Alan F. Hamlet Andy Wood Dennis P. Lettenmaier JISAO Center for Science in the Earth System Climate Impacts Group and Department of Civil and Environmental Engineering University of Washington October, Water Resources Outlook for the Columbia River Basin

Recap of Water Year 2005

Observed Nino3.4 anomally

Historic Water Years vs January Nino 3.4 Anomalies

Red = Unconditional mean Blue = Ensemble mean Black = 2005 Observed Bias Corrected Long Range Streamflow Forecast for the Columbia River at The Dalles January Nino3.4 index between 0.2 and 1.2 Natural Streamflow (cfs)

Red = Unconditional mean Blue = Ensemble mean Black = 2005 Observed Bias Corrected Long Range Streamflow Forecast for the Columbia River at The Dalles January Nino3.4 index between 0.2 and 1.2 and warm PDO (epochs) Natural Streamflow (cfs)

Red = Unconditional mean Blue = Ensemble mean Black = 2005 Observed Bias Corrected Long Range Streamflow Forecast for the Columbia River at The Dalles Nino3.4 index between 0.2 and 1.2 and warm PDO (interannual) Natural Streamflow (cfs)

ColSim Reservoir Model VIC Hydrology Model Climate Forecast

Linkage to Reservoir Models Streamflow Forecast Bias Correction Reservoir Model Observed Reservoir Contents Storage Ensemble Demand Scenarios

All Years from for which J. Nino3.4 Anom. >= 0.2 AND <=1.2 Obs. System Storage Oct 1, 2005

October 1 Spin Up System Storage Forecast from SnakeSim: Jackson Lake Palisades Island Park Ririe American Falls Lake Walcott Nino3.4 anomaly between 0.2 and 1.2 C Demand aligned with water cond. Active Reservoir Storage (kaf) Obs. System Storage Oct 1, 2005

Outlook for Water Year 2006

December Winter Climate Forecasts Dominate Hydrologic State Variables Dominate JuneMarch Range =16.7% of ensemble summer mean April 1 SWE (mm)

Used range: Jan3.4 >= -0.4 Jan3.4 <= 0.6

Historic Water Years vs January Nino 3.4 Anomalies Red lines show approximate range for 2006 forecast

Red = Unconditional mean Blue = Ensemble mean Bias Corrected Long Range Streamflow Forecast for the Columbia River at The Dalles January Nino3.4 index between -0.4 and 0.6 Natural Streamflow (cfs)

Red = Unconditional mean Blue = Ensemble mean Bias Corrected Long Range Streamflow Forecast for the Columbia River at The Dalles January Nino3.4 index between -0.4 and 0.6 AND PDO neutral Natural Streamflow (cfs)

Used range: Jan3.4 >= 0.0 Jan3.4 <= 0.6

Red = Unconditional mean Blue = Ensemble mean Bias Corrected Long Range Streamflow Forecast for the Columbia River at The Dalles January Nino3.4 index between 0.0 and 0.6 Natural Streamflow (cfs)

ColSim Reservoir System Storage Forecast All Years from for which J. Nino3.4 Anom. >= -0.4 AND <= 0.6

Overview of Experimental Energy- Related Forecasting Products

Covariation of Normalized PNW and CA Hydropower Production California and PNW hydropower resources show a strong covariance in the second half of the 20 th century. R 2 =0.541

Probability of Exceedance for Spring Surplus Energy Resources in the PNW Voisin, N., A. F. Hamlet, L. P. Graham, D. W. Pierce, T. P. Barnett, and D. P. Lettenmaier, 2005: The role of climate forecasts in western U.S. power planning, Journal of Applied Meteorology (in press).

System-Wide Energy Production (MMW-hr/month) Forecast of System-Wide Energy Production from the Colsim Reservoir Model All Years from for which J. Nino3.4 Anom. >= -0.4 AND <= 0.6 Energy targets in each year of the simulation are for WY 2000

Selected References on Compositing Techniques: Hamlet, A.F., Lettenmaier, D.P., 1999: Columbia River Streamflow Forecasting Based on ENSO and PDO Climate Signals, ASCE J. of Water Res. Planning and Mgmt., 125 (6) : Werner K, Brandon D, Clark M, et al., 2004: Climate index weighting schemes for NWS ESP-based seasonal volume forecasts, J. of Hydrometeorology, 5 (6):