Interannual variability of Severe Weather over the USA since 1991 (121)

Grace Ruhbeck, University of Missouri, Columbia, MO

Caleb Brown, University of Missouri

Joseph Renken, KOPN Radio

Anthony Lupo, University of Missouri



Previous studies have showed that ENSO-related variability in tornadoes and other severe weather in the USA is a function of the primary location where the severe weather occurs. This study examines the occurrence of the severe weather events and days by calendar month in relation to ENSO for three categories tornadoes, high winds, and hail. Using the National Severe Storms Laboratory database, all events with more than 20, 145, 135 reports of tornadoes, high wind, and hail, respectively, were collected to provide a large sample size. The sample size was 271 days for tornadoes and high winds, and 275 days for hail. Initial results show that, as expected the pear number of severe weather events occurred in the spring. However, the La Nina phase produced more high-impact event days than either El Nino or Neutral year events. Also, the absolute peak occurrence was in April for La Nina and May for El Nino and Neutral years.

The first two authors are undergraduate students.