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FXAK67 PAJK 262313

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
313 PM AKDT FRI AUG 26 2016

.SHORT TERM...The upper level trough continues to move southeast
over the southern panhandle this evening and overnight. The wrap
around moisture band associated with an upper level low is
starting to slide past the northern third of the panhandle on the
British Columbia side of the coastal range. Lower level clouds
are still persisting south of Yakutat and along the coast and
western parts of the panhandle, however these should be eroding
away from the northwest through tonight. Tonight most of the
northern panhandle should see scattered cloud cover, and the
central could be seeing that towards sunrise. A few local areas of
fog may develop where the it will be sheltered from the northerly
winds overnight or where the near surface winds have decoupled
from the lower levels.

Am expecting Saturday to be a sunnier day for the northern
panhandle with above normal temperatures, and should see highs in
the upper 60s to lower 70s. The southern panhandle will be dealing
a few more clouds however do expect that they should reach the
upper 60s.

No hazards expected this evening other than small craft advisories
for winds and or combines seas of the coastal marine waters.
Locally gusty winds from terrain enhancements near Cape Spenser
and Cape Decision this evening.

.LONG TERM...Broad area of upper level low pressure moves in from
Northwestern Canada Sunday becoming main feature through mid
week. High pressure ridge over the western gulf begins to shift
east mid week then flattens out. Inverted trough over the
panhandle shifts west moving over the eastern AK Gulf Sunday
evening. By Monday developing surface low in the southeast gulf
will begin to bring precip back in over the southern panhandle.
Some uncertainty if this low will begin to track northward or remain
in the southern gulf. More likely a second low center forming in
the ne gulf as another upper low moves in from the Yukon with the
low in the southeast gulf dissipating. Began to increase some
winds over the southern gulf and bump up pops for Monday into
Tueday. Position of the low in the south may still keep the
northern panhandle drier for Monday but expect showers to spread
further north by Tuesday. As the gulf ridge shifts east potential
for another dry period late in the week before another system for
next weekend moves east. Large model spread by this time so expect
this scenario may change. Decreasing temperatures for the start of
the week as a combination of increased cloud cover, precip and
cooler temps aloft move in from the north with the next series of
upper level troughs. Northerly winds will pick back up Saturday
night due to pressure gradient as the seas breeze weakens. Winds
then begin to lighten as the surface trough moves over the gulf
and increasing cloud cover limits differential heating.

Not much change through late Sunday as models were still showing
good agreement. EC/GFS 12z runs falling more in line for Monday
and Tuesday as the NAM becomes an outlier. Still differences on
position and timing of the low center so went with a blend. Once
again large model spread mid week onward so kept with a WPC
ensemble solution. Forecast confidence is above average through
the weekend then begins to drop.


.AVIATION...The band of MVFR to IFR conditions due to cloud cover
has shifted southward to the southern half of the panhandle
through the day. Should see this continue move with upper trough
to the southern panhandle tonight and out of the forecast area on
Saturday. Juneau, Wrangell and Petersburg may see some local fog
develop overnight to shorty after sunrise. Overall visibilities
could drop to a mile or so, however not expecting a widespread fog
event tonight.


.HYDROLOGY...The heavier rains (0.5 to 1 inch) this morning over
the Taiya River Basin raise the water levels to reach the minor
flood stage of 16.5 feet, and then receded through day. The
Salmon river and the minor Glacier Outburst there crested about
midnight last night and has fallen rapidly.

We are also watching Mendenhall Lake as they were reporting a
quick rise during the morning hours. Mendenhall lake is expected
to stay below action stage.


.AJK Watches/Warnings/Advisories...
MARINE...Small Craft Advisory for PKZ012-013-033-035-041>043.



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