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The meteorological history of Hurricane Dean began in the second week of August 2007 when a vigorous tropical wave moved off the west coast of Africa into the North Atlantic ocean. Although the wave initially experienced strong easterly wind shear, it quickly moved into an environment better suited for tropical development and gained organization. On the morning of August 13, the National Hurricane Center recognized the system's organization and designated it Tropical Depression Four while it was still more than 1,500 mi (2,400 km) east of the Lesser Antilles. A deep layered ridge to its north steered the system west as it moved rapidly towards the Caribbean and into warmer waters. On August 14 the depression gained strength and was upgraded to Tropical Storm ''Dean''. By August 16, the storm had intensified further and attained hurricane status. Hurricane Dean continued to intensify as it tracked westward through the Lesser Antilles. Once in the Caribbean Sea, the storm rapidly intensified to a Category 5 hurricane on the Saffir-Simpson Hurricane Scale. Weakening slightly, it brushed the southern coast of Jamaica on August 19 as a Category 4 hurricane and continued towards the Yucatán Peninsula through even warmer waters. The favorable conditions of the western Caribbean Sea allowed the storm to intensify and it regained Category 5 status the next day before making landfall in southern Quintana Roo. Hurricane Dean was one of two storms in the 2007 Atlantic hurricane season to make landfall as a Category 5 hurricane and was the seventh most intense Atlantic hurricane ever recorded, tied with Camille and Mitch. After its first landfall, Hurricane Dean crossed the Yucatán Peninsula and emerged, weakened, into the Bay of Campeche. It briefly restrengthened in the warm waters of the bay before making a second landfall in Veracruz. Dean progressed to the northwest, weakening into a remnant low which finally dissipated over the southwestern United States. ==Formation== On August 11, 2007, a vigorous tropical wave moved off the west coast of Africa, producing disorganized showers and thunderstorms. It encountered conditions favorable for gradual development, and on August 12 it gained organization and became a low.〔 Strong upper-level easterly winds slowed development, but on August 13 the tropical wave gained enough organization that the National Hurricane Center designated it ''Tropical Depression Four''. At this time it was centered about 520 mi (835 km) west-southwest of Cape Verde. The depression was already exhibiting persistent deep convection in the western portion of its circulation. It moved quickly westward, south of a deep layered ridge, escaping the easterly wind shear that had been slowing its development and moving over warmer waters. At 1500 UTC on August 14, the depression was upgraded to Tropical Storm Dean while still 1450 mi (2300 km) east of Barbados.〔 Even as its convection waned slightly that afternoon, its intensity grew, and convection flared in the center that night. Dry air and cooler air inflow from the north slowed structural development; nevertheless, ragged bands began to form on August 15. By mid-morning, a rough banding eye had formed, and by the next morning a full eye developed.〔 The storm was upgraded to Hurricane Dean at 0900 UTC August 16, 550 mi (890 km) east of Barbados.〔 A strong ridge of high pressure continued to push the system west, towards the Caribbean Sea. That afternoon, convective banding and increasing upper-level outflow strengthened the storm to a Category 2 hurricane on the Saffir-Simpson Hurricane Scale. The eye disappeared briefly overnight, possibly as part of a diurnal fluctuation, but returned by the morning of August 17. 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 Dean」の詳細全文を読む スポンサード リンク
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