According to NOAA, the U.S. set a record yesterday for most observed gusts >hurricane force (74 mph), just 5 days since the historic tornado outbreak on December 10th.  According to NOAA, more than 55 reports of gusts >74 mph were observed in Midwestern States. According to NOAA, the previous record was 53 reports set on August 10, 2020 (period of record 2004-2021).  

An evolving longwave upper trough extending from Western Russia to Southwest Europe causes deepening and expansion of Western Eurasia snow cover and steady intensification of an attendant winter chill. Supported by strong negative phase of both the arctic oscillation and North Atlantic oscillation this feature locks-in for the last third of December into early January.

The Australia Bureau of Meteorology identifies the developing heat wave across Northern Australia as rare for this early in the season! The aerial coverage and risk BOTH peak during the 3-day period of Dec. 16-18. During that time maximum temperatures are well over 100F with very warm nights offering limited recovery.

A rare super-outbreak of violent tornadoes occurred December 10, 2021. There were two primary tornado "lines". One stretched from eastern Missouri to east-central Illinois while a second began in northeast Arkansas and reached southwest Kentucky. The second line featured (potentially) the longest path of one tornado on record. The violent weather was caused by interaction with the East Pacific tropics, Gulf of Mexico and cold snow-covered areas to the north and enhanced by a vigorous jet stream and low-level jet out of the western Gulf.