|
The 2009 Atlantic hurricane season was a below-average Atlantic hurricane season that produced eleven tropical cyclones, nine named storms, three hurricanes, and two major hurricanes. It officially began on June 1 and ended on November 30, dates that conventionally delimit the period of each year when most tropical cyclones develop in the Atlantic basin. The season's first tropical cyclone, Tropical Depression One, developed on May 28, while the final storm, Hurricane Ida, dissipated on November 10. The most intense hurricane, Bill, was a powerful Cape Verde-type hurricane that affected areas from the Leeward Islands to Newfoundland. The season featured the lowest number of tropical cyclones since the 1997 season, and only one system, Claudette, made landfall in the United States. Forming from the interaction of a tropical wave and an upper level low, Claudette made landfall on the Florida Panhandle with maximum sustained winds of 45 mph (75 km/h) before quickly dissipating over Alabama. The storm killed two people and caused $228,000 (2009 USD) in damage. Pre-season forecasts issued by Colorado State University (CSU) called for fourteen named storms and seven hurricanes, of which three were expected to attain major hurricane status.〔A major hurricane is a storm that ranks as Category 3 or higher on the Saffir-Simpson Hurricane Scale.〕 The National Oceanic and Atmospheric Administration (NOAA) later issued its initial forecast, which predicted nine to fourteen named storms, four to seven hurricanes, and one to three major hurricanes. After several revisions in the projected number of named storms, both agencies lowered their forecasts by the middle of the season. Several storms made landfall or directly affected land outside of the United States. Tropical Storm Ana brought substantial rainfall totals to many of the Caribbean islands, including Puerto Rico, which led to minor street flooding. Hurricane Bill delivered gusty winds and rain to the island of Newfoundland, while Tropical Storm Danny affected the U.S. state of North Carolina, and Erika affected the Lesser Antilles as a poorly organized tropical system. Hurricane Fred affected the Cape Verde Islands as a developing tropical cyclone and Tropical Storm Grace briefly impacted the Azores, becoming the farthest northeast forming storm on record. The season's final storm, Ida, affected portions of Central America before bringing significant rainfall to the Southeast United States as an extratropical cyclone. ==Seasonal forecasts== Forecasts of hurricane activity are issued before each hurricane season by noted hurricane experts Philip J. Klotzbach, William M. Gray, and their associates at Colorado State University; and separately by NOAA forecasters. Klotzbach's team (formerly led by Gray) defined the average number of storms per season (1950 to 2000) as 9.6 tropical storms, 5.9 hurricanes, 2.3 major hurricanes (storms reaching at least Category 3 strength in the Saffir-Simpson Hurricane Scale) and ACE Index 96.1. NOAA defines a season as above-normal, near-normal or below-normal by a combination of the number of named storms, the number reaching hurricane strength, the number reaching major hurricane strength and ACE Index. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「2009 Atlantic hurricane season」の詳細全文を読む スポンサード リンク
|