1. December Briefing

2. Outline Current Conditions Primary Factors – 2 nd Year La Nina – Drought Region / Feedback – Role of AO/NAO Streamflow Outlook – Historical – SERFC Ensemble Streamflow Prediction

4. Past 30 Day (% of Normal) Rainfall

5. Past 60 Day (% of Normal) Rainfall

6. YTD (% of Normal) Rainfall

9. Drought Monitor

10. Recent enhanced inflows have stabilized but not increased pool elevation

12. Typical US Temperature, Precipitation and Jet Stream Patterns during La Niña Winters Jet Stream / Active Weather Generally North of ACF

14. Take Away: Correlation between ENSO & SE US Rainfall never fully made up deficits from past drought?

15. Lanier Pool (ft) Rainfall Deficits Increase from Winter 2007 to Spring 2008 Lanier Pools recover In 2009

16. 1 st vs 2 nd Year La Niña Composites Year 1 Year 2 Year 1 - worked out fairly well Year 2 - generally drier

17. ‘Double-Dip’ Las Niñas Data courtesy of Melissa Griffin (Florida Asst. SC)

18. Weather Can Override Climate

23. Summary La Niña will dominate this winter. Generally, this will continue to reinforce reduced rainfall and overall drought across the Southeast U.S. AO/NAO can tend to either enhance or override the ENSO signal. Extremely low stream flow and soil moisture will reduce inflows. Very tight rainfall gradient over basin north of Lake Lanier. A switch to El Niño by next fall, the record of the last decadewould favor an end of the 2010-12 drought.

24. SERFC Journal 2-3 times a week Water Resources Outlook – bi-weekly weather.gov/serfc