Area Forecast Discussion
Issued by NWS
FXAK67 PAJK 232322
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
322 PM AKDT MON MAY 23 2016
.SHORT TERM...An upper low will move ESE across central SE Alaska
tonight and Tue morning. An upper trof will move into the NW gulf
Tue. A flat low level ridge will remain over the gulf through Tue.
Models were fairly close on the main features...and used a 12z
NAM/GFS blend to update pressures and winds.
Main forecast concerns will be precip potential and winds. Some
shower activity is moving onshore over the area attm as upper low
moves in. Think shower coverage will increase during the evening
as upper low moves onshore especially over the central area. One
thing that will need to be watched is the potential for some
precip to move SW into the N panhandle later tonight. Will have
some warm advection going on as upper low moves past the area and
possible shortwave trof moving into the N late tonight. At this
point going with mainly scattered showers to handle the N tonight
and Tue morning. As upper low moves out of the area Tue...should
see a diminishing trend over most of the area. There may be
another increase in shower activity over the N gulf coast Tue
afternoon though as upper trof moves in.
Winds will diminish some over the gulf tonight and Tue as low
level ridge weakens a bit. Still have 20-25 KT winds over most of
the E gulf right now. The far N part of the gulf will show more
weakening later tonight and Tue to 10-20 KT. The enhanced winds
along the headlands on the outer coast will weaken some as well.
Inner channel winds will generally weaken some tonight with N Lynn
Canal dropping the most...from 25-30 Kt down to 10-15 by late
tonight. However...they will increase again to 25-30 KT Tue
afternoon. Rest of inner channels will be mainly 10-20 KT.
.LONG TERM...Tues night into Wed morning another mid/upper level
trough will drop into the NE gulf. This develops into a cut off
low and will bring another round of scattered showers moving
across the region from NW to SE. After this low passes there will
be increasing offshore flow and improving conditions Wed night. A
strong NW jet stream extending from far NW Alaska & Siberia will
set up over the eastern Gulf on Thurs. This flow pattern tends to
be a dry one for us and may last into Friday. Expect temps to be
slightly above normal due to some sunshine Thurs/Fri.
Flow turns more onshore going into next weekend meaning increased
risk of precip...however models are showing quite different
solutions 6-8 days out. 2/3 of extended models are now showing a
continuation of the scattered shower regime from the first part of
the week and some sunny breaks while the 12z GFS still had a bigger
rain event. The 18z run was closer to the other 2 models so that
is promising. Due to the model spread and inconsistency from run
to run forecaster confidence is lower than normal and the extended
forecast remains closer to climatology.
MARINE...Small Craft Advisory FOR PKZ012-021-022-041-042.
SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ043-051-052.
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