Previous studies have identified meteorological variables linked with intense mesoscale convective systems (MCSs) known as derecho-producing MCSs (DCSs). The prediction of MCS intensity is of concern to operational meteorologists, and this study provides discussion on meteorological variables derived from proximity soundings that can be used to discriminate among non severe MCSs (NCSs), severe but non derecho-producing MCSs (SCSs), and DCSs. These variables have been grouped into three categories: kinematics, instability, and moisture. Each one of 269 warm season MCSs was rated based on intensity, and the stage within8 the typical MCS lifecycle of each was determined. Decaying and dissipating MCSs were removed from the data set to focus on the most intense stages of the MCS lifecycle. Variables were calculated from the proximity sounding associated with each MCS, and statistical analyses were performed on these calculations. System-relative inflow and mid-level environmental lapse rates were found to be variables that discriminate among all three MCS environments. Knowledge of the variables affecting MCS intensity can allow for improved forecasts and warnings of convective wind events.