Small Craft Advisory 60, NWS Juneau, AK

060 
FZAK51 PAJK 310041
CWFAJK

Coastal Waters Forecast for Southeast Alaska
National Weather Service Juneau AK
341 PM AKST Sat Jan 30 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.

PKZ098-311715-
341 PM AKST Sat Jan 30 2021
.SYNOPSIS FOR SOUTHEAST ALASKA INNER CHANNELS COASTAL WATERS...
A low west of Haida Gwaii moves south as a new low develops near 
Yakutat on Monday morning. This low travels south along the coast 
Monday evening. Offshore flow increases on Monday. 

$$

PKZ011-311715-
Glacier Bay-
341 PM AKST Sat Jan 30 2021

.TONIGHT...Light winds becoming N 15 kt. Seas building to 3 ft
late. 
.SUN...N wind 15 kt. Seas 3 ft.
.SUN NIGHT...N wind 15 kt. Seas 3 ft. Freezing spray. 
.MON...NW wind 20 kt. Seas 4 ft. Freezing spray and snow showers.
.MON NIGHT...NW wind 20 kt. Seas 4 ft. Freezing spray. 
.TUE...E wind 15 kt. Seas 3 ft. 
.WED...E wind 10 kt becoming light. Seas 2 ft or less. 
.THU...Light winds becoming E 10 kt. Seas 2 ft or less. 

$$

PKZ012-311715-
Northern Lynn Canal-
341 PM AKST Sat Jan 30 2021

...SMALL CRAFT ADVISORY THROUGH SUNDAY...

.TONIGHT...N wind 15 kt increasing to 25 kt late. Seas 3 ft
building to 5 ft. Freezing spray late. 
.SUN...N wind 30 kt. Gusts to 40 kt. Seas 6 ft. Freezing spray in
the morning. 
.SUN NIGHT...N wind 30 kt. Seas 6 ft. Freezing spray. 
.MON...N gale to 35 kt. Gusts to 50 kt. Seas 7 ft. Freezing
spray. Snow showers. 
.MON NIGHT...N wind 30 kt. Seas 6 ft. Heavy freezing spray.
Snow showers. 
.TUE...NW wind 25 kt. Seas 5 ft. 
.WED...N wind 10 kt. Seas 2 ft or less. 
.THU...N wind 10 kt. Seas 2 ft or less. 

$$

PKZ013-311715-
Southern Lynn Canal-
341 PM AKST Sat Jan 30 2021

...SMALL CRAFT ADVISORY THROUGH SUNDAY...

.TONIGHT...N wind 25 kt. Seas 5 ft. 
.SUN...N wind 30 kt. Seas 6 ft. 
.SUN NIGHT...N wind 30 kt. Seas 6 ft. Freezing spray late. 
.MON...N gale to 35 kt. Seas 7 ft. Freezing spray. 
.MON NIGHT...N wind 30 kt. Seas 6 ft. Freezing spray and snow 
showers.
.TUE...N wind 25 kt. Seas 5 ft. 
.WED...N wind 15 kt. Seas 3 ft. 
.THU...Light winds. Seas 2 ft or less. 

$$

PKZ021-311715-
Icy Strait-
341 PM AKST Sat Jan 30 2021

.TONIGHT...E wind 15 kt. Seas 3 ft. 
.SUN...NE wind 20 kt. Seas 4 ft. 
.SUN NIGHT...E wind 15 kt. Seas 3 ft. 
.MON...E wind 25 kt. Seas 5 ft. 
.MON NIGHT...E wind 20 kt. Seas 4 ft. Snow showers. 
.TUE...E wind 15 kt. Seas 3 ft. 
.WED...E wind 10 kt. Seas 2 ft or less. 
.THU...E wind 10 kt. Seas 2 ft or less. 

$$

PKZ022-311715-
Cross Sound-
341 PM AKST Sat Jan 30 2021

.TONIGHT...NE wind 15 kt. Seas 7 ft. SW swell. 
.SUN...NE wind 15 kt. Seas 6 ft. S swell. 
.SUN NIGHT...NE wind 15 kt. Seas 5 ft. S swell in the evening.
.MON...NE wind 25 kt. Seas 5 ft. Snow showers. 
.MON NIGHT...E wind 25 kt. Seas 5 ft. Snow showers. 
.TUE...E wind 20 kt. Seas 3 ft. 
.WED...E wind 15 kt. Seas 5 ft. 
.THU...E wind 10 kt becoming W. Seas 6 ft. 

$$

PKZ031-311715-
Stephens Passage-
341 PM AKST Sat Jan 30 2021

.TONIGHT...N wind 20 kt. Seas 4 ft. 
.SUN...N wind 20 kt. Seas 4 ft. 
.SUN NIGHT...N wind 15 kt. Seas 3 ft. 
.MON...N wind 25 kt. Seas 5 ft. 
.MON NIGHT...N wind 25 kt. Seas 5 ft. Freezing spray and snow 
showers. 
.TUE...N wind 20 kt. Seas 4 ft. 
.WED...SE wind 15 kt. Seas 3 ft. 
.THU...S wind 10 kt. Seas 2 ft or less. 

$$

PKZ032-311715-
Northern Chatham Strait-
341 PM AKST Sat Jan 30 2021

.TONIGHT...NE wind 15 kt. Seas 3 ft. 
.SUN...NE wind 20 kt. Seas 4 ft. 
.SUN NIGHT...NE wind 15 kt. Seas 3 ft. 
.MON...N wind 25 kt. Seas 5 ft. 
.MON NIGHT...N wind 20 kt. Gusts to 35 kt. Seas 4 ft. 
.TUE...N wind 15 kt. Seas 3 ft. 
.WED...S wind 10 kt. Seas 2 ft or less. 
.THU...S wind 10 kt. Seas 2 ft or less. 

$$

PKZ033-311715-
Southern Chatham Strait-
341 PM AKST Sat Jan 30 2021

.TONIGHT...N wind 15 kt. Seas 3 ft. Near ocean entrances, seas 8 
ft. 
.SUN...NE wind 15 kt. Seas 3 ft, except 7 ft near ocean 
entrances.
.SUN NIGHT...NE wind 10 kt. Seas 2 ft or less, except 6 ft
near ocean entrances. 
.MON...N wind 20 kt. Seas 4 ft. Rain showers. 
.MON NIGHT...N wind 15 kt. Seas 3 ft. Snow showers and rain
showers. 
.TUE...N wind 20 kt. Seas 4 ft. 
.WED...S wind 15 kt. Seas 3 ft. 
.THU...S wind 10 kt. Seas 2 ft or less. 

$$

PKZ034-311715-
Frederick Sound-
341 PM AKST Sat Jan 30 2021

.TONIGHT...NE wind 15 kt. Seas 3 ft. 
.SUN...NE wind 20 kt. Seas 4 ft. 
.SUN NIGHT...E wind 15 kt. Seas 3 ft. 
.MON...E wind 20 kt. Seas 4 ft. Snow showers. 
.MON NIGHT...E wind 15 kt. Seas 3 ft. Snow showers. 
.TUE...NE wind 15 kt becoming SE. Seas 3 ft. 
.WED...SE wind 15 kt. Seas 3 ft. 
.THU...S wind 10 kt. Seas 2 ft or less. 

$$

PKZ035-311715-
Sumner Strait-
341 PM AKST Sat Jan 30 2021

.TONIGHT...E wind 15 kt. Seas 3 ft. 
.SUN...E wind 15 kt. Seas 3 ft. 
.SUN NIGHT...NE wind 15 kt. Seas 3 ft.
.MON...NE wind 20 kt. Gusts to 35 kt. Seas 4 ft. Rain and snow 
showers. 
.MON NIGHT...E wind 10 kt. Seas 2 ft or less. Snow and rain 
showers. 
.TUE...SE wind 15 kt. Seas 3 ft. 
.WED...SE wind 15 kt. Seas 3 ft. 
.THU...S wind 10 kt. Seas 2 ft or less. 

$$

PKZ036-311715-
Clarence Strait-
341 PM AKST Sat Jan 30 2021

.TONIGHT...N wind 15 kt. Seas 3 ft. 
.SUN...NW wind 15 kt. Seas 3 ft. 
.SUN NIGHT...NW wind 15 kt. Seas 3 ft.
.MON...NW wind 20 kt. Seas 4 ft. 
.MON NIGHT...SE wind 15 kt. Seas 3 ft. Snow showers. 
.TUE...SE wind 15 kt becoming NW. Seas 3 ft. 
.WED...SE wind 15 kt. Seas 3 ft. 
.THU...S wind 15 kt. Seas 3 ft. 

$$

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
302 PM AKST Fri Jan 29 2021

.SHORT TERM.../Friday evening through Sunday/ The main forecast
concerns in the short term will be over the next 24 hours before
drier weather moves in by Sunday. This afternoon, a complex low
continues to spin in the central gulf with a wave developing along
the triple point just southwest of Prince of Wales Island. This
wave will be the focus tonight and tomorrow as it rides up along
the coast. By tomorrow, the parent low in the central gulf weakens
and sags south before being absorbed by a larger area of low
pressure just SW of Haida Gwaii.

For tonight, a developing low off the coast of Prince of Wales
will move NW along the eastern gulf coast increasing precipitation
coverage and rates across much of the Southern Panhandle. P-type
is expected to remain snow as a persistent E/NE gradient from a
high over NW Canada will help keep cold air entrenched at the
surface. Model soundings also indicate a very stable layer from
the surface to 900mb, which will keep any warmer air aloft from
mixing down to the surface. Above 900mb, an unstable layer
exists with lapses rates upwards of 7-8C/km extending up into the
dendritic growth zone, indicating efficient dendrite production,
higher snow ratios, and the potential for heavy bands of
precipitation. The heaviest precipitation is expected around
midnight tonight as the low passes by. Expect anywhere from 1 to 4
inches of snow across the Southern Panhandle, including Ketchikan
and much of Prince of Wales Island. A Winter Weather Advisory has
been issued for these areas through 6am tomorrow morning. Areas
near sea level on the western coast of POW Island and near
Metlakatla may mix with rain at times as the maritime influence
should keep surface temps above freezing.

Elsewhere, across the northern and central Panhandle, persistent
northeasterly flow from the strong Canadian high to the north
will keep the boundary layer relatively dry due to downsloping.
Snowfall rates have been light from Petersburg to Juneau to Haines
so far this evening where observations show only traces despite
numerous snow shower activity. Expect the downsloping and drier
air to offset the effects of the passing wave and keep snowfall
rates light through the overnight hours. Minor accumulations under
an inch expected in the Central and Northern Panhandle with higher
amounts possible in easterly upslope favored areas.

By Sunday, as the area of low pressure in the gulf becomes
absorbed by a low SW of Haida Gwaii, offshore flow will increase
once again drying most of the region. Expect an increase in
northerlies through the Inner Channels with the strongest winds
expected in Lynn Canal and out of interior passes along the Coast
Mountains. With the main area of low pressure near Haida Gwaii,
enough moisture may be thrown northward for scattered showers to
rotate into the far Southern Panhandle; otherwise expect partly
cloudy to mainly sunny skies across the Central and Northern
panhandle Sunday. Expect temperatures to remain below average
through the period.

Overall confidence is around average for the short term. Used the
NAM for minor updates to the forecast.

.LONG TERM.../Saturday night through next Friday night/ The long
term forecast begins with a return to drier weather across SE
Alaska as an upper low over the Gulf of Alaska stalls and another
deep low rolls off the Kamchatka Peninsula, effectively creating
an omega block. Northerly flow will rush back into the panhandle
as the synoptic flow turns more offshore. Cooler temperatures and
drier conditions will return across the area through Sunday,
though do not expect temperatures to be as cold as they have been
this past week.

The confidence in dry weather will not stay long as a new surface
low develops south of the area underneath the upper level trough
over SE Alaska. Models fall into disagreement on the exact
movement of this low, as it interacts with a separate system which
develops over the Central Gulf. There are some indications
however that a band of precipitation-possibly snow, given the
cool 850mb temperatures-may try to develop across the area on
Monday. Should this happen, accumulating snow will become a
concern. For the time being, have chosen to keep the QPF on the
lower side, but did increase chances of PoP across much of the
area. Offshore flow could be enough to keep this at bay, or it
may prove insufficient to meet the task, and this feature will
need to be closely monitored as additional data becomes available.

The next big system looks likely to arrive sometime between
Tuesday and Wednesday. The blocking pattern will quickly decay
and a system forming in the Aleutians will race west towards the
panhandle. Ensembles are hinting at the possibility that this
system may have a more tropical moisture connection associated
with it, which would lead to higher precipitation totals.
Temperatures at 850 mb look likely to remain cold enough for snow
ahead of this system, and so think that accumulating snow will
become much of a possibility across much of the area. How far
south the snow reaches will ultimately depend on the orientation
of the system which will either open the southerly gates to warm
oceanic air early or keep it at bay for some time. Chose to
continue the trend of allowing warming to occur through Wednesday,
which would see many places switch over to rain. However, this is
dependent on warm air advection being able to overwhelm snow-melt
cooling. Should southerly warm air advection prove weak, it is
quite possible that snow-melt cooling will keep precipitation in
some parts of the panhandle as snow substantially longer.
Afterwards, another break in the weather could arrive Thursday
and Friday before ensembles hint at the arrival of a new system.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Weather Advisory until 6 AM AKST Saturday for AKZ027-028.
MARINE...Gale Warning for PKZ041>043-051-052.
     Small Craft Advisory for PKZ012-013-021-022-031-033>036-053.

&&

CM/GFS

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