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fxak67 pajk 212206 

Southeast Alaska forecast discussion
National Weather Service Juneau Alaska
206 PM akdt Fri Jul 21 2017

Synopsis...a high pressure ridge over the Panhandle will slowly
weaken through Friday evening as an upper level low moves across
the southern Gulf. A frontal band will move into the southern Gulf
and southern Panhandle on Friday then track northward over the
rest of the Panhandle on Saturday. Showers diminish Sunday with
fair but cloudy weather expected through the first half of next


Short term.../tonight through Saturday night/satellite imagery
and surface analysis indicate a surface low near 53n/145w with
the first in a pair of frontal bands moving into the southern
Panhandle early this afternoon. This band will push into the
central Panhandle this evening before dissipating as energy
becomes absorbed into the second frontal band approaching this
evening/overnight. The first band will bring the stronger winds
with 30kt over the southern/southeast Gulf and Small Craft Advisory winds over pkz036
tonight. Little Break in precip over the S Panhandle as the
second band will push into the region shortly after the first band
moves N, but winds will diminish tonight. Seas will remain at or
above 8 ft in the East Gulf Sat before subsiding Sat evening. This
second band will bring precip further N, moving into Juneau area
early Sat morning and expanding north to Haines and Skagway by late
morning/early afternoon. Precip will transition to showers behind
this band with stratiform precip diminishing by Sat night. Other
area of concern remains the potential for thunderstorms as the
upper low drifts across the S Panhandle Sat afternoon. Modeled
instability indices continue to support mention of schc ts Sat
afternoon over the southeast Gulf and southern Panhandle. Model solutions
in good agreement and inherited forecast represented this thinking
well. Only minor changes made to reflect current conditions and
for local effects. Overall forecast confidence remains above

Long term.../Sunday through Friday as of 10 PM Thursday/
Sunday will begin with showers diminishing across the Panhandle
associated with the remnants of a weather front. Showers will
likely end by the afternoon hours for most of the Panhandle. As
the front diminishes a surface ridge of high pressure builds over
the eastern Gulf and Panhandle and persists through most of the
week. Winds over the Gulf will be relatively light and westerly,
while the Inner Channels will become more southerly. Significant
winds are not expected beyond the possibility of small craft level
winds in northern Lynn Canal and Cross Sound. While this weather
pattern will keep conditions cloudy for most of the Panhandle,
chances of precipitation remain low in the extended forecast.

Most significant changes in the extended forecast were made
Sunday diminishing the shower activity across the Panhandle faster
than originally forecasted. This follows the trend models have
had for the past few days of speeding up this system. In addition,
the ridge over the northern Panhandle was intensified which lead
to an increase in winds within Lynn Canal and Haines and Skagway
area. Forecast confidence is average in the long term with a blend
of the NAM and GFS being used to handle Sunday and Monday and wpc
being the primary guidance Tuesday and beyond.


Ajk watches/warnings/advisories...
Marine...Small Craft Advisory for pkz036-041>043.
Small Craft Advisory due to seas for pkz051-052.


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