Overview
- SPC forecasters said Monday afternoon that the supercell tornado risk will rise into the evening, with a Tornado Watch likely for southern Illinois, southeast Missouri, western Kentucky, western Tennessee and northeast Arkansas.
- Multiple Tornado and Severe Thunderstorm Watches are already in effect across the region, and SPC signaled more watches with probabilities as high as 95 percent.
- Storm structure is shifting in places as earlier supercells merge into lines that favor damaging wind, while discrete supercells remain possible near outflow boundaries and a warm front.
- A very moist air mass with dew points in the upper 60s to low 70s, strong instability of roughly 1500–4000 J/kg, steep mid‑level lapse rates, and a strengthening low‑level jet support intense supercells and very large hail up to about 3 to 3.5 inches.
- This is part of a multi‑day outbreak that produced an EF‑4 tornado in Enid, Oklahoma, and deadly twisters in Texas, and today’s severity hinges on clearing and how morning storms set the boundaries that surface‑based storms can use.