During the TEXAS 2000 Air Quality experiment the NOAA Environmental Technology Laboratory collected detailed atmospheric radiation measurements at the La Porte, Texas air chemistry site. We will compare these measurements with the real time MM5 forecast values for the August 27-30 tropospheric ozone event. Similar comparisons were carried out using data gathered during the 1995 and 1999 Nashville Southern Oxidants Experiments. These studies show that uncertainty in the forecast radiative fluxes can have a strong impact on the meteorological and chemical dispersion forecasts. In our paper we will examine MM5's radiative transfer parameterization performance near Houston. We will also examine the differences in the radiative properties of the atmospheres over Texas and Tennessee during high tropospheric ozone events.