Tornadoes are very severe weather events that plague much of the U.S. - in a year that NOAA is claiming to be the "warmest", year-to-date 2012 tornadoes declined significantly from average
(click on image to enlarge - source)
In fact, just the opposite has occurred in 2012, which NOAA confirms. As the U.S. has experienced a very warm year compared to previous recent years, the tornado count reported has declined by over 50% from the really cold year of 2008.
And as historical evidence has substantiated, cold weather (colder climate) generates more frequent and stronger severe weather events than a warmer climate.
Of course, the likes of Gore and the anti-science Obama never mention the very warm climate that Mexico has and the resulting massive number of tornadoes that occur there - ooops....oh that's right, a warm Mexico doesn't have many tornadoes.
Update: The above NCDC chart is a plot of Y-T-D (Jan-Oct) temperatures over the last 15 years, through October 2012.