Weather event in the United States and Canada
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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. This included a historic outbreak of 37 tornadoes in Colorado 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 destructive high-end EF3 tornado that killed 4 people in Matador, Texas on June 21, and another EF3 tornado south of Granada, Colorado on June 23. Multiple EF2 tornadoes touched down 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 sequence, a second tornado outbreak sequence began on June 20 with a few weak tornadoes in North Dakota and Minnesota. 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 major 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 tornadoes that over largely open country. A total of 37 tornadoes touched down in Colorado that day, 27 of which were spawned by a single slow-moving supercell near Akron. 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. This included a rain-wrapped EF1 tornado that moved through the Denver suburb of Highlands Ranch.
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, some of which were strong. This included an EF2 tornado that injured eight workers at the North Antelope Rochelle Mine in Campbell County, Wyoming. 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, including an EF3 tornado that completely destroyed a farmstead near Granada, Colorado. 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 EF2 tornado near Mahnomen, Minnesota. To the south, combined clusters of convection produced sporadic damaging winds across Iowa and Illinois.
An expansive level 3/Enhanced risk encompassed much of the Ohio River Valley and Mid-South on June 25. The greatest threat for potentially strong tornadoes was focused across Indiana, Ohio, and Kentucky. Here, the environment rapidly destabilized amid daytime heating, CAPE upwards of 2,000 J/kg, and the approach of an upper-level trough. An arcing band of supercells quickly developed by midday along a pseudo-dryline feature, producing very large hail and multiple strong tornadoes. To the north across Michigan, a line of convection in a more marginal environment produced sporadic damaging winds. Across the Southeastern United States, a moist and unstable environment devoid of strong low-level shear aided a long-lived mesoscale convective system that produced widespread damaging winds as well. Multiple rounds of linear convection contributed to additional severe reports through the evening. The threat for severe weather shifted eastward into the Mid-Atlantic on June 26, where the SPC issued a broad level 3/Enhanced risk stretching from The Carolinas into Pennsylvania and New Jersey. An area of low pressure moved across Michigan and supported a cold front across the Ohio River Valley. To the east, a pre-frontal trough also developed along the Blue Ridge Mountains. Mixed-layer CAPE of 1,000-2,500 J/kg and dewpoints in excess of across a wide region were forecast to materialize. However, diurnal heating was at least somewhat hampered by multiple rounds of convection and widespread cloudiness through the morning hours. Clusters of storms developed throughout the region ahead of the cold front, contributing to numerous instances of damaging winds and a few tornadoes as far north as Ontario until they began to weaken with the loss of daytime heating or pushed offshore beyond the coastline.
Confirmed tornadoes.
Matador, Texas.
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This very intense tornado touched down along CR 205 to the north-northwest of Matador and tracked due-south at EF2 strength, snapping multiple power poles and trees. The tornado turned in a more south-southeastward direction and rapidly intensified to high-end EF3 intensity near FM 94 just northwest of Matador. A house was swept completely away in this area with only its basement left behind, where a family of three survived as the house was swept away above them. Two vehicles parked at this residence were thrown long distances and were never located, while a third was found hundreds of yards away. A large metal canopy on the property was also destroyed, and trees near the residence were uprooted and significantly debarked. The tornado then moved south through an open field, producing a swath of ground scouring before it destroyed two homes near SH 70 as it entered the far northwestern outskirts of Matador. A truck was thrown over 200 feet from one home and was mangled beyond recognition, two more homes near Pipkin Street had their roofs torn off, extreme debarking of trees was observed in this area, and damage along this segment of the path was rated mid-range EF3. The tornado reached high-end EF3 intensity again as it continued due-south, completely destroying multiple buildings at the intersection of US 62 and SH 70 at the west edge of town. A two-story brick home and several nearby outbuildings were completely swept away near Stewart Avenue, and another brick home was flattened at the intersection of Dundee Avenue and Echols Road. 
Several other homes in this area were significantly damaged and multiple vehicles were rolled and mangled, one of which had a metal pole driven into it. A tractor-trailer was tossed as well, and debris was strewn throughout this area. A recently-built, metal-framed Dollar General store on the south side of US 62 was completely leveled at high-end EF3 intensity, with its beams twisted and bolted anchor plates torn from the building's concrete foundation. Concrete parking bollards at this location were snapped at ground-level as well, and a semi-truck was torn from its chassis and destroyed, killing the driver. Two convenience stores to the east of the Dollar General store were damaged, and a restaurant and motel were both partially destroyed. A small house and several metal buildings were completely destroyed nearby, one of which had sections of its tile floor removed. Trees in this area were again debarked, some of which were torn of out the ground by their root balls. An RV was thrown and a power substation was partially collapsed as well, leaving 99% of the town without electricity. Past the intersection, the tornado maintained high-end EF3 strength as it paralleled SH 70 and kept moving south, causing major damage at the southwest edge of town. A home was completely leveled and mostly swept from its foundation, and large trees were completely debarked and stripped of their branches nearby. Several other houses suffered major structural damage, and a large metal outbuilding was completely swept off its foundation. A truck was thrown and had its Ford Power Stroke engine ripped out, which was tossed into a pond. A livestock trailer was thrown as well, and debris from destroyed buildings was scattered across fields.
The tornado started to weaken and began moving in a more south-southeasterly direction as it crossed SH 70, where it destroyed a guyed 500-foot (150 m) tall radio tower and caused additional major tree damage. A house near the highway was destroyed, and damage in this area was rated low-end EF3. Some ground scouring was observed in this area, and multiple fence posts, power poles, light poles, and signs were blown to the ground along the highway as well. The tornado then weakened rapidly and turned further to the southeast, inflicting minor damage to a house and a barn before it dissipated in a nearby field. In total, four people were killed and 15 others were injured by the tornado. One of the four people killed by the tornado was first reported as injured and later died at a local hospital.
Controversy.
The tornado caused several meteorologists and scientists to pose questions regarding the tornado, including issues with the tornado sirens and the finalized EF3 rating on the Enhanced Fujita scale. National Weather Service meteorologist James LaDue stated the local tornado sirens for Matador did not activate until the tornado was already destroying homes in northwestern portion of the town. This only gave four-minutes or less of lead time to residents in the town to take shelter.
There was also controversy regarding the tornado's rating of EF3, with some meteorologists and storm chasers saying it was "a gross underestimate of such a violent tornado", as it completely leveled and swept away multiple structures and produced extreme contextual damage to vehicles and vegetation. Mechanical engineer Ethan Moriarty stated with regards to the extreme vehicle damage that "the problem is that we can't really go outside of the confines of the scale"..."that's the thing with standards like this. You have to stay consistent, even if they are limiting the actual classification of the tornado". One issue with the Enhanced Fujita scale stated by Moriarty is that vehicles are not a specific damage indicator on the scale, meaning they cannot be used to rate the tornado. In addition, the tornado was slow moving, which may have exacerbated the severity of the damage. Chief meteorologist for KWTV-DT David Payne stated the damage in Matador, "looks like EF4 damage to me".
Non-tornadic events.
Great Plains.
On June 21, a downburst produced estimated winds of near Selfridge, North Dakota. A manufactured home was completely destroyed with debris strewn downstream. One person was injured. That day, a person was killed in Nebraska due to a lightning strike.
Around 9:30 p.m. MDT, a hailstorm impacted the Red Rocks Amphitheatre in the Denver metropolitan area during a concert. Hailstones up to in diameter pelted concertgoers and accumulated several inches deep in the stands. Three acts were scheduled that night with the second being delayed 15 minutes prior to the storm's arrival. Attendees did not seek shelter until a warning to do so was given 3 minutes before the hail started. Nearly 100 people were injured, with injuries ranging from cuts and bruises to broken bones, as they were unable to get indoors or to their cars in time; 8 people required hospitalization. An employee described people as having panic attacks and other workers