April started with a bang across the Midwest, featuring an Enhanced severe weather risk across central and southern portions of Illinois and Indiana, extending into far southwest Ohio. This was due to an area of low pressure moving across the Kansas City area and a warm front extending across the Ohio Valley.

The Storm Prediction Center (SPC) issued a Tornado Watch across central and south-central Illinois at 4:50 PM CDT on April 1st, and a Severe Thunderstorm Watch was issued that evening across central and south-central Indiana into southwest Ohio. During this time, a round of storms moved across southern portions of the Ohio Valley, prompting Severe Thunderstorm and Tornado Warnings. Several tornadoes were reported across southern Illinois and southwestern Indiana. However, the bigger story could be how this overnight convection impacted severe weather the next day.

A Moderate risk of severe weather was outlined across southeastern Indiana, northern Kentucky, and portions of Ohio on April 2nd. While damaging winds and large hail were expected, the possibility of strong tornadoes existed due to a very strong upper-level trough bringing powerful jet-stream winds through the region. Coupled with high levels of moisture and instability, this created a dangerous environment for severe thunderstorms.

However, the thunderstorms from the night before lingered through the morning hours on April 2nd. Morning analysis indicated that these storms essentially removed moisture from the environment across much of the Ohio Valley. Without sufficient time to destabilize into the afternoon, the focus of the most severe weather shifted closer to and south of the Ohio River. Although 60 tornadoes and 153 damaging wind reports were received, the primary impact was felt south of much of the region.

On the back side of the system that brought severe weather to the Ohio Valley, a late shot of cold air moved in. As this caught up with the area of moisture on the back side of the low-pressure center that was occluding across Lake Michigan, snow began to fall across portions of the Upper Midwest. Winter Storm Warnings were issued across much of Wisconsin and the Upper Peninsula (U.P.) of Michigan, with late-season Blizzard Warnings issued for some counties in Michigan’s U.P. By the time the winter storm ended, 4-10 inches of snow had fallen across Wisconsin, with up to 33 inches reported in the Upper Peninsula of Michigan!

Over five consecutive days, severe weather occurred across the heart of the country, starting on April 14th and continuing through April 18th. Three of these five days featured Enhanced Risks of severe thunderstorms, while the other two days saw Slight Risks. Throughout the entire event, the 17th and 18th produced most of the severe weather, with 241 severe weather reports on April 17th and 175 reports on April 18th. Thirteen tornadoes were reported from the St. Louis area into central Illinois late afternoon into the evening on April 18th.

The most impactful event of the month unfolded across eastern Nebraska and Iowa on April 26, 2024. During the morning into the afternoon, a strong area of low pressure moved north-northeast across the region, allowing for a warm front and dryline to intersect in association with the low. This convergence is known as a triple point.

The Storm Prediction Center (SPC) outlined an Enhanced risk of severe weather for eastern Nebraska, western portions of Iowa, northwest Missouri, and northeast Kansas. Within the same area, a 10% probability of tornadoes was highlighted, with some of those tornadoes potentially being strong. At 12:55 PM CDT, the SPC issued a Tornado Watch across eastern Nebraska, far northern Kansas, far northeastern Missouri, and far western Iowa. By 1:45 PM, Tornado Warnings were being issued in southeastern Nebraska.

These same supercell storms that developed along the dryline in Nebraska continued to move north-northeast through the afternoon, producing large, destructive tornadoes across southeastern Nebraska into western Iowa later that day and evening. Tornado Emergencies were declared for the Elkhorn and Bennington, Nebraska areas as a large tornado moved through heavily populated regions north of Omaha. A textbook debris ball was visible on radar as it swept through the populous area!

As of April 30, 2024, 99 tornadoes were reported for that day (a few were further south in Texas). Several of these tornadoes were rated EF-3. Notably, the tornado that passed through Bennington, Nebraska had estimated peak winds of 165 mph and was on the ground for 31.2 miles! Despite major damage and numerous injuries, there was thankfully only a single fatality from Friday’s major tornado outbreak.