Thunderstorm Wind — Williamson, Illinois
2025-05-20 · near Herrin, Williamson, Illinois
$12K
Property damage
52 EG
Magnitude
Event narrative
A tree was blown down onto a car in Herrin.
Wider weather episode
A squall line pushed eastward overnight across the warm sector of a low pressure system in Iowa. A surging portion of the line produced wind damage in portions of Southern Illinois, including the formation of a brief tornado in eastern Union County. MLCAPE was around 1000-1500J/kg, effective bulk shear was 40-50kts, and 0-3km SRH was 200-300m2/s2, with dewpoints in the mid to upper 60s.
View location on OpenStreetMap → (37.8000, -89.0300)
Source: NOAA Storm Events Database, event_id 1272611. Narrative written by the NWS forecast office that issued the report.