Small Craft Advisory 189, NWS Seattle, WA

Area Forecast Discussion
National Weather Service Seattle WA
859 PM PDT Fri Jul 28 2017

.SYNOPSIS...Typical summer weather will continue through the
weekend with areas of morning low clouds and sunny warm days. A
few days of hot weather are likely next week with record highs
possible Tuesday through Thursday.

&&

.SHORT TERM...Upper heights will gradually rise over the area the
next few days as an upper ridge builds over the western United
States. There will be a corresponding gradual warming trend into
early next week but low level onshore flow will keep things from
warming too much. Onshore flow should also produce some low clouds
the next couple of days but less than in recent days. Schneider

.LONG TERM...Previous discussion...The strong upper ridge over
the Western U.S. will bulge into the area. Thermal low pressure
may very well visit Western WA and the global models show a few
hot days are likely. 850mb temps peak around 24c next Thursday--
the average of the 12z GFS ensemble members. New daily high
temperature records will probably be set. Even the coast could get
a hot day or two if the thermal trough sets up as the models show
--with the most likely day for that probably next Wednesday. The
forecasts have been pushed in the direction of the 12z guidance
but are not yet as warm as today's guidance--we have had a few
false starts this season, but some hot weather is looking more
likely with each run.

&&

.AVIATION...Dry southwesterly flow aloft will continue tonight and
Saturday. At the surface, onshore flow will continue. The air mass
is generally dry, but there will be local fog and stratus Saturday
morning before everything evaporates again.

KSEA...VFR skies tonight. The potential for stratus Saturday morning
is less than today but MVFR is still possible for 2-3 hours, mainly
within the 13-17z window. Northerly wind 3-7 kt becoming southwest
after midnight. CHB

&&

.MARINE...Onshore flow will continue through Saturday night. A gale
warning is in effect in the central and east strait this evening,
and gales are occurring there. Gales are also possible in the
strait Saturday evening, and a gale watch is now in effect for that
period.

Onshore flow will begin to weaken on Sunday with generally light
northerly flow Monday through Wednesday. Northwesterly winds may
reach small craft strength over the coastal waters early next
week. Typical diurnal winds in the Strait Sunday into early next
week could still produce small craft advisory strength westerlies
during the evening hours. CHB

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Gale Watch from Saturday afternoon through Saturday evening for
     Central U.S. Waters Strait Of Juan De Fuca-East Entrance
     U.S. Waters Strait Of Juan De Fuca.

     Gale Warning until midnight PDT tonight for Central U.S. Waters
     Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of
     Juan De Fuca.

     Small Craft Advisory until midnight PDT tonight for Admiralty
     Inlet-Northern Inland Waters Including The San Juan Islands.

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www.weather.gov/seattle

You can see an illustrated version of this discussion at
www.wrh.noaa.gov/sew/gafd/latest_webafd.html