Latest extended range forecast predicts 2012 Atlantic basin hurricane season will have reduced activity.
The reason for their conclusions are given in a report (see below) and are mainly due to an anomalously cool tropical Atlantic and the development of El Nino.
AccuWeather.com agrees with the El Nino scenario and says why:
El Niño is part of the El Niño Southern Oscillation (ENSO), which represents a cyclical variation in sea-surface temperatures over the tropical Pacific Ocean.
During the El Niño phase, water is warmer than average in the tropical Pacific. During the La Niña phase, like the past two winters, water is colder than average over the same area.
Both phases of ENSO, along with other factors, can have profound effects on weather patterns around the globe.
Simply put, during an El Niño, air is generally rising over the tropical Pacific and generally sinking over the tropical Atlantic.
More technically, wind shear is generally lower on the Pacific side and often higher on the Atlantic side, based on the setup of strong steering winds high in the atmosphere known as the jet stream.
Rising air and low wind shear favors tropical storm and hurricane development, while sinking air and wind shear inhibits it.
For much more on this go to:
http://www.accuweather.com/en/weather-news/el-nino-and-the-2012-hurricane/67636
They also give the warning, “Even during a building El Nino within hurricane season, there are still concerns for near-coast trouble.”