December 2021 has been very warm overall for a big majority of the country especially parts of the south, the Midwest and Ohio Valley. On December 10th warm very unstable moist air from the Gulf Of Mexico led to a massive severe weather outbreak. CAPE (Convective Available Potential Energy) was extremely high. The severe weather outbreak spawned tornadoes in Tennessee, Kentucky, Arkansas, Missouri, Illinois and Ohio. The outbreak featured some a very long lived supercell thunderstorm. Kentucky and Arkansas and parts of western Illinois was hardest hit. Tennessee set a new record for the most tornadoes ever in the month of December. Over 40 tornadoes have been confirmed. Some severe weather also occurred December 11th then a rare December Derecho (long lived intense wind storm) on December 15th across many states in the Midwest and parts of the western US. See more below:
