Dataset to accompany the publication "Weakly Forced Thunderstorms in the Southeast U.S. are Stronger Near Urban Areas" in Geophysical Research Letters by Paul Miller and Neil Debbage. The file contains the urban versus non-urban mean values for 31 cities in the Southeast US for the following variables: initiation time (decimal hours since 1200 UTC), duration (min), total lifetime thunderstorm pixels, maximum composite reflectivity (dBZ), maximum number of thunderstorm pixels during any single volume scan, maximum pixel ratio. T statistics and p values for the urban vs non-urban t-tests are also provided. More information can be found in the associated manuscript.