textproduct: Seattle/Tacoma

SYNOPSIS

Mountain snow and spotty lowland rain showers will dwindle into Friday evening. A trend towards cooler and drier conditions will emerge over the weekend with areas of morning fog through Monday before the next weather system arrives by the middle of next week.

SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/

Light shower activity continues to become more isolated across the north interior this afternoon. Expect this trend to continue as broad, low amplitude ridging gradually slides east into the area for the weekend. This will lead to mainly dry conditions areawide Saturday through at least Monday. The exception may be across far southwestern Washington where dynamics associated with a cutoff low moving near the Oregon/California border could spread some clouds or even stray precipitation across into those areas. Where we are cloud-free overnight, expect areas of patchy fog to develop and temperatures to fall into the low to mid-30s.

LONG TERM /TUESDAY THROUGH FRIDAY/

As the pattern evolves Tuesday through late next week, the door will open to fairly typical winter frontal systems. The most likely scenario is precipitation spreading from west to east across the area Tuesday into Tuesday night bringing lowland rain, mountain snow, and some areas with breezy winds. At this time, the potential for significant weather hazards appears low and the precipitation looks primarily beneficial for the region, adding some much needed snow to the snowpack in the mountains. That said, given a weak favoring of above normal temperatures, snow levels may limit the overall additions. -Wolcott-

AVIATION

West to northwest flow aloft will continue into Saturday with a weak upper ridge centered offshore. Low end VFR ceilings will prevail most areas this afternoon into the evening. Ceilings will then deteriorate to low MVFR or occasional IFR areawide overnight before scattering out again Saturday afternoon.

KSEA...Low end VFR will lower back to low MVFR or tempo IFR 10Z-20Z Saturday. Low clouds are expected to scatter out Saturday afternoon. Surface winds S/SW 7 to 10 knots through this evening...then backing to N/NE overnight and rising to 9 to 12 knots Saturday afternoon.

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MARINE

Surface high pressure will build into the waters today with onshore flow easing. Winds will transition more northerly or weak offshore over the weekend as a surface ridge settles over the interior of British Columbia. The next frontal system will move into the waters Tuesday into Wednesday.

Seas will hover near 10 feet for the outer Coastal Waters through today, before subsiding back into the 4 to 7 foot range over the weekend through Tuesday.

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HYDROLOGY

No river flooding is expected during the next seven days.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory until 4 PM PST this afternoon for Central U.S. Waters Strait Of Juan De Fuca-Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm.