Here is an amazing radar image this morning (thanks to blog-follower Paul for bringing it to my attention). Looks just like a mini-hurricane with rainbands! The animation is even more impressive:
http://www.atmos.washington.edu/~ovens/loops/wxloop.cgi?atx_n0r+16/3h/
and here it is in the visible satellite image:
The origin? The atmosphere this morning is relatively unstable (thus convection) and there is an atmospheric vortex centered over Vancouver Island. You could see the signs of the instability yesterday: thunderstorms over the Cascades with some mid-level convection over the western lowlands. The "hurricane" is probably not forced by the terrain...the atmospheric circulation, forced by the larger scale flow, happens to be located over the island.
