Tornado Ingredients in the United States: Climatology and Trends

Keywords: Tornadoes, Climatology, Climate change, United States
Session Type: Virtual Poster Abstract
Day: Sunday
Session Start / End Time: 2/27/2022 03:40 PM (Eastern Time (US & Canada)) - 2/27/2022 05:00 PM (Eastern Time (US & Canada))
Room: Virtual 27

Abstract

Spatiotemporal trends have been detected in the tornado record of the United States over the past several years. Some trends, for example the growing number of annual tornadoes, are largely explained by non-climatological/meteorological factors like improved detection and reporting. Other trends, for example the contrasting decreasing and increasing trends seen in the Great Plains and Southeast (i.e., a spatial shift in tornado activity), are more difficult to explain with non-climatological/meteorological factors. Now that these regional trends have been identified, numerous studies have sought to attribute these trends by looking to see if atmospheric conditions that are favorable for tornadoes (i.e., tornado ingredients) are also shifting—to determine whether climatic changes are consistent with the observed spatial shift in tornado activity. On this poster, I present seasonal climatologies (mean and variability) and trends of tornado ingredients in the United States. These ingredients are found to change in different ways, creating unique seasonal spatiotemporal combinations. For example, mean instability, wind shear, and moisture increased in the Midwest and Mid-South in spring but, in winter, only wind shear and moisture increased in the Midwest and Mid-South. As other examples, instability became more variable in the western portions of the north and south Great Plains in spring and summer while wind shear became more variable in the Midwest and Mid-South in fall. In general, this study illustrates that tornado ingredients interact in complex ways and that long-term climatic changes in these ingredients will not have a homogenous influence on tornado activity across time and space.