The National Weather Service says multiple waves of severe thunderstorms, which could bring damaging winds and torrential rainfall, are likely Friday in the Chicagoland area.
The National Weather Service (NWS) issued a hazardous weather outlook for Lake, McHenry, Boone, Winnebago, Cook, DuPage, Kane, Will, Ogle, Lee, DeKalb, LaSalle, Kendall, Grundy, Kankakee, Livingston, Iroquois and Ford counties.
The outlook said dangerous heat is expected Friday afternoon with peak indices between 100 and 110 degrees.
Following isolated thunderstorms in the morning, additional thunderstorms — some severe — are expected late Friday afternoon into the evening.
Some may produce large hail and damaging winds, the outlook said.
Some of the storms will produce torrential rainfall which could lead to localized flash flooding.
Wind up to 70 mph and hail up to half-dollar size are possible.
The winds could be capable of downing trees and fences and the hail could be capable of denting cars and siding, according to the NWS.
The heavy rain may flood roads, low-lying areas, fields and basements and cause rapid creek rises.
A graphic from the NWS showed northern Illinois with a risk rating of three out of five for severe weather.
The timing for the storms is between 4 p.m. and 12 a.m. The NWS did not mention any tornado threat.
Forecasters say they recommend residents have multiple ways to get weather warnings and take cover if one is issued.