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Tornado outbreak and derecho of April 1–3, 2024

From April 1 to 3, 2024, a significant tornado outbreak, which also included a derecho, affected much of the Midwestern and Southeastern United States. The National Weather Service issued dozens of severe thunderstorm and tornado warnings across West Virginia, Kentucky, Tennessee, Ohio, Oklahoma, Kansas Illinois, Indiana, and Missouri during the event. A total of 32 million people were estimated to be under watches or warnings, and over 150,000 people were estimated to be without power. and 15 people were injured. The event was given an outbreak intensity score of 28 points, ranking it as a significant tornado outbreak, and five people were killed by non-tornadic events as well.

Meteorological synopsis

On March 28, the Storm Prediction Center (SPC) first delineated a risk of organized severe weather across the Central and Southern Plains, as well as the Mississippi and Ohio River valleys for the beginning of April. By the morning of April 1, a broad category 3/Enhanced risk existed from north-central Texas northeastward toward the Illinois–Indiana border, where widespread supercell thunderstorms were anticipated. The impetus for the severe weather setup came as a large, positively tilted upper-level trough progressed eastward from the Southwestern United States into the Central Plains region. Morning surface observations revealed an area of low pressure over central Kansas, supporting a north-moving warm front to the east into Ohio and a trailing cold front southwestward into Oklahoma and the Texas Panhandle. Meanwhile, an eastward-shifting dry line resided from the Texas Panhandle southward into northern Mexico. Within the warm sector of this low, an unstable environment was expected to develop, with averaged instability values of 2,000–3,000 J/kg, dewpoints in the mid- to upper-60s °F, very strong wind shear throughout the atmosphere, and rapidly cooling temperatures with height. Given these conditions, the SPC upgraded much of the eastern half of Oklahoma and a small section of northern Texas to a category 4/Moderate risk. In this area, the capping inversion aloft was expected to erode throughout the afternoon, giving way to multiple supercells capable of producing large hail in excess of 3 in (7.6 cm). A conditional threat of strong/EF2+ tornadoes existed too as wind shear close to the surface strengthened with time.

Derecho

Through the afternoon hours, semi-discrete supercells developed across north and central Texas, contributing to widespread reports of large hail the size of baseballs, in addition to hurricane-force wind gusts upwards of 90 mph (140 km/h). Farther to the northeast, isolated severe weather occurred in Oklahoma, though it was curtailed by persistent cloud cover and a broad rain shield across the risk area. Even farther to the northeast, training supercell thunderstorms tracked across the St. Louis metropolitan area, contributing to large hail. By the evening hours, a quasi-linear convective system developed across eastern Oklahoma and progressed toward Missouri and Illinois. As it did so, the squall line interacted with boundaries produced by earlier storms; this resulted in several tornadic circulations along the line. In spite of modest instability, strong vertical wind shear maintained organized convective activity as it spread eastward from southern Illinois and eventually into West Virginia during the pre-dawn and early morning hours. Numerous reports of damaging winds were received, including gusts in excess of 90 mph (140 km/h) near Huntington, West Virginia. The squall line posthumously met the criteria of a derecho, and post-storm surveys revealed dozens of tornadoes along its track. In particular, 10 tornadoes were confirmed across West Virginia on April 2, the most observed in a single calendar day on record. Convective activity finally lost vigor as it moved toward the West Virginia–Virginia border into a more stable environment.

As the derecho tracked from Missouri to West Virginia early on April 2, another widespread outbreak of severe weather and tornadoes was expected to occur across the broader Ohio River Valley region. On April 1, the SPC issued a category 4/Moderate risk across much of Ohio and adjacent portions of surrounding states. Despite questions about the influence of widespread morning thunderstorms, forecasters felt there was sufficient confidence that the atmosphere would recover over subsequent hours, contributing to discrete or clusters of storms capable of producing damaging winds, large hail, and multiple significant tornadoes. By the afternoon hours of April 2, forecasters expressed concern that morning convection would stunt the degree of destabilization across portions of the risk area, particularly in Ohio. Farther to the west, an environment characterized by surface temperatures of in the low- to mid-70s °F, dewpoints between 65–70 °F (18–21 °C), and strong vertical wind shear was still expected to promote a substantiative risk for strong tornadoes. Storms across southern Indiana and western Kentucky initially struggled to intensify during the afternoon, but they eventually matured into tornado-producing supercells as they continued eastward into western Ohio. As convective activity to the north continued eastward into a drier and more stable environment, a cluster of storms developed farther south across Alabama and Georgia, contributing to additional tornadoes. Into April 3, additional severe weather occurred along frontal boundaries from Florida to Virginia before activity pushed offshore.

Confirmed tornadoes

April 1 event

April 2 event

April 3 event

Non-tornadic effects

Heavy flooding in the Midwest was observed in the days leading up to the outbreak, mainly March 31. Many areas of Ohio, Kentucky, Indiana and West Virginia were put on flood watches and flash flood warnings. Ground-to-cloud lightning was observed throughout the entire outbreak. In Carthage, Missouri, which is northeast of Joplin, straight-line wind damage was reported. Winds gusted up to 100 mph (160 km/h) during that event. Power poles were broken, and trees were snapped as a direct result of these storms. Ground scouring was also observed in parts of Central Oklahoma. In West Virginia, there were nearly 100 reports of straight-line wind damage along with the tornadoes. A wind gust of 92 mph (148 km/h) was recorded at Tri-State Airport in Huntington, West Virginia.

The University of Kentucky campus in Lexington suffered minor damage from high winds, and afternoon classes and on-campus activities were canceled. The Scioto Audubon Metro Park was completely flooded.

Severe storms across the Northeastern United States on April 3 produced a daily rainfall record of 1.75 in (44 mm) of precipitation at LaGuardia Airport in New York City, with even more rain in Newark, New Jersey. Lightning also struck the Statue of Liberty during the storms, resulting in viral social media attention. Two Major League Baseball games at Citi Field were postponed during the storm. On April 2, two people were fatally crushed by fallen trees in Pennsylvania. Another fatality occurred in New York on April 3 due to downed trees. Further north, up to 21.5 in (55 cm) of snow fell in Northern New England, with over 600,000 customers losing power.

Aftermath

Over 250,000 people were left without power in the wake of the storm; with many of those outages in West Virginia. At around 4:10 pm on April 2, the state of Kentucky issued a state of emergency. West Virginia also declared a state of emergency for 21 counties.

The tornado outbreak was historic in West Virginia according to the National Weather Service. Their Charleston office stated that "The 17 confirmed tornadoes are the most tornadoes for any calendar day and event on record for the NWS Charleston County Warning Area. The previous record was 6 tornadoes on April 4, 1974. To further put this number into perspective, the previous record number of tornadoes for an entire calendar year over the NWS Charleston County Warning Area was 11 set in 1980, and it took 7 different days with tornadoes to reach that number."

Ten tornadoes occurred in West Virginia; which also set a state record for the most tornadoes confirmed in a single day. The previous record was seven; set on both April 4, 1974 and June 2, 1998.