UNSTABLE AIR

I am currently working on the west coast.  I watch the clouds go by.  Most are harmless - some simply are turbulent and threatening.  I watch some extremely unstable air go by overhead several days ago and thought to myself:  watch out people to the east.....

Here is the result:

    http://www.youtube.com/watch?feature=player_embedded&v=VoO89cqDgJU

It happens so frequently you can just pick when the tornadoes will hit the upper plains and midwest areas.