Small Craft Advisory 73, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
319 PM AKST Sun Jan 28 2018

.SHORT TERM...As of 2 PM Sunday, the immediate short term
forecast will be windy and snowy. A weather front is currently
progressing northward over the Panhandle with snow being reported
as far north as Petersburg as of writing. Snow will be heavy at
times as this frontal band progresses northward. Currently,
heaviest accumulations expected near Hyder (winter storm warning
for around 12 inches of snow is in effect through noon tomorrow)
and near Eastern Chichagof Island (winter storm warning for around
6 inches of snow in effect from 6 PM tonight through 6 AM Monday
morning). Winter weather advisories for snowfall amounts between
3 and 6 inches also exist across much of the Panhandle. Near
Skagway and White Pass, stronger winds coupled with snowfall may
significantly reduce visibilities after midnight into the early
morning hours of Monday. After the front passes snow showers will
diminish from north to south over the Panhandle tomorrow. Not much
snow accumulation is expected beyond tomorrow morning; however,
due to the showery nature of the weather pattern, localized
accumulations will widely vary. The far southern Panhandle will
transition back to rain tomorrow.

Winds remain strongest early this evening before diminishing
through the overnight hours. Strongest winds remain near Downtown
Juneau and Douglas Island, where gusts up to 70 mph remain likely
through the evening. However, the pressure gradient looks to
re-intensify tomorrow night, which will bring a return to
stronger winds over the northern Panhandle.

Significant changes were not made to the existing short term
forecast. A blend of the NAM, NAMnest, and GFS were used as
needed. Confidence is above average in the first 24 hrs but lower
tomorrow due to the showery nature of the storms.

.LONG TERM.../Tuesday through Saturday/ As of 10pm Saturday...The
extended forecast period begins with showers starting diminishing
across the northern panhandle but continuing over the southern
areas. The assoc low pressure center has strengthened and shifted
slightly northward with the latest model runs. Now the low crosses
over POW Island or even as far north as Cape Decision then slowly
weakens to a trough through Tuesday evening. This will cause a
shift in wind direction and some of the bands of showers to be
stronger. Have increased POP and QPF as a starting point but will
need to make further adjustments based on where the low center
ends up.

For the northern half of the panhandle, the low to the south and
continued high pressure in the Yukon will cause northerly outflow
to continue all week. This will keep temps on the cool side but
with a more dry airmass and offshore flow.

Some models continue to bring a front across the gulf Thursday
night into Friday. There is some better agreement with some POP
reaching the southern outer coast, but the northern areas look to
stay out of it. Have shifted slightly in this direction with an
emphasis on the ECMWF since it continues to be the most
consistent.

&&

.AVIATION...Expect lowering visibilities associated with snowfall and
strong low level wind shear as the front progress northward
tonight. Tomorrows conditions look to improve as a whole with much
less wind; however, during periods of heavier snow showers
visibilities will be significantly reduced. Shower activity will
diminish from north to south.

&&

.MARINE...Strong northerly outflow will continue through much of
the week. Strongest winds are expected this evening; however, the
pressure gradient over the northern inner channels is persistently
strong through most of the week.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Winter Weather Advisory until 6 AM AKST Monday for AKZ018-026-
     028.
     Strong Wind until 6 PM AKST this evening for AKZ027.
     Winter Weather Advisory until 9 AM AKST Monday for AKZ024.
     High Wind Warning until 9 PM AKST this evening for AKZ025.
     Winter Weather Advisory from 6 PM this evening to 6 AM AKST
     Monday for AKZ020-022.
     Strong Wind from 6 PM AKST this evening through late tonight for
     AKZ023.
     Winter Storm Warning from 6 PM this evening to 6 AM AKST Monday
     for AKZ021.
     Winter Storm Warning until noon AKST Monday for AKZ029.
     Strong Wind until midnight AKST tonight for AKZ019.
     Strong Wind from late tonight through Monday afternoon for
     AKZ018.
     Strong Wind through late tonight for AKZ017.
MARINE...Heavy Freezing Spray Warning for PKZ012.
     Storm Warning for PKZ012-013-022.
     Gale Warning for PKZ011-021-031-033-035-041>043-051-052.
     Small Craft Advisory for PKZ032-034-036-053.

&&

JB/Ferrin

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