Categorical Graphic Day 2 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area SLIGHT 53,980 4,102,535 Allentown, PA...Billings, MT...Reading, PA...Bethlehem, PA...Scranton, PA... MARGINAL 590,978 61,928,877 Philadelphia, PA...Phoenix, AZ...Detroit, MI...Columbus, OH...Baltimore, MD... 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.