The National Climatic Data Center is the host of the historical as well as current climate and weather data for the entire nation. It also has access to data at foreign countries. You can find up-to-date information on developing storms and major climate and weather events from NCDC's web page. The two regional climate centers in the Great Plains and central U.S. are the High Plains Regional Climate Center at Lincoln, NE, and the Midwestern Regional Climate Center in Champaign, IL. These regional centers provide climate data of individual weather stations in the region and data products from automated weather station networks in the region. Should you have problems in getting the data and understanding the data I will be glad to help, just send an e-mail to qhu2@unl.edu.