The illustration above illustrates simulated composite radar reflectivity (in dBZ) generated by Wei-Kuo Tao and co-workers from the Weather Research and Forecasting (WRF) model in conjunction with the Goddard Cumulus Ensemble (GCE) model. Note how the model output captures the timing and transition of lake effect snow bands to the synoptic snowfall event that occurred during the period from January 20-22, 2007. The model results will be compared to measurements made by C3VP ground-based and aircraft-based instruments that operated during the same period. Once the validation of the model output is completed, and assuming that there is sufficient fidelity in results, the model output will be used in forward radiative transfer models to simulate GPM Microwave Imager (GMI) radiance and Dual Precipitation Radar (DPR) reflectivity. The GMI and DPR radiances and reflectivities will be used to test the precipitation retrieval algorithms that are now under development for GPM.