textproduct: Seattle/Tacoma

SYNOPSIS

Upper level ridge building into the British Columbia coast today will progress over western Washington by Tuesday. Ridging will vary in intensity through midweek before exiting on Friday. Temperatures remaining above average through much of the upcoming week. A dissipating front will arrive Friday evening into Saturday.

SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/

It has been an unseasonably warm day here across western Washington. As of 2100z, temperatures are anywhere between 10-20 degrees above average while still a couple of hours away from peak-heating. Numerous daily record highs are under threat as official numbers will be posted in this evening's climate report. Tonight, dry conditions are in the forecast area wide as an upper-ridge shifts gently towards the region. We'll cool off into the lower to mid 50s, offering a bit of reprieve from the heat.

The heat will remain into Monday but'll show signs of relenting. Upper-ridging holding steady over the region, allowing for more large- scale subsidence across the PNW. However, a surface thermal trough previously along the coast will shift inland and cross the Cascades - bringing a return of natural AC in the form of a marine push by the evening. High temperatures will top out well into the upper 70s to lower 80s across the interior but the coast and adjacent areas will cool-down into the 60s. HeatRisk for the most part remains in the minor category on Monday due to the temperatures cooling off nicely in the overnight hours.

The aforementioned marine push will bring stratus into Tuesday as the cool-down ensues. Clouds will gradually burn off into the morning to abundant sunshine for the remainder of the day Daytime highs are expected to be in the upper 60s to mid 70s, cooler than previous days but still above average. The coast will remain in the mid 60s.

LONG TERM /WEDNESDAY THROUGH SUNDAY/

Upper level ridge over the area weakening Wednesday, rebuilding Thursday then starts to move east Friday. Low level flow remaining light onshore. Relatively warm air aloft combined with only a shallow marine layer over the interior in the late night and morning hours will keep daytime highs above normal through the week. A little cooling Friday as the ridge starts to exit the area and a weak front replaces it into Saturday. Highs Wednesday and Thursday in the 60s to lower 70s, before settling into the 60s area wide on Friday and Saturday before potentially warming again into early next week.

AVIATION

North to northeast flow aloft through Monday with an upper ridge located offshore. VFR conditions continue through Monday for the interior locations. A shallow LIFR/IFR marine layer is expected to be reach HQM Monday morning (between 12-15z). Stratus will continue along the immediate coast into Monday afternoon. Stratus will then slowly spread inland Monday night. North surface winds this afternoon will become light tonight and transition more SW on Monday.

KSEA...VFR conditions. North surface winds 7 to 12 kts this afternoon, becoming NE 4 to 7 kts tonight. Winds will become light Monday morning and transition to SW mid-late morning. JD

MARINE

Thermally induced low pressure will lead to weak northerly to offshore flow into tonight. The thermal trough will shift inland on Monday. Onshore flow will then persist through the majority of the week as a surface ridge is positioned offshore. Westerly pushes through the Strait are expected during most evening and overnight periods this week. A Small Craft Advisory has been issued for the central and eastern Strait of Juan de Fuca for the initial westerly push Monday night. Seas will range between 7 to 9 feet along the Coast into Monday, with brief 10 foot seas possible for the outer Coastal Waters tonight. Seas will then subside to 4 to 6 feet on Tuesday. JD

HYDROLOGY

No river flooding in the next 7 days.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory from 5 PM Monday to 5 AM PDT Tuesday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca.