The GOES imager radiance observations on board Geostationary Operational Environmental Satellite (GOES), GOES-11/12, that are of high spatial and temporal resolution were added to the assimilation of AMSU-A and conventional observations, which produced the best 24-h quantitative precipitation forecasts (QPFs) for a coastal storm over the northern Gulf of Mexico. Both the National Centers for Environmental Prediction (NCEP) Gridpoint Statistical Interpolation (GSI) analysis system and the Community Radiative Transfer Model version 2.02 (CRTM2.02) were utilized to ingest GOES IR clear-sky data and the Weather Research and Forecast (WRF) model was used for model forecasts. The WRF outputs of temperature, water vapor, hydrometeor profiles and surface winds in Gulf region were then used as input to CRTM2.02 and RTTOV10 to simulate brightness temperatures (TB) of microwave sounding instruments as a function of cloud liquid water and ice water contents for a given surface wind speed and SST condition (ocean only). The TB responses to cloud and other surface parameters such as sea surface temperature and surface wind speeds are simulated by both CRTM 2.02 and RTTOV10 and compared for understanding and quantifying O-B biases. The observation error covariances are derived and parameterized as functions of observed and model cloud and surface parameters. These are required inputs for improving uses of cloudy radiances at surface-sensitive channels in NWP.