A mesoscale convective system (MCS) is a complex of thunderstorms that is organized on a much larger scale than an individual thunderstorm and can persist for several hours. MCS characteristics (intensity, structure, propagation speed) are thought to be influenced by the thermodynamic properties of the environment and vertical wind shear. Past studies have typically characterized MCS environments on the basis of a single sounding, but there are few studies using detailed thermodynamic measurements of the environments of these systems to validate this approach. Data for this study were from the Bow Echo and Mesoscale Convective Vortices Experiment (BAMEX) to investigate the thermodynamic environment a convective system. This research was unique because there were approximately 35 soundings taken within and near this convective system. To quantify the environmental structure, selected parameters were used to estimate the buoyancy of hypothetically lifted parcels at several levels and the vertical wind shear through the lower and middle troposphere. Results suggest that the northern limit of the MCS is determined by environmental stability, not by processes internal to the MCS. There were significant differences in the intensity of the MCS between the northern and southern halves of the MCS that corresponded to the variation of the lifted index north to south. The variance of soundings in the path of the MCS suggests that it is not possible to characterize the degree of instability in this case. Furthermore, there was nearly a factor of two uncertainties in environmental wind shear. The results of this research further the understanding of the thermodynamic environment of a mesoscale convective system.