Convective Mode of Thunderstorms Producing Significant Cool Season Tornadoes in the National Weather Service's Central Region

This study examines the convective mode of thunderstorms that produced significant tornadoes (F2-F5) in the Central Region of the National Weather Service between December and February. Fifty tornadoes were recorded on 10 days between 1997 and 2008. A previous analysis of tornadoes that occurred in eastern Missouri and southwest Illinois revealed that significant tornadoes comprise a large percentage of all tornadoes that occur during meteorological winter.

Radar imagery is examined at the time and location of each tornado to determine convective mode. Preliminary results suggest that significant tornadoes in the cool season are produced by discrete cells with greater frequency when compared to quasi-linear systems by a ratio of two to one. Data from regional proximity soundings and the North American Regional Reanalysis (NARR) are compared to this analysis to gain insight on how environmental parameters may force a particular convective mode.