Tornado Alley (T.A.)
The Tornado Alley is in the Midwestern U.S. Tornadoes in "T.A." usually happen in the early summer.
Warm moist air blows from the gulf of Mexico
Warm dry air blows from the Rocky Mountains
Cool dry air blows down from Canada
Tornadoes are more likely to form in the "T.A." because the area around there is more flat.
When all of the air reaches each other it forms a tornado!