Northwest River Forecast Center

1. Northwest River Forecast Center Seasonal Volume Forecasts Using Ensemble Streamflow Prediction for the 2010 Water Year Steve King, Hydrologist Northwest River Forecast Center

2. Topics for Presentation • Northwest River Forecast Center • Overview • NWRFC Long Range Forecasting Models and Products • Statistical Water Supply Forecasts • Ensemble Streamflow Prediction (ESP) • Recap of WY 2009 Forecasts • 2010 Volumetric Streamflow Outlook • Update on new Statistical Water Supply procedures • New Web Tools for Users

3. Northwest River Forecast Center Total Area: 314,000 Columbia and Snake River Basins Coastal Drainages of Oregon and Washington 6 States & CANADA Support for 9 NWS Field Offices (WFOs) Grand Coulee Dam Lower Granite Dam The Dalles Dam The Willamette at Salem

4. NWRFC Forecasting Models • Statistical Water Supply • Seasonal Volumetric Forecasts • Regression techniques • 168 forecast locations • NWS Driver for ‘Official’ Federal Coordinated Forecasts • NWS River Forecast System • Short, Medium, and Longterm capabilities • Deterministic AND probabilistic (ESP) products • Water Supply capabilities

5. Seasonal Volume Forecastshttp://www.nwrfc.noaa.gov/water_supply/ws_fcst.cgihttp://www.nwrfc.noaa.gov/espws/espws.cgi ESP Volume Forecasts Statistical Water Supply

6. Monthly Water Supply Live Call / Webinar New Service Water Supply Release Schedule http://www.nwrfc.noaa.gov/water_supply/ws_fcst.cgi

7. 2009 WS Forecast Recap Seasonal Precipitation Above Grand Coulee ~ 89% Above Lower Granite ~ 109% Above The Dalles ~ 97%

8. 2009 WS Forecast Recap Spring Temperatures

9. 2009 Runoff Recap Red = Apr-Sep Blue = Jan-Jul Columbia R Grand Coulee 79% Dworshak Inflow 95% Snake R Lower Granite 96% Salmon River 111% Columbia The Dalles 84% Jackson Lake Inflow 104% Boise River 87% Owyhee Inflow 70% Palisades Inflow 108%

10. Legacy WS vs New SWS vs ESP Comparison for 2009 Season

11. LWS/SWS/ESP Verification

12. LWS/SWS/ESP Verification In summary,SWS looks promising, but we can’t draw conclusions based on one season of use

13. Spring 2010 Outlook • Ensemble Streamflow Prediction (ESP) • Driven by: Antecedent Snow/Soil Moisture 10 day Precip and Temp Forecast • Updated weekly • Capability of including climate forecasts/signals

14. 2010 Outlook (ESP Forecasts) Issued Oct 20, 2009 50% Ex. Prob = 29 MAF 97% of Normal (30 MAF) 50% Ex. Prob = 100 MAF 93% of Normal (107 MAF)

15. 2010 ESP Outlook Issued Oct 20, 2009 Red = Apr-Sep Blue = Jan-Jul Columbia R Grand Coulee 90% Dworshak Inflow 105% Snake R Lower Granite 97% Salmon River 100% Columbia The Dalles 93% Jackson Lake Inflow 84% Boise River 93% Owyhee Inflow 99% Palisades Inflow 85%

16. CPC 90 Day Temp/Precip OutlookDec-Jan-Feb

17. 2010 ESP Outlook CPC Pre-Adjust (Jan-Jul) Blue = No CPC Red = CPC Issued Sep 19, 2009 Columbia R Grand Coulee 96% 91% Snake R Lower Granite 96% 90% Columbia The Dalles 95% 91%

18. Post-Adjusted ESP Forecasts 6 ‘Weak’ El Nino Years In ESP Run

19. Post-Adjusted ESP Forecasts 14 El Nino Years In ESP Run

20. Western Water Supply Webpage http://www.nwrfc.noaa.gov/westernwater/ Upgrade v4.0 Nov 2010

21. ESP Interactive Ensemble Analyzer http://www.nwrfc.noaa.gov/espadp/espadp.cgi

22. ESP Interactive Ensemble Analyzer

23. ESP Interactive Ensemble Analyzer

24. Northwest River Forecast Centerwww.nwrfc.noaa.gov

25. Thanks!