A heat dome occurs when a large area of high pressure in the upper atmosphere acts as a reservoir that traps heat and humidity, said Ricky Castro, a National Weather Service meteorologist in Illinois.
Heat dome will blanket much of the United States, with worrisome temperatures in Midwest
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All of the concrete in the metropolitan area prevents the rain from seeping into the earth, resulting in flooding, he said.
Heavy rains flood Chicago roads and force NASCAR to cut short a downtown street race
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