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Hurricane Leslie was an Atlantic tropical cyclone that had minor effects in Bermuda and Atlantic Canada in September 2012. The twelfth tropical cyclone of the annual hurricane season, Leslie developed from a tropical wave located nearly east of the Leeward Islands on August 30. About twelve hours later, it strengthened into Tropical Storm Leslie. Tracking steadily west-northwestward, it slowly intensified due to only marginally favorable conditions. By September 2, the storm curved north-northwestward while located north of the Leeward Islands. Thereafter, a blocking pattern over Atlantic Canada caused Leslie to drift for four days. Late on September 5, Leslie was upgraded to a Category 1 hurricane. However, due to its slow movement, the storm causing upwelling, which decreased sea surface temperatures (SST's), weakening Leslie back to a tropical storm on September 7. The storm drifted until September 9, when it accelerated while passing east of Bermuda. Relatively strong winds on the island caused hundreds of power outages and knocked down tree branches, electrical poles, and other debris. Slight re-intensification took place, with Leslie becoming a hurricane again, before transitioning into an extratropical cyclone near Newfoundland on September 11. In Atlantic Canada, the storm brought heavy rainfall to both Nova Scotia and Newfoundland. In the latter, localized flooding occurred, especially in the western portions of the province. Also in Newfoundland, strong winds from Leslie ripped off roofs, destroyed trees, and left 45,000 homes without power. Additionally, a partially built house was destroyed and several incomplete homes were damaged in Pouch Cove. Overall, Hurricane Leslie caused $10.1 million (2012 USD) in damage and no fatalities.〔 ==Meteorological history== A tropical wave, which was accompanied by a broad surface low pressure area, emerged into the Atlantic Ocean from the west coast of Africa late on August 26. Tracking generally westward, the system remained disorganized for the next several days. By August 29, the system became increasingly organized as showers and thunderstorms concentrated toward the center.〔 Based on Dvorak satellite classifications and scatterometer surface wind data, it is estimated that Tropical Depression Twelve developed at 0000 UTC on August 30, while located about east-southeast of the northern Leeward Islands.〔 Situated to the south of a subtropical ridge, the system tracked west-northwestward over warm waters. As a result, the depression strengthened into Tropical Storm Leslie by 1200 UTC on August 30.〔 After becoming a tropical storm on August 30, the subtropical ridge caused Leslie to turn west-northwestward.〔 By the early on August 31, the storm featured well-define outflow in all directions and the center of circulation was close to the main area of convection. Intensity estimates around that time indicated sustained wind speeds of 70 mph (110 km/h).〔 However, intensification halted later on August 31 as wind shear increased over the storm, causing convection to become displaced from the center. Early on September 1, an eye-like feature appeared on satellite imagery; however, there was uncertainty as to whether or not the feature was displaced from the low-level center. The storm became increasingly disorganized, with the circulation displaced from the main convective area several hours later. Relentless wind shear caused Leslie to weaken to slightly to a 60 mph (95 km/h) tropical storm, despite sea surface temperatures (SSTs) exceeding . Early on September 3, the storm decelerated and curved northwestward, while approaching a weakness in Bermuda high pressure ridge. Eventually, Leslie turned to a more northerly motion. A blocking pattern over Atlantic Canada caused the storm to drift at forward speeds under for four days. Wind shear also decreased, allowing Leslie to re-organize and strengthen into a hurricane at 1200 UTC on September 5.〔 Six hours later, Leslie attained its maximum sustained wind speed of 80 mph (130 km/h). However, the slow movement of the storm caused upwelling – a process by which warm SSTs are replaced with colder waters. As a result, Leslie slowly began to weaken and fell to tropical storm intensity by early on September 8. Despite weakening, the storm's circulation expanded to a radius of more than ; the wind field also expanded, with tropical storm force winds reaching about in diameter from the center.〔 By early on September 9, the blocking pattern diminished as a broad mid- to upper-level trough and associated cold front moved off the East Coast of the United States. As a result, Leslie accelerated north-northeastward. Later that day, the storm passed about east of Bermuda. After leaving the region of upwelled waters, Leslie began to re-strengthen and became a hurricane again at 1200 UTC on September 10. Early on the following day, the storm reached its minimum barometric pressure of . However, a combination of cold SSTs, strong wind shear, and merging with a cold front caused the storm to become an extratropical cyclone at 0900 UTC on September 11, while located about south of St. Lawrence, Newfoundland.〔 Leslie was operationally considered a tropical cyclone when it made landfall on the Burin Peninsula of Newfoundland. The remnants of Leslie moved rapidly across Newfoundland and re-emerged into the Atlantic later on September 11. At 0600 UTC on the following day, the remnants of Leslie merged with another extratropical low pressure area over the Labrador Sea.〔 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 Leslie (2012)」の詳細全文を読む スポンサード リンク
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