Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 192242 CCA

Area Forecast Discussion...CORRECTED
National Weather Service Seattle WA
342 PM PDT Thu Apr 19 2018

.SYNOPSIS...An upper ridge over the area will bring dry weather
into Friday morning. A frontal system will move quickly across the
area Friday night, followed by showers and sun breaks on Saturday. A
stronger upper ridge has the potential to bring the longest stretch
of dry weather this month beginning Sunday and continuing into the
middle of next week.


.SHORT TERM...An upper ridge over the area will shift inland
tonight. An approaching frontal system will bring increasing
clouds on Friday. The main rain threat with this system will be
Friday night as the front moves inland. It will become breezy
early Saturday behind the front as moderate onshore flow develops.
Showers will taper on Saturday and become mostly confined to the
mountains and a Puget Sound Convergence Zone. An upper ridge will
build over the area on Sunday for dry and warmer weather.

.LONG TERM...The Monday through Thursday period is looking largely
dry with high pressure aloft in control. Highs will be above
normal - mostly in the 60s although a few lower 70s are possible
around Tuesday. Schneider


.AVIATION...High pressure aloft will weaken tonight and slowly
shift east through Friday. A surface front and associated upper
trough will push through Western Washington Friday night. Light
southerly flow aloft will become strong southwesterly flow Friday
afternoon and evening. Westerly flow aloft weakens by Saturday
morning as split flow aloft develops. Air mass stable and somewhat
moist above 5,000 ft. Lower level moisture increases Friday
evening. Dry through Friday, then rain reaching the coast by late
Friday afternoon or early evening and pushes into the interior
Friday night. VFR conditions except patchy MVFR possible early
Friday morning.

KSEA...Northwest 6 to 10 kt easing to 4 to 6 kt by midnight, then
switching to south-southwesterly 5 to 8 kt Friday morning. Mostly
VFR through Friday with sct-bkn clouds around 5k ft and above 12k
ft. Brief MVFR possible around 2500 ft late tonight/Friday
morning. dtm


.MARINE...Surface high pressure offshore will shift inland this
evening and east of the Cascades after midnight. Onshore flow will
gradually increase with small craft winds in the central and
eastern Strait tonight. A lull in winds late Friday, then a front
brings more widespread small craft winds to most of the waters
Friday night and Saturday, except possible gales in the central
and eastern Strait. Lighter flow develops Sunday through Tuesday.


PZ...Small Craft Advisory until 3 AM PDT Friday for Central U.S.
     Waters Strait Of Juan De Fuca-East Entrance U.S. Waters
     Strait Of Juan De Fuca.


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