Providing Research and Estimates of Changes In Precipitation Act or the PRECIP Act This bill directs the National Oceanic and Atmospheric Administration (NOAA) to take actions regarding precipitation estimation. NOAA shall, no less than every 10 years, update probable maximum precipitation estimates for the United States. NOAA must include specified information in the updates and must make publicly available certain probable maximum precipitation studies developed by NOAA. NOAA must seek to enter an agreement with the National Academies of Science, Engineering, and Medicine to conduct a study on the state of practice and research needs for precipitation estimation, including probable maximum precipitation estimation. NOAA, in consideration of the study's recommendations, shall consult with relevant partners on the development of a plan to update probable maximum precipitation estimates. NOAA shall develop a national guidance document regarding probable maximum precipitation estimates that (1) provides best practices for federal and state regulatory agencies, private meteorological consultants, and other users that perform probable maximum precipitation studies; (2) considers the recommendations provided in the National Academies study; (3) facilitates review of probable maximum precipitation studies by regulatory agencies; and (4) provides confidence in regional and site-specific probable maximum precipitation estimates.