Ensemble precipitation and temperature forcing is needed to drive the Ensemble Streamflow Prediction (ESP) system to produce probabilistic hydrologic forecasts NWS Advanced Hydrologic Prediction Services (AHPS). Pre-processing procedures have been developed to apply operational NWS forecast products to produce the required ensemble forcing for ESP. These procedures are being tested in pilot projects at four NWS River Forecast Centers. This paper presents verification statistics comparing the precipitation and temperature ensemble forecasts to observed data in these pilot projects. The ensemble forecasts produced highly reliable probability estimates for locations where there were sufficient forecast archives to estimate the climatalogical properties of the NWS forecast products used as input to the ESP pre-processing procedures.