NOAA Atlas 15 - Generating National Climate-Informed Precipitation Frequency Estimates

Abstract Submission: Precipitation frequency estimates derived from historical gauge observations are used to plan and design national infrastructure projects. These estimates must be periodically updated to account for new data and improved methodologies. In the presence of a changing climate, such methodologies must now also incorporate nonstationarity reflecting observed trends in the data. In addition, anticipated precipitation changes derived from climate models can be used to obtain precipitation frequency estimates for future time periods. The Office of Water Prediction (OWP) of the National Oceanic and Atmospheric Administration’s (NOAA) National Weather Service (NWS) has been responsible for the development, production, and publication of such estimates for the United States and affiliated territories. NOAA recently received federal funding under the Bipartisan Infrastructure Law to update precipitation estimates nationwide, now accounting for nonstationarity. Building upon the work of NOAA Atlas 14, which has provided updated estimates for various parts of the country since the early 2000s, NOAA Atlas 15 will include seamless estimates for the contiguous United States (CONUS) and outside CONUS domains (including Hawaii and Alaska). Once complete, NOAA Atlas 15 will provide seamless high-resolution gridded estimates in two volumes: Volume 1 will provide a snapshot of estimates for present day (2023) that accounts for observed trends, and Volume 2 will provide projected estimates for 2030 - 2100 under different carbon emissions scenarios. Estimates developed from a prototype framework are now available through a new web interface for both volumes over the state of Montana. Preliminary estimates for CONUS are expected to be released in 2025, followed by final peer-reviewed estimates in 2026, and outside CONUS estimates in 2027. This presentation describes ongoing efforts to develop NOAA Atlas 15, including the creation of a data repository for CONUS and outside CONUS areas, the evolution of a nonstationary framework, and the computation of future estimates.

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