Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 100457
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
857 PM PST Sat Dec 9 2017

.SYNOPSIS...A strong upper ridge will maintain dry and stagnant
conditions across Western Washington through most of next week.
The ridge looks like it will break down late in the week with the
a chance of rain Thursday or Thursday night.

&&

.SHORT TERM...An upper ridge will remain over the area through
early next week for dry weather. A front offshore will brush the
area to the north and west tonight but only bring some high
clouds. Otherwise, expect little change in the pattern with some
night and morning fog each day and stagnant conditions for the
interior lowlands. Schneider

.LONG TERM...Previous discussion...Dry weather will continue
through at least Wednesday as the ridge begins to weaken. By
Thursday, showers return as the flow aloft turns more zonal. This
system is a little faster in the models compared to previous
solutions. Showers will continue into the weekend with moist west
to northwest flow over the area. Temperatures are trending close
to normal over this period. 33

&&

.AVIATION...A strong upper ridge axis over Central Washington will
remain in place through Sunday night. Flow aloft will be light to
moderate from the southwest, with low-level offshore gradients.
The air mass will remain dry and very stable. Shallow dense fog
over the Puget Sound lowlands will continue to be the main
challenge. Thicker cirrus clouds appear to be delaying the
development of fog this evening, compared to timing of the last
few evenings. Areas of fog will slowly shrink during the afternoon
on Sunday.

KSEA...No fog in the vicinity of the terminal yet. Just to the
east at RNT, the air is a little drier this evening compared to
last evening. Based on current trends, fog development should hold
off until the overnight hours. High cirrus clouds will continue to
be an inhibiting factor to fog development and persistence.
Assuming fog develops, it should burn off from the terminal around
noon on Sunday. Haner

&&

.MARINE...Lower pressure offshore along with a 1041 mb high over
Eastern Washington will keep gradients easterly through Monday
morning. The offshore flow will weaken on Monday afternoon.
Expect light northerly offshore flow on Tuesday and Wednesday.

&&

.HYDROLOGY...River Flooding is not expected for the next 7 days.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Air Stagnation Advisory until noon PST Monday for Admiralty
     Inlet Area-Bellevue and Vicinity-Bremerton and Vicinity-
     East Puget Sound Lowlands-Eastern Strait of Juan de Fuca-
     Everett and Vicinity-Hood Canal Area-Seattle and Vicinity-
     Southwest Interior-Tacoma Area-Western Skagit County-
     Western Whatcom County.

PZ...Small Craft Advisory until 9 PM PST Sunday for Coastal Waters
     From Cape Flattery To James Island Out 10 Nm-West Entrance
     U.S. Waters Strait Of Juan De Fuca.

&&

$$

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