textproduct: Seattle/Tacoma

SYNOPSIS

A weak front will cross the region today followed by dry and mild weather Wednesday and Thursday. High pressure will lead to warmer conditions on Friday. An upper level low will shift inland Friday night and Saturday for cloudy and cooler weather with a chance of showers. High pressure returns early next week.

SHORT TERM /TODAY THROUGH THURSDAY NIGHT/

A weak front is pushing inland this afternoon with isolated to scattered light showers in the interior and Cascades. There's a 15-20 percent chance of thunderstorms in Whatcom County but so far not seeing too much activity on radar. Temperatures are noticeably cooler and in the 60s and 70s - a few degrees cooler than average.

Broad low pressure will spin off B.C. Wednesday and Thursday with generally dry and mild conditions over western WA. Near the surface, onshore flow prevails, for a mix of morning clouds and afternoon sunbreaks. Temperatures will track in the 60s and 70s again, a degree or two shy of average. 33

LONG TERM /FRIDAY THROUGH MONDAY/

Low pressure continues to spin offshore on Friday while high pressure builds inland. The air mass over western WA will be a little warmer and drier with daytime temps in the low to mid 80s across the interior. The coast will be in the 60s to lower 70s. The low starts to slowly shift inland Friday night and Saturday with a chance of showers. We may also see showers with a convergence zone over the north sound Saturday afternoon with a chance of thunderstorms in the North Cascades. The upper departs N/NE on Sunday with a return to dry and stable weather. A weak upper level ridge will lead to warmer conditions early next week with interior lowlands seeing the 80s again. 33

AVIATION

Southwesterly flow aloft, with low level onshore flow maintaining the marine layer over much of western Washington. Pockets of MVFR ceilings lingering along the coast, strait and central Puget Sound. VFR conditions this afternoon will lower again to 2500 to 3000 ft, with some areas below 2000 ft Wednesday morning.

KSEA...VFR ceilings above 5000 feet through the at or just below 3000 feet Wednesday morning. Both LAMP and REFS guidance showing a 25-35% chance of of a brief period of ceilings less than 3000 feet around 15z. Southerly winds 10 to 15 knots easing after 03z, and then are expected to shift to northerly. 75% of REFS members have this shift by 04Z.

MARINE

High pressure will return to area waters Wednesday through Friday. Another weak system will reach the waters over the weekend. Periods of small craft advisory winds remain possible with onshore flow via the Strait of Juan de Fuca particularly Thursday evening and again Friday evening into Saturday morning. Seas over the coastal waters are expected to remain in the 4 to 5 foot range into the weekend.

FIRE WEATHER

Drier and warmer conditions return Wednesday through Friday, with minimum humidity values dipping into the 30s on Friday. However, low-level flow remains onshore to provide for good to excellent overnight recoveries, and this looks to be a short-lived trend as the pattern shifts back to cooler and cloudier conditions for the weekend.

SEW WATCHES/WARNINGS/ADVISORIES

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