No, although in the U.S. tornadoes have occurred in nearly every state and in every month of the year. Wisconsin has reported a tornado in every month except February. There have been nine confirmed tornadoes in Wisconsin during November between the years 1844 to 2012.
Tornadoes form in regions of the atmosphere that have abundant warm and moist air near the surface with drier air above, a change in wind speed and direction with height. It is generally accepted that tornado season begins in the springtime. Because vertical wind shear is closely related to the presence of a jet stream, tornado season in the U.S. moves north and south during the year.
The National Weather Service issued a Particularly Dangerous Situation (or PDS) tornado watch for Janesville and southern Wisconsin on Nov. 17. A weather watch indicates that possible hazardous weather may occur. A watch is intended to provide people with enough time to set safety plans in motion for possible hazardous weather. A PDS is issued to indicate that there is an enhanced risk of very severe and life-threatening weather.
The intense thunderstorms that moved across the Midwest on Nov. 17 hit Illinois the hardest. The severe weather that day killed at least eight people and injured dozens. The weather included tornadoes, large hail and strong winds. The threat of severe weather from these storms caused a delay in the Chicago Bears-Baltimore Ravens football game at Soldier Field.