Small Craft Advisory 342, NWS Juneau, AK

672 
FZAK51 PAJK 232339
CWFAJK

Coastal Waters Forecast for Southeast Alaska
National Weather Service Juneau AK
339 PM AKDT Fri Jul 23 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.

PKZ098-241715-
339 PM AKDT Fri Jul 23 2021
.SYNOPSIS FOR SOUTHEAST ALASKA INNER CHANNELS COASTAL WATERS...
A surface low pressure over the central Gulf moves slowly to the
southeast while weak disturbances rotate around the low and
impact the southern Panhandle through the weekend. Outlook. The 
surface low meanders over the southeastern Gulf while weakening 
through early next week. 

$$

PKZ011-241715-
Glacier Bay-
339 PM AKDT Fri Jul 23 2021

.TONIGHT...Light winds. Seas 2 ft or less. Showers.
.SAT...Light winds. Seas 2 ft or less. 
.SAT NIGHT...Light winds. Seas 2 ft or less. 
.SUN...SE wind 10 kt. Seas 2 ft or less. 
.SUN NIGHT...Light winds. Seas 2 ft or less. 
.MON...Light winds becoming W 10 kt. Seas 2 ft or less. 
.TUE...Light winds becoming S 10 kt. Seas 2 ft or less. 
.WED...Light winds becoming SW 10 kt. Seas 2 ft or less. 

$$

PKZ012-241715-
Northern Lynn Canal-
339 PM AKDT Fri Jul 23 2021

.TONIGHT...S wind 20 kt diminishing to 10 kt. Seas 4 ft subsiding
to 2 ft or less. Showers in the evening. 
.SAT...SE wind 15 kt. Seas building to 3 ft in the
afternoon. 
.SAT NIGHT...SE wind 15 kt in the evening becoming light. Seas 3 
ft in the evening then 2 ft or less. 
.SUN...S wind 15 kt. Seas 3 ft. 
.SUN NIGHT...SE wind 10 kt. Seas 2 ft or less. 
.MON...Light wind becoming S 10 kt. Seas 2 ft or less. 
.TUE...S wind 15 kt. Seas 3 ft. 
.WED...S wind 15 kt. Seas building to 3 ft. 

$$

PKZ013-241715-
Southern Lynn Canal-
339 PM AKDT Fri Jul 23 2021

.TONIGHT...Light winds. Seas 2 ft or less. Showers.
.SAT...SE wind 10 kt. Seas 2 ft or less. 
.SAT NIGHT...S wind 10 kt. Seas 2 ft or less. 
.SUN...S wind 10 kt. Seas 2 ft or less. 
.SUN NIGHT...S wind 10 kt. Seas 2 ft or less. 
.MON...Light wind becoming S 10 kt. Seas 2 ft or less. 
.TUE...S wind 15 kt. Seas building to 3 ft. 
.WED...S wind 10 kt. Seas 2 ft or less. 

$$

PKZ021-241715-
Icy Strait-
339 PM AKDT Fri Jul 23 2021

.TONIGHT...E wind 10 kt. Seas 2 ft or less. Showers.
.SAT...E wind 10 kt. Seas 2 ft or less. Showers in the
morning. 
.SAT NIGHT...SE wind 10 kt. Seas 2 ft or less. 
.SUN...E wind 10 kt. Seas 2 ft or less. 
.SUN NIGHT...W wind 10 kt. Seas 2 ft or less. 
.MON...Light winds becoming W 10 kt. Seas 2 ft or less. 
.TUE...SW wind 10 kt. Seas 2 ft or less. 
.WED...W wind 10 kt. Seas 2 ft or less. 

$$

PKZ022-241715-
Cross Sound-
339 PM AKDT Fri Jul 23 2021

.TONIGHT...E wind 10 kt. Seas 4 ft. Showers.
.SAT...E wind 10 kt. Seas 4 ft. Showers in the morning. 
.SAT NIGHT...SE wind 10 kt. Seas 4 ft. 
.SUN...E wind 10 kt. Seas 3 ft. 
.SUN NIGHT...W wind 10 kt. Seas 3 ft. 
.MON...NE wind 10 kt becoming W. Seas 3 ft. 
.TUE...W wind 15 kt. Seas 3 ft. 
.WED...W wind 15 kt. Seas 3 ft. 

$$

PKZ031-241715-
Stephens Passage-
339 PM AKDT Fri Jul 23 2021

.TONIGHT...S wind 10 kt. Near Young Bay, SE wind 20 kt diminishing
to 10 kt late. Seas 2 ft or less. Showers.
.SAT...Light winds becoming S 10 kt in the afternoon. Seas
2 ft or less. Showers in the morning. 
.SAT NIGHT...S wind 10 kt. Seas 2 ft or less. 
.SUN...S wind 10 kt. Seas 2 ft or less. 
.SUN NIGHT...S wind 10 kt. Seas 2 ft or less. 
.MON...S wind 10 kt. Seas 2 ft or less. 
.TUE...S wind 10 kt. Seas 2 ft or less. 
.WED...SW wind 10 kt. Seas 2 ft or less. 

$$

PKZ032-241715-
Northern Chatham Strait-
339 PM AKDT Fri Jul 23 2021

.TONIGHT...SE wind 10 kt in the evening becoming light. Seas 2 ft
or less. Showers.
.SAT...Light winds. Seas 2 ft or less. Showers.
.SAT NIGHT...Light winds. Seas 2 ft or less. 
.SUN...Light winds. Seas 2 ft or less. 
.SUN NIGHT...Light winds. Seas 2 ft or less. 
.MON...Light winds becoming S 10 kt. Seas 2 ft or less. 
.TUE...S wind 10 kt. Seas 2 ft or less. 
.WED...S wind 10 kt. Seas 2 ft or less. 

$$

PKZ033-241715-
Southern Chatham Strait-
339 PM AKDT Fri Jul 23 2021

.TONIGHT...S wind 10 kt. Seas 3 ft early in the evening then 2 ft
or less. Near ocean entrances, seas 5 ft. Showers.
.SAT...S wind 10 kt. Seas 2 ft or less. Showers in the
morning. 
.SAT NIGHT...Light winds. Seas 2 ft or less, except 4 ft
near ocean entrances. 
.SUN...Light winds. Seas 2 ft or less. 
.SUN NIGHT...Light winds. Seas 2 ft or less. 
.MON...NE wind 10 kt becoming W. Seas 2 ft or less. 
.TUE...Light winds. Seas 2 ft or less. 
.WED...Light winds becoming SW 10 kt. Seas 2 ft or less. 

$$

PKZ034-241715-
Frederick Sound-
339 PM AKDT Fri Jul 23 2021

.TONIGHT...SE wind 10 kt. Seas 2 ft or less. Showers.
.SAT...S wind 10 kt. Seas 2 ft or less. Showers in the
morning. 
.SAT NIGHT...S wind 10 kt. Seas 2 ft or less. 
.SUN...S wind 10 kt. Seas 2 ft or less. 
.SUN NIGHT...Light winds. Seas 2 ft or less. 
.MON...E wind 10 kt becoming SW. Seas 2 ft or less. 
.TUE...SE wind 10 kt becoming light. Seas 2 ft or less. 
.WED...SW wind 10 kt. Seas 2 ft or less. 

$$

PKZ035-241715-
Sumner Strait-
339 PM AKDT Fri Jul 23 2021

.TONIGHT...SE wind 10 kt. Seas 2 ft or less. Showers.
.SAT...S wind 10 kt in the morning becoming light. Seas 2 ft
or less. Showers in the morning. 
.SAT NIGHT...Light winds. Seas 2 ft or less. 
.SUN...Light winds. Seas 2 ft or less. 
.SUN NIGHT...Light winds. Seas 2 ft or less. 
.MON...E wind 10 kt becoming light. Seas 2 ft or less. 
.TUE...SE wind 10 kt becoming light. Seas 2 ft or less. 
.WED...SW wind 10 kt. Seas 2 ft or less. 

$$

PKZ036-241715-
Clarence Strait-
339 PM AKDT Fri Jul 23 2021

.TONIGHT...S wind 15 kt. Seas 3 ft. Showers.
.SAT...S wind 10 kt. Seas 2 ft or less. 
.SAT NIGHT...S wind 10 kt in the evening becoming light.
Seas 2 ft or less. 
.SUN...SE wind 10 kt. Seas 2 ft or less. 
.SUN NIGHT...SE wind 10 kt. Seas 2 ft or less. 
.MON...S wind 10 kt. Seas 2 ft or less. 
.TUE...S wind 10 kt. Seas 2 ft or less. 
.WED...NW wind 15 kt. Seas building to 3 ft. 

$$

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
249 PM AKDT Thu Jul 22 2021

.SHORT TERM.../Thursday afternoon through Saturday night/...
This afternoon's polar satellite images show a low in the central
gulf with a front approaching the SE AK coast. Offshore buoy
winds right now support the 25-30kt wind forecast for the outside
waters associated with the front. The surface low will sag
southward as the front pushes into the panhandle through the day
on Friday. The winds will remain mostly over the outside waters,
with the exception of Clarence Strait, where small craft
conditions are expected. Models continued to slow down the
progress of the front with rain arriving along the coast and over
the southern panhandle tonight and the central panhandle tomorrow
morning. The GFS, Canadian, and EC were in good agreement with the
timing, with the NAM being a faster outlier. So leaned toward the
GFS for timing on the progression of the front.

Rainfall amounts with the initial front look to be around
0.25-0.5 inches for the central panhandle with higher amounts
around an inch for the southern panhandle. A short wave is
forecast to follow the front and enhance precipitation for the
Ketchikan/Annette/Metlakatla area, with up to 2 inches of rain
expected by Saturday in the very moist environment. Temperatures
will be slightly cooler Friday with the rain and clouds. Showers
will remain in the wake of the front but diminish in coverage and
intensity through the day on Saturday with slightly warmer
temperatures on Saturday as compared to Friday. The shower
activity will continue to become more scattered heading into
Sunday with another small bump in temperatures and maybe even a
few breaks in the clouds, especially for northern Lynn Canal.

.LONG TERM.../Saturday through Thursday as of 10 PM Tuesday/...
The long term period features a low in the gulf which will meander
and weaken there through the weekend and into early next week.
The low eventually dissipates as ridging builds into NW canada and
Southern Alaska by the middle of next week. Deterministic models
and ensembles are all in a general agreement with this pattern.
Going into next week deterministic models diverge on the details
regarding the exact strength and placement of the ridging; however
both EC and GFS ensemble are in good agreement it will generally
be over NW Canada and Southern Alaska.

As far as sensible weather, showers will be present Saturday
through early next week with continuous southerly/southeasterly
onshore flow and waves of energy rotating in. Guidance currently
depicts the greatest coverage of showers across the Southern
Panhandle and along the higher terrain of Baranof Island and the
Coast Mountains. Expect the driest portion of the Panhandle to be
Upper Lynn Canal as the mountains tend to wring out much of the
moisture as it makes its way SE to NW across the Panhandle.
Overall not expecting a complete washout as shower activity will
have a slow diminishing trend through mid next week across the
Central and Northern Panhandle. Guidance hints at a stronger wave
early next week increasing showers across mainly across the
south. Further details regarding timing of each wave and where the
most widespread shower activity occurs will be fine tuned in the
coming days.

Winds through the period remain relatively light, especially
through the Inner Channels. Winds 10 kt or less expected for much
of the weekend and into next week. If more sunshine and surface
heating occur in between showers, then stronger afternoon sea
breezes may occur in Icy Strait and Lynn Canal. An increase in
winds in Northern Lynn Canal is also possible mid next week as
surface ridging builds into the Panhandle; however confidence is
still low regarding the exact pressure gradient pattern associated
with the surface ridge.

Expect temperatures to remain close to climatological norms for
this time of year with smaller diurnal fluctuations due to
increased cloud cover and showers. With 850mb temps steady around
+3-5C and mostly cloudy skies, expect highs generally in the lower
60s with lows in the low 50s. Breaks in the clouds during the
afternoon could lead to a few warmer spots, especially across
Upper Lynn Canal.

Confidence remains higher through the weekend then drops off next
week as guidance diverges regarding waves rotating around the
gulf low and the building ridge mid week. Used a blend of GFS/EC
for the mid range transitioning to mostly WPC by next week. No
major changes made to the long term forecast.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Small Craft Advisory for PKZ036-041>043-051-052.

&&

BFL/CM

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