textproduct: Seattle/Tacoma

SYNOPSIS

Low pressure will bring showers and thunderstorms to portions of western Washington through Sunday, with warmer and drier conditions returning early next week. Offshore flow will lead to slightly warmer weather midweek. The next disturbance will bring a return of cooler conditions and shower chances later next week.

SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/

Isolated showers continue to weaken this evening, with a few lingering showers tonight. The upper low continues to move over the region but begins to finally slide away on Sunday. With generally light flow aloft, this should keep showers more confined to the mountains. The chances will remain highest over the Cascades south of I-90, and there could be locally higher rainfall amounts with the slower moving storms.

Expect showers to be mostly limited and generally dry conditions Monday for much of the area with the upper low finally pushing well inland and away from the region. Onshore flow increases at the low-level, bringing a steady push of marine clouds for the morning before some clearing in the late afternoon.

LONG TERM /TUESDAY THROUGH SATURDAY/

Expect a shift to warmer and drier conditions toward midweek with the region remaining in between any significant weather disturbances. Light offshore flow in the lower levels will bring a slight warming back into the mid to upper 70s for mid- week, corresponding to minor (yellow) HeatRisk values. Another disturbance arrives later in the with a return of cooler temperatures and rain chances.

AVIATION

VFR for all terminals this evening with patchy middle and high clouds overhead from what's left of this afternoons convection. Flow is light and primarily out of the NNW. VFR conditions will remain overnight, the exception being HQM, where brief low clouds may develop Sunday morning (09z-14z) with MVFR/IFR conditions. KOLM may see brief vis reductions and mist tomorrow morning (12Z-14Z). Elsewhere, VFR continuing into Sunday.

KSEA...VFR with light northerly to northeasterly flow at the terminal this evening, with similar conditions expected overnight. SCT to BKN clouds aloft expected. VFR conditions continue into Sunday, with flow becoming more northerly around 17Z and westerly after 00Z.

21

MARINE

Marine seas and winds are benign and remaining under any advisory criteria. Northerly winds will continue over most of the area waters through the rest of this weekend and into early next week. Onshore flow looks to increase late Sunday into Monday, which could bring a push of westerlies down the Strait of Juan De Fuca for potential headlines.

Coastal seas remaining generally around 3 to 6 feet through the rest of the weekend, with some locations in the outer coastal waters increasing to 6 to 7 feet on Monday. Seas will level back down to 3 to 5 feet through midweek.

Mazurkiewicz/21

SEW WATCHES/WARNINGS/ADVISORIES

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