Abstract:
The climatology of tornadoes is considered using only the most fundamental aspects of the historical tornado record: the daily number of tornadoes and the annual number of tornadoes for the period 1955-1999. This study attempts to define what is a normal tornado year given the fact that the raw number of tornadoes has nearly doubled since 1955. Two methods are employed to determine a normal year: the first is to remove any secular trends from the observed data while the second uses a rudimentary numerical model to simulate 10,000 years of daily tornado activity. Once a normal year has been defined, climatological aspects of any year such as departures from normal can be computed. Results suggest that data through the end of April are required in order to make judgments about the outcome of the tornado year.
Paper available upon request.