Scientists forecast above-average Atlantic hurricane activity in 2013

The Tropical Storm Risk consortium has predicted above-average hurricane activity in the Atlantic basin in 2013. 

Its recent report, co-written by Mark Saunders and Adam Lea of the University College London (UCL)’s department of space and climate physics, uses forecasts of both the speed of the trade winds over the Caribbean and tropical North Atlantic in September, and the sea surface temperatures forecast for August-September.

“Based on current and projected climate signals, Atlantic basin tropical cyclone activity is forecast to be about 30% above the 1950-2012 long-term norm but slightly below the recent 2003-2012 10-year norm,” according to the report.

The Extended Range Forecast for Atlantic Hurricane Activity in 2013, issued Dec. 5, uses a measure known as the accumulated cyclone energy (ACE) index, which in turn is based on maximum sustained wind speeds for storm systems.

“There is a 59% probability that the 2013 Atlantic hurricane season ACE index will be above-average (defined as an ACE index value in the upper tercile historically (>121)), a 27% likelihood it will be near-normal (defined as an ACE index value in the middle tercile historically (72 to 121) and a 14% chance it will be below-normal (defined as an ACE index value in the lower tercile historically (<72)),” according to the report.

The TSR consortium includes experts from Aon Benfield, RSA Insurance Group and Crawford & Company. Its science group includes climate physicists, meteorologists and statisticians from both UCL and the Aon Benfield UCL Hazard Research Centre.

Saunders is a UCL professor of climate prediction and head of seasonal forecasting and meteorological hazards at the Aon Benfield UCL Hazard Research Centre. Lea is a UCL research fellow, specializing in seasonal prediction of tropical cyclone activity.