On June 20, a sequence of multiple severe weather events and tornado outbreaks began across large portions of the Great Plains, Midwestern, and Eastern United States as well as Manitoba and Ontario in Canada near the country borders. This includes the “historic” tornado outbreak on June 21. A slow moving trough interacted with extremely high moisture and atmospheric instability to produce favorable conditions for supercells. Large hail and damaging winds accompanied a multi-day tornado risk which produced multiple strong tornadoes, including a catastrophic high-end EF3 tornado in Matador, Texas on June 21, and another high-end EF3 tornado south of Granada, Colorado on June 23, and multiple EF2 tornadoes from Indiana to Kentucky on June 25. Reports of power outages, wind damage, hail damage, and tornadic damage accumulated across the affected region. In all, five people died from tornadoes, and three other non-tornadic deaths also occurred. Over 120 people were injured as well.
Meteorological synopsis
On the heels of another tornado outbreak, a second multi-day tornado outbreak began on June 20. On June 21, strong southwesterly winds associated with a large upper-level trough over the Western United States began overspreading central portions of the country. The Storm Prediction Center (SPC) issued a bimodal level 3/Enhanced risk, one encompassing the tri-state region of Wyoming, Colorado, and Nebraska, and the second stretching from the Texas/Oklahoma panhandles into North Texas. To the south, an extraordinarily moist environment with dewpoints in the mid-70s °F over the spread area. High moisture combined with daytime heating resulted in an unstable airmass characterized by mixed-layer convective available potential energy (CAPE) in excess of 4,500 J/kg. Favorable wind shear overspread this environment, while the combination of outflow from morning storms and a nearby dry line became the focal point for thunderstorm development. A broken line of supercells developed from Kansas southward into Texas, contributing to large hail, damaging winds, and a few tornadoes. An especially intense tornado moved through western sections of Matador, Texas, killing four people and causing significant damage. To the north across Colorado, Wyoming, and Nebraska, storms similarly developed along remnant outflow. Although low-level shear was weak, this outflow enhanced shear in the immediate vicinity of storms, resulting in numerous, mainly brief tornadoes over largely open country. A less active day occurred on June 22, although sporadic severe weather occurred across the Southern Plains, including a few brief tornado touchdowns in Colorado and Wyoming.
On June 23, the focal point for active weather shifted northward into eastern Wyoming and The Dakotas, where the SPC outlined a level 3/Enhanced risk. Stronger wind shear associated with an approaching shortwave trough overspread an unstable airmass with mixed-layer CAPE upwards of 2,500 J/kg. Through the afternoon, convection developed along the Laramie and Bighorn mountains, and along a warm front/outflow boundary across Wyoming and Nebraska. A few supercells evolved in this region, particularly later into the afternoon as low-level shear increased, producing large hail and numerous tornadoes. With time, outflow from ongoing convection merged, leading to a line of storms that pushed eastward. Farther south in southeastern Colorado and western Kansas, more isolated but significant supercells developed along a dryline and in an area of strong orographic lift. These highly structured cells moved east in a favorable environment, producing large hail and long-lived, photogenic tornadoes. On June 24, the risk area shifted deeper into the Midwestern United States. A low-pressure area tracked across southeastern North Dakota during the afternoon, supporting a warm front across northern Minnesota. Modest CAPE of 1,500 J/kg combined with strong shear along the boundary fostered low-topped convection and multiple tornadoes, including a strong tornado. To the south, combined clusters of convection produced sporadic damaging winds across Iowa and Illinois.