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000
FXAK67 PAJK 091426
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
526 AM AKST Fri Dec 9 2016

.SYNOPSIS...Broad, weak, and complex upper level trough over the
Panhandle this morning with -40C aloft over the NW Territories and
as warm as -31C at 500 MB on the PANT 12Z RAOB. There is much more
definition at the surface with a 1057 MB arctic high over the
northern Yukon and a strong pressure gradient over most of our
area.

&&

.SHORT TERM...Clear skies over the Panhandle this morning and
chilly arctic air. Outflow winds are strong and should increase to
frequent gusts to 60 MPH for Downtown Juneau and Douglas this
morning. 0.8F at the office this morning for a chilly walk home.
Expect outflow wind to continue most areas into tomorrow. Could
see temperatures close to zero tomorrow morning for locations off
the water and out of the wind maybe even a minus reading.

.LONG TERM...The extended forecast remains on track with a
persistent clear and cold pattern along with northerly outflow
winds. Long range models have no chance of precip in the forecast
except for some ocean effect showers offshore from outflow areas.

850mb temperatures are progged to cool to -20c along the northern
border by Saturday morning and down to -8c along the southern outer
coast. Temperatures at White Pass fall into the negative teens at
night with resulting wind chills as low as 35-45 below zero. These
advisory level wind chills (cooler than -30F) look to persist until
temperatures warm some next week. Cold temperatures and strong winds
will continue favorable conditions for freezing spray near northern
interior passes. Things look to warm slightly on Monday, then the
next true warm up or change in pattern after that doesn`t look to
happen until late next week.

As mentioned above, the High Wind Warning for Taku winds in
Downtown Juneau continue through noon Saturday. However there is
potential for the event to last longer into Saturday night. Since
the event is just getting going this will be re-evaluated over the
next 24hrs.

Only minor adjustments were made to the inherited forecast,
largely for local effects. Nudged up temperatures for windy
locations and down somewhat in known wind sheltered areas to align
closer to the 20+ degree difference currently happening between
the valley and downtown Juneau and in Gustavus vs Bartlett Cove.

&&

.AVIATION...Excellent performance curves over the next few days in
cold dense air and clear skies. A few TAFs have mentions of LLWS
due to the very strong outflow. Channel wind flow will cause some
turbulence today and for the next few days.

&&

.MARINE...Gales and freezing spray are predominant hazards in this
arctic outflow setup. We also ramped up the sea state inland due
to fully arisen sea and many channels particularly Lynn to
Chatham. There will be a few places to hole-up, but watch for
dragging your hook in all this wind.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...High Wind Warning until noon AKST Saturday for AKZ025.
     Strong Wind through this evening for AKZ019.
     Strong Wind through this evening for AKZ018.
     Wind Chill Advisory until 11 AM AKST Monday for AKZ018.
MARINE...Heavy Freezing Spray Warning for PKZ012.
     Gale Warning for PKZ012-013-021-022-031-043.
     Small Craft Advisory for PKZ011-032>036-041-042-051-053.
     Small Craft Advisory due to Seas for PKZ052.
&&

$$

JC/Ferrin

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