textproduct: Seattle/Tacoma

SYNOPSIS

Upper level ridge building over the area today will remain in place through the weekend. The ridge will drift east Monday. Upper level trough moving by to the north Monday night and Tuesday will induce a marine push. Dry northwesterly flow aloft Wednesday through Friday with an upper level low well southwest of Western Washington.

SHORT TERM /TODAY THROUGH MONDAY/

Dry weather in the short term with an upper level ridge building over the area today and tonight. Fog in the valleys of the Southwest Interior and the Snoqualmie valley have mostly dissipated and will continue to erode through the top of the hour. The ridge will remain in place Sunday then slowly drift east Monday. Upper level flow becoming southwesterly later tonight into Monday. High clouds embedded in the flow aloft moving through Sunday and Monday. Low level flow turning offshore today. Offshore flow continuing through Sunday night with the low level flow becoming light Monday. Warming trend through Monday. Highs today in the mid 50s to lower 60s, Sunday and Monday 60s to lower 70s. Lows in the 40s. Felton

LONG TERM /MONDAY NIGHT THROUGH FRIDAY/

Classic marine push scenario Monday night into Tuesday. Upper level shortwave riding by to the north inducing an increase in low level onshore flow. Much cooler Tuesday with highs in the lower to mid 50s. Next upper level trough will go by well to the north and east Wednesday. Dry northwesterly flow aloft Wednesday through Friday with an upper low off the Northern California coast remaining stationary. Highs recovering into the mid 50s to lower 60s Wednesday through Friday. Lows in the 30s through Thursday morning, mid 30s to lower 40s Friday morning. Could see another round of frost advisories for the Southwest Interior and Lower Chehalis Valley Wednesday and Thursday morning.

AVIATION

High pressure aloft remains over the region today. Expect northerly surface winds to increase this afternoon across the region, easing a bit overnight and increasing again Sunday. A few patches of fog developed in the more prone locations (KOLM south through KCLS/KTDO and west along the Chehalis River, as well as the Snoqualmie River valley and around Whidbey Island). Passing high clouds at times today and increasing into Sunday will yield little change. Expect to see some patchy development of shallow fog again late tonight through early Sunday morning, but elsewhere continued VFR conditions under mostly clear skies.

KSEA...VFR is expected through period under mostly clear skies. Northerly surface winds increase today to around 10-12 kt by 21z through the day, easing only slightly overnight. North surface winds continue Sunday. Any low clouds that form late tonight/early Sunday will remain well away from the terminal area. Cullen

MARINE

High pressure will remain over the waters this weekend while a thermally induced trough expands northward along the Oregon coast. This will shift the flow northerly or weakly offshore. Onshore flow resumes early next week as a frontal system passes to the north. A strong westerly push is possible along the central and eastern Strait of Juan de Fuca Monday night into Tuesday.

Seas across the coastal waters will build towards 7-10 ft Tuesday into Wednesday.

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HYDROLOGY

No river flooding is expected in the next seven days.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...None.