Previous research has identified the Gulf of Mexico as an important source of low-level moist warm air for the generation of SLS environments over the Eastern United States. This work investigates the role of this feature through “component denial” experiments in the Community Atmosphere Model version 5 (CAM5). In particular, CAM5 simulations where the Gulf of Mexico is converted to land is compared to a CAM5 control simulation of current climate following the Atmospheric Model Intercomparison Project (AMIP) protocols. In addition to exploring differences in general characteristics of the large-scale environments, SLS changes will be explored through standard large-scale environmental proxies for SLS activity that include convective available potential energy, vertical wind shear, and storm-relative helicity. This initial work is a crucial first step to building a reduced-complexity framework within CAM5 to quantify how land-ocean contrast and elevated terrain control SLS environments.