National Weather Service United States Department of Commerce

National Precipitation Frequency Standard Proposed Update
The NOAA/NWS Office of Water Prediction is updating the modeling framework of the NWS’s authoratitive precipitation frequency analysis product (currently NOAA Atlas 14) which provides precipitation depth/intensity duration frequency information and derived complementary information. This update would allow for the modeling of temporal nonstationarity and the integration of future climate projections. The update will provide continuous spatial coverage for the United States and affiliated territories.

The NWS is soliciting comments and feedback on this proposed update through November 15, 2022. The NWS Public Information Statement (PNS) with additional details on this update is available here.

For any questions or additional feedback, please get in touch with us at

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frequency estimates
The NWS-OWP Hydrometeorological Design Studies Center provides precipitation frequency (PF) estimates for various areas of the U.S. as Volumes of NOAA Atlas 14. Estimates in a variety of formats with supplementary information and documentation are available from the PF Data Server (PFDS). Publications for states not covered by Atlas 14 are also available.
Probable maximum 
The National Weather Service (NWS) has provided probable maximum precipitation (PMP) guidance and studies at the request of various federal agencies . Probable maximum precipitation updates are currently not being developed. Legacy NWS PMP documents are available at this link.
Also available on this site: 

- NWS publications of interest for PF and PMP studies (NOAA Atlas 14, NOAA Atlas 2, Technical Reports,
Technical Papers, Hydrometeorological Reports)
- Probability analysis for selected historical storm events
- Record point precipitation for the USA and the world

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