1. Drought in California How Did We Get Here and What Can We Expect This Year? November 7th 2014 APWA Sacramento Chapter Meeting Alan Haynes Service Coordination Hydrologist NOAA / National Weather Service California-Nevada River Forecast Center Sacramento, CA

2. How Did We Get into a Drought?

3. High Year to Year Variability

5. 8-Station Index (2012-2014)

6. 5-Station Index (2012-2014)

8. Oct 2011 Oct 2012 Oct 2013 Cumulative Effects on Storage

10. Blocking Semi-permanent upper level high pressure October 2013 to April 2014 Blocking Semi-permanent upper level high pressure October 2013 to April 2014 COL D Warm Dry H L Departure from Normal Weather Pattern (storm track)

11. Sources of Knowledge of Future Conditions Climate-Based Information Observed Weather Streamflow Weather Forecasts 0-15 Days Weather Forecasts 0-15 Days Immediate Past Hydrologic Model States - soil moisture -snowpack Hydrologic Model States - soil moisture -snowpack - Climate forecasts -Hydrologic ensemble forecasts using past weather inputs - Climate forecasts -Hydrologic ensemble forecasts using past weather inputs

12. Sources of Knowledge of Future Conditions Biggest source of skill in predicting water supply is the accumulated snowpackBiggest source of skill in predicting water supply is the accumulated snowpack Some knowledge from weather forecastsSome knowledge from weather forecasts Climate forecasts provide limited information – mainly from ENSO signal (i.e., El Nino)Climate forecasts provide limited information – mainly from ENSO signal (i.e., El Nino)

13. So What About El Nino?

14. Drought Busting3 Impact of El Nino on Water Supply

15. El Nino Evolution

17. El Nino Strength Forecast Strong Moderate Weak

18. Three Month Outlook Temperature Precipitation

19. Summary Drought brought about by cumulative multi-year precipitation shortagesDrought brought about by cumulative multi-year precipitation shortages Droughts are historically broken by a very wet yearDroughts are historically broken by a very wet year California starting year with dry antecedent conditions and low reservoir levelsCalifornia starting year with dry antecedent conditions and low reservoir levels ENSO-neutral conditions continue, for nowENSO-neutral conditions continue, for now El Nino favored to begin in the next 1-2 months and last into spring 2015El Nino favored to begin in the next 1-2 months and last into spring 2015 Chance of El Nino conditions is near 60-65%Chance of El Nino conditions is near 60-65% El Nino not likely to help much in ending the droughtEl Nino not likely to help much in ending the drought

20. Questions?