 On December 9 , 2014 , Tropical Storm Risk ( TSR ) , a public consortium consisting of experts on insurance , risk management , and seasonal climate forecasting at University College London , issued its first outlook on seasonal hurricane activity during the 2015 season . In its report , the organization forecast activity about 20 % below the 1950 – 2014 average , or about 30 % below the 2005 – 2014 average , totaling to 13 ( ± 4 ) tropical storms , 6 ( ± 3 ) hurricanes , 2 ( ± 2 ) major hurricanes , and a cumulative ACE index of 79 ( ± 58 ) units . This forecast was largely based on an enhancement of low @-@ level trade winds across the tropical Atlantic during the July to September period . TSR 's report stressed that uncertainty in this forecast existed due to the unpredictability in the El Niño Southern Oscillation and North Atlantic sea surface temperatures . 
