William A. Gallus, Jr., Department of Geological and Atmospheric Sciences, Iowa State University


This research examined tornado outbreaks with the intent to find a correlation between North/South extents of daily tornado reports to the North/South extents of atmospheric parameters. Thresholds were examined for Mixed Layer Convective Available Potential Energy, Convective Inhibition, jet streaks strengths at 300, 500, and 850 millibar levels, Supercell Composite Parameter, Significant Tornado Parameter, 0-1 km Storm Relative Helicity, and 0-3 km Storm Relative Helicity while synoptic features such as warm fronts, outflow boundaries, cold fronts, drylines, stationary fronts, and squall lines were noted for tornado outbreak days with at least 15 filtered tornado reports. Statistical analysis indicates the North/South extent of MLCAPE ≥ 3000 J/kg, Significant Tornado Parameter ≥ 2, Supercell Composite Parameter ≥ 8, 0-1 km Storm Relative Helicity and 0-3 km Storm Relative Helicity correlate with statistical significance with the north/south extent of tornado reports. 850mb jet streak strengths ≥ 25 kts have a strong statistical significance and show a correlation in tornado extent. Tornado reports also extend farther latitudinally when more than one synoptic feature is associated with an outbreak. While analysis shows the natural northern progression of tornado activity through the March to June time period, results show a slight decrease in latitudinal extents. Due to small sample size, caution should be used in generalizing the results for forecasting technique improvements until future research is expanded for this subject.

Copyright Owner

Joseph R. Krastel


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