This product is a case study summarizing the original work authored by David Gutzler, Shaleene Chavarria, and Nels Bjarke. The content will be part of a collection of Case Studies shared via the Collaborative Conservation and Adaptation Strategy Toolbox (CCAST). The research featured in this case study is an analysis of historical observations and climate models developed by the US Bureau of Reclamation. The work aims to identify changes to streamflow predictability, assess future predictability, and inform the development of more reliable water supply outlooks essential for planning purposes in the Upper Rio Grande Basin.