The National Weather Service has issued a flood watch for all of northern Illinois.
The flood watch begins at 6 p.m. Monday and runs through 3 a.m. Tuesday. The weather service says excessive rainfall is possible throughout Monday evening as severe weather, including tornadoes, remains in the forecast.
Underpasses may flood. Area creeks and streams are already elevated, according to the weather service, increasing the risk of flooding because of additional rainfall. Extensive street flooding is also possible.
“With portions of far northern Illinois having observed widespread flash flooding on Saturday and Sunday nights, additional heavy rain will likely cause rapid water rises and the potential for renewed significant flash flooding,” according to the weather service.