The availability and application of remote sensing products and weather forecasts from ensemble prediction systems (EPS) have transformed river forecasting capability over the last decade, and is of interest to India. In this talk, we review the potential predictability of river flow contributed by remotely-sensed and weather forecasting products within the framework of the physics of water migration through a watershed in the context of the Ganges, Brahmaputra, and Meghna river basins. We focus on satellite rainfall estimation, river height and width estimation, and EPS weather forecasts. We discuss how atmospheric predictability, as measured by an EPS, is transformed into hydrometeorological predictability, providing in some cases skillful daily flow forecasts out to weeks in advance. We provide an overview of the strengths and weaknesses of each of these data sets to the river flow prediction problem, generalizing their utility across spatial- and temporal-scales, and highlight the benefits of joint utilization and multi-modeling to minimize uncertainty and enhance operational robustness. Finally, we compare improved forecasts utilizing information from these data sets with our past efforts in the region.