Seasonal sub-basin-scale runoff predictions: A regional hydrometeorological Ensemble Kalman Filter framework using global datasets

•Data-driven seasonal prediction of sub-basin-scale runoff is performed using an EnKF.•This framework allows skillful forecasts up to two months ahead in most sub-basins.•Sub-basins with low anthropogenic influence achieve the best forecast performance.•This prototype is computationally efficient and easily transferable.