In an effort to fully utilize satellite observations on GOES platform, NOAA's Forecast Systems Laboratory(FSL) has been testing one dimensional variational analysis of cloud parameter method by combining both sounder and imager radiances. In order to minimize the differences between measured cloudy and computed cloudy radiances we introduce fractional clouds as control variables. Sensitivities to background errors and measurement bias errors are investigated with emphasis on moistures channel radiance data. Examples that use 20km Rapid Update Cycle forecasts as background and GOES sounder and imager data will be shown.