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What We’ve Heard Thus Far: ACF Basin Outlook and Impacts

What We’ve Heard Thus Far: ACF Basin Outlook and Impacts. David Brown December 1, 2011. Introduction. Today’s gathering is a very specific example of regional climate services in action Promoting the delivery of region-specific climate information to a diverse community of users.

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What We’ve Heard Thus Far: ACF Basin Outlook and Impacts

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  1. What We’ve Heard Thus Far:ACF Basin Outlook and Impacts David Brown December 1, 2011

  2. Introduction • Today’s gathering is a very specific example of regional climate services in action • Promoting the delivery of region-specific climate information to a diverse community of users

  3. Introduction • Today’s gathering is a very specific example of regional climate services in action • Promoting the delivery of region-specific climate information to a diverse community of users • But – much of the information is highly technical

  4. Introduction • Today’s gathering is a very specific example of regional climate services in action • Promoting the delivery of region-specific climate information to a diverse community of users • But – much of the information is highly technical • What we (NOAA etc.) need to remember is – how do we package long-term (climate) information in a way that is useful for (short-term) decision-making? (W. Rooks, ~8:30am)

  5. ACF Outlook and Impacts Looking at Last Winter

  6. Dave Z – Review of 2010 • When we met in Albany in Nov 2010 – strong La Nina was in place, and the forecast for continued La Nina throughout the winter did verify • Impact on rainfall across ACF generally as expected: drier-than-normal in the north, somewhat wetter than expected to south • Impact on temperatures across ACF not as expected: AO/NAO led to unusually cold December; some return to above-normal temperatures in Jan/Feb • Spring impacts were largely La Nina-like

  7. ACF Outlook and Impacts Current Conditions

  8. Victor M – Current Conditions • ACF Basin “dancing on the edge” of significant, long-term drought especially in southwest GA • Based on season-to-date and year-to-date precip • There has been some short-term improvement in conditions over the past 60-90 days, which has helped ameliorate some of the drought risk • 2011-2012 winter and spring recharge in the ACF Basin will be crucial in determining the persistence and intensity of drought conditions

  9. ACF Outlook and Impacts Winter and Long-Lead Outlooks

  10. Mike H – Winter Outlook • La Nina has redeveloped and is expected to persist throughout the winter • AO/NAO continues to be erratic and difficult to predict – like last winter, it is possible that short-term variations could be more dominant than the La Nina signal, for short periods (especially for temperature) • Expected La Nina impacts for this winter: • Better chance for warmer-than-normal temperatures • Better change for drier-than-normal precipitation • Bottom line: drought likely to persist in ACF

  11. Jeff D – La Nina & ACF Recharge • Forecast for the primary recharge period (winter and spring) for ACF Basin is as follows: • Greatest likelihood is for below-normal inflows into Lake Lanier • Greatest likelihood is for below-normalstreamflow in the Flint, Chattahoochee, and Apalachicola Rivers • There is some uncertainty in these outlooks • Factors other than La Nina can become dominant over short periods (e.g., AO/NAO)

  12. Klaus – La Nina Forecast • La Nina is back • It will continue through the winter • But, this La Nina is weaker than last winter’s • Slight odds of a third winter of La Nina conditions in 2012-2013 (“triple delight”) • Any return to El Nino in 2012 would likely benefit ACF (but historically, more reliable impact would be in other drought-stricken areas such as Texas)

  13. ACF Outlook and Impacts Current Impacts

  14. Bailey C – Reservoir Update • Lake Lanier and other ACF reservoirs are unlikely to recover during upcoming recharge period • Several “system drivers” during current drought: • “Balanced system” operations • State water quality flow requirements • Revised Interim Operating Plan (most demanding) • Until recharge season begins, Corps will store as water while meeting basin-wide needs • Corps management decisions utilize both short- (e.g., QPFs) and long-term (e.g., CPC) information

  15. Brenda O – Agriculture Update • Observed impacts in ACF from ongoing drought: • Delayed planting (corn and peanuts) • Delayed emergence (peanuts) • Slow early season crop growth development (all) • Above-normal irrigation needs (corn and peanuts) • Delayed fruit set and maturity due to heat (peanuts) • Increased field abandonment (corn and peanuts) • Pronounced yield impacts (cotton, corn, peanuts) • Impacts less in northern Alabama/Georgia

  16. Steve G – Ecosystems Update • Recent droughts have resulted in lower stream flows than those prior to development activities • Potential impacts in ACF from ongoing drought: • Loss of habitats, stream aeration, and fish passage • Stressed or lost aquatic life • Reduced assimilative capacity, recreational activity, water supply, and stream health • System is already stressed • Record minimum flows in 2011 in Lower Flint

  17. Questions • Did we miss any key points? • Is there anything else to add? • Will this summary be useful to decision-makers within the ACF Basin?

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