14th Conference on Applied Climatology


Tornado Trends Over the Past Thirty years

Daniel W. McCarthy, NOAA/NCEP/NSSL/SPC, Norman, OK; and J. Schaefer

Dr. Stanley Changnon studied many aspects of climatology including tornado trends and frequencies. One study in 1982 looked at the trends of tornadoes across Illinois. During the last few years, Changnon has looked at trends of damaging thunderstorm activity across the United States.

This paper will look at these types of trends over the last 30 years. The time span was chosen specifically to exclude major events which occurred the mid-1960s and early 1970s, such as the Palm Sunday Outbreak of 1965 and the Super Outbreak of 1974. These events dramatically increased media coverage and public awareness of tornadoes in regions other than the publically perceived “tornado alley” of Texas, Oklahoma, and Kansas. This limited the period of analysis to 30 years and gives a “normal” for comparison.

The trend in tornado activity shows a gradual increase through the 1980s, followed by a rapid increase during the 1990s across the United States. These are mostly due to increases in the spotter network and advanced warning technology including the WSR-88D (NEXRAD) radar. This paper will also examine tornado characteristics and occurrence tendencies of long-tracked tornadoes over various regions of the country. This is similar to that methodology outlined by Changnon in 1982.

extended abstract  Extended Abstract (220K)

wrf recording  Recorded presentation

Session 3, The Lifelong work of Stan Changnon (Invited Presentations) (Room 619/620)
Tuesday, 13 January 2004, 11:00 AM-5:30 PM, Room 619/620

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