The numbers are in, July 2009 was the warmest since record-keeping began at Sea-Tac Airport (late 40s).
The air above remains very warm above us right now...at 850 mb--around 5000 ft-- it is 20C (68F)...which is much above normal. At low levels we have had weak onshore flow, bringing marine air and some clouds in the lower few thousand feet. A vertical profile at Sand Point is shown below. Notice the inversion at low levels, with temperatures increasing with height. The cool low-level air warms during the day and the inversion is slowly burned out in the morning hours...producing rapid warming. Temps remain warm in the mountains where they are above the marine layer.
In the lowlands away from the water temps will rise in the mid to upper 80s..with a few 90s. And very warm hiking weather in the Cascades. This hot period doesn't want to end.
There are some major changes suggested in the latest computer runs for the end of next week, when a strong upper low swings through....convection--thunderstorms--often come with such changes. We will see.