arly indications show it could be an active year for the North Atlantic tropical storm season.
The Met Office will publish its initial forecast for the season, which runs from June to November, within the next month, but key indications point to an active season.
For the past three years, the Met Office forecast has given good indication of the number of storms and their combined strength (Accumulated Cyclone Energy or ACE Index) in its range.
Last season recorded just nine tropical storms, making it one of the quietest for a decade, but 2010 looks set to be more active.
Joanne Camp, climate scientist at the Met Office, said: “There are key indicators, such as sea-surface temperatures in the Pacific and Atlantic oceans, which determine how active a storm season is likely to be. These indicators currently suggest above-normal activity for the upcoming season.
“Certainly the current conditions create a favourable environment for tropical storms. These influences are represented in our forecasting system and will have an impact on the forecast.”
This year the Met Office has moved to a new prediction system called GloSea4. The new generation model has better representation of the complex physical processes that cause tropical storms and hurricanes to form. It is hoped this will further improve the accuracy of the forecast.
One of the key indicators for a tropical storm season is the El Niño Southern Oscillation (ENSO), which affects sea-surface temperatures in the tropical Pacific and, remotely, conditions in the North Atlantic. It’s therefore vital to be able to accurately predict the ENSO cycle, and GloSea4 has shown good skill in such predictions.
Observations show there is a declining El Niño, meaning tropical Pacific sea-surface temperatures are cooling. This has a tendency to increase the likelihood of tropical storms in the North Atlantic. Met Office predictions show this decline is likely to continue throughout the North Atlantic tropical storm season.
Forecasts and background information on tropical storms can be found on our tropical cyclones pages.
Our Climate Services for Reinsurance provide expert advice on tropical storms.
http://www.metoffice.gov.uk/corporate/p ... 00525.html