Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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953
FXUS66 KSEW 010403
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
903 PM PDT THU JUN 30 2016

.SYNOPSIS...Onshore flow will result in seasonable temperatures
with night and morning clouds and partly to mostly sunny
afternoons for the next several days. Weak upper troughs will
bring a slight chance of showers at times.

&&

.SHORT TERM...Quiet weather tonight. Low level stratus clouds
will push back inland with onshore flow.

A weak cold front and upper level trough will move inland on
Friday for a chance of showers, mainly along the coast. Otherwise
it will be mostly cloudy with temperatures near normal.

Onshore flow will continue on Saturday with patchy drizzle on the
coast. The interior looks dry but skies will likely remain mostly
cloudy.

Another weak system will cross the region on Sunday for isolated
to scattered showers. This system is a little wetter compared to
the Friday system. Models show showers from a Puget Sound
Convergence Zone lingering into Sunday evening for Snohomish/King
counties. 33

.LONG TERM...Previous Discussion...An upper trough will keep a
small chance of showers in the forecast Independence day through
Wednesday. An upper low could bring an increase in the showers
activity Wednesday but models are still struggling with the
details. An upper ridge is expected to bring a return to dry
weather Thursday. Schneider

&&

.AVIATION...Moderate westerly flow aloft will prevail tonight and
Friday. A weak upper trough and weak front will brush the area
Friday with increasing onshore flow at the surface. The air mass is
stable and moist in the lower levels due to onshore flow. Generally
dry air in the mid and upper levels will become somewhat moist aloft
as the decaying front pushes across the area Friday. Sprinkles or
spotty light rain is possible Friday as the weak front moves into
Western Washington.

Patchy stratus this evening will fill in overnight with ceilings
gradually lowering. Widespread MVFR ceilings appear likely again at
most terminals by 10-12z through midday Friday. Ceilings should then
lift to VFR with sct-bkn clouds at multiple levels associated with
the weak frontal band.

KSEA...Light and variable wind tonight. Stratus will develop in
place overnight, with MVFR ceilings likely by 11 or 12Z through
midday Friday. Patchy drizzle or spotty light rain is possible
Friday as a decaying front moves through the area. Expect multiple
sct-bkn VFR cloud layers Friday afternoon. CHB

&&

.MARINE...Higher pressure offshore with low pressure inland will
maintain moderate to strong onshore flow through Tuesday. Gale force
winds are likely in the strait tonight. Small craft winds are likely
in portions of the northern inland waters and admiralty inlet near
the east entrance to the strait. A front on Friday could enhance the
onshore flow Friday/Friday night. Another system on Saturday night
and Sunday could bring stronger onshore flow. dtm/CHB

&&

.SEW Watches/Warnings/Advisories...
WA...None.
PZ...Gale Warning until 5 AM PDT Friday for Central U.S. Waters
     Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of
     Juan De Fuca.

     Small Craft Advisory until 5 AM PDT Friday for Admiralty Inlet-
     Northern Inland Waters Including The San Juan Islands.

&&

$$

www.weather.gov/seattle

You can see an illustrated version of this discussion at
www.weather.gov/seattle/gafd/latest_webafd.html



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