Small Craft Advisory 69, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
603 AM AKST Wed Feb 1 2017

.SHORT TERM...As weak high pressure wanes over the Gulf of
Alaska, high pressure across northwest Canada will build into
tonight. Outflow winds have already begun increasing in the
northern inner channels including Skagway. Winds will increase to
25 kt tonight through Northern Lynn Canal, but it is a little
concerning that high res models indicate winds may increase more
rapidly than our forecast. Farther south, the ridge of high
pressure holds across the bulk of the panhandle as winds remain
generally light even through tonight.

Clouds will likely spill eastward over the upper level ridge in
the gulf as moisture interacts with a short-wave diving south from
northwest Canada. Thus skies over the northern panhandle will
become increasingly cloudy through tonight. Meanwhile to the
south, skies will remain mainly clear.

While high temperatures today will be generally similar from
yesterday, lows tonight will likely drop a little cooler than this
morning...especially near the coast from the absence of a
stratocumulus deck.

Forecast confidence is good.

.LONG TERM...Strong northerly outflow event remains on track
through the first portion of the extended range. Little change
from the previous forecast with gale to storm force winds over the
central and northern inner channels. This will increase the threat
of freezing spray which likely will become heavy in Northern Lynn
Canal late Friday and early Saturday. Taku wind ingredients still
look favorable so have issued a high wind watch for downtown
Juneau and Douglas beginning Thursday afternoon and lasting until
Saturday afternoon. Gusts of 60 to 80 mph are possible during
this time frame. The critical level will initially be favorable as
a potent upper level shortwave drops across the area Thursday
evening. Flow will become uni-directional throughout the profile
but a weakness in the upper level flow will persist resulting in
continued favorable conditions for Taku wind gusts through
Saturday. There is the potential this may need to be extended into
Sunday as another strong shortwave drops south over the
panhandle. The remainder of Southeast Alaska can expect gusty
northerly winds through the weekend.

There still remains considerable disagreement on how this pattern
evolves next week, but at this point it looks like below normal
temperatures will continue.

Used the NAM/GFS for updates that were made.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...High Wind Watch from Thursday afternoon through Saturday
     afternoon for AKZ025.
MARINE...Small Craft Advisory for PKZ012.
     Small Craft Advisory due to Seas for PKZ041>043-051>053.
&&

JWA/TPS

Visit us at http://www.weather.gov/Juneau