22May2003Bthumb.jpg (15895 bytes) 22May2003Cthumb.jpg (16637 bytes) 22May2003Athumb.jpg (17448 bytes)
This is not a severe storm, or any sort of storm at all.  It's simply a cumulus cloud doing some strange things in a parched boundary layer, but with enough midlevel instability to generate convection.   This was a high shear environment, as evident from the rounded sculptures of the base cloud. 

Basically, there's enough low level shear to spin and sculpt these bases, but not enough instability to keep the updrafts vertical against the shear. The result, at least on this day, was a perfect balance of continuous horizontal updrafts! Quite a  sight.

Jeff Gammons has great time lapse of this on his Weathervine site. Considering we saw this after declaring the day a bust, we were happy as could be.

Amos Magliocco's Stormpage