textproduct: Seattle/Tacoma

SYNOPSIS

An upper-low will continue to bring rain and showers to the area today before exiting later this evening. More benign conditions Monday before additional troughing returns on Tuesday with another shot of showers. Drier and warmer midweek onward as upper-level ridging builds.

SHORT TERM /TODAY THROUGH TUESDAY/

The upper-low center is currently along the Oregon coast as it continues to spin rain and showers across W WA. Rain has largely ended along the coast, but will continue across the interior of western Washington through this afternoon, and through the mountains overnight. The main swath of precipitation is favored to be generally Snohomish County southward. An additional 0.50-1.50" of rainfall is possible for the Cascades with 0.25-0.50" throughout the Puget Sound lowlands. Elsewhere should see generally less than 0.25" of rainfall. Winds will also increase today as the system departs, but remain mostly benign with peak gusts in the 20-30 mph range.

Expect drier conditions on Monday. The aforementioned upper-low will be well east of the area, near the northern Great Plains by Monday evening. We'll be left in a regime of northwesterly flow aloft as a stout upper-ridge positions over the Gulf of Alaska. Models are showing the development of an additional upper-low within this flow regime on Tuesday with a possible return of showers. High temperatures on Sunday mainly in the mid 60s before warming into the upper 60s to near 70 F. Overnight lows in the 50s with a few 40s possible.

LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/

Models have an upper-level ridge over the northeast Pacific moving over the Pacific Northwest through the end of the week, bringing a drier, sunnier, and warmer pattern. A surface thermal trough will develop, allowing winds to turn lightly offshore. Highs look to rise by Thursday into the upper 70s to low 80s.

AVIATION

Upper level low over the North Oregon Cascades early this morning will move northeast ending up over Western Montana by late tonight. High pressure building offshore behind the low. Northeasterly flow aloft this morning becoming northerly this afternoon and northwesterly tonight. In the lower levels, increasing onshore flow this afternoon and tonight.

Mostly IFR to MVFR this morning in rain. Ceilings lifting to VFR late this afternoon and evening. However, MVFR ceilings developing tonight near the East Entrance of the Strait of Juan de Fuca with a convergence zone. The zone will remain over Snohomish County into Monday morning.

KSEA...Ceilings this morning in IFR to MVFR range with rain. Ceilings improving this afternoon to VFR, then back down to MVFR overnight and into Monday morning. Southeast wind 4 to 8 knots becoming southwest 10 to 15 knots this afternoon. Winds easing to 6 to 10 knots early Monday morning. 33/Felton

MARINE

Increasing onshore flow today and tonight with Small Craft Advisory winds over Puget Sound/Hood Canal, Northern Inland Waters and the strait. High pressure will build over the area Monday and remain through Wednesday. A thermally induced surface trough will move up the coastline Wednesday night then shift inland Thursday afternoon.

Seas remaining in the 3 to 5 foot range over the inner coastal waters and mostly 4 to 6 feet over the outer coastal waters. 33/Felton

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory from 6 PM this evening to 5 AM PDT Monday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca-Northern Inland Waters Including The San Juan Islands-Puget Sound and Hood Canal.