National Weather Service United States Department of Commerce

A more spring-like pattern begins to develop Sunday into Monday as the region undergoes a warming trend. Showers, some heavy, appear likely on Monday and some areas may see thunderstorms. The combination of heavy rain, frozen ground, and any lingering snowmelt may result in rises on area streams and rivers early next week.
An unseasonably warm and moist air mass will overspread the region early next week with several rounds of showers and thunderstorms expected. Through early Wednesday, expect area-wide precipitation totals of an inch or more with some locations possibly seeing 2 to 4 inches of rainfall. Heaviest rainfall is favored over far northern Illinois on Monday and will shift into east-central Illinois and northwest Indiana on Tuesday. Grounds are still frozen over much of the area and will result in rapid runoff. In addition, some areas in northern Illinois may still have snow on the ground and additional melting will compound runoff from heavy rainfall. Expect rises on area rivers and streams, and flooding will be a distinct possibility. Stay tuned to the latest forecasts for updates.