Oceanic and atmospheric processes associated with the Oregon coastal upwelling system were observed during the multi-institutional COAST (Coastal Ocean Advances in Shelf Transport) research program. After several days of upwelling-favorable wind-stress, air temperature data collected by aircraft during COAST showed a pocket of cool air over the cold coastal water and within the marine atmospheric boundary layer (MABL). This pocket of cool air was an internal boundary layer (IBL) that formed through sensible heat flux form the air into the ocean as warmer air was advected over the cooler, upwelled water. Presented in this paper are comprehensive views of the IBL created from the following COAST data products: (1) atmospheric data acquired by aircraft, (2) subsurface ocean temperature and near surface air temperature acquired by 6 moorings, and (3) subsurface ocean temperature measured by Aircraft-deployed eXpendable Bathy Thermographs (AXBTs). A simple analytical model, created from the 3-D advection-diffusion equation and using parameters set by the observational data, is used to visualize the near-surface air temperature structure, where no observational data exists, and to estimate the contribution of thermal wind-shear and enhanced stability on the wind field.