Tornadoes in the United States
The Midwestern states are very prone to tornado activity, as they are part of "Tornado Alley." States included in the area that are hit by tornadoes the most are Oklahoma, Kansas, Missouri, Nebraska, Iowa, and South Dakota. The Midwestern States are often hit by tornadoes during the late spring and early summer months, especially the months of May and June. This is due to the aforementioned air mass moving northward into the Midwest and combining with another air mass that move southward from Canada. This creates unstable air, creating the potential for storms to strike the most during these months. The frequency begins to decrease in the middle of the summer, as the air mass moves northward into the Great Lakes states.
Canada Tornado Alley
In the Canadian Tornado Alley in Central/Western Canada, warm, humid air from the United States meets cool, dry air from Northern Canada and the Rocky Mountains. This creates an ideal environment for severe thunderstorms which could produce tornadoes. In the Great Lakes region towards the St. Lawrence River, severe thunderstorms which could produce tornadoes forms from warm, humid air from the United States and cooler air across the Great Lakes, these are triggered alongside lake-breeze fronts. The amount of precipitation in storms around the Great Lakes is normally more than the prairies as the warm temperatures and Great Lakes fuel the storms with heavy precipitation right from the lakes.