Small Craft Advisory 29, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
414 PM AKST Sun Jan 15 2017

.SHORT TERM...Satellite shows a large cyclone moving northeast
across the eastern gulf. Its related front aims a deep swath of
moisture with integrated vapor moisture of up to 4 standard
deviations above normal. This is already producing moderate
rainfall for the central and southern Panhandle and even some
lower elevation snow initially this afternoon at Yakutat. The
changeover to rain should be complete at sea level by early this
evening but Yakutat and the Haines Highway could receive up to 2
inches of snow before rain begins again. All told, this frontal
system along with a short-wave behind it continuing the deep
moisture transport into Monday should amount to 1 to 2 inches of
rainfall with locally higher amounts. At higher elevations on the
Klondike Highway, we still are forecasting heavy snow tonight and
and into late Monday. Winds are still forecast to ramp up Monday
so we expect blizzard conditions developing with areas of blowing
snow reducing visibility to near zero. Winter Storm Warning
begins at 6 PM this evening and continues into early Tuesday
morning.

A high wind warning was pulled forward in time earlier in the day
to begin at 3 PM. But already, Prince of Wales observations are
gusting to 60 mph. We think winds across the southern panhandle
will remain high this evening before diminishing somewhat
overnight. Then winds will rise again into early Monday morning
before diminishing by afternoon. These trends correlate well with
two low level jets that cross the area through Monday morning.
Farther north, we upgraded the high wind watch for Skagway and
lower elevations of the Klondike to a high wind warning effective
for Monday afternoon into Monday evening. As a cold front jumps
inland across the Wrangell St. Elias range Monday, pressure falls
will occur Monday with pressure rises across the panhandle late
Monday afternoon. This will rapidly increase gradients along the
Klondike producing 60 mph gusts from the southwest.

Storms and strong gales still spread across the gulf and Inner
Channels. Aside from high winds above, most other land areas will
receive gusts between 40 and 50 mph with very wet conditions.
Outdoor activities will not be for the faint of heart. Seas of up
to 25 feet will plague the gulf.

.LONG TERM...There remains considerable model disagreement as a
split flow pattern persists through the week. One of the few
things there is increased confidence in is a decreasing trend in
the temperatures.

A few things of note are increasing model agreement at the start
of the long range with a couple waves developing and tracking
across the central/southern panhandle Tuesday and Wednesday. Will
need to fine-tune the track and strength of these features as
models converge on a solution. The other period of interest is
Thursday with a potential overrunning situation setting up across
the northern panhandle as depicted by the GFS. Again, other models
have differing solutions so little confidence in any one solution
at this time but this is something to watch.

Used the 12z NAM/GFS through 84 hours then the latest WPC guidance
from thereafter.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind through Monday morning for AKZ026.
     High Wind Warning until noon AKST Monday for AKZ027.
     Strong Wind until 9 PM AKST this evening for AKZ021-024.
     Strong Wind through Monday morning for AKZ025.
     Strong Wind through late tonight for AKZ022.
     Strong Wind Monday afternoon for AKZ022.
     Strong Wind until 3 AM AKST Monday for AKZ023.
     Strong Wind Monday morning for AKZ023.
     High Wind Warning until 9 AM AKST Monday for AKZ028.
     Strong Wind from 3 AM AKST Monday through Monday afternoon for
     AKZ019.
     High Wind Warning from noon Monday to midnight AKST Monday night
     for AKZ018.
     Winter Storm Warning until 6 AM AKST Tuesday for AKZ018.
     Strong Wind from 9 PM this evening to 3 AM AKST Monday for
     AKZ017.
     Strong Wind Monday afternoon for AKZ017.
MARINE...Storm Warning for PKZ036-041>043-051-052.
     Gale Warning for PKZ011>013-021-022-031>035-053.
&&

JWA/TPS

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