Public Information Statement
Issued by NWS National HQ
Issued by NWS National HQ
506 NOUS41 KWBC 261240 PNSWSH Public Information Statement 24-61 National Weather Service Headquarters Silver Spring MD 840 AM EDT Thu Sep 26 2024 To: Subscribers: -NOAA Weather Wire Service -Emergency Managers Weather Information Network -NOAAPort Other NWS Partners, Users and Employees From: Mark Glaudemans, Chief Water Resources Services Branch Subject: Soliciting Comments on Prototype NOAA Atlas 15 Precipitation Frequency Services over Montana through January 31, 2025 Through January 31,2025, the NWS is seeking user feedback for a prototype of NOAA Atlas 15 covering the state of Montana. NOAA Atlas 15 represents a new generation of precipitation frequency estimates that communicate the probability of observing extreme precipitation events of a specified duration, at a particular location of interest (e.g., the probability of observing 4 inches of precipitation over 6 hours at a given location). This information is used for the planning and design of infrastructure nationwide (e.g., roadways, culverts, drainage ponds, etc.). The NOAA Atlas 15 information, when published in 2026 and 2027, will update the current NOAA Atlas 14 precipitation frequency standard, providing new estimates for the entire U.S. and territories in a two Volume set that accounts for climate trends and climate projections. Volume 1 will account for temporal trends in historical observations, and Volume 2 will use future climate model projections to generate adjustment factors for Volume 1. NOAA Atlas 15 techniques are based on methods previously shared for comment in Public Information Statement (PNS) 22-59, issued November 15, 2022: https://www.weather.gov/media/notification/pdf2/pns22- 59_atlas_15.pdf The prototype NOAA Atlas 15 dataset will be available for viewing within the operational National Water Prediction Service (NWPS) website, which was deployed into operations in May 2024. NWPS is the NWS hydrologic web page for access to official river forecasts, output from the National Water Model and other water related products. The precipitation frequency information is contained under the main menu heading "Extreme Precipitation Estimates". The sub-menu contains options for: (a) "Precipitation Frequency Estimates", which in turn provides menu options for the current NOAA Atlas 14 standard, and the future NOAA Atlas 15 standard. Selecting the NOAA Atlas 15 option will display a page with links to the prototype. The prototype is provided for only the state of Montana; the final Atlas 15 volumes will cover the U.S. and territories. Preliminary estimates for the contiguous U.S. will be released in 2025 to begin the peer review process. (b) "Probable Maximum Precipitation (PMP) Estimates", which in turn provides menu options to current and future standards. This PMP information is provided for informational purposes only and is not part of the prototype evaluation being requested. The NWPS is accessible here: https://water.noaa.gov Background and supporting information on this prototype Atlas 15 data can be found in the Services Description Document (SDD) at the following link: https://nsdesk.servicenowservices.com/api/g_noa/nwspc/res2/4082d 73a87f05e904b0fa8a60cbb3574 The prototype data and website are being shared to facilitate awareness of the development of NOAA Atlas 15 and to solicit feedback on the methods, data content, visualizations, and web services, and help ensure practitioners have the precipitation information they need, upon final publication. The NOAA Atlas 15 methods, data, and website will be refined through 2026 and 2027, when the final NOAA Atlas 15 is published with national coverage. Feedback on the Atlas 15 precipitation frequency services is being sought from the users of this information. Please submit all feedback using the following form: https://forms.gle/4VwpkHBKsVv6BXJE8 There will be additional opportunities for comment on NOAA Atlas 15 as part of the extensive peer review process. Any questions, comments, or requests regarding this evaluation should be directed to the contact below. Fernando Salas Director, Geo-Intelligence Division Office of Water Prediction National Weather Service Tuscaloosa, AL atlas15.info@noaa.gov National Public Information Statements are online at: https://www.weather.gov/notification/