H.R. 4302 — Improving Atmospheric River Forecasts Act

This section establishes at least one pilot project within NOAA's U.S. Weather Research Program, administered by the Oceanic and Atmospheric Research office, to improve subseasonal to seasonal precipitation forecasts for water management in the western United States. The pilot project must address key science challenges—(1) improving model resolution for mountainous terrain (e.g., precipitation intensity and rain-versus-snow fractions); (2) enhancing modeling of the atmospheric boundary layer and atmospheric rivers in mountainous regions; (3) predicting winter atmospheric circulation and storm tracks over the eastern North Pacific and western United States; and (4) advancing understanding and prediction tools for atmospheric river landfalls and penetration—and must be coordinated with NOAA's Office of Oceanic and Atmospheric Research and National Weather Service to implement recommendations from the National Weather Service's 2019 subseasonal and seasonal forecasting report, achieve measurable operational improvements, and engage institutions of higher education and NOAA entities such as the Western Regional Climate Center and National Centers for Environmental Information. The section authorizes $15 million annually for FY2026 through FY2030 and sunsets the authority five years after enactment.

This section establishes an atmospheric river forecast improvement program to be carried out by the Under Secretary of Commerce for Oceans and Atmosphere, in collaboration with the weather industry and academic partners, with the goal of reducing loss of life, property damage, and economic losses from atmospheric rivers (i.e., narrow corridors of concentrated water vapor in the atmosphere that produce heavy precipitation and flooding, primarily affecting the U.S. West Coast) through improved forecasts, warnings, modeling, and research-to-operations transitions. The program requires (1) development of a public plan within 270 days of enactment, in consultation with the Secretary of the Air Force or Commander of the 53rd Weather Reconnaissance Squadron, detailing research, partnerships, technology transfer, resources, and timelines; (2) annual budget submissions to Congress; (3) evaluation of innovative observations, data assimilation, and modeling; (4) prototype high-resolution modeling, enhanced data assimilation from satellites and ocean observations, artificial intelligence applications, and improved baseline weather monitoring in affected areas; (5) aircraft, equipment, and personnel for reconnaissance missions aligned with the National Hurricane Operations Plan and National Winter Seasons Operations Plan, including data sharing for research, partnerships for flight planning, and data management strategies; and (6) research on quantitative intensity scales for atmospheric river and tropical cyclone hazards and best practices for hazard communication.