Area Forecast Discussion
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FXAK67 PAJK 202336
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
236 PM AKST Tue Nov 20 2018

.SHORT TERM...As of Tuesday afternoon, an elongated upper level
trough has pushed the weather front through the northern two-
thirds of the panhandle. Moderate rainfall rates are beginning to
taper off across the southern panhandle where many locations
recorded around 1-2 inches of rain over the past 24 hours. The
front should push entirely out of the panhandle by this evening.
Low pressure system spinning in the northern Gulf is providing
ample onshore flow which will allow showers to continue stream
across the panhandle, especially the outer coast and northern
inner channels through Wednesday morning when the low is forecast
to dissipate.

A complex area of low pressure will begin developing around the
southeastern Gulf Wednesday as an upper wave lifts NE over Haida
Gwaii and the jet digs into the backside of the upper trough. The
lifting wave is currently forecast to clip the far SE`rn portion
of the panhandle Wednesday morning and afternoon, most likely
producing more rain near Hyder, and possibly increased shower
activity near Ketchikan. Wednesday night weak low centers over the
SE Gulf will continue to develop. Isolated to scattered showers
are likely over the outside waters and along the gulf coast, while
precipitation over the northern inner channels will likely
diminish as the low level flow turns more off shore, especially
into Thursday morning. Morning temps will also be a bit more
chilly than has been recently with a more northern gradient
setting up over the northern interior of the panhandle. Winds will
also increase over the northern inner channels Thursday, but don`t
expect more than SCA levels.

Minimal changes made to the inherited forecast as model guidance
has been fairly consistent in the near term. Forecast confidence
is average.

.LONG TERM.../Thursday through Tuesday as of 10 pm Monday/
Models getting closer on handling of Thu-Fri system that should
mainly be over the far S. Have used the ECMWF to handle this
system as it looks better given upper level environment. Then, the
other main adjustment was for 12z Sat to 12z Sun, showing a
stronger system moving N into the area.

There were some changes outside these time frames, mainly to warm
temps some from Sat onward. Did bump POPs up some for the S Thu
into Fri with system nearby that area, and dried out the N some.
Limited POPs to likely for the weekend and beyond systems due to
some timing differences in the models, although WPC was close to
the ECMWF idea for the weekend system. There could be some snow
with initial precip starting early Sat, but all except the far N
inner channels should be rain by the afternoon. Depending on low
track, could see several inches or more of snow over the far N
especially at higher elevations. Based on large scale pattern
evolution, a warmer and wetter forecast are realistic especially
from Sat-Tue. Freezing levels may end up above 3000 feet for a
while during this period.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...None.
MARINE...Small Craft Advisory for PKZ052.
     Small Craft Advisory due to Seas for PKZ041>043-051-053.

&&

$$

DDH/RWT

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