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Hurricane Gordon was the first tropical cyclone since 1992 to affect the Azores while retaining tropical characteristics. The eighth tropical storm, third hurricane, and first major hurricane of the 2006 Atlantic hurricane season, Gordon formed on September 10 in the tropical Atlantic Ocean. It gradually matured into a hurricane as it tracked northward, reaching its peak intensity with winds of 120 mph (195 km/h) early on September 14 while located about southeast of Bermuda. After becoming nearly stationary, Gordon weakened to minimal hurricane status, although it re-intensified after accelerating to the east. It weakened again after moving over cooler waters, and passed through the Azores on September 20. Shortly thereafter, it became an extratropical cyclone and subsequently affected Spain, Ireland, and the United Kingdom. The only land area affected while Gordon was tropical – the Azores – sustained little damage, in spite of wind gusts reaching hurricane force on Santa Maria Island. Impact was much more significant from the storm in its extratropical phase. In Spain, wind gusts reached along the northwest coast and left 100,000 people without power. Five people in the country sustained storm-related injuries. Further north, the storm brought a surge of tropical air to Ireland and the United Kingdom, contributing to record warm temperatures. In Northern Ireland, high winds left 120,000 people without power and caused one injury. ==Meteorological history== On September 1, a tropical wave exited the west coast of Africa and quickly showed signs of organization. It possessed a low pressure area and some convection as the system moved generally westward. The National Hurricane Center (NHC) first pinpointed the system as an area for potential development late on September 2 while it was about west-southwest of Cape Verde. However, an upper-level trough associated with the developing Hurricane Florence to its west increased wind shear across the region, which prevented significant tropical cyclone development over the next week.〔 However, on September 5, the NHC noted the potential for the storm system to organize into a tropical depression within the next several days, but its close proximity to Florence continued to stall its strengthening. By September 9, the trough moved far enough away from the system to allow wind shear to relent, signalling an increase in convective thunderstorm activity. At around 1800 UTC that day, the system developed into a tropical depression about east-northeast of the Lesser Antilles.〔 Upon developing, the depression, small in physical size, moved slowly west-northwestward. Initially, the NHC faced difficulties in forecasting the future of the system due to the potential for resumed strong wind shear, as well as uncertainty in its path of direction. It gradually organized and intensified, and based on observations from the Hurricane Hunters, the NHC assessed the depression as a tropical storm late on September 11; upon doing so, they gave it the name Gordon. As it strengthened, Gordon developed more substantial outflow and increasing banding features. On September 12, the storm slowed and turned toward the north through a weakness in the subtropical ridge created by Florence. Wind shear decreased further,〔 and the storm's convection became more symmetric with an intermittent eye feature in the center. Based on the presence of the eye and estimates from satellite imagery, it is estimated that Gordon intensified into a hurricane early on September 13. After becoming a hurricane, Gordon underwent rapid deepening as the eye became better defined and more intense. In 24 hours, the winds increased by to a peak intensity of 120 mph (195 km/h) early on September 14, while located about southeast of Bermuda. This made Gordon a major hurricane, as well as a Category 3 on the Saffir-Simpson scale, the first of 2006. As it curved to the northeast, the hurricane maintained its peak intensity for about 24 hours, during which the eye decreased in size and the eyewall convection weakened.〔 Afterward, Gordon began weakening due to moving over an area of cooler water temperatures. On September 15, the trough that was previously guiding the hurricane moved further away, allowing the ridge to build to the north and causing Gordon's motion to become nearly stationary. Increased wind shear imparted further weakening, and the hurricane's slow motion resulted in upwelling – the motion of cooler water to the ocean's surface. On September 17, a building ridge to the east caused Gordon to begin a steady northeast motion. By that time, the convection had diminished significantly and the winds weakened to minimal hurricane-force.〔 One NHC forecast predicted extratropical transition to occur within 48 hours. On September 18, Hurricane Gordon began accelerating to the northeast around a strengthening ridge, and later toward the east as guided by a trough. Wind shear decreased, which allowed for convection to redevelop near the eye. Unexpectedly, the hurricane began restrengthening, despite moving over slightly cooler waters; instability from cooler upper-level temperatures allowed for the reintensification.〔 Despite continued forecasts of a weakening trend, Gordon's resiliency presented a rare threat – the first since Hurricane Charley in 1992 – to the Azores, a Portuguese archipelago in the northeast Atlantic Ocean. At about 0600 UTC on September 19, the hurricane attained its secondary peak intensity of about 485 mi (775 km) west-southwest of the Azores.〔 By that time, the cyclone consisted of a solid ring of convection around a contracting eye.〔 Shortly thereafter, Gordon began steadily weakening due to the combination of increasing wind shear and even cooler water temperatures. Its motion became just south of due east, causing the strongest winds to remain south of the islands. At around 0900 UTC on September 20, Gordon passed through the Azores between the islands of Santa Maria and São Miguel, producing hurricane-force wind gusts on the former island. At the time, its sustained winds were estimated around , which remained south of any landmasses.〔 The cloud pattern had become less organized and more ragged. After passing the Azores, Gordon began interacting with an approaching cold front. Early on September 21, it completed the transition into an extratropical storm while simultaneously weakening below hurricane-force, located about west-northwest of the west coast of Portugal. The cyclone maintained its identity as the system turned sharply northeastward and later northward, after passing about 100 mi (160 km) northwest of the Spanish province of Galicia. Its forward motion accelerated to about , steered by another extratropical storm, while still maintaining sustained winds of . After moving along the west coast of Ireland, the extratropical remnants of Gordon turned to the northwest and intensified to hurricane-force winds. It turned to the southwest and later to the southeast, completing a large cyclonic loop before dissipating on September 24 to the south of Ireland.〔 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「Hurricane Gordon (2006)」の詳細全文を読む スポンサード リンク
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