Dramatic lightning peppers Tuesday downpours
A barrage of cloud-to-ground lightning strokes accompanied clusters of downpour-generating thunderstorms Tuesday. At the storms’ peak in the late afternoon and evening, AM radio broadcasts included a nearly continuous chorus of thunderstorm sferics—the unmistakeable crackling which pours from radio receivers as lightning occurs. The generation of lightning produces electromagnetic pulses responsible for the radio crackles. Cloud-to-ground lightning from all the thunderstorms within a 150 mile radius of Chicago was measured at a rate of more than 900 strokes every ten minutes late Tuesday afternoon and evening. The day’s heat and humidity produced t-storms—some 52,000 ft. high. Thundery downpours swamped localized areas with as much as 1-2” of rain, covering some roads in McHenry, Lake and Grundy counties—among others—with as much as 4-6” of water.
-Tom Skilling