A First Alert Action Day was issued through Tuesday as the Heartland faced the threat of severe weather, including tornadoes, and a Tornado Watch was posted for most of the region until 11 p.m.
Portions of the Heartland were upgraded to threat level 4 out of 5 for severe storms, with the highest risk covering most of southeast Missouri and the western counties of southern Illinois. The rest of the Heartland remained under threat level 3.
Grant Dade said models currently show a very favorable environment for severe storms to develop. That setup could support very large hail, damaging winds and tornadoes, with multiple intense supercells looking possible.
A cluster of strong to severe storms was possible throughout Monday morning, and gusty winds and large hail were the main threats during those hours. More severe weather was then expected Tuesday afternoon into Tuesday evening, when the southern half of the Heartland was outlooked at threat level 2 out of 5.
Damaging winds and large hail were expected to be the primary concerns on Tuesday afternoon into Tuesday evening, though an isolated tornado could not be ruled out. After the system moves east Tuesday night, the remainder of the week is expected to turn calmer and cooler, with highs on Wednesday back in the upper 60s to low 70s and a slight chance for another round of showers by Friday.
The forecast leaves the most dangerous corridor over southeast Missouri and southern Illinois, where the combination of instability, hail, wind and tornado potential is strongest. For people under the watch, the key question is not whether the weather will change, but whether the next round organizes fast enough to turn scattered storms into a more destructive line.
