Gap wind frequently occurs during the winter through the Chivela Pass located in southern Mexico. As a result, the outflow from gap over the Gulf of Tehuantepec generated significant disturbances in the water on the Pacific side of the Gulf of Tehuantepec and to the lower atmosphere. Gap outflow winds create significant horizontal inhomogeneities in the area as strong sea surface temperature (SST) gradient forms because the wind forcing from strong northerlies increases mixing and enables upwelling along the coast. In general, the strongest SST fronts were found along the leading edge and peripheral boundaries of the gap wind outflow. This region is thus filled with coupled response between the ocean and the atmosphere that varies significantly relative to the outflow jet and distance from the coast. In this study, we use aircraft measurements of ocean and atmospheric conditions from several flights during the 2004 Gulf of Tehuantepec Experiment (GOTEX) with the focus on the evolution of the lower atmosphere and upper ocean. The vertical structure of the marine boundary layer and ocean mixed layer will be examined using a combination of measurements from aircraft in situ soundings, dropsondes, and AXBTs, while the characteristics of turbulence exchange in the vicinity of strong SST gradients will be studied from aircraft measurements near the surface and in the lower atmosphere. This study revealed the complication in parameterizing the air-sea coupling with substantial mesoscale variations.