Photo and weather - prettier than Doppler radar

Storm clouds over Puget Sound.  Photo by Lee Lageschulte.

Lee Lageschulte sent this photo she took from Innis Arden as a storm was brewing on Friday, November 18, 2011. WeatherWatcher Carl Dinse talks us through the picture, from a weather perspective.

Carl Dinse:

In the lower right side over the mountains is precipitation, probably in the form of snow falling out of the cloud and onto the ground below.  These clouds are called Cumulus clouds.  They are typically formed around here when there is an unstable air mass over Western Washington.  

Friday evening we had cold and unstable air over the Puget Sound.  Pockets of warmer moist air moving upward are called updrafts.   These updrafts eventually cool enough that the air in the updraft reaches its dew point, causing the water vapor in the air to condense.  As the updraft continues to pump more warmer, moist air into this cloud or cell, it grows bigger and heavier until eventually it starts precipitating, much like the clouds further in the distance in the lower right of this photograph.  

These are the types of clouds that can grow in to thunderstorms if they are not disrupted.  Westerly winds were too strong Friday night to allow these to develop big enough to produce a thunder shower.