On Wednesday, Lake Michigan demonstrated yet again its ability to alter Chicago's
weather. While temperatures climbed into the 80s in the southern suburbs, lakeside
residents in northern sections donned jackets and sweaters to ward off the fog and
chill of afternoon readings only in the 50s. But that's a fading memory 24 hours later.
Borne in on brisk southerly winds, heat and humidity spread to all sections of the
Chicago area today. Such sharp temperature contrasts, aided by the energy from
strengthening winds aloft, fueled thunderstorms —many of them severe—Wednesday
afternoon and evening. A tornado touched down seven miles south of Flanagan (91
miles south of Chicago) near Pontiac in Livingston County at about 8 p.m. Wednesday
and another occurred near Rensselaer, Ind., at 7:30 p.m. Severe storms were ongoing as
of 9 p.m.
GULF-COAST LEVEL DEW POINTS ARRIVE
Humid air of Gulf origin arrives in the city Thursday in the wake of morning
thunderstorms. Dew-point temperatures, a preferred measure of atmospheric moisture,
become uncomfortable for most people when they surpass 65 degrees. Computer
forecasts indicate the level will be attained this afternoon.
--By Richard Koeneman, WGN Weather Center Meteorologist
