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FXAK67 PAJK 280752 CCA

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
243 PM AKDT Thu Jul 27 2017

.SHORT TERM.../ Friday night to Sat night / A narrow ridge has
set up along the Southeast Alaska panhandle tonight and will
continue into Friday before a low pressure over the far southern
Gulf of Alaska strengthens and moves northeast, closer to the
panhandle Saturday and Saturday night. We should see scattered
showers around the panhandle Friday and Friday night. Late Friday,
with the developing low approaching, we have rain/showers spreading
north through the panhandle. With a little tighter pressure
gradient, we have increased winds slightly for southern areas from
southern Baranof Island to Prince of Wales for later Saturday, with
25 to 30 kt of winds and possibly even minimum Gale force for a
brief period of time. We should see gusts 40 to 45 for the marine
waters, but we`re not sure if it will catch the coast at this point.

Also, as the upper level low nears the coast, there looks to be a
pocket of good instability on the south-southeast side of the low
that will approach the southern panhandle. We added in a mention for
a small area of thunder potential.

.LONG TERM.../Sat through Thu/ As of 930pm Wednesday... Little
change to inherited forecast as model solutions remain fairly
similar to the past couple of days with a series of perturbations
eject across SE AK from an upper low in the gulf. Models in a
little better agreement with the first low moving N-NW across the
SE gulf Sat into Sun. NAEFS and ECENS show 1000mb and 850mb
windspeeds 2-3 std dev above normal into the S panhandle during
this time so the main change to forecast was to increase winds.
Biggest increases were over the SE gulf where strong to near gales
expected. Otherwise, Clarence Strait along the the ocean
entrances to S Chatham and Sumner Strait will see advisory level
winds. Less confident in strength of winds in Cross Sound so kept
them in 15-20kt range attm, but could increase/decrease on how far
N the low moves before W in the gulf.

Little change in model solutions with upper low persisting over
the gulf with a series of minor short waves ejecting across the
region maintaining an active weather pattern through the extended.
Minimal spread in ensembles 500H lead to above average confidence
in the synoptic pattern, but surface features differ significantly
from run to run and between models leading to lowering confidence
in surface features by early next week. Minor changes to inherited
forecast through the weekend the trended towards latest WPC
guidance towards the middle of next week.


.AJK Watches/Warnings/Advisories...




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