The National Weather Service issued a flood advisory from 11 a.m. to 2 p.m. Thursday in McHenry and surrounding counties.
The advisory is in effect for Lake County, northern Kane County, southeastern McHenry County and northwestern Cook County.
At 11:04 a.m., radar and rain gauges indicated heavy rain of up to two inches in these areas that could cause urban and small stream flooding. There could also be additional rainfall of at least half an inch Thursday morning, according to the service.
A heat advisory was also issued from 10 a.m. to 11 p.m. Friday.