Categorical Graphic Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area SLIGHT 168,386 34,990,116 Chicago, IL...Jacksonville, FL...Milwaukee, WI...Cleveland, OH...Tampa, FL... MARGINAL 273,893 30,624,330 Detroit, MI...Boston, MA...Minneapolis, MN...Pittsburgh, PA...Buffalo, NY... Probabilistic Tornado Graphic Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.