Validation of NWS Stage IV Multi-Sensor Precipitation Estimates (MPE) in the Mid-Atlantic Region Boone F. Larson a Ali Tokay b Emad Habib a Brian R. Nelson c a Center for Louisiana Water Studies, Institute of Coastal Ecology and Engineering, and Department of Civil Engineering, University of Louisiana at Lafayette, P.O. Box 42991, Lafayette, LA, 70504 USA. b Joint Center for Earth Systems Technology, University of Maryland Baltimore County NASA – Goddard Space Flight Center Greenbelt, MD 20771 USA c NOAA National Climatic Data Center, 151 Patton Ave, Asheville, NC 28801 USA Mentor: Ali Tokay Abstract Multi-Sensor Precipitation Estimates (MPE) is a regional multi-sensor hourly surface rainfall product that was developed for input into hydrologic forecast models and decision- making systems for river forecasting, flood and flash flood warning, and other hydrologic monitoring purposes. MPE result from merging operational radar, automated gauge, and Geo- stationary satellite rainfall estimates following quality control and bias adjustment. MPE are superimposed over a nominal grid size of 4 square kilometers termed Hydrologic Rainfall Analysis Project (HRAP). Stage IV is a final stage term used to describe nationwide mosaicking of manually-edited, regional MPE products produced by each of River Forecast Center (RFC) on an hourly basis. Stage IV is a readily available operational product which makes it attractive to validate various satellite rainfall estimates including NASA's Tropical