textproduct: Seattle/Tacoma

SYNOPSIS

Active weather continues this week with periods of lowland rain and mountain snow through midweek. More frontal systems will cross over the region over the weekend and into the early half of next week, bringing breezy winds, periods of lowland rain, and more heavier mountain snow.

SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/

Scattered showers over the region this afternoon as upper level troughing brings disturbances to western Washington. Unsettled shower activity will continue throughout the remainder of the evening, with high temperatures in the low to mid 50s. Snow levels will remain generally around 4500 to 5000 feet, with snow accumulations likely in the higher backcountry, especially in areas around Mount Baker.

Upper level troughing will continue into Wednesday along with post frontal showers across much of the interior. Snow levels will lower slightly, generally around 3000 to 4000 feet. Mountain snow will continue, with some light accumulations at the passes into Thursday. Latest guidance generally shows around 2 to 4 inches at Stevens and Snoqualmie Pass, with the higher end being focused at Stevens Pass. Hi-res guidance also shows a Puget Sound Convergence Zone developing late afternoon/early evening hours, along the King/Snohomish County line. Can't rule out a chance of locally heavier showers in these areas, along with a few lightning strikes.

Slightly drier conditions on Thursday with some lingering shower activity around (mainly for the mountains). High temperatures in the upper 40s.

LONG TERM /FRIDAY THROUGH TUESDAY/

Additional systems will continue over western Washington throughout the weekend and into early next week. A stronger frontal systems looks to enter the area Sunday into Monday which could bring breezy winds across much of the interior, along with more lowland rain and heavier mountain snow.

Mazurkiewicz

AVIATION

Moist southwest flow over western WA tonight with rain and largely MVFR conditions. We're in post-frontal onshore flow on Wednesday with a slightly unstable air mass and a chance of thunderstorms. Showers with a Puget Sound Convergence Zone may form over King and Snohomish counties Wednesday afternoon. Showers will be mainly confined to the Cascades Wednesday evening. 33

KSEA...Rain and MVFR conditions expected tonight. S/SW winds around 10 kt. Showers with a convergence zone in the vicinity Wednesday afternoon and evening. 33

MARINE

A warm front will clip the area tonight followed by a cold front early Wednesday, with increasing onshore flow Wednesday afternoon. Highest winds will be over the Coastal Waters and through the Strait of Juan de Fuca. Seas will build over 10 ft Wednesday night and Thursday as a larger swell train reaches the coast. The flow will remain onshore Friday and through the weekend with possible SCA conditions. Stronger S/SW flow will develop on Monday over all waters, keeping conditions active. 33

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 Wednesday 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-West Entrance U.S. Waters Strait Of Juan De Fuca.