Dear Tom,
I have noticed over the last few years that every time a hurricane hits the southern part of the U.S., the weather in Chicago is perfect! Is there a scientific explanation, or is it just a coincidence?
Thanks, Audrey, Chicago (Edgewater)

Dear Audrey,

It’s more than a coincidence. Any hurricane will vent heat as the air rising out of it sinks and warms areas hundreds of miles away. When Gulf or Atlantic tropical cyclones approach the U.S., the sinking air typically brings warm, sunny weather to portions of the central and eastern United States. In September 2017, the city baked in a heat wave that established seven record highs in the lower and mid-90s from Sept. 20-26, while hurricanes Jose and Maria were moving north along the East Coast. Not only do the approaching tropical cyclones lead to higher temps, but they slow the eastward progress of approaching weather systems, limiting rainfall. In September 1979, Chicago logged just 0.01 inches of rain, its driest month ever. That September, there were four hurricanes approaching the U.S. that prevented rain-producing systems from moving into Chicago.