Chicago area residents, in the midst of extraordinarily low 21% relative humidities only two days ago, awaken to a different environment Tuesday. Muggy Gulf air behind one of the most challenging early May opens in recent memory across the Plains, has reached Chicago. It raises the specter of thundery downpours here possibly accompanied by hail, especially Tuesday afternoon and night. 80° warmth—tempered only by light, localized (limited area) lake breezes expected in the absence of a well organized wind regime here through Thursday—should “mix the atmospheric pot”, heating the humid air and encouraging it to rise.
Rainfall within this air mass the past 7 days has reached historic proportions in the Plains. Epiphany, S.D. has been swamped by 10” of rain while Omaha, Neb. has logged more than 8 times its typical early May rain—recording 7.46”.
--By Tom Skilling, WGN-TV Chief Meteorologist
