Observations and modeling of Houston air quality have demonstrated the importance of the subtropical sea breeze in controlling winds and transport in the area. Because Houston is just south of 30 degrees, so that the diurnal frequency is slightly larger than the inertial frequency, the sea breeze is fundamentally different from the more familiar midlatitude variety. The characteristics of the Houston sea breeze include maximum onshore winds at night, a horizontal extent of 400 km or more, vertical propagation, and occasional development of an intense alongshore low-level jet.

Compared to special observations taken during TexAQS-2000, high-resolution MM5 simulations of the sea breeze are deficient in a few key areas. First, the large-scale onset of the sea breeze is delayed in the model compared to observations. Second, the model does not reproduce the apparent upward phase propagation of the onshore winds. Finally, the model does not produce a realistic low-level jet.