Small Craft Advisory 147, NWS Seattle, WA

Area Forecast Discussion
National Weather Service Seattle WA
844 PM PDT Tue Jun 26 2018

.SYNOPSIS...A flat upper ridge will keep Western Washington dry
tonight as it moves inland from the offshore waters. Mostly cloudy
skies Wednesday morning should give way to some afternoon sunshine,
but a few showers could develop over the mountains. An upper
trough will bring mostly cloudy cooler weather Thursday through
Saturday, and a chance of showers. Sunday should be dry and a
little warmer.

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.SHORT TERM...Weak high pressure aloft will cross the area tonight
for dry weather. A weak upper trough will move into the area on
Wednesday. A short wave in the flow aloft could bring a few
showers, mainly in the afternoon. A somewhat more organized
weather system will reach the area later Thursday for a better and
more general chance of showers. Moist northwest flow aloft will
continue into Friday for a continued chance of showers, mainly
over the mountains and perhaps in a Puget Sound Convergence Zone.
Highs will be mostly in the 60s the next few days which is a few
degrees below normal. Schneider

.LONG TERM...Previous discussion...Another shortwave embedded in
the northwest flow will move through Western Washington on
Saturday; it should be another day of mostly cloudy skies, a
chance of light showers mainly over the mountains, and
temperatures a little below normal. The air mass should be drier
on Sunday with weak onshore flow, and it looks like the sunnier
and warmer of the weekend days. Confidence in the models for
Monday and Tuesday is less certain, and the forecast is close to
climatology. McDonnal

&&

.AVIATION...Weak high pressure aloft will cross the area tonight
with a weak upper trough moving into the area on Wednesday. The
flow aloft will be westerly. At the surface, onshore flow will
continue with high pressure offshore and lower pressure inland.
The air mass is stable and mostly dry this evening.

Mostly clear this evening. Some MVFR low clouds could reform
again tonight - mainly near the coast and over the south sound -
but overall less low clouds are expected Wednesday morning. Mid
and high clouds should increase on Wednesday.

KSEA...Mostly clear tonight. Mid and high clouds will increase on
Wednesday. Northerly wind 5-10 knots becoming light southerly
Wednesday morning. Schneider

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.MARINE...Onshore flow will continue for the next several days
with high pressure offshore and lower pressure inland. Small
craft advisory strength west winds are likely most evenings for
the Central and Eastern Strait of Juan de Fuca. Low end gales are
also possible Wednesday evening. There will also be small craft
advisory strength northwest winds for parts of the Coastal Waters
tonight. A weak front will move onshore later Thursday which will
briefly weaken the onshore flow and turn winds more southerly.
Schneider

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 5 AM PDT Wednesday for Central U.S.
     Waters Strait Of Juan De Fuca-Coastal Waters From James
     Island To Point Grenville 10 To 60 Nm-Coastal Waters From
     Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal
     Waters From Point Grenville To Cape Shoalwater Out 10 Nm-
     East Entrance U.S. Waters Strait Of Juan De Fuca-Northern
     Inland Waters Including The San Juan Islands.

     Small Craft Advisory until 11 PM PDT this evening for Coastal
     Waters From James Island To Point Grenville Out 10 Nm.

     Gale Watch from Wednesday afternoon through late Wednesday night
     for Central U.S. Waters Strait Of Juan De Fuca-East
     Entrance U.S. Waters Strait Of Juan De Fuca.

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