Continued Success for Seasonal North Atlantic Tropical Storm Forecast

The Met Office (UK) accurately predicted the above-average North Atlantic tropical storm season again this year, maintaining the excellent record of its forecast since it was introduced in 2007.

The 2010 North Atlantic hurricane season was one of the most active seasons on record with a total of 19 tropical storms. The Met Office public seasonal forecast, issued in June, predicted that there would most likely be 20 tropical storms (with a range 13–27) during July to November 2010 — the number of North Atlantic tropical storms in an average year is about 12.

For the accumulated cyclone energy (ACE) index — which summarises the combined strength and duration of storms within the season — the most likely predicted value was 204, with a range 90–319. The average value is about 130. The observed ACE index between July and November 2010 was 170.

Forecasts for commercial customers were also issued from April 2010 and consistently forecast an active season.

Joanne Camp, climate scientist at the Met Office, said: “The performance of the forecast over the last three years has been particularly good, with our forecast successfully predicting the above average seasons in 2008 and 2010 interspersed by the below average season in 2009.”

The Met Office seasonal tropical storm forecast is created using dynamical numerical models from the Met Office and the European Centre for Medium-Range Weather Forecasts (ECMWF). These simulate important interactions between the ocean and atmosphere, such as the El Niño Southern Oscillation (ENSO), which has a strong influence on Atlantic tropical storm development.

Despite the active tropical storm season in the Atlantic, unusually there were no hurricane strikes on the USA in 2010. Joanne Camp continued: “It remains a long term research goal of the Met Office to develop a seasonal tropical storm forecast which can deliver more detailed information on the local variability of storm activity within the Atlantic region.”