The near-resonance of the coastal diurnal temperature forcing and the inertial period along the northern Gulf of Mexico produces a substantial large-scale wind oscillation. We call this the "coastal oscillation" to distinguish it from the more conventional sea breeze front. The horizontal and vertical structure of the coastal oscillation is investigated through analysis of data from a network of wind profilers installed for up to 18 months in Texas as part of the TexAQS-II field program. Special care is taken to preserve the amplitude of the diurnal cycle across data gaps caused by signal contamination by migratory birds. The coastal oscillation signal is found to be strongest in the lowest several hundred meters of the atmosphere and is most regular near the coastline. Farther inland, the coastal oscillation often takes the form of a low-level jet, as the onshore flow accelerates in response to frictional decoupling from the land surface. The resulting wind patterns significantly affect the nighttime transport and dilution of airborne pollutants.