As unseasonably warm air and rain move into the area, a Flood Watch has been issued for much of northern Illinois and northwest Indiana.
The watch, which will go into effect Monday evening, covers numerous counties in Illinois, including McHenry, Lake, DeKalb, Kane, DuPage, Cook, LaSalle, Kendall, Grundy, Will, and Kankakee counties.
The watch will run through Tuesday night, according to the National Weather Service.
According to forecasts, 2-to-4 inches of rain could fall in some areas as a weather system moves into the area. That, combined with warm temperatures that will accelerate snow melt, leaves open the possibility of isolated flooding of streams and rivers, according to the NWS.
Forecasters are concerned that the flooding could be made worse by the ground remaining frozen in most areas, which means water will run off faster rather than simply absorbing.
Ice jams could also break on streams and rivers during that time, potentially leading to flooding downstream from those sites.