May 20, 2019 Super Outbreak (Dixie)

List of tornadoes in the May 20-21, 2019 Super Outbreak
The May 20-21, 2019 Super Outbreak, also known as the 2019 Super Outbreak, was one of the largest, costliest, and deadliest tornado outbreaks ever documented in the United States, occurring in the Southern Great Plains of the United States. The event was part of a larger tornado outbreak sequence that lasted from May 17th through May 29. States impacted included Arkansas, Kansas, Missouri, New Mexico, Oklahoma, and Texas. In total, 200 tornadoes touched down in 24 hours across the Southern Great Plains. May 20th had been given a high risk convective outlook, centered over north Texas through southwest and central Oklahoma. This was the first high risk issued since May 18, 2017. The Storm Prediction Center issued a 45% chance of a significant tornado occurring in a 25 mile radius over central Oklahoma. This was the first instance of such a warning since April 27, 2011 in Alabama. Out of the 200 tornadoes, 41 of which were violent, an unprecedented amount. And 10 of which were rating EF5 on the Enhanced Fujita Scale, the highest possible rating for damage.

In total, 334 people were killed as a result of the outbreak as well as over 3,500 injured. Other fatalities have occurred due to other thunderstorm-related events such as straight-line winds, hail, flash flooding or lightning.

The tornado outbreak set multiple records, including most violent tornadoes in a single day at 41. The previous record was held by the 1974 Super Outbreak at 30. This was also the second most active tornado day with 200 tornadoes being confirmed by the National Weather Service, only behind April 27, 2011 of the 2011 Super Outbreak with 219 tornadoes being confirmed on that day. The high fatality rate was in part due to the sheer speed of the tornadic storms, which were moving at times in excess of 60 miles per hour. This event was also one of the costliest tornado outbreaks and one of the costliest natural disasters in United States history (even after adjustments for inflation), with estimated total damages of $10.2 billion (2019 USD).

"See also: List of tornadoes in the May 20-21, 2019 Super Outbreak"

"Confirmed tornadoes by  Enhanced Fujita rating"

Meteorological Synopsis
On May 12th, meteorologists began monitoring an area in the Southern Great Plains for the possibility of severe weather. Over the next few days, signs of active weather for May 20th became more apparent with models agreeing that a tornado outbreak could occur over Texas and Oklahoma. By May 15th, confidence has increased to the point that the activation of spotters and emergency management may be needed for May 20th due to the high possibility of severe storms. Rapid cyclogenesis over southeastern Colorado would likely develop. By May 17th, the Storm Prediction Center was certain for the occurrence of a dangerous tornado outbreak. On the SPC Day 4 Outlook, wind fields were also impressively strong, with southwesterly 500 mb flow approaching 80 knots on top of 50 knot 850 mb southerly flow and 20-25 knot southeasterly surface winds. The overall result of these factors was an environment strongly supportive of severe storms. An initial discrete mode capable of all severe hazards, including tornadoes, was anticipated. If a discrete mode could be maintained, strong tornadoes would occur. Upscale growth was eventually expected, with a strong MCS then tracking eastward across OK and adjacent portions of southern KS and north TX. On May 18th, a moderate convective outlook was issued by the SPC stating that the setup was indicative of a potentially significant severe weather event on Monday. May 19th’s outlook added that severe thunderstorms capable of all severe hazards, including strong tornadoes, are expected across portions of the southern Plains on Monday. On the morning of May 20, 2019, the SPC issued a high risk for severe weather across western and central Oklahoma and northwest Texas. This was the first high risk issued since My 18, 2017. The risk area included areas of Oklahoma that were affected by an EF5 tornado that devastated portions of Moore on the 6 year anniversary of that tornado. Many schools in the Oklahoma City and El Reno school districts responded by cancelling classes the day before. By midday, the SPC increased the risk of significant tornadoes in northern portions of the Texas Panhandle, southwestern and central Oklahoma (including Oklahoma City) from 30% to 45%. This was the first 45% significant tornado risk since April 27, 2011 during the 2011 Super Outbreak.