This bill reauthorizes and updates the Snow Water Supply Forecasting Program, which is run by the Department of the Interior to improve how water supplies are predicted based on mountain snowpack data. It shifts the program's focus from initial technology development toward ongoing deployment of advanced tools like imaging spectroscopy, machine learning, and hydrologic modeling to produce more accurate and timely water supply forecasts. The program will prioritize river basins where better forecasting can support water management decisions spanning multiple water users, basins, or states, including interstate water issues, and will work to build the technical capacity of partner agencies and organizations. It also updates reporting requirements, directing officials to assess which technologies work best for multi-jurisdictional water planning and to benchmark new forecasts against those from the Department of Agriculture and NOAA. Funding is reauthorized at $3 million per year for fiscal years 2027 through 2031, replacing the previous funding level of $15 million total for 2022 through 2026. This primarily affects federal water management agencies, state and local water districts, and communities that rely on accurate snowpack and water supply forecasts for planning and reservoir operations.