NOAA SPC’s Greg Carbin writes:
 
After a busy start, tornado events in the U.S. in 2012 have dropped well below the expected norm. The preliminary total of 886 tornadoes through 30 November 2012 is nearly 400 tornadoes below what might be expected in a “normal” year.

http://www.spc.noaa.gov/wcm/2012/2012-NOAA-NWS-tornado-facts.pdf