LONDON, England, Thursday June 6, 2013 – Tropical Storm Risk (TSR), which provides real-time mapping and prediction of tropical cyclone windfields worldwide, has released their June forecast update for the 2013 Atlantic hurricane season and the outlook continues to be bleak.
The TSR June forecast update is still anticipating above-norm activity this year. Based on current and projected climate signals, Atlantic basin tropical cyclone activity and United States landfalling activity is forecast to be approximately 30 percent above the 1950-2012 long-term norm but about 10 percent below the recent 2003-2012 10-year norm.
The updated forecast spans the period from June 1 to November 30, 2013 and employs data through to the end of May 2013.
The key factors behind the TSR forecast for an above-norm hurricane season this year are the forecast July-September trade wind speed over the Caribbean and tropical North Atlantic, and the forecast August-September 2013 sea surface temperatures in the tropical North Atlantic.
The former influences cyclonic vorticity (the spinning up of storms) in the main hurricane track region, while the latter provides heat and moisture to power incipient storms in the main track region.
These factors would help to energise and sustain more storms, and there is a 61 percent likelihood that activity will be in the top one-third of years historically.
For Atlantic basin hurricane activity referenced to long-term norm values, TSR forecasts:
• 16 tropical storms including eight hurricanes and four intense hurricanes. This compares to long-term norms of 11, six and three respectively.
• An ACE (Accumulated Cyclone Energy) value of 134. The long-term norm is 103.
• Five tropical storm and two hurricane landfalls on the US mainland.
According to Professor Mark Saunders and Dr Adam Lea of the Department of Space and Climate Physics, University College London, the precision of TSR’s June forecasts for upcoming Atlantic hurricane activity since 2000 is moderate.