The Short and Long-term Variability of F2 or Stronger (Significant) Tornadoes in the Central Plains F. Adnan Akyuz1,2 Matthew D. Chambers1,3 and Anthony R. Lupo*,1 1Department of Atmospheric Science 389 Mc Reynolds Hall University of Missouri – Columbia Columbia, MO 65211 2Missouri Climate Center 365 Mc Reynolds Hall University of Missouri – Columbia Columbia, MO 652111 3KRCG – TV 13 P.O. Box 659 Jefferson City, MO 65102 Submitted to: Transactions of the Missouri Academy of Science October 2003 Revised: August 2004 *Corresponding Author Address: Department of Atmospheric Science, 389 Mc Reynolds Hall, University of Missouri, Columbia, Columbia, MO 65211, Email:
[email protected] ii Abstract An analysis of the interannual and interdecadal variability of significant tornado events that occurred over a four state region in the central plains was performed over a 53 year period (1950 – 2002) using the Storm Prediction Center (SPC) archives and simple statistical techniques. A synoptic composite analysis using the National Centers for Environmental Prediction (NCEP) – National Center for Atmospheric Research (NCAR) re-analyses was performed in order to determine whether there was support for the statistical relationships through the large-scale composite dynamics. The results showed that when the 53 year raw annual tornado occurrences are used, there was no statistically significant El Nino-related variability, and El Nino years produced slightly more tornado occurrences. However, when annual tornado occurrences were examined across different phases of the Pacific Decadal Oscillation, there was a likely tendency for more tornado occurrences in El Nino years during PDO2 and no significant interannual variability during PDO1 years.