During the past five years, the National Severe Storms Laboratory has been developing and testing techniques to estimate precipitation using a variety of sensors in complex terrain. The system, Quantitative Precipitation Estimation and Segregation Using Multiple Sensors (QPESUMS), ingests data from multiple WSR-88Ds, satellite, the RUC-II numerical model, and surface observations. The QPESUMS has been undergoing testing and assessment in Arizona for several cool and warm seasons. This paper provides an overview of QPESUMS verification and highlights the difficulties and successes of using a multi sensor approach to estimating precipitation in mountainous and desert regions. The paper will highlight a case for comparison of standard WSR-88D estimates and QPESUMS estimates for the 13-14 February 2003 rain event. Additional results and considerations for improvement will be discussed, for example, the incorporation of model-derived precipitation. Using model-derived precipitation will likely improve the performance of rain/no rain logic for areas of poor radar coverage. Additional improvement will also be discussed in the context of improved radar gauge biasing as it applies to the western United States.