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

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

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

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

b – La Niña a – El Niño

THC (or AMO) STRONG THC (or AMO) WEAK

12 3 H H Courtesy of John Marshall (MIT)

Goldenberg et al. (2001)

YEARS 23 MH YEARS 9 MH % as frequent U.S. MAJOR HURRICANE IMPACTS

2014 Atlantic Hurricane Season Forecast Verification

ATLANTIC BASIN SEASONAL HURRICANE FORECASTS FOR 2014 Forecast Parameter and Median (in parentheses) 10 April 2014 Update 2 June 2014 Update 1 July 2014 Update 31 July 2014 Observed 2014 Total % of Median Named Storms (NS) (12.0) % Named Storm Days (NSD) (60.1) % Hurricanes (H) (6.5) % Hurricane Days (HD) (21.3) % Major Hurricanes (MH) (2.0) % Major Hurricane Days (MHD) (3.9) % Accumulated Cyclone Energy (ACE) (92) % Net Tropical Cyclone Activity (NTC) (103%) %

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

2015 Atlantic Hurricane Season Initial Outlook

Forecast Parameter Statistical Forecast Final Forecast Median Named Storms (NS) Named Storm Days (NSD) Hurricanes (H) Hurricane Days (HD) Major Hurricanes (MH) Major Hurricane Days (MHD) Accumulated Cyclone Energy (ACE) Net Tropical Cyclone Activity (NTC) FORECAST AS OF 9 APRIL 2015

Current Global Sea Surface Temperature Anomaly Map

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

El Niño Neutral

El Niño Latest Climate Forecast System Prediction

El Niño La Niña

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

NSNSDHHDMHMHDACENTC MEAN Forecast BEST ANALOG YEARS FOR 2015 (APRIL FORECAST)

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%)

Landfalling Hurricane Web Application Currently Available at the following URL: In partnership with the GeoGraphics Laboratory – Bridgewater State University, Bridgewater MA

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%)

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%)

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

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.”

Contact Info: Phil Klotzbach Web: Facebook: CSU Tropical Meteorology Project Contact Info: Phil Klotzbach Web: Facebook: CSU Tropical Meteorology Project