Alert archive / Alaska / Small Craft Advisories in 2021

Small Craft Advisory 408, NWS Juneau, AK

September 12, 2021

NWS Juneau, AK issued this small craft advisory at Sep 12, 2021, 3:21 PM AKDT. It was in force for 12 hr.

The area

The counties it named.

The facts

Issued
Sep 12, 2021, 3:21 PM AKDT (23:21 UTC)
Expired
Sep 13, 2021, 3:38 AM AKDT
In force
12 hr
Issued by
NWS Juneau, AK

The text

As transmitted.

724 
FZAK53 PAJK 122321
CWFYAK

Marine Forecast for Yakutat Bay
National Weather Service Juneau AK
321 PM AKDT Sun Sep 12 2021

Coastal Waters Forecast for Yakutat Bay

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.

PKZ053-131730-
Yakutat Bay-
321 PM AKDT Sun Sep 12 2021

...SMALL CRAFT ADVISORY LATE TONIGHT THROUGH MONDAY...

.TONIGHT...E wind 10 kt increasing to 20 kt late. Seas 4 ft 
building to 10 ft late. Rain.
.MON...E wind 20 kt becoming SW 10 kt in the afternoon. Seas
9 ft. Rain in the morning, then showers and slight chance of
thunderstorms in the afternoon. 
.MON NIGHT...Light winds becoming E 10 kt late. Seas 8 ft. S
swell. Showers.
.TUE...E wind 10 kt. Seas 8 ft. S swell. Showers.
.TUE NIGHT...Light winds. Seas 7 ft. S swell. 
.WED...W wind 10 kt becoming E. Seas 6 ft. 
.THU...E wind 15 kt. Seas 8 ft. 
.FRI...E wind 15 kt becoming light. Seas 7 ft. 

$$
1 follow-up statement
207 
FZAK53 PAJK 131138
CWFYAK

Marine Forecast for Yakutat Bay
National Weather Service Juneau AK
338 AM AKDT Mon Sep 13 2021

Coastal Waters Forecast for Yakutat Bay

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.

PKZ053-140545-
Yakutat Bay-
338 AM AKDT Mon Sep 13 2021

.TODAY...E wind 20 kt becoming SW 10 kt in the afternoon. Gusts 
to 35 kt early in the morning. Seas 4 ft. S swell in the morning. 
Rain early in the morning, then slight chance of thunderstorms in
the afternoon. 
.TONIGHT...S wind 10 kt becoming E late. Seas 2 ft or less. S
swell. Slight chance of thunderstorms in the evening. Showers.
.TUE...E wind 10 kt in the morning becoming light. Seas 2 ft
or less. S swell. Showers.
.TUE NIGHT...Variable wind 10 kt. Seas 2 ft or less. S swell. 
.WED...E wind 10 kt. Seas 2 ft or less. 
.THU...E wind 15 kt. Seas 2 ft or less. 
.FRI...E wind 15 kt becoming N. Seas 5 ft. 

$$

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 Sep 12, 2:42 PM AKDT, 39 minutes earlier.

Area forecast discussion, Sep 12, 2:42 PM AKDT, 39 minutes before
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
242 PM AKDT Sun Sep 12 2021

.SHORT TERM.../Through Tuesday night/...Leftover scattered to
isolated showers from today will be replaced with rain tonight as
a front moves into the panhandle.

The best chance for the rain on Monday is in the morning with
generally decreasing chances of rain in the afternoon as the front
clears the panhandle. Behind the front, there are hints at some
breaks in the clouds late Monday afternoon to Monday evening
before rain showers and clouds fill back in Monday night.

Chances for rain showers last into Tuesday as a reinforcing front
moves into the panhandle.

Thunder is included in this forecast beginning tomorrow afternoon
for the gulf and northeast coast near Yakutat. The thunder
chances move southeast along the coast to near Sitka late Monday
and last into Monday night.

As this front tracks into the panhandle, the winds are expected
to pick up tonight and tomorrow. Strongest winds speeds will be
found along the coastal waters tonight with speeds around 25 to 35
mph. Then tomorrow, the winds speeds along the coastal waters
will calm but the winds speeds in the inner channel should pick
up. Winds speeds will peak at around 20 to 25 mph during the day.
Several Small Craft Advisories have been issued for the inner
channels.

Temperatures will continue to be mild (from a climate
perspective) with highs in the 50s to near 60 and lows in the 40s
to near 50.

.LONG TERM.../Tuesday through Sunday as of 10 pm Saturday/ As we
progresses towards the ides of September we are reminded that
this is fall for SE Alaska and damp, rainy, and cooler weather
along with increasing darkness is our new lot in life. The long
range forecast will do little to change this paradigm. For
Tuesday into early Wednesday the remnants of the Monday low and
front will exit to the east and as is typical, there are timing
differences between models on how long it will take the low to
fully weaken into an open wave trough. Ridging behind the low
moves across the gulf Wednesday with a diminishing trend in
precipitation. Note diminishing, not fully ending due to
continued onshore flow. Wednesday night into Thursday will bring
the next strong fall system into the region. Ensembles as well as
operational models were telling similar stories with a split
between a strong gale force low brining in heavy rain once again
to the region, as seen with the ECMWF, or a weaker system with
upper level small craft winds and seasonable rainfall amounts, as
seen with the GFS. In addition to differences in this lows
strength, timing and position differences were evident, not only
between models but also run to run.

Evidence for the deeper low pressure system as seen with a strong
upper level jet core depicted by most models and newer
operational model runs leaning towards a deeper surface low.
Indications that this would be a run of the mill fall system are:
NAEFS standardized anomalies for this time being unimpressive at
best and 10 year QPF return intervals at most 30 to 40. Obviously
will keep a sharp eye on this system with hopefully better
resolution soon. But prepare yourselves for these wet and windy
times to be a staple in your lives. For the end of the week and
into the weekend expect the low to weaken and take a southeasterly
track, but low confidence in details at this time.

As ensembles and operational models were telling similar stories
made only minor changes to the inherited forecast. Early on
leaned toward ECMWF then transitioned to WPC for the rest of the
long range. With the cooler air high elevations will have temps
nearing freezing and snow levels dropping below 4000 ft. Forecast
confidence is below average.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Gale Warning for PKZ043-051-052.
     Small Craft Advisory for PKZ012-013-022-031>036-041-042-053.

&&

GJS/PRB

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

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 12, 3:53 AM AKDTGale WarningAJK35 hr
Sep 12, 3:33 PM AKDTGale WarningAJK23 hr
Sep 12, 3:41 PM AKDTSmall Craft AdvisoryAJK42 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.