Small Craft Advisory 96, NWS Seattle, WA

Area Forecast Discussion
National Weather Service Seattle WA
815 PM PDT Sun May 6 2018

.SYNOPSIS...Marine air is pushing into Western Washington this
evening. A cold front will move through Western Washington Tuesday
night. Cool showery onshore flow is expected Wednesday and Thursday.
Dry and warmer weather is expected Friday into next weekend.

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.SHORT TERM...A marine push has already brought stratus to the coast
early this evening. At 8pm Shelton had stratus, and the rest of
Western Washington will fill in overnight. Monday will be a typical
day with morning clouds and afternoon sun. Tuesday will be warmer
and sunny before clouds increase in the afternoon or evening. Rain
arrives with a cold front late Tuesday afternoon or early evening on
the coast, then spreading inland by midnight.

.LONG TERM...Cool, showery conditions will continue Thursday, as a
low-amplitude upper trough slowly makes its way across the Pac NW.
As the trough axis moves east of the forecast area late Thursday,
low-level onshore flow will peak. This favors a fairly sharp Puget
Sound Convergence Zone on Thursday as showers elsewhere start to
weaken and taper off. By Friday morning, just looking for a few
lingering showers in the Cascades.

As a strong upper ridge strengthens between 130W and 135W on
Friday and low-level flow becomes more northerly, clearing skies
are expected on Friday and Friday night.

The ridge will make its way across Western Washington next Sunday.
Should be a thermal pressure trough along the coast by Sunday
morning, a pattern which confidently supports dry weather with
well above normal temperatures. Confidence in next weekend's ridge
forecast has increased today, given stronger model agreement, a
slower progression of the ridge across the forecast area, and the
elimination today of a dissenting cluster of ensemble members.
Haner

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.AVIATION...The convection near the Cascades is ending this
evening. Marine stratus on the coast will spread inland overnight
then burn off in the afternoon. At 8pm Shelton already had OVC012 so
it will fill in pretty quickly over Puget Sound tonight.

KSEA...A marine push will bring stratus into Seattle around
midnight. The marine layer low clouds should burn off Monday
afternoon.

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.MARINE...Onshore flow with a marine push this evening. Small
craft advisory west winds 20-30kt for the Strait, and it is a little
breezy now in Puget Sound as well this evening. Weak onshore flow
will continue Monday and Tuesday. A front will move through the
forecast area Tuesday night and Wednesday with moderate southerly
flow, followed by onshore flow Thursday and Friday.

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.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory central and eastern Strait of Juan de
Fuca...Small Craft Advisory Puget Sound and Hood Canal.

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www.weather.gov/seattle