Tornado Outbreak And Floods Of April 2–7, 2025

From April 2–7, 2025, a slow-moving weather system and a stationary front caused both a widespread and devastating tornado outbreak and historic, life-threatening flash flooding across much of the Southern and Midwestern United States.

The Storm Prediction Center (SPC) began monitoring the Mississippi Valley and surrounding regions on March 28 for the potential of future severe weather, eventually issuing a rare high risk for April 2, just weeks after a historic tornado outbreak in the same general area. Later that day, a tornado struck Owasso, Oklahoma, causing damage to homes. A significant tornado struck Nevada, Missouri, removing roofs from homes and injuring at least one person. An EF2 tornado struck Pilot Grove, Missouri, destroying a manufactured home and tossing cars. The tornado sirens in the town did not sound due to a malfunction, though no-one was hurt. A large, multiple-vortex EF3 tornado moved through the city of Lake City in Arkansas, prompting a tornado emergency issuance. At least one person was killed by a tornado that struck Advance and Delta in Missouri, leaving significant damage to homes. In the early morning hours of April 3, an EF3 tornado struck Selmer, Tennessee, killing three people within the city and two others in surrounding McNairy County. Another supercell produced another EF3 tornado near Slayden, Mississippi, prompting the issuance of another tornado emergency. Near La Grange, Tennessee, two fatalities occurred when a tornado destroyed a mobile home.

The slow progression of the weather system also resulted in days of heavy rainfall and caused catastrophic flash flooding across much of the Ohio Valley. A broad swath of of rain fell across the same areas, especially in the state of Kentucky. Multiple major rivers overflowed their banks, causing widespread damage in neighboring towns, with some nearing record crest levels. Due to multiple rounds of severe weather hitting the same areas, storm surveys had to be delayed for several days. In total, 24 people in total have died as a result of the system; nine from tornadic activity and 15 from non-tornadic activity, including the flooding. Furthermore, at least 47 have been injured. With a total of 156 confirmed tornadoes, the outbreak received a score of 96 on the Outbreak Intensity Score (OIS), classifying it as a "devastating" outbreak.

Meteorological synopsis

April 2–3

Forecast

Starting on March 28, 2025, the Storm Prediction Center began monitoring the risk of a severe weather event on April 2. Following a lack of expected severe potential the previous day, strong moisture return and the development of an upper-level system was discussed, with a 15% risk for severe weather being outlined over much of the middle Mississippi and Ohio Valleys. The next day, as forecast models came into greater agreement about the mode and timing of the system, a 30% risk was introduced over parts of Arkansas, Missouri, Mississippi, Tennessee, Illinois, Indiana, and Ohio, with forecasters describing that confidence existed for "a widespread, potentially substantial severe event". On March 30, the forecast was expanded to include parts of Texas, Louisiana, and Michigan in the risk area, as forecasted shear supported a primarily supercell-focused storm mode.

Three days out from the event, on the morning of March 31, an enhanced (3/5) risk was outlined over an area overlapping the previous 30% zone, now also including small parts of Oklahoma, Iowa, and Alabama, while now covering the majority of Kentucky, Illinois, Arkansas, and Indiana. The system, now described as a negatively-tilted trough, was expected to produce a widespread outbreak of severe weather over the region. A large warm sector over the Great Lakes region, a powerful jet streak of , and an intense cold front, were all expected to contribute to the event, with the forecast outlining the risk for significant tornadoes, strong wind, and large hail. A higher risk category for the forecast was discussed over the middle Mississippi Valley, fueled by the threat of "multiple long-lived significant supercells", but was ultimately decided against due to a lack of confidence in how the storm system developed throughout the day.

An outlook on April 1 introduced a moderate (4/5) risk over small parts of Mississippi, Arkansas, Tennessee, Missouri, Kentucky, Illinois, and Indiana, driven by the threat of "significant to intense tornadoes", as outlined in updated model guidance. Due to significantly less uncertainty regarding the development of the storms, the Storm Prediction Center issued a high risk (5/5) convective outlook over southern Illinois, eastern Missouri, western Kentucky and Tennessee, eastern Arkansas, and extreme northwest Mississippi for "multiple EF3+ tornadoes".

A mid-level trough was positioned over the central United States and will move northeastward, while at the surface, a strong surface cyclone will move through the upper Mississippi Valley, accompanied by a jet streak ejection of , while a cold front moves through much of the region. A moist airmass was moving into the Ozarks and middle Mississippi Valley region, which was expected to rapidly destabilize throughout the day while convection along the cold front continued. MLCAPE, a measure of atmospheric instability, was forecast to reach 2,500–3,500 J/kg in the middle Mississippi Valley, while a rapid ejection of the mid-level jet will bring strong ascent into the warm sector, conducive for intense storm development. The initiation of discrete storms was initially expected to occur east of the cold front inside of an unstable airmass, a region expected to – around 4 to 7p.m. CDT – harbor around 400 m²/s² of storm-relative helicity