textproduct: Seattle/Tacoma

SYNOPSIS

A cold upper level trough will continue to pass through western Washington through Sunday morning as showers taper off tonight. An upper level ridge will build offshore thereafter, with western Washington remaining on the backside of the ridge throughout much of next week.

SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/

Lingering showers will continue to taper off tonight into early Sunday morning. The Winter Weather Advisory continues generally south of I-90 above 4000 feet into tonight. Otherwise, cooler conditions into Sunday morning may allow for patchy frost to develop around Shelton and south of Olympia.

The upper level trough will shift southeastward by Sunday morning, with an upper level ridge building offshore. Conditions across much of western Washington will dry out despite a mostly cloudy morning and some sun breaks in the afternoon. Wrap around moisture may result in lingering shower activity across the North Cascades with little to no accumulation. Cooler temperatures will continue across the region on Sunday, with highs peaking in the low 60s across much of the lowlands.

Low clouds are favored to develop across much of the lowlands again into Monday morning as high pressure builds into the region. The clouds are favored to break up for most areas by the afternoon, with near normal temperatures and mostly dry conditions for Monday.

LONG TERM /TUESDAY THROUGH SATURDAY/

Ensembles remain in good agreement over high pressure remaining situated offshore through much of next week. A series of low pressure systems will move inland next week, but are favored to split apart or stay north of the Washington/Canada border. Conditions across western Washington are favored to remain mostly dry through the forecast period with near normal temperatures.

JD/15

AVIATION

The trough continues to move south, generally ending showers for most of western Washington. Areas of the southern Washington Cascades will see showers continue over the next several hours. Areas of northern Puget Sound are generally west to northwest, with southwesterly winds returning to central and southern Puget Sound. Winds outside of this area will remain out of the southwest- northwest 5-10 kt with a few gusts to 20 kt for terminals near waters. VFR/MVFR ceilings are likely Sunday morning before clearing in the afternoon.

KSEA...Showers have ended for the terminal and immediate vicinity. Surface winds have returned to a south to southwesterly, and will linger as such throughout the night between 4-7 kts. MVFR cigs possible between 13Z-16Z tomorrow morning before returning to VFR in the afternoon. Northerly winds 4-6 kts returning after 18Z Sunday, lingering through the rest of the TAF period.

21

MARINE

Gusty winds will continue with the onshore flow for the coastal waters, Strait of Juan de Fuca and Admiralty Inlet. There remains a chance of a brief gale gust in the eastern section of the strait early this evening. The onshore push will diminish late tonight/Sunday morning. The pattern will remain onshore as high pressure builds back over the waters Sunday. Another weak front will pass through Monday into Tuesday. Continual pushes of winds down the Strait of Juan de Fuca remain likely through midweek.

Seas of 8-11 ft will continue in the coastal waters through early Sunday (with rough bar conditions). They will drop back to 6-8 ft later Sunday through Tuesday before increasing to 8-10 ft Wednesday, and then dropping to 5-6 ft through the end of the week.

HPR/21

HYDROLOGY

The daily hydrology discussion has ended until the start of the next rainy season; it will only be updated during this time as needed.

SEW WATCHES/WARNINGS/ADVISORIES

WA...Winter Weather Advisory until 1 AM PDT Sunday for Cascades of Pierce and Lewis Counties-Cascades of Southern King County.

PZ...Small Craft Advisory until 3 AM PDT Sunday for Admiralty Inlet- Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca-Grays Harbor Bar.

Small Craft Advisory until midnight PDT tonight for West Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until 2 AM PDT Sunday for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From Cape Flattery To James Island Out 10 Nm- Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From James Island To Point Grenville Out 10 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm.