...N wind 25 kt. Seas 5 ft. 
.FRI...N wind 25 kt diminishing to 10 kt. Seas 5 ft then 2 ft
or less. 
.SAT...N wind 10 kt. Seas 2 ft or less. 
.SUN...NE wind 10 kt. Seas 2 ft or less. 



$$

PKZ021-211430-
Icy Strait-
1248 AM AKDT Wed Apr 21 2021

UPDATED

.EARLY THIS MORNING...W wind 15 kt. Seas 3 ft. Patchy fog. 
.WED...NW wind 10 kt. Seas 2 ft or less. Patchy fog in the
morning. 
.WED NIGHT...NW wind 15 kt. Strongest winds near Couverden. Seas 
building to 3 ft late.
.THU...W wind 15 kt. Seas 3 ft. 
.THU NIGHT...W wind 15 kt. Seas 3 ft. 
.FRI...NE wind 15 kt. Seas 3 ft. 
.SAT...NE wind 10 kt. Seas 2 ft or less. 
.SUN...N wind 10 kt becoming E. Seas 2 ft or less. 



$$

PKZ022-211430-
Cross Sound-
1248 AM AKDT Wed Apr 21 2021

UPDATED

...SMALL CRAFT ADVISORY THROUGH EARLY THIS MORNING...

.EARLY THIS MORNING...W wind 20 kt. Seas 8 ft. Patchy fog. 
.WED...NE wind 15 kt. Seas 5 ft. Patchy fog in the morning.
.WED NIGHT...Light winds becoming E 10 kt late. Seas 5 ft. 
.THU...NE wind 15 kt. Seas 6 ft. 
.THU NIGHT...NE wind 15 kt. Seas 6 ft. 
.FRI...NE wind 20 kt. Seas 6 ft. 
.SAT...NE wind 15 kt. Seas 5 ft. 
.SUN...NE wind 15 kt. Seas 4 ft. 



$$

PKZ031-211430-
Stephens Passage-
1248 AM AKDT Wed Apr 21 2021

UPDATED

...SMALL CRAFT ADVISORY THROUGH THIS AFTERNOON...

.EARLY THIS MORNING...W wind 10 kt. Seas 2 ft or less. 
.WED...N wind 25 kt. Seas 5 ft. 
.WED NIGHT...N wind 20 kt. Seas 4 ft. 
.THU...N wind 15 kt. Seas 3 ft. 
.THU NIGHT...N wind 20 kt. Seas 4 ft. 
.FRI...N wind 20 kt becoming light. Seas 4 ft then 2 ft or
less. 
.SAT...Light winds. Seas 2 ft or less. 
.SUN...N wind 10 kt. Seas 2 ft or less. 



$$

PKZ032-211430-
Northern Chatham Strait-
1248 AM AKDT Wed Apr 21 2021

.TONIGHT...NW wind 15 kt. Seas 3 ft. 
.WED...N wind 20 kt. Seas 4 ft. 
.WED NIGHT...N wind 20 kt. Seas 4 ft. 
.THU...N wind 10 kt. Seas 2 ft or less. 
.THU NIGHT...N wind 15 kt. Seas 3 ft. 
.FRI...N wind 15 kt becoming light. Seas 3 ft. 
.SAT...Light winds. Seas 2 ft or less. 
.SUN...Light winds. Seas 2 ft or less. 



$$

PKZ033-211430-
Southern Chatham Strait-
1248 AM AKDT Wed Apr 21 2021

UPDATED

...SMALL CRAFT ADVISORY THIS AFTERNOON...

.EARLY THIS MORNING...NW wind 10 kt. Seas 2 ft or less, except
6 ft near ocean entrances. 
.WED...N wind increasing to 25 kt in the afternoon. Seas building
to 5 ft.
.WED NIGHT...N wind 20 kt. Seas 4 ft. 
.THU...N wind 15 kt. Seas 3 ft, except 6 ft near ocean
entrances. 
.THU NIGHT...N wind 10 kt. Seas 2 ft or less, except 6 ft near 
ocean entrances. 
.FRI...N wind 15 kt becoming light. Seas 3 ft then 2 ft or less. 
.SAT...Light winds. Seas 2 ft or less. 
.SUN...Light winds. Seas 2 ft or less. 



$$

PKZ034-211430-
Frederick Sound-
1248 AM AKDT Wed Apr 21 2021

.TONIGHT...NW wind 15 kt. Seas 3 ft. 
.WED...NW wind 15 kt. Seas 3 ft. 
.WED NIGHT...N wind 15 kt. Seas 3 ft. 
.THU...N wind 10 kt. Seas 2 ft or less. 
.THU NIGHT...NE wind 20 kt. Seas 4 ft. 
.FRI...E wind 20 kt becoming light. Seas 4 ft then 2 ft or
less. 
.SAT...Light winds. Seas 2 ft or less. 
.SUN...NE wind 10 kt. Seas 2 ft or less. 



$$

PKZ035-211430-
Sumner Strait-
1248 AM AKDT Wed Apr 21 2021

.TONIGHT...NW wind 15 kt. Seas 3 ft. 
.WED...NW wind 15 kt. Seas 3 ft. 
.WED NIGHT...N wind 10 kt. Seas 2 ft or less. 
.THU...NE wind 10 kt. Seas 2 ft or less. 
.THU NIGHT...E wind 15 kt. Seas 3 ft. 
.FRI...E wind 20 kt becoming light. Seas 4 ft then 2 ft or
less. 
.SAT...Light winds. Seas 2 ft or less. 
.SUN...Light winds. Seas 2 ft or less. 



$$

PKZ036-211430-
Clarence Strait-
1248 AM AKDT Wed Apr 21 2021

.TONIGHT...NW wind 15 kt. Seas 3 ft. 
.WED...NW wind 20 kt. Seas 4 ft. 
.WED NIGHT...NW wind 20 kt. Seas 4 ft. 
.THU...NW wind 10 kt. Seas 2 ft or less. 
.THU NIGHT...NW wind 10 kt. Seas 2 ft or less. 
.FRI...NW wind 10 kt. Seas 2 ft or less. 
.SAT...NW wind 10 kt. Seas 2 ft or less. 
.SUN...SE wind 10 kt. Seas 2 ft or less. 



$$
007 
FZAK51 PAJK 211134
CWFAJK

Coastal Waters Forecast for Southeast Alaska
National Weather Service Juneau AK
334 AM AKDT Wed Apr 21 2021

Southeast Alaska Inside Waters from Dixon Entrance to Skagway

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.

PKZ098-220245-
334 AM AKDT Wed Apr 21 2021
.SYNOPSIS FOR SOUTHEAST ALASKA INNER CHANNELS COASTAL WATERS...
A ridge of high pressure will remain over the eastern Gulf of
Alaska today. Also, high pressure from the interior will move 
southeast across the Yukon and create a strong northerly pressure 
gradient over the inner channels today and tonight. 

$$

PKZ011-220245-
Glacier Bay-
334 AM AKDT Wed Apr 21 2021

.TODAY...NW wind 15 kt. Seas 3 ft. Patchy fog early in the 
morning. 
.TONIGHT...NW wind 10 kt. Seas 2 ft or less. 
.THU...N wind 10 kt. Seas 2 ft or less. 
.THU NIGHT...N wind 20 kt. Seas 4 ft. 
.FRI...N wind 15 kt. Seas 3 ft. 
.SAT...N wind 15 kt. Seas 3 ft. 
.SUN...N wind 15 kt. Seas 3 ft. 

$$

PKZ012-220245-
Northern Lynn Canal-
334 AM AKDT Wed Apr 21 2021

...SMALL CRAFT ADVISORY THIS MORNING THROUGH THIS AFTERNOON...

.TODAY...N wind 15 kt increasing to 25 kt. Seas 5 ft. 
.TONIGHT...N wind 20 kt. Seas 4 ft. 
.THU...N wind 20 kt. Seas 4 ft. 
.THU NIGHT...N wind 25 kt. Gusts to 40 kt. Seas 5 ft. 
.FRI...N wind 25 kt. Seas 5 ft. 
.SAT...N wind 25 kt. Seas 5 ft. 
.SUN...N wind 15 kt. Seas 3 ft. 

$$

PKZ013-220245-
Southern Lynn Canal-
334 AM AKDT Wed Apr 21 2021

...SMALL CRAFT ADVISORY THIS MORNING THROUGH THIS AFTERNOON...

.TODAY...N wind 15 kt increasing to 25 kt. Gusts to 40 kt. Seas
5 ft. 
.TONIGHT...N wind 20 kt. Seas 4 ft. 
.THU...N wind 15 kt. Seas 3 ft. 
.THU NIGHT...N wind 25 kt. Seas 5 ft. 
.FRI...N wind 25 kt. Seas 5 ft. 
.SAT...N wind 20 kt. Seas 4 ft. 
.SUN...N wind 15 kt. Seas 4 ft then 2 ft or less. 

$$

PKZ021-220245-
Icy Strait-
334 AM AKDT Wed Apr 21 2021

.TODAY...NW wind 15 kt. Seas building to 3 ft. Patchy fog early 
in the morning. 
.TONIGHT...NW wind 20 kt. Seas 4 ft. 
.THU...W wind 10 kt becoming NE in the afternoon. Seas
building to 3 ft in the afternoon. 
.THU NIGHT...NE wind 15 kt. Seas 3 ft. 
.FRI...NE wind 15 kt. Seas 3 ft. 
.SAT...NE wind 15 kt. Seas 3 ft. 
.SUN...E wind 10 kt. Seas 3 ft. 

$$

PKZ022-220245-
Cross Sound-
334 AM AKDT Wed Apr 21 2021

.TODAY...NE wind 15 kt. Seas 7 ft. Patchy fog early in the
morning. 
.TONIGHT...E wind 15 kt. Seas 6 ft. 
.THU...E wind 10 kt. Seas 6 ft. 
.THU NIGHT...E wind 20 kt. Seas 6 ft. 
.FRI...NE wind 20 kt. Seas 6 ft. 
.SAT...E wind 20 kt. Seas 5 ft. 
.SUN...NE wind 10 kt. Seas 4 ft. 

$$

PKZ031-220245-
Stephens Passage-
334 AM AKDT Wed Apr 21 2021

...SMALL CRAFT ADVISORY THIS MORNING THROUGH THIS EVENING...

.TODAY...N wind 15 kt increasing to 25 kt. Seas 5 ft. 
.TONIGHT...N wind 25 kt decreasing to 15 kt. Seas 4 ft.
.THU...N wind 20 kt. Seas 4 ft. 
.THU NIGHT...N wind 20 kt. Seas 4 ft. 
.FRI...N wind 20 kt. Seas 4 ft. 
.SAT...N wind 15 kt. Seas 4 ft. 
.SUN...N wind 15 kt. Seas 4 ft then 2 ft or less. 

$$

PKZ032-220245-
Northern Chatham Strait-
334 AM AKDT Wed Apr 21 2021

.TODAY...N wind 20 kt. Seas 4 ft. 
.TONIGHT...N wind 20 kt. Seas 4 ft. 
.THU...N wind 15 kt. Seas 3 ft. 
.THU NIGHT...N wind 15 kt. Seas 3 ft. 
.FRI...N wind 15 kt. Seas 3 ft. 
.SAT...N wind 15 kt. Seas 3 ft. 
.SUN...N wind 15 kt becoming light. Seas 3 ft. 

$$

PKZ033-220245-
Southern Chatham Strait-
334 AM AKDT Wed Apr 21 2021

...SMALL CRAFT ADVISORY LATE THIS MORNING THROUGH TONIGHT...

.TODAY...N wind 15 kt increasing to 25 kt. Seas 5 ft, except 7 ft
near ocean entrances. 
.TONIGHT...N wind 25 kt. Seas 5 ft. 
.THU...N wind 15 kt. Seas 3 ft, except 6 ft near ocean
entrances. 
.THU NIGHT...N wind 15 kt. Seas 3 ft, except 6 ft near ocean
entrances. 
.FRI...N wind 15 kt. Seas 3 ft. 
.SAT...N wind 15 kt. Seas 3 ft. 
.SUN...N wind 15 kt becoming light. Seas 3 ft. 

$$

PKZ034-220245-
Frederick Sound-
334 AM AKDT Wed Apr 21 2021

.TODAY...NE wind 20 kt. Seas 4 ft. 
.TONIGHT...NW wind 20 kt becoming E late. Seas 4 ft. 
.THU...NE wind 10 kt. Seas 2 ft or less. 
.THU NIGHT...NE wind 20 kt. Seas 4 ft. 
.FRI...E wind 15 kt. Seas 3 ft. 
.SAT...E wind 15 kt. Seas 3 ft. 
.SUN...NE wind 15 kt. Seas 3 ft. 

$$

PKZ035-220245-
Sumner Strait-
334 AM AKDT Wed Apr 21 2021

.TODAY...W wind 15 kt. Seas 3 ft. 
.TONIGHT...N wind 15 kt becoming E late. Seas 3 ft. 
.THU...E wind 10 kt. Seas 2 ft or less. 
.THU NIGHT...E wind 20 kt. Seas 4 ft. 
.FRI...E wind 10 kt. Seas 2 ft or less. 
.SAT...E wind 10 kt. Seas 2 ft or less. 
.SUN...E wind 10 kt becoming light. Seas 2 ft or less. 

$$

PKZ036-220245-
Clarence Strait-
334 AM AKDT Wed Apr 21 2021

.TODAY...NW wind 20 kt. Seas 4 ft. 
.TONIGHT...N wind 20 kt. Seas 4 ft. 
.THU...NW wind 10 kt. Seas 2 ft or less. 
.THU NIGHT...NW wind 10 kt. Seas 2 ft or less. 
.FRI...SE wind 10 kt. Seas 2 ft or less. 
.SAT...NW wind 10 kt. Seas 2 ft or less. 
.SUN...SE wind 10 kt. Seas 2 ft or less. 

$$

What forecasters said that day

The local office's own words before this small craft advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Juneau, AK wrote its last area forecast discussion before this small craft advisory went out at Apr 20, 2:43 PM AKDT, 7 hours 17 minutes earlier.

Area forecast discussion, Apr 20, 2:43 PM AKDT, 7 hours 17 minutes before
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
243 PM AKDT Tue Apr 20 2021

.SHORT TERM.../Through Wednesday night/...An extensive marine
layer present along the outer coast early today largely
diminished by late morning. Farther inland, broken to overcast
conditions gave way to sunny skies by this afternoon. Clouds over
the eastern Gulf continue to flow west towards the outer coast,
but have the appearance of a more convective environment rather
than a stratiform marine layer. Higher up in the atmosphere,
mostly cloudy conditions at the start of the day gave way to
partly cloudy or even sunny skies. Current forecast calls for
mostly cloudy skies north of Frederick Sound tonight, but
satellite imagery shows the present cloud deck to be somewhat
thin. This could result in another night with a large diurnal
spread and overnight lows in the low to mid 30s. Complicating
this, models are indicating a short wave dropping southeast out of
the interior and the Yukon later tonight. Models are in good
agreement that this feature will contain some measurable
precipitation. This feature can be seen easily on IR satellite
imagery, but current visible channel imagery shows the
corresponding colder clouds to be rather thin and not very
representative of precipitation bearing clouds. The afternoon
forecast issuance reflects the idea that models are correct, but
no precipitation being reported where those clouds currently are
does not instill a sense of confidence. If, in fact, the
precipitation does happen as modeled, the outcome could likely be
snow for White Pass. Other locations are not expected to get cold
enough for snow before the short wave passes into British
Columbia.

In the wake of this short wave, strong high pressure over the
interior will build southeast in the Yukon and create a stiff
northerly pressure gradient over the far northern inner channels.
Have included small craft advisories for Lynn Canal, Stephens
Passage, and southern Chatham Strait for tomorrow as a result.
Clearing skies early tomorrow should provide for slightly warmer
daytime highs in spite of the weak cold air advection that will
accompany the short wave tonight.

.LONG TERM.../Thursday through Tuesday as of 10 pm Monday
evening/...A large blocking ridge over the eastern Pacific
extending into the Northwest portion of Alaska continues Thursday.
Part of an upper level (500 mb) low, south of the central
Aleutians, slides southeast. As it does, the low continues to move
southeast of the CONUS into Saturday. The upper level ridge
repositions to extend from the north central pacific, through the
gulf to Alaskan interior for Sunday and Monday. The pattern Monday
starts to look more chaotic as another low from the Bering moves
into the western gulf.

With the blocking pattern in place aloft, the forecast for SEAK
is expected to be dry. There may be a possibility of rain around
Friday night/early Saturday from a low in the gulf, or maybe some
drizzle along the coast from the marine layer on Wednesday.

Although conditions remain dry, sky cover may not remain as clear.
A marine layer is expected to push into Southeast Alaska Tuesday
night into early Wednesday. With this, temperatures are expected
to be cooler. Seasonal normals include Highs in the 50s to 60s.
The marine layer is expected to move offshore or be eroded by
Thursday and late Thursday into weekend as the potential for
sunshine returns. This being said don't think the temps will push
back to the warmth of the last couple days for SEAK.

Did not need to make many changes to the forecast package.
Forecast confidence is average to above average as a more stable
forecast pattern develops.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Small Craft Advisory for PKZ012-013-031-033-041>043-051-052.

&&

FCF/CDC/Bezenek

Visit us at http://www.weather.gov/Juneau

The office that day

Everything else NWS Juneau, AK issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 21, 3:26 PM AKDTSmall Craft AdvisoryAJK12 hr

Nearby

Small Craft Advisories in Alaska, 2021Every small craft advisory in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text.