1. Climate and Atmospheric Science Section, Division of State Water Survey, Prairie Research Institute, University of Illinois, Champaign, Illinois
2. Department of Agronomy, Iowa State University, Ames, Iowa
3. Department of Meteorology and Atmospheric Science, The Pennsylvania State University, University Park, Pennsylvania
4. Climate and Atmospheric Science Section, Division of State Water Survey, Prairie Research Institute, University of Illinois, Champaign, Illinois, and Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana