Hansen says that 2010 was the hottest year ever. The tornado count was just below the mean.
http://en.wikipedia.org/wiki/File:2010_United_States_tornado_count_graph.png
Temperatures have plummeted since last spring, and we are having a very active tornado season.
Romm adds 2+2 and comes up with zero.
Real Science 
Roy W. Spencer’s take on this: http://www.drroyspencer.com/2011/04/more-tornadoes-from-global-warming-thats-a-joke-right/