SPRINGFIELD, ILLINOIS — A few scattered thunderstorms were possible across Illinois Tuesday afternoon and evening of April 21, 2026, with the strongest storms capable of containing small hail. The National Weather Service Storm Prediction Center issued a Marginal Risk covering northern and central Illinois, while southern portions of the state including Carbondale, Marion, and East St. Louis fell outside the primary risk zone. The outlook was last updated April 20, 2026 at 12:47 AM CDT and remained valid through April 22 at 7:00 AM CDT.
Scattered Thunderstorms Possible Tuesday Afternoon and Evening Across Illinois
The severe weather outlook for Tuesday April 21 highlighted Illinois as the primary area of focus for scattered thunderstorm development during the afternoon and evening hours. The storms were not expected to be widespread or organized in nature, with a few scattered cells the most likely scenario for the day across the highlighted zone.
The strongest of the scattered thunderstorms were identified as capable of producing small hail, making them worth monitoring for residents across northern and central Illinois heading into Tuesday afternoon.
Marginal Risk Covers Northern and Central Illinois — Chicago to Champaign in the Zone
The SPC Marginal Risk zone covered a significant portion of northern and central Illinois, encompassing major cities including Chicago, Rockford, DeKalb, Aurora, Moline, Galesburg, Kankakee, Peoria, Bloomington, Champaign, and Springfield. A Marginal Risk represented the lowest level of severe weather concern on the SPC scale, indicating that isolated severe storms were possible but a widespread severe weather outbreak was not anticipated for Tuesday.
The thunderstorm shading on the outlook extended eastward into portions of Indiana and Ohio as well, suggesting the scattered storm activity was not confined solely to Illinois but was part of a broader regional thunderstorm pattern developing Tuesday.
Southern Illinois Falls Outside Primary Risk Zone
The southern tip of Illinois including Carbondale, Marion, Mt. Vernon, and East St. Louis fell outside the Marginal Risk shading on the Tuesday outlook, placing those communities at lower concern for severe weather compared to the northern and central portions of the state. The risk gradient dropped off noticeably south of the Effingham and Mt. Vernon corridor on the SPC map.
Residents across the Marginal Risk zone from Chicago southward through Springfield were advised to remain aware of the scattered thunderstorm potential Tuesday afternoon and evening and to have a way to receive any warnings that may be issued if storms strengthened. Stay with GordonRamsayClub.com for the latest weather updates and detailed forecast coverage.
Leave a Reply