Small Craft Advisory 79, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
328 PM AKST Mon Jan 29 2018

.SHORT TERM...As of 3 PM Monday, rain and snow shower activity
remains ongoing over the Panhandle this afternoon. Shower activity
will diminish from north to south this evening. This places the
northern Panhandle within a drier pattern that will continue into
the extended forecast.

The southern Panhandle will remain showery through the middle of
the week due to a low pressure system that is currently west of
Haida Gwaii. This low will track northeast through Tuesday and
pass over the Southern Panhandle Tuesday morning. Showers
associated with the low will be a mix of rain and snow.
Temperatures will be more supportive of rain over southern Prince
of Wales Island and near Ketchikan and Annette Island. Snow
accumulations are expected to be minimal; however, some heavy snow
showers with localized accumulations are possible.

Strong northerly outflow persists over the Panhandle through the
short term with wind gusts up to 40 mph still likely for Downtown
Juneau and Douglas, as well as near Skagway for much of the short
term. Windiest conditions remain in Lynn Canal where the pressure
gradient continues to favor periods of storm force winds.

Significant changes were not made to the short term forecast.
Temperatures were cooled at upper elevations. In addition, local
effects were added to many of the marine and land winds. Used a
blend of the NAM, NAMNest, and GFS to handle updates as needed.
Forecast confidence remains above average.

.LONG TERM.../Wednesday through Sunday/ As of 10pm Sunday
Temperatures remain below freezing until Friday, when the southern
areas warm into the mid 30s during the day. By the weekend
temperatures will be in the mid to upper 30s as far north as
Sumner Straits and up to Sitka along the outer coastal area. GFS
was the coldest solution, so used blend approach which resulted a
a small adjustment to lower day time temperatures late in the
week.

The bigger concern is the winds with a tight gradient lingering
over the northern Panhandle, with a trof over the southern area.
For Wednesday Northern Lynn Canal will likely be northerly Gale
force, while most of the other northern inside waters will have
Small Craft winds. Winds diminish slightly by Thursday, but most
of the northern inside waters will remain Small Craft winds into
the weekend diminishing by Sunday. With the low to the south and
high pressure continuing to reside over the Yukon, the northerly
outflow winds will continue all week.

Precipitation, which will fall mostly over the southern half of
the Panhandle on Wednesday. Used the ECMWF for POP/QPF/Snow
elements, as it has been the most consistent of the models.
Precipitation type will be a mix mainly becoming snow overnight,
and changing over to rain during the afternoon by Friday. There
are hints of heavier snowfall in the south on the weekend and even
potential for freezing rain. This will get another close look
with the next go around.

Models are continuing to bring a front across the gulf Thursday
night into Friday. The ECMWF was the main model of choice.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind through late Tuesday night for AKZ025.
     Winter Weather Advisory from 9 PM this evening to noon AKST
     Wednesday for AKZ018.
     Strong Wind from Tuesday afternoon through late Tuesday night
     for AKZ018.
MARINE...Storm Warning for PKZ012.
     Gale Warning for PKZ013-022-031-043.
     Small Craft Advisory for PKZ011-021-032>036-041-042-051-052.
     Small Craft Advisory due to Seas for PKZ053.

&&

JB/KV

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