The National Weather Service issued a severe thunderstorm warning for portions of DeKalb and LaSalle counties on Sunday afternoon as a band of thunderstorms approached the area.
The NWS enacted a warning for northwestern LaSalle County and southwestern DeKalb County after weather radar located severe thunderstorms along a line extending from near Sublette to Mendota to Depue, moving east at 40 miles per hour.
Damage to roofs, siding and trees, as well as 60 mile per hour wind gusts, were possible. The warning was set to expire at 4:45 p.m.
According to the National Weather Service, a severe thunderstorm watch will remain in effect through Sunday evening in McHenry, Lake, DeKalb, Kane, DuPage, Cook, LaSalle, Kendall, Grundy, Will, and Kankakee counties in Illinois, as well as Lake and Porter counties in Indiana.
Officials caution that the main threat with any storms that develop will be the gusty winds, which could exceed 60 miles per hour at times. Winds could also develop ahead of the storm line, arriving 15-to-20 minutes before the storms do, according to alerts from NWS.
There is also a small chance of damaging hail, which could exceed one inch in diameter, and a non-zero chance of brief tornadoes, according to forecast models.
Heavy rains could also lead to flash flooding in the area, especially after sunset, according to the NWS.
In addition to the threat of severe weather, an air quality alert remains in effect for most of the Chicago area, with poor air quality causing difficulties for at-risk individuals, including those suffering from pulmonary or respiratory issues, active adults who spend six or more hours outdoors, and also children and older adults.