Technical Abstract: The National Weather Service River Forecast System uses the Sacramento Soil Moisture Accounting (SAC-SMA) rainfall-runoff model to produce daily river and flood forecasts and issue flood warnings. The manual observations of total sky cover used to estimate solar radiation and potential evapotranspiration in the SAC-SMA model, however, have recently been phased out. This study explores the value of incoming solar radiation estimates derived from Geostationary Operational Environmental Satellites (GOES) as an alternative solar radiation data source. At twenty-seven sites in the United States, the GOES-based solar radiation (R2 = 0.79) and ETp (R2 = 0.94) estimates agreed well with the ground-based estimates. There was a slight positive bias for the GOES-based solar radiation (7%) and potential evapotranspiration (11%) estimates compared to the ground-based estimates, with the strongest bias noted during the warm seasons. Daily streamflow predictions from four watersheds from the NOAA Distributed Model Intercomparison Project (DMIP) show that although notable peak storm flow differences occurred occasionally during extended drying periods, on average, the GOES-based potential evapotranspiration estimates slightly outperformed the simulations using ground-based data. This suggests that satellite-derived solar radiation data are capable of producing accurate predictions of streamflow with the SAC-SMA model.