1. 2015 Monsoon Season Outlook Daniel Henz Meteorologist Flood Warning Branch Flood Warning Users Workshop June 24, 2015 Phoenix, Arizona Monsoon t-storm looking WNW from Papago Park, 08-17-2014, D. Henz

2. 2015 Monsoon Season Outlook June 24, 2015 Phoenix, Arizona Monsoon Outlook (Its complicated…) Image courtesy of SNL

3. 2015 Monsoon Season Outlook June 24, 2015 Phoenix, Arizona Topics For Today

4. 2015 Monsoon Season Outlook June 24, 2015 Phoenix, Arizona Topics For Today

5. El Niño, What is it? El Niño is the positive (warm) phase of the El Niño Southern Oscillation (ENSO). ENSO is a large scale ocean-atmosphere climate phenomenon occurring in the Equatorial Pacific Ocean Oscillates between positive (warm), neutral, negative (cold) phases in 3-10year cycles. 1 3 2 -1 -2 -3 0 Image Courtesy of NOAA/ESRL Ocean: Warm waters central & eastern equatorial Pacific. Atmosphere: Enhanced convection East-Pac 2015 Monsoon Season Outlook June 24, 2015 Phoenix, Arizona

6. Neutral La Niña El Niño Moderate Strength into 2016

7. Chances of El Niño continuation through the remainder of the year, ≈90% through Summer, ≥80% through the Winter.Chances of El Niño continuation through the remainder of the year, ≈90% through Summer, ≥80% through the Winter. CPC ENSO Forecast 2015 Monsoon Season Outlook June 24, 2015 Phoenix, Arizona

8. Chances of El Niño continuation through the remainder of the year, ≈90% through Summer, ≥80% through the Winter.Chances of El Niño continuation through the remainder of the year, ≈90% through Summer, ≥80% through the Winter. CPC ENSO Forecast 2015 Monsoon Season Outlook June 24, 2015 Phoenix, Arizona

9. Pacific Decadal Oscillation 2015 Monsoon Season Outlook June 24, 2015 Phoenix, Arizona Well Above Normal SST’s have persisted Winter into Spring

10. Key Large Scale Players 2015 Monsoon Season Outlook June 24, 2015 Phoenix, Arizona Anomalously Warm SST’s: Positive PDO Anomalously Warm SST’s: El Niño

11. East Pacific Hurricane Outlook 70% chance for an ABOVE AVERAGE Season (May 15 th – November 30 th ) Courtesy of NOAA’s National Hurricane Center 15-22 Named Storms Average year: 15 7-12 Hurricanes Average year: 8 5-8 Major Hurricanes Average year: 4

12. Tropical Cyclone Scorecard (as of mid June) 2015 Monsoon Season Outlook June 24, 2015 Phoenix, Arizona

13. Historical Monsoon Season Rainfall AZ Tropical System or remnants Onset Moderate/Strong El Niño ?

14. CPC 3-month Outlooks (Spring/Summer 2015) Jun-Jul-Aug Jul-Aug-Sep Aug-Sep-Oct Forecast Calling For: Early Summer: equal chances for above or below average rain. Early Summer: equal chances for above or below average rain. Late Summer: increasing probability for above average rain (Peak of Pacific hurricane season + strengthening El Ni ñ o response into Fall). Late Summer: increasing probability for above average rain (Peak of Pacific hurricane season + strengthening El Ni ñ o response into Fall). 2015 Monsoon Season Outlook June 24, 2015 Phoenix, Arizona

15. El Niño is HERE and looking to stay a while… El Niño is HERE and looking to stay a while… Below Avg. Rainfall ≠ Reduced Flooding Threat! Below Avg. Rainfall ≠ Reduced Flooding Threat! El Niño + Warm PDO = Active E-Pac TC Season El Niño + Warm PDO = Active E-Pac TC Season Wild Card…(cautious optimism) Wild Card…(cautious optimism) It only takes one widespread heavy rain event to reach the historical Monsoon rainfall quota or even double it! It only takes one widespread heavy rain event to reach the historical Monsoon rainfall quota or even double it! What to Take Away Fearless Forecast: Moderate/Strong El Niño 2015 AZ Monsoon Season: 85%-100% of avg. rainfall, ≈ 2.60”- 3.00” * * Rainfall forecasts above are averaged totals across all Maricopa County ALERT gages * 2015 Monsoon Season Outlook June 24, 2015 Phoenix, Arizona

16. A Long Look Ahead… (Fall/Winter 2015) Oct-Nov-Dec Dec-Jan-Feb Jan-Feb-Mar CPC Forecast Calls For: Above average rainfall predicted this fall/winter (Oct-Mar) should El Ni ñ o persist & strengthen. Above average rainfall predicted this fall/winter (Oct-Mar) should El Ni ñ o persist & strengthen. Highest probabilities of above avg. rainfall shift south and east: This mimics continuation of El Niño pattern. Highest probabilities of above avg. rainfall shift south and east: This mimics continuation of El Niño pattern. 2015 Monsoon Season Outlook June 24, 2015 Phoenix, Arizona

17. Chances of El Niño continuation through the remainder of the year, ≈90% through Summer, ≥80% through the Winter.Chances of El Niño continuation through the remainder of the year, ≈90% through Summer, ≥80% through the Winter. CPC ENSO Forecast 2015 Monsoon Season Outlook June 24, 2015 Phoenix, Arizona

18. El Niño observational and forecast images, Climate Prediction Center: http://www.cpc.ncep.noaa.gov/ Historic Monsoon rainfall data, NWS Tucson WFO: http://www.wrh.noaa.gov/twc/monsoon/monsoon_tracker.php Satellite Imagery, Unisys Weather: http://weather.unisys.com/archive/sat_ir/ SST Anomaly Data, NOAA/NESDIS: http://www.ospo.noaa.gov/Products/ocean/sst/anomaly/ Correlation Plots, NOAA/ESRL, PSD: http://www.esrl.noaa.gov/psd/data/usclimdivs/correlation/ Historic ALERT rainfall data, Flood Control District of Maricopa County: http://www.fcd.maricopa.gov/Rainfall/rainfall.aspx El Niño and La Niña Episodes and Their Impact on the Weather in the Tucson Metropolitan Area: Glenn Lader, WFO Tucson, AZ, 2012: http://www.wrh.noaa.gov/wrh/talite1201.pdf Data Sources/References 2015 Monsoon Season Outlook June 24, 2015 Phoenix, Arizona

19. Thank You! Questions…? www.fcd.maricopa.gov www.fcd.maricopa.gov@FCDFloodInfo www.facebook.com/FCDMaricopa DanielHenz@mail.maricopa.gov 2015 Monsoon Season Outlook June 24, 2015 Phoenix, Arizona