Severe weather threat for southern Chicagoland
This Tuesday, May 21, southern parts of the Chicago area remain under the influence of a volatile weather system that began sweeping through Monday afternoon. A low-pressure system moving through the region continues to generate scattered showers and thunderstorms, with some becoming severe, especially in the southern suburbs.
Areas at risk
The Storm Prediction Center has placed portions of southern LaSalle, southern Grundy, southwest Kankakee, and the far southern corners of Newton and Jasper Counties under a Slight Risk (Level 2 out of 5) for severe storms. This zone remains the most susceptible to damaging wind gusts, hail, and the potential for brief tornadoes, particularly through the early evening hours.
What’s fueling the storms
The activity is being driven by a warm front lifting northward through Illinois, injecting warmth and moisture into the lower atmosphere and adding a twisting motion (vorticity) that enhances the storm threat. While the severe risk is expected to taper off after around 8:00 p.m. CDT, scattered rain and thunderstorms may persist well into the overnight hours.
Tonight’s outlook
Overnight temperatures will dip into the upper 40s to around 50°F (8–10°C), offering cooler but still unsettled conditions for the region. Rain chances linger, though any remaining storms are expected to lose strength with the sunset and diminishing instability.
Midweek pattern: cooler and unsettled
Looking ahead to Wednesday and Thursday, expect intermittent showers with temperatures holding in the mid to upper 50s°F (13–15°C). These values are below seasonal averages, keeping the area chilly and damp for mid-May.
Memorial Day Weekend preview
Heading into the Memorial Day Weekend, skies should begin to clear by Friday, with dry conditions prevailing but still accompanied by cooler-than-average highs around 60°F (16°C). Saturday and Sunday will bring cool but comfortable weather, with daytime highs in the low 60s°F (16–17°C). A few isolated showers could return on Memorial Day Monday, but no widespread storm systems are expected at this time.
Stay weather-aware, especially in the southern Chicagoland region, as this springtime storm system continues to roll through.
