Tropical cyclones are known as typhoon in the western Pacific and as hurricane in the A These storms most often develop in the later aummer and autumn over just north and south of the In the Atlantic ocean there are usually about six hurricanes and ten smaller tropical storms each But there is no way to know for sure how many storms will happen each year and how severe they will In the United States， experts at the government agency， the Nationla Hurricane Center near Miami Watch for the development of severe weather and warn people about the The National Hurricane Center depends mainly on modern satellites to observe developing It also uses information collected by passenger airplanes and ships and by American government Satellite pictures give the scientists a great idea about weather in a large Scientists use comlputers to increase the size of pictures that show a developing They study these pictures to learn more about the storm’s direction and The National Harricane Center’s adivisories are concerned mainly with ships in the ocean while a storm is moving over the But the center’s experts are most famous for their work when a hurricane begins moving towards At first the National Hurricane Center makes public weather advisories every six But as a storm gets closer to land， the weather warnings are made every three Experts at the center are on duty twenty-four hours each day to provide new
