Small Craft Advisory 12, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
355 PM AKST Fri Jan 6 2017

.SHORT TERM...Wind remains the focus for the forecast today.
Mountain wave winds occurring in the Juneau area and likely the
Yakutat area as well. Gusts in Juneau 45 to 75 mph on various
observation sites. A strong low level jet southeast of Yakutat
has been mixing to the surface and Yakutat has been 20 to 30 with
gusts 40 mph today. Broken to overcast clouds over the northern
Panhandle are expected to breakup towards morning...while the
southern panhandle should hang on to them for the afternoon.

the only falling precipitation is flurries to a thin band of
measurable (less than a 1/4 inch) along Dixon Entrance, and the
flurries will taper off overnight and early Saturday.

Cooler temperatures starting to spread south to the northern
panhandle as well...though not really moving in until Saturday.

.LONG TERM...Large scale pattern will begin to transition during
next week. The strong upper ridge over W AK will weaken early next
week then reform further W over the Bering Sea and E Russia. The
upper trof over the E gulf will dig S into the NE Pacific during
the weekend. Another upper trof will dig S into the N gulf toward
the latter part of next week. Also, models suggest southern stream
energy will get picked up by this trof. There is some model
spread on how far W the late week trof will dig, and how much
interaction there will be with southern stream trof, which lowers
confidence in forecast for late week, but trend toward wetter
pattern is increasing.

Wind (and wind-induced effects) will be the big issue this
weekend. Strong high over NW Canada and low to S of the panhandle
will maintain a very strong pressure gradient Sat night. However,
as low to the S moves away, the gradient will begin to weaken
slowly during Sun into early next week. Coldest airmass will be in
place Sat night, then a gradual moderation in temps will occur
into late next week. Did not change the public headlines except to
extend out some of the strong wind headlines.

During latter part of next week, with upper trof digging S into
the gulf and southern stream trof moving NE toward the gulf,
looking like increasing threat for precip over the area then. How
significant the precip will be and ptype will depend on how far W
the northern stream trof is over the gulf and whether phasing
occurs with southern stream trof. Still lots of time to work out
the details on this.

&&

.AVIATION...Most of panhandle seeing a strong off shore northeast
wind pattern. Northern panhandle has the largest impact with winds
causing moderate turbulence up to roughly 6 to 10k feet. Low level
wind shear also reported of 5 to 15 kt at a few of the northern
TAF sites Southern locations should be seeing light to mod
Turbulence near the rougher terrain.

&&

.MARINE...Gale to storm force winds mainly across the northern
inner channels. Seas building to 10 to 15 feet in some locations
were Fetch allows for fully developed status today and into today.
Sustained winds of 35 to 50 kt... gusts down channels or through
interior passes up to 80 kt likely tonight. Areas of freezing
spray and areas of Heavy Freezing spray over the northern
channels the other hazard.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...High Wind Warning until 3 PM AKST Sunday for AKZ025.
     Strong Wind through Saturday morning for AKZ022.
     Strong Wind through Saturday afternoon for AKZ019-020.
     Strong Wind from midnight AKST tonight through Saturday morning
     for AKZ021.
     Winter Weather Advisory until 10 AM AKST Monday for AKZ018.
     Strong Wind until 6 PM AKST this evening for AKZ018.
     High Wind Warning until 3 PM AKST Saturday for AKZ017.
MARINE...Heavy Freezing Spray Warning for PKZ022.
     Heavy Freezing Spray Warning for PKZ011-012.
     Heavy Freezing Spray Warning for PKZ013.
     Storm Warning for PKZ012-013-022-043-051.
     Gale Warning for PKZ011-021-031>036-041-042-053.
     Small Craft Advisory due to Seas for PKZ052.
&&

Bezenek/RWT

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