1. Atlantic Basin Seasonal Hurricane Prediction Phil Klotzbach Department of Atmospheric Science Colorado State University National Tropical Weather Conference April 9, 2015

2. Outline Introduction Atlantic Basin Multi-Decadal Hurricane Variability Recent Downturn in US Landfalling Hurricane Activity 2014 Atlantic Basin Seasonal Forecast Verification 2015 Atlantic Basin Seasonal Outlook

4. “It's tough to make predictions, especially about the future” HOWEVER… “You can see a lot by looking” Yogi Berra

5. August – October SSTs: Ten Most Active – Ten Least Active Atlantic Hurricane Seasons Since 1950

6. b – La Niña a – El Niño

12. THC (or AMO) STRONG THC (or AMO) WEAK

13. 12 3 H H Courtesy of John Marshall (MIT)

14. 1860 1900 1940 1980 2020 Goldenberg et al. (2001)

19. 1915-1964 50 YEARS 23 MH 65 54 4450 60 59 60 54 55 54 55 45 47 49 48 38 35 29 26 28 33 1965-2014 50 YEARS 9 MH 89 85 04 05 04 92 96 40% as frequent U.S. MAJOR HURRICANE IMPACTS 21 19 65 93

21. 2014 Atlantic Hurricane Season Forecast Verification

22. ATLANTIC BASIN SEASONAL HURRICANE FORECASTS FOR 2014 Forecast Parameter and 1981- 2010 Median (in parentheses) 10 April 2014 Update 2 June 2014 Update 1 July 2014 Update 31 July 2014 Observed 2014 Total % of 1981- 2010 Median Named Storms (NS) (12.0)910 867% Named Storm Days (NSD) (60.1)3540 3558% Hurricanes (H) (6.5)3444692% Hurricane Days (HD) (21.3)1215 17.7583% Major Hurricanes (MH) (2.0)11112100% Major Hurricane Days (MHD) (3.9)23333.7596% Accumulated Cyclone Energy (ACE) (92) 5565 6773% Net Tropical Cyclone Activity (NTC) (103%) 6070 8280%

24. Relative Humidity Anomalies (600 mb) from mid-Aug to mid- Oct

26. 2015 Atlantic Hurricane Season Initial Outlook

27. Forecast Parameter Statistical Forecast Final Forecast 1981-2010 Median Named Storms (NS)7.4712.0 Named Storm Days (NSD)28.03060.1 Hurricanes (H)3.536.5 Hurricane Days (HD)9.01021.3 Major Hurricanes (MH)0.712.0 Major Hurricane Days (MHD)0.40.53.9 Accumulated Cyclone Energy (ACE)384092 Net Tropical Cyclone Activity (NTC)4445103 2015 FORECAST AS OF 9 APRIL 2015

28. Current Global Sea Surface Temperature Anomaly Map

29. August – October SSTs: Ten Most Active – Ten Least Active Atlantic Hurricane Seasons Since 1950

33. El Niño Neutral

34. El Niño Latest Climate Forecast System Prediction

35. El Niño La Niña

39. EQ. New April Forecast Predictors March SLP Jan-Mar SST ` ECMWF SST Forecast 1`1` 4`4` 3`3` February- March SLP 2`2`

41. NSNSDHHDMHMHDACENTC 1957838.00321.0026.508486 1987737.2535.0010.503446 1991824.2548.2521.253658 1993830.0049.5010.753952 2014835.00617.2523.506681 MEAN7.832.94.012.31.62.65265 2015 Forecast 73031010.504045 BEST ANALOG YEARS FOR 2015 (APRIL FORECAST)

42. 2015 PROBABILITIES FOR AT LEAST ONE MAJOR (CATEGORY 3-4-5) HURRICANE LANDFALL IN EACH OF THE FOLLOWING AREAS (20 th CENTURY PROBABILITIES IN PARENTHESES) 1)Entire U.S. coastline – 28% (52%) 2)U.S. East Coast including Peninsula Florida – 2)U.S. East Coast including Peninsula Florida – 15% (31%) 3)Gulf Coast from the Florida Panhandle westward to Brownsville – 15% (30%) 4)Caribbean (10-20°N, 60-88°W) – 22% (42%) 1)Entire U.S. coastline – 28% (52%) 2)U.S. East Coast including Peninsula Florida – 2)U.S. East Coast including Peninsula Florida – 15% (31%) 3)Gulf Coast from the Florida Panhandle westward to Brownsville – 15% (30%) 4)Caribbean (10-20°N, 60-88°W) – 22% (42%)

43. Landfalling Hurricane Web Application Currently Available at the following URL: In partnership with the GeoGraphics Laboratory – Bridgewater State University, Bridgewater MA http://www.e-transit.org/hurricane

44. 2015 Probabilities (20 th Century Probabilities in Parentheses) State Hurricane Impact Prob. MH Impact Prob. Florida 27% (51%) 10% (21%) Louisiana 15% (30%) 5% (12%) Massachusetts 3% (7%) 1% (2%) Mississippi 5% (11%) 2% (4%) New York 3% (8%) 1% (3%) North Carolina 14% (22%) 3% (8%) Texas 16% (33%) 5% (12%)

45. 2015Probabilities (20 th Century Probabilities in Parentheses) Country/Island Hurricane within 100 Miles MH within 100 Miles The Bahamas 28% (51%) 15% (30%) Cuba 28% (52%) 14% (28%) Haiti 13% (27%) 6% (13%) Jamaica 12% (25%) 5% (11%) Mexico 32% (57%) 11% (23%) Puerto Rico 14% (29%) 6% (13%) US Virgin Islands 15% (30%) 6% (12%)

46. Date 9 April 1 June 1 July 3 Aug SeasonalForecastXXXX 2015 Forecast Schedule 2015 Forecast Schedule

47. Arago’s Admonition: “Never, no matter what may be the progress of science, will honest scientific men who have regard for their reputations venture to predict the weather.” Arago’s Admonition: “Never, no matter what may be the progress of science, will honest scientific men who have regard for their reputations venture to predict the weather.”

48. Contact Info: Phil Klotzbach Email: philk@atmos.colostate.edu Web: http://tropical.atmos.colostate.edu Twitter: @philklotzbach Facebook: CSU Tropical Meteorology Project Contact Info: Phil Klotzbach Email: philk@atmos.colostate.edu Web: http://tropical.atmos.colostate.edu Twitter: @philklotzbach Facebook: CSU Tropical Meteorology Project