Regional SST and SLP conditions related to tornado 'outbreak' environments 15 days later

Keywords: Tornado, Climate, Atmospheric Environments, Weather, Meteorology
Session Type: Virtual Paper Abstract
Day: Friday
Session Start / End Time: 2/25/2022 11:20 AM (Eastern Time (US & Canada)) - 2/25/2022 12:40 PM (Eastern Time (US & Canada))
Room: Virtual 17

Abstract

Global climate features are known to influence tornado frequency and convective environments in the US. Here, the author quantifies the conditional relationships between precursor sea surface temperatures and sea level pressure variables and localized extremes of convective available potential energy and shear associated with clusters of ten or more tornadoes. The author fits linear regressions to global climate variables averaged over the fifteen days before the outbreak. The fifteen day averages prior to the cluster help estimate the changes in convective available potential energy and shear on days with at least ten tornadoes. Results show that for every 1 degree C increase in the sea surface temperature gradient between the Gulf of Alaska and the Caribbean, deep-layer bulk shear increases by 0.88 m/s, shallow-layer bulk shear increases by 0.62 m/s, and convective available potential energy decreases by 50.6 J/kg, conditional on at least ten tornadoes, and holding the other variables constant. This result highlights the role of the thermal wind on environmental factors that influence clusters with at least ten tornadoes. Further, model results show that for every 1 degree E increase in longitude of the cluster centroid, deep-layer bulk shear increases by 0.15 m/s, shallow-layer bulk shear increases by 0.38 m/s, and convective available potential energy decreases by 39.3 J/kg, conditional on at least ten tornadoes, and holding the other variables constant. Additionally, shallow-layer bulk shear is the only environmental factor that has a significant upward annual trend which could lead to increased tornado activity.