High Wind in Alaska, March 10, 2017

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
403 PM AKST Thu Mar 9 2017

.SHORT TERM...Precipitation in the form of snow finally ended over
the southern panhandle this morning and skies are clearing out
nicely in the northeasterly offshore flow. Short term forecast
issues are limited to wind speeds and temperatures. Temperatures
will continue to run well below normal for both tonight and
tomorrow.  High end gales over some of the inner channels will
result in heavy freezing spray with light to moderate freezing
spray extending all the way down to the Dixon Entrance and out
into the eastern gulf. Strong northeasterly outflow winds will
gust to 40 mph or higher in Skagway, the Klondike Highway and near
downtown Juneau/Douglas tonight. Windy conditions will persist
through tomorrow for the Juneau area. Wind chills along the
Klondike Highway still dangerously low, and the wind chill
advisory remains in effect...now until Saturday morning.

Little change to the short term forecast other than to adjust
temperatures up or down by a degree or two. Overall forecast
confidence is average.

.LONG TERM...Offshore flow pattern continues into the long term
period, but not for long. Flow turns more onshore from south to
north on Saturday at the mid levels. Expect W-SW flow as far
north as Sitka/Icy Strait Sat morning and over the northern inner
channels Sat afternoon.

Precip looks to move into the southern panhandle on Saturday, but
somewhat weak at first. Another trough/wave in the onshore flow
develops near the southern outside waters Sat night into Sunday.
This trough looks to move north across the region on Sunday. The
12z GFS and ECMWF were in good agreement for a developing low
center moving northward into the SE gulf Sunday night into
Monday with this wave. Have moderate snow accumulations Sunday
morning for the southern panhandle, then those areas transition
to rain in the afternoon. This will likely be the most impactful
part of the forecast. On Monday morning the low center looks to be
off the coast of Sitka. This will force the winds to shift
southerly up to the central inside waters and help change the snow
to rain in more locations. As the low/trough moves north expect
the northern panhandle to get accumulating snow as well.
Currently looking at moderate or advisory level amounts.

The upper level pattern remains onshore through next week with
multiple waves or new low centers passing by. This will bring in
warmer/moist air. It may take until the 3rd impulse mid next week
before the warmer air makes it as far north as the Juneau area for
more of a mix or change over. Timing of this will be one to watch.

&&

.AVIATION...VMC conditions will prevail over the next 24 hours,
but turbulence below ridge tops will continue to affect air
operations.

&&

.MARINE...Significantly colder than normal temperatures persist,
as do strong outflow winds. Heavy freezing spray expected tonight
in Lynn Canal, Stephens Passage, and Glacier Bay. Light to
moderate freezing spray possible over remaining inner channels as
well as along the outer coast near strong outflow winds.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind through Friday afternoon for AKZ025.
     Strong Wind until midnight AKST tonight for AKZ018.
     Wind Chill Advisory until 9 AM AKST Saturday for AKZ018.
     Strong Wind through late tonight for AKZ017.
MARINE...Heavy Freezing Spray Warning for PKZ013-051.
     Heavy Freezing Spray Warning for PKZ031.
     Heavy Freezing Spray Warning for PKZ011.
     Heavy Freezing Spray Warning for PKZ012.
     Heavy Freezing Spray Warning for PKZ035.
     Gale Warning for PKZ011>013-022-043-051.
     Small Craft Advisory for PKZ021-031>036-042-053.
&&

Fritsch/Ferrin

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