The Global Energy and Water Cycle Experiment (GEWEX) Panel of the National Research Council (NRC) was tasked by the U.S. Global Change Research Program (USGCRP) to provide a rapid and succinct assessment to relevant agencies on the general merit of the GEWEX America Prediction Project (GAPP), as well as the Coordinated Enhanced Observing Period (CEOP). In addition, the panel was asked to provide guidance to the agencies on the relationships between the agencies’ newly proposed hydrologic research activities, GAPP, and CEOP. Providing this guidance is critical, in part, because the federal agencies tend to have somewhat differing priorities across the wide span of GEWEX activities.