May 7, 2023
An outflow boundary from convection that occurred during the early morning served as the focusing mechanism for additional severe thunderstorm development during the afternoon and evening of May 7th. The storms initially focused along a Macomb...to Springfield...to Mount Vernon line and were very slow-moving in nature. Due to a feed of highly unstable air characterized by CAPE values in excess of 3000J/kg, vigorous updrafts quickly developed and supported giant hail. Hailstones as large as 3.
Source: NOAA National Weather Service Storm Events Database (event 1095178). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Sangamon County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.