A new study finds that the severity and locations of tornadoes is strongly influenced by the natural Pacific Decadal Oscillation, with more severe tornadoes occurring during the warm phase and fewer during the cold phase.
The cold phase of the ~60-year Pacific Decadal Oscillation [PDO] started in the year 2000, and would explain why the US is currently experiencing the fewest tornadoes on record, and why higher CO2 is correlated with fewer severe tornadoes.
|The US is currently experiencing the fewest tornadoes on record|
|Increased CO2 has nothing to do with tornadoes|
McCoy and Lupo found that the tornadoes that occurred when surface sea temperatures were above average were usually located to the west and north of tornado alley, an area in the Midwestern part of the U.S. that experiences more tornadoes than any other area. McCoy also found that when sea surface temperatures were cooler, more tornadoes tracked from southern states, like Alabama, into Tennessee, Illinois and Indiana.