A strong area of low pressure moved across the northern tier of the United States on Tuesday, May 7, 2024. The associated cold front swept across the Ohio Valley region throughout the day. Strong dynamics were in place ahead of the front in the storm system’s warm sector, prompting an Enhanced Risk of severe weather across much of Indiana and western Ohio. This risk included the threat for strong tornadoes.

At 2:25 pm EDT, a Tornado Watch was issued for portions of eastern Illinois and Indiana as storms began to develop. It didn’t take long for severe thunderstorm and tornado warnings to be issued as the storms moved ahead of the front, stretching from southern Wisconsin to western Indiana.

Severe weather persisted across Indiana, Ohio, and Michigan into the afternoon and evening hours. Tornado Emergencies were declared for Kalamazoo, Michigan and surrounding areas after a large and extremely dangerous tornado was observed.

By the time severe weather exited the region late in the evening on the 7th, 72 tornadoes had been reported across the United States, with most of them occurring in the Ohio Valley. The tornado that impacted Kalamazoo, Michigan, was rated an EF-2 with 135 mph maximum winds and was on the ground for 11 miles.

Another significant tornado outbreak occurred on May 21st across southeastern Nebraska, Iowa, southern Minnesota, Illinois, and Wisconsin, impacting some of the same areas hit by the April 26th tornado outbreak. The Storm Prediction Center outlined a Moderate Risk of severe weather, including a 15% probability of tornadoes, some of which could be strong.

At 11:10 am CDT, the first Tornado Watch was issued across eastern Nebraska and western Iowa, lasting until 5 PM CDT. Later, at 1:10 PM CDT, a rare Particularly Dangerous Situation (PDS) Tornado Watch was issued for much of Iowa, southeast Minnesota, and far northwestern Illinois, indicating the possibility of several tornadoes, including a few intense. Additional Tornado Watches were issued east of these locations later in the afternoon and evening.

Storms initiated across eastern Nebraska in the early afternoon, moving eastward. At 3:05 pm CDT, a tornado was reported near Corning, Iowa. This storm continued northeast into Adair County, Iowa. At 3:41 pm, radar confirmed a large tornado impacting the town of Greenfield, Iowa, as a debris ball on radar reflectivity and CC dropout could be seen via NEXRAD Dual-Pol radar scans. By 3:45 pm, reports of damage in the city of Greenfield, IA were received.

Storms persisted to the east and northeast through the afternoon, with numerous reports of tornadoes and damaging winds from Nebraska to Illinois and Wisconsin. Overall, 48 tornadoes were reported, along with 431 instances of damaging winds. However, none were hit harder than the town of Greenfield, Iowa. This tornado was rated an EF-4 with maximum winds of 175-185 mph and was on the ground for 44 miles. 35 injuries and 5 deaths were reported in association with this tornado.

A line of severe storms developed across portions of the Central Plains on Thursday, May 23, 2024, and moved across eastern Nebraska, Iowa, and northern Illinois through the morning hours on Friday, May 24, 2024. This line of thunderstorms prompted Severe Thunderstorm Watches to be issued from Nebraska east to Illinois.

Around 2:30 AM on May 24th, a powerful line of severe thunderstorms moved across the eastern Nebraska area into western Iowa, then continued across Iowa through 8:15 am before entering Illinois. Numerous Severe Thunderstorm and Tornado Warnings were issued as this line of storms moved across the state.

As the line of severe storms reached northern Illinois after sunrise, it continued to produce severe/damaging winds and tornadoes. However, by 9:30 am, the line had weakened considerably. A swath of damaging winds and tornadoes was reported from western Nebraska through western Illinois from the 23rd through the 24th of May, resulting in a total of 801 severe weather reports for the combined days!

The initial round of rain and thunderstorms moved across the Tennessee Valley through the morning hours on Sunday, May 26th, prompting multiple severe weather Watches and Warnings. One of the big stories of the day was a Severe Thunderstorm Warning issued for Indianapolis, Indiana, where the Indy 500 was about to begin. The incoming thunderstorms forced the Indianapolis Motor Speedway to evacuate hundreds of thousands of people in the stands until lightning cleared the area several hours later.

The more significant round of severe weather occurred later in the afternoon and evening hours, stretching from Missouri across southern Illinois, southern Indiana, Kentucky, and Tennessee. At 4 PM CDT, the SPC issued another rare Particularly Dangerous Situation (PDS) Tornado Watch across southeastern Missouri, southwestern/southern Illinois, northern Arkansas, far western Kentucky, and northwest Tennessee, lasting until 11 PM. This was the fourth PDS Tornado Watch issued for the month of May! Additional Tornado and Severe Thunderstorm watches were issued across the region as the evening wore on.

By 7 PM CDT, a line of powerful storms had developed across southern Illinois into southeastern Missouri, prompting Severe Thunderstorm and Tornado Warnings. However, discrete supercells also formed ahead of the line across southern Illinois and western Kentucky, leading to multiple severe weather warnings and reports!

Storms continued to march east-southeast through the evening, leaving a trail of destruction behind them. This day featured 65 tornado reports, 1016 severe wind reports, and a total of 1384 severe weather reports!