Get your tee shirts and shorts out...you will need them on Friday.
After a short rainy interlude today and early Thursday, high pressure will build inland on Friday morning with offshore flow, sunny skies, and warm air over us. The results will be the warmest temperatures this year,with much of western Washington soaring into the upper 60s and lower 70s.
Here is the latest UW WRF forecast for 5 PM on Friday. Amazing...much of western Washington away from coast is in the 70s.
The National Weather Service and the Weather Channel are playing it more conservatively, with temps in the mid-60s.
The National Weather Service has a short-range ensemble forecast system in which many models are run. Here is the forecast "plume" for Sea-Tac airport, showing the temperature predictions from these varied solutions. Many reach the upper 60s.
Saturday will bring serious rain as an atmospheric river plows into the coast....here is the 24-h precipitation ending 5 AM on Sunday. Several inches in the mountains and even eastern Washington getting some rain.
So if you want to go hiking, take Friday off...it will be amazing in the Cascades and Olympics.