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Hurricane Karen was a hurricane of non-tropical origin that formed in October of the 2001 Atlantic hurricane season. It developed out of the interaction between a cold front and an upper level trough on October 10 located to the south of Bermuda, and quickly strengthened as an extratropical storm. The storm passed near Bermuda on October 12, producing hurricane-force winds on the island. It then organized, becoming a subtropical cyclone on the 12th and a tropical cyclone on the 13th. Karen strengthened to reach 80 mph (130 km/h) winds as a Category 1 hurricane on the Saffir-Simpson Hurricane Scale, and after weakening over cooler waters, it made landfall on Nova Scotia as a tropical storm. It quickly became extratropical. On Bermuda, winds from the precursor extratropical storm produced moderate damage, primarily to power lines and marine interests. Over 2/3 of the island's power subscribers were left without power during the worst of the storm, and several boats sank or ran aground from the high winds. Damage on Bermuda totaled to over $1.4 million (2001 USD; $1.7 million 2008 USD). In Atlantic Canada, Tropical Storm Karen produced light winds and rain, but caused minimal damage. ==Meteorological history== A cold front stalled a couple hundred miles southeast of Bermuda on October 10. During that day, a strong upper-level trough moved southeastward off the southeast coast of the United States. Due to several factors, including upward motion and strong diffluence—the rate at which a fluid moves—the area became baroclinically unstable. This caused the interaction between the trough and the front to develop into an extratropical low about 345 miles (555 km) southeast of Bermuda on October 11. The low moved quickly northward, then northwestward, strengthening quickly due to the instability of the atmosphere. Late on October 11, the system slowed, and the upper-level circulation became aligned with the low-level circulation. The extratropical storm began to develop tropical characteristics late on October 11, including surface temperatures warmer than the surrounding environment, and vertical wind characteristics of a tropical cyclone. Based on its organization, the system developed into Subtropical Storm One early on October 12 while located about 35 miles (55 km) south of Bermuda. While passing to the south of Bermuda, the subtropical storm maintained winds of 70 mph (110 km/h), with wind gusts on the island surpassing 100 mph (160 km/h). After becoming dissociated from the Westerlies, the system turned northward, and began to develop convection over the center. In addition, the frontal characteristics of the subtropical storm continually weakened. On October 13, based on an Advanced Microwave Sounding Unit observation that stated that a warm core was present throughout the system, the National Hurricane Center designated the system as a tropical storm, and gave it the name ''Karen''. At this point, Karen was located 200 miles (320 km) north of Bermuda.〔 Karen slowly strengthened over the warm waters of the Gulf Stream, and the storm intensified to a hurricane later on October 13.〔 Convection continued to develop, and organized into a ring around the eye as Karen reached its peak intensity of 80 mph (130 km/h) on October 14 while located about 400 miles (640 km) south of Halifax, Nova Scotia.〔 Karen quickly weakened as it moved over cooler waters,〔 and late on October 14 it degenerated back into a tropical storm as it accelerated northward. Convection gradually decreased, and Karen made landfall on southwestern Nova Scotia with winds of 45 mph (70 km/h) on October 15.〔 Karen retained its tropical characteristics during and after making landfall, based on a research flight out of Halifax intended to study the early stages of extratropical transition. The flight reported arced bands and a warm-core system transitioning into a more typical mid-latitude system. Under the influence of a mid-latitude system, the storm turned sharply to the northeast, and after losing the remaining of its convection it became extratropical shortly after landfall. Continuing northward, the remnant low quickly weakened, and dissipated as it was absorbed by a larger extratropical storm over the Gulf of Saint Lawrence.〔 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 Karen (2001)」の詳細全文を読む スポンサード リンク
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