SEASONAL STREAMFLOW FORECASTING USING CLIMATE INFORMATION

Note:This paper is a companion to “INCORPORATING SEASONAL STREAMFLOW FORECASTS INTO OPERATIONAL DECISIONMAKING” (Waage et al, this volume). It represents the text of a forecast provided to Denver Water in early November 2000.We present forecasts for 2001 April-July streamflow volume at four gages: Dillon Reservoir (DL), Williams Fork (WF), Fraser River at Winter Park (FR), and the South Platte at South Platte (SP). The first three gages are aggregated since they are highly correlated. We include recent information on the PDO and NIN03 indices to provide tercile probabilistic forecast and associated analog years. We rely on the nearest-neighbor analog (NNA) methodology. There is increased chance of upper tercile volume at DL, WF, FR and increased chance of lower tercile volume at PL.