Nov 6, 2014

Variability of tornado climatology across the continental United States

Farney, Tory J., Dixon, P. Grady
International Journal of Climatology
  • Analyzes the spatial and temporal variability of tornado days to achieve a more comprehensive understanding of the climatological distribution of tornadoes
  • Expands on previous literature by using a longer period of study and investigating variables other than the mean, which has been shown to be easily biased and less susceptible to the impacts of a changing climate
  • Analyzes tornado days for predefined areas across the continental United States for 1950–2011
  • Finds variability in the record, but the results signify that a change in tornado climatology may have occurred between the periods
  • Discovers what appears to be a cycle in the annual number of tornado days in the contiguous United States
    • States that finding the cause of such a pattern, if it truly exists, may have great implications for the understanding of seasonal tornado risk
  • Identifies a pattern of increasing tornado day activity across portions of the Eastern Seaboard from New York to the Carolinas, the Deep South, the southern and western Midwest, southern Florida, eastern Colorado, and much of Kansas
    • The pattern matches many of the locations that previous research indicated as likely locations to see increases in strong tornado days, defined as days with EF2 or stronger tornadoes, by the 2090s
  • Finds that tornado days and multi-day events have shown only weak trends since 1960 and no trends since about 1990
  • States that non-typical events may present increased risks to the public and also serve as an early indicator of changing tornado climatology
  • States that consecutive tornado days present an alternative method to assess the seasonal repeatability and risk for historic, multi-day tornado outbreaks
  • The results of this research better define the climatological variability of tornado events in addition to offering insight regarding the spatial patterns of locations with the greatest tornado risks, especially those with higher interannual variability