I just stumbled across a lovely interface for tracking precipitation in the U.S.: http://water.weather.gov/precip/. Previously I’d been using this site: http://www.cpc.ncep.noaa.gov/products/precip/realtime/. Alas, NOAA has discontinued that page and replaced it with something that is, to me at least, not very useful; fortunately, water.weather.gov is a great improvement.
It is also worth mentioning that I’ve always found NOAA’s website hopelessly baffling. They seem to be improving that; water.weather.gov is surprisingly easy to navigate to from either weather.gov or noaa.gov, but the cpc.ncep.noaa.gov side is hopeless. Suppose you start at the CPC’s “Monitoring and Data” page. Then you click on “United States Climate Data and Maps”, then “Precipitation and Temperature”, then “Recent Precipitation Maps”… and that sends you to http://www.cpc.ncep.noaa.gov/products/precip/realtime/, where you are redirected to http://www.cpc.ncep.noaa.gov/products/Global_Monsoons/gl_obs.shtml, which is apparently intended for global monsoon monitoring. Huh?