textproduct: Seattle/Tacoma

SYNOPSIS

Low pressure will bring mountain showers today with dry and mild weather moving toward midweek. The next disturbance will bring a return of cooler conditions and shower chances late in the week.

SHORT TERM /TODAY THROUGH TUESDAY/

An upper level low continues to spin over the Pac NW today. Unlike the past few days, though, showers will mainly stick over the mountains with highest PoPs over Mount Rainier. Thunderstorm probabilities have decreased with the greatest threat over eastern OR/WA and ID. With sunbreaks we should see afternoon temperatures near average with highs in the lower to mid 70s. The coast will be cooler and in the 60s.

The upper low departs to the N/NE on Monday with weak troughing over western WA. Low level onshore flow will be stronger for morning clouds and possible drizzle. Expect late afternoon sunbreaks with temps mostly in the 60s.

Tuesday will be dry and mild with western WA in between weather systems. Morning lows will be a little cooler and in the 40s around the south sound. Expect afternoon highs close to average. 33

LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/

The air mass will be a little warmer Wednesday and Thursday with strong high pressure forming over the Four Corners. In western WA, expect highs in the 70s to lower 80s. Toward the end of the week, the ridge flattens and low pressure over western Canada will sag south and into WA. This will bring cooler conditions with a chance of showers Friday and into the weekend. 33

AVIATION

VFR conditions early this morning with light surface winds. VFR expected to prevail today, with the exception of HQM. Brief low clouds may develop this morning with MVFR/IFR conditions. Brief vis reductions also possible in the southern interior this morning. Surface flow will transition to onshore starting this afternoon, resulting in the marine layer bringing widespread MVFR cigs this evening along the coast and by Monday morning for the interior terminals.

KSEA...VFR today. Northeasterly winds this morning around 5 kt or less will transition NW this afternoon around 7-10 kt. Southwesterly winds this evening. MVFR ceilings likely Monday morning with marine stratus.

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MARINE

The low pressure system that has been hovering over the coastal waters the past days will finally push inland today. Behind the low pressure system, high pressure will build over the waters. A strong area of broad high pressure over the NE Pacific will continue to strengthen and expand into area waters Monday through the middle of the week. High pressure will weaken on Thursday as the next frontal system arrives. Onshore flow will increase this afternoon, bringing a push of westerlies through the Strait of Juan de Fuca. Guidance is in good agreement (70%+) for small craft winds starting afternoon through Monday morning. Therefore, a Small Craft Advisory has issued for the Central and East portions of the Strait of Juan de Fuca. Increasing northwesterly winds over the coastal waters Tuesday through Thursday, but at this time look to remain below small craft thresholds.

Seas generally between 4-7 ft through the middle of the week and will build to 7-10 ft late in the week.

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SEW WATCHES/WARNINGS/ADVISORIES

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