More thunderstorms with heavy rain will continue to move across the area this morning and later in the day.
The National Weather Service noted that recent rainfall already has saturated the ground across much of the area and that more rain could cause flash flooding. A flash-flood watch was in effect until 10 a.m. for much of northern and central Illinois.
Today's forecast calls for likely showers in the morning with a slight chance of thunderstorms, then a chance of showers and thunderstorms in the afternoon. The chance of precipitation is 90 percent. Some of those storms may produce heavy rainfall.
New rainfall could amount to a half to three-quarters of an inch.
More rain is expected this evening and again after midnight.
High temperatures will be in the mid 70s to lower 80s, except near the lake, where the mercury will only reach the low 70s.
Thursday's temperature plunge was so extreme it was as if the city had been exposed to a switch in seasons in just 28 hours, said WGN-TV meteorologist Tom Skilling. That's the time it took readings here to dive from a near record 95 degrees Wednesday to Thursday afternoon's chilly low 50s. The 45-degree plunge at O'Hare fell just short of June's all time record two-day pullback of 49 degrees recorded between June 25 and 26, 1988. That period saw the temperature dive from 103 to 54.
While Thursday's thermal retreat was not a record, the cooldown was of a magnitude which has been observed in only four other Junes here over the past 141 years.
While O'Hare dipped to 50 degrees late Thursday, readings at a number of locations near Lake Michigan were even cooler. Late afternoon readings fell to 47 at WeatherBug thermometers at Wilmette and the University of Chicago, while temperatures reached mid to late March-level 48-degree readings at Glencoe and Chesterton, Ind., and 49 at Niles and Highland Park.
Thursday saw widespread flooding of area streets, particularly in the southwest suburbs where more than 3 inches of rain fell.
In Orland Park this morning, stretches of Wolf Road, Southwest Highway and West 143rd Street were closed by flooding. In Homer Glen,Will Cook Road was closed between West 151st and West 159th streets.