Tropical Storm Risk (TSR), part of Aon Benfield Research’s academic and industry collaboration, is forecasting 12 named storms, six hurricanes and two major (Category 3+) hurricanes between the months of June and November.
The April forecast for the Atlantic Hurricane season, issued on Tuesday, is similar to a preliminary forecast late last year, which forecast 13 named storms, five hurricanes and two major hurricanes.
The projected activity, from TSR’s Professor Mark Saunders and Dr. Adam Lea, is expected to be 20% below both the long-range norm since 1950 and 15% below the recent 2006-2015 norm, TSR said in a press release.
The report specifies two primary factors as to why a slightly below normal hurricane season has been forecast. The main reason is that sea surface temperatures across the tropical North Atlantic and Caribbean Sea during the peak development months of August and September are now expected to have a largely neutral influence on cyclogenesis. The forecast for the region is also slightly cooler than previously forecast in December 2015, the release noted. [click image below to enlarge]
Additionally, current projections indicate that trade winds over the same regions will be slightly stronger than originally anticipated, which may provide a small suppressing effect on developing tropical cyclones. The July-September trade wind prediction is based on the expectation of El Niño transitioning to near neutral conditions. This is in line with current consensus ENSO (El Niño-Southern-Oscillation) outlooks by both the dynamical and statistical models. Atmospheric and oceanic uncertainties remain for the upcoming season, the release said, and forecast skill for sea surface temperature and trade winds at this timeframe is less than 25%.
Drs. Saunders and Lea currently project that there is a 25% probability that the 2016 Atlantic Hurricane Season ACE Index will be above-average, a 35% likelihood that it will be near-normal and a 40% chance it will be below-normal.
TSR also states that if the 2016 forecast verifies, it may imply that the active phase of hurricane activity in the Atlantic basin has come to an end. It would be by far the lowest four year total (2013-2016) since 1991-1994. The active phase in the basin began in 1995.