“Hit or miss” rainfall events in the Chicago area

Dear Tom,
While Chicago has had record rainfall this spring and summer, many times I have seen on radar where the rain goes around us in Kankakee County. A local newspaper garden writer referred to the Chicago Ridge as causing that. What can you tell me about why rain has missed us so much this summer?
— Chris Keller, Bourbonnais
Dear Chris,
As far as the atmosphere is concerned, northern Illinois is flat. Features such as the Chicago Ridge are too low to affect weather systems that move across the region. The explanation for the lack of rainfall in portions of Kankakee County is chance: just bad luck. Showers and thunderstorms have missed your area, or have produced little rain when they do occur this spring and summer, but it’s a function of “hit or miss” rain events that have happened to miss you.