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.
Tornadoes of 2018
The Storm Prediction Center issued an enhanced risk of severe weather for portions of the Great Lakes region of the United States on September 20. This outlook included a 10% hatched risk area for tornadoes. A line of severe thunderstorms with numerous embedded tornadoes impacted the region that evening. Twenty-five tornadoes touched down in Minnesota alone, making September 20, 2018 the third-most prolific tornado day in state history.