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The meteorological history of Hurricane Andrew, the strongest tropical cyclone of the 1992 Atlantic hurricane season, lasted from mid to late August 1992. The hurricane developed from a tropical wave that moved off the coast of Africa on August 14. Tracking westward due to a ridge, favorable conditions allowed it to develop into Tropical Depression Three on August 16 in the deep tropical Atlantic Ocean. The cyclone gradually intensified, becoming a tropical storm on August 17. However, wind shear soon impacted the storm, causing significant increases in barometric pressure and nearly destroying its low-level circulation by August 20. Wind shear sharply decreased starting on August 21, and with warm sea surface temperatures, Andrew began rapid deepening, starting on the following day. By August 23, Andrew peaked as a Category 5 hurricane on the Saffir–Simpson hurricane wind scale while approaching The Bahamas. The cyclone weakened slightly before making landfall on Eleuthera later that day and the Berry Islands early on August 24. However, the storm then rapidly, but briefly restrengthened into a Category 5 hurricane, and was at that intensity when it struck Elliott Key and just south of Homestead, Florida on August 24. Andrew weakened while crossing Florida, but only reduced to a Category 4 hurricane while it emerged into the Gulf of Mexico. The storm re-intensified slightly in the Gulf, causing it to maintain its status as a Category 4 hurricane. Early on August 26, Andrew weakened slightly to a low-end Category 3 hurricane before making landfall near Morgan City, Louisiana. Once inland, the cyclone rapidly weakened, and less than 24 hours after landfall, Andrew was merely a tropical depression. It continued northeastward across the Southern United States, before merging with a frontal system on August 28, while centered over the southern Appalachian Mountains. ==Origins== A tropical wave moved off the coast of Africa on August 14. Under the influence of a ridge of high pressure to its north, the wave tracked quickly westward. An area of convection developed along the wave axis to the south of the Cape Verde islands, and on August 15 meteorologists began classifying the system with the Dvorak technique. The thunderstorm activity became more concentrated, and narrow spiral rainbands developed around a developing center of circulation. Based on a Dvorak T-number of 2.0, it is estimated Tropical Depression Three developed late on August 16 about east-southeast of Barbados. Embedded within the deep easterlies, the depression tracked west-northwestward at . Initially, moderate wind shear prevented strengthening, though a decrease in shear allowed the depression to intensify into Tropical Storm Andrew at around 1200 UTC on August 17.〔 By early on August 18, the storm maintained concentrated convection near the center with spiral bands to its west as the winds increased to . Shortly thereafter the thunderstorms decreased markedly during the diurnal minimum, and as the storm turned to the northwest increased southwesterly wind shear from an upper-level low prevented Andrew from maintaining deep convection.〔 On August 19, a Hurricane Hunters flight into the storm failed to locate a well-defined center, and the next day a flight found that the cyclone had degenerated to the extent that only a diffuse low-level circulation center remained; observations indicated the pressure rose to an unusually high 1015 mbar. The flight indicated Andrew maintained a vigorous circulation aloft, with winds of recorded at flight level. Subsequently, the upper-level low weakened and split into a trough, which decreased the wind shear over the storm. Simultaneously, a strong high pressure cell developed over the southeastern United States, which built eastward and caused Andrew to turn to the west.〔 Convection became more organized as upper-level outflow became better established. An eye formed, and Andrew attained hurricane status early on August 22 while located about eastsoutheast of Nassau, Bahamas.〔 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「Meteorological history of Hurricane Andrew」の詳細全文を読む スポンサード リンク
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