Those Strange Clouds Over West Seattle? Mammatus Clouds

You may have looked up in the skies over West Seattle on Saturday evening and seen some uniquely shaped clouds. If you're wondering what they were, KIRO 7 Meteorologist Morgan Palmer has the answer:

"It's a pocket of mammatus, forming because it looks like a small deformation axis, or area has developed. That's where the typically laminar air flow is being interrupted or 'held up' as air is moving through. This is causing billowing as the air stream is buckling a bit. It probably resulted from a combination of topographic effects and the increasing instability late Saturday. Air pockets were bouncing up and down all over the place ahead of the front."