| description abstract | he 2011 Atlantic season was marked by above-average tropical cyclone activity with the formation of 19 tropical storms. Seven of the storms became hurricanes and four became major hurricanes (category 3 or higher on the Saffir?Simpson hurricane wind scale). The numbers of tropical storms and hurricanes were above the long-term averages of 12 named storms, 6 hurricanes, and 3 major hurricanes. Despite the high level of activity, Irene was the only hurricane to hit land in 2011, striking both the Bahamas and the United States. Other storms, however, affected the United States, eastern Canada, Central America, eastern Mexico, and the northeastern Caribbean Sea islands. The death toll from the 2011 Atlantic tropical cyclones is 80. National Hurricane Center mean official track forecast errors in 2011 were smaller than the previous 5-yr means at all forecast times except 120 h. In addition, the official track forecast errors set records for accuracy at the 24-, 36-, 48-, and 72-h forecast times. The mean intensity forecast errors in 2011 ranged from about 6 kt (~3 m s?1) at 12 h to about 17 kt (~9 m s?1) at 72 and 120 h. These errors were below the 5-yr means at all forecast times. | |
