Relationships between ENSO and Daily Precipitation in the United States

In this ATLAS we examine relationships between warm (El Nino) and cold (La Nina) episodes in the tropical Pacific and daily precipitation statistics over the conterminous United States. For this purpose we employ a set of gridded daily precipitation analyses over the conterminous United States (Higgins et al. 1996) which cover the period 1948-1996. One of the main goals of this project is to provide an in depth analysis of the seasonal relationships between warm and cold episodes, and the amount, intensity and frequency of daily precipitation events over the conterminous United States. Maps which show the geographical distribution of seasonal means as well as time series of various statistics for selected major metropolitan areas are included in the ATLAS. These results provide the necessary background for an investigation of trends in precipitation amount, intensity and frequency in the United States. The purpose of this document is to serve as a users guide to the complete ATLAS, which is found on the CPC Home Page at http://nic.fb4.noaa.gov/research_papers/ncep_cpc_atlas.