1. Recap of Water Year 2008 Hydrologic Forecast and Forecasts for Water Year 2009 Francisco Munoz-Arriola Alan F. Hamlet Shraddhanand Shukla Dennis P. Lettenmaier JISAO/CSES Climate Impacts Group Dept. of Civil and Environmental Engineering University of Washington

2. Recap of WY 2008

3. ECMRWF ENSO anomaly 2008 European Centre for Medium-Range Weather Forecasts

4. Validation Plot for 2008 Forecast (All Cool ENSO composite) Modified Flow (cfs)

5. WY 2007WY 2008 Potential Implications of ENSO Transition States

6. 19041.47 19071.00 19211.00 19250.49 19320.39 19430.88 19650.90 19711.55 19742.22 19840.58 1989-0.40 19960.93 19990.89 Historic Dalles Apr-Sept streamflow anomalies for water years with previous winter warm ENSO, current winter cool ENSO Stats: 12 of 13 above 0.39 11 of 13 above 0.49 9 of 13 above 0.88

7. Modified Flow (cfs) Validation Plot for 2008 Forecast (All Warm to Cool ENSO composite)

8. WY 2009 Forecast

9. WY 2007WY 2008 Potential Implications of ENSO Transition States WY 2009

10. http://www.ecmwf.int/products/forecasts/d/charts/seasonal/forecast/seasonal_range _forecast/nino_plumes_public_s3/ European Centre for Medium-Range Weather Forecasts ECMRWF ENSO anomaly 2009 0.2 -0.6

11. 1916-2002 April-September Naturalized Flow for the Columbia River at The Dalles, OR from Historic Water Years vs January Nino 3.4 Anomalies.

12. Soil Moisture and Snow Water Anomalies

13. SWE and SM Simulated Climatological March April February

14. SWE and SM Simulated Climatological MarchFebruaryApril JulyAugustSeptember

15. Based on Dalles Climatology 1901-2005 All Years Ensemble Mean Climatological Mean Ensemble Members Climatological Extremes

16. Based on Dalles Climatology 1901-2005 ENSO-Neutral Years Ensemble Mean Climatological Mean Ensemble Members Climatological Extremes

17. 3.4 Range 2009 -0.6 to 0.2 Based on Dalles Climatology 1901-2005 Ensemble Mean Climatological Mean Ensemble Members Climatological Extremes

18. West-Wide Hydrologic Forecast

19. West Wide Forecast (1961-2000) All Years Ensemble Mean Climatological Mean Ensemble Members Climatological Extremes ENSO-years Mean (N)

20. ENSO-Neutral Years West Wide Forecast (1961-2000) Ensemble Mean Climatological Mean Ensemble Members Climatological Extremes ENSO-years Mean (N)

21. 3.4 Range 2009 -0.6 to 0.2 West Wide Forecast (1961-2000) Ensemble Mean Climatological Mean Ensemble Members Climatological Extremes ENSO-years Mean (N)

22. UW Forecast System in the Hydropower-related stations

23. Conclusions:. Cold ENSO conditions favored the prediction of wet conditions during the WY 2008. Flows above the average were observed late in the spring. Dry soil moisture conditions at the end of the winter and beginning of the spring evidenced the above average snow pack. Neutral ENSO conditions are expected for the winter of 2008- 2009, which will maintain streamflow levels around the climatological mean. Current soil moisture conditions may contribute to slightly reduce streamflow generation during the Jan-June period by 3%. Streamflow in hydropower-related stations and in all the stations forecasted for the Columbia River basin was within the average limits.

24. Soil Moisture and Snow Water Equivalent Percentiles

25. SWE and SM Simulated FebruaryMarchApril Climatological