Abstract Hurricane Opal (1995) experienced a rapid, unexpected intensification in the Gulf of Mexico that coincided with its encounter with a warm core ring (WCR). The relative positions of Opal and the WCR and the timing of the intensification indicate strong air–sea interactions between the tropical cyclone and the ocean. To study the mutual response of Opal and the Gulf of Mexico, a coupled model is used consisting of a nonhydrostatic atmospheric component of the Naval Research Laboratory’s Coupled Ocean–Atmosphere Mesoscale Prediction System (COAMPS), and the hydrostatic Geophysical Fluid Dynamics Laboratory’s Modular Ocean Model version 2 (MOM 2). The coupling between the ocean and the atmosphere components of the model are accomplished by conservation of heat, salt, momentum, as well as the sensible and latent heat fluxes at the air–sea interface. The atmospheric model has two nests with spatial resolutions of 0.6° and 0.2°. The ocean model has a uniform resolution of 0.2°. The oceanic model domain ...