|
Tropical Storm Emily was a weak Atlantic tropical cyclone that brought torrential rains to much of the northern Caribbean in 2011. The fifth named storm of the annual hurricane season, Emily developed from a strong but poorly organized tropical wave that tracked the open Atlantic for several days in late July. On August 1, it approached the Lesser Antilles and became better defined, producing inclement weather over much of the area. Two days later, the disturbance developed a closed wind circulation center, marking the formation of Tropical Storm Emily. The storm remained fairly disorganized as it proceeded into the Caribbean, though it generated strong thunderstorms and gusty winds along its path. On August 4, Emily was declassified as a tropical cyclone, after the mountainous areas of Hispaniola disrupted its weak circulation. Upon exiting the northeastern Caribbean on August 6, its remnants regenerated into a tropical storm, ultimately dissipating the next day. Despite its poor organization, Emily wrought havoc across many Caribbean nations. Gusty winds felled trees and heavy rains triggered widespread flooding throughout the Lesser Antilles; any significant damage in those islands was confined to Martinique, however, where one fatality occurred. In Puerto Rico, similar floods affected residences and roads, with infrastructural losses in the territory estimated at $5 million. Even after dissipating, the remnants of Emily continued to produce prolonged rainfall over much of Hispaniola. Extensive floods and mudslides in the Dominican Republic displaced over 7,000 residents, and three people drowned in the capital of Santo Domingo. In neighboring Haiti, hundreds of homes were flooded in the Artibonite Department, prompting evacuations. Only minor wind damage occurred throughout the country's southern peninsula, but one death was reported in the region. ==Meteorological history== The cyclogenesis of Tropical Storm Emily was complicated, extending over several days from late July into early August. An easterly tropical wave—an equatorward trough of low pressure—exited the west African coast in the fourth week of July, at which point it became largely embedded within the monsoon trough. Located to the south of a ride of high pressure, the wave moved west-northwestward across the open Atlantic; it retained a broad circulation with little to no precipitation for a day or two. Over time, clusters of convection increased around the broad system, and it developed two distinct centers of circulation on July 30.〔 During the morning of July 31, the large low markedly gained in organization, and the National Hurricane Center (NHC) noted it was close to becoming a tropical depression. Later that day, however, the main circulation became increasingly elongated; its westernmost component soon detached to form a separate tropical wave. This new disturbance featured widely scattered convection and rainbands, which briefly affected the Lesser Antilles. The next day, a new area of deep convection with a dominant center formed as the circulation became better defined. It passed through the Leeward Islands with some improvement in its structure, and the surface winds rose to near tropical storm force.〔 A reconnaissance flight into the system revealed the circulation center had become well defined near the deep convection. The system was upgraded to tropical storm status and given the name Emily at 0000 UTC on August 2, when it was located to the south of Dominica. During the initial stages of its existence, the storm accelerated toward the west-northwest in response to the strong high pressure to its north.〔 With a relatively dry environment along its projected path, Emily was expected to strengthen only gradually until its predicted passage through the Greater Antilles. For several hours into August 2, the cyclone fluctuated little in intensity and organization as it developed banding features. Emily's appearance later improved on satellite images, and it developed a ragged central dense overcast; the NHC estimated that the storm had reached its peak sustained winds of 50 mph (80 km/h) by 0000 UTC on August 3.〔 Nevertheless, reconnaissance revealed that its circulation remained poorly organized, and at the time, several forecast models even supported dissipation prior to landfall in Hispaniola. An increase in upper wind shear removed the deepest convection from the circulation center, and it would remain so for the rest of the storm's duration. On August 4, the cloud pattern and convective banding became better organized near the center as the upper outflow over the cyclone expanded. Emily proceeded to track just south of the Dominican Republic, where its weak circulation became increasingly disrupted due to the adjacent high terrain and increasing vertical wind shear. The cyclone accelerated over Hispaniola and degenerated into an open trough around 2100 UTC that day.〔 The remnant trough proceeded northwestward into the Bahamas, where the NHC assessed a high chance of redevelopment based on relenting upper wind shear. Over the next couple of days, it moved over the Bahamas and proceeded east of southern Florida. Late on August 6, the trough developed a new center of circulation and regenerated into a weak tropical depression by 1800 UTC near Grand Bahama. Emily briefly reattained tropical storm strength six hours later, although it once again dissipated to a remnant low the next day owing to increasing wind shear. The low took on an accelerated east-northeastward motion, bypassing Bermuda before heading eastward over the open Atlantic. It briefly retained a broad area of gale-force winds with deep convection, which prompted the NHC to remonitor the system.〔 The combination of strong wind shear and its rapid forward speed inhibited significant development, and the remnant dissipated around 1200 UTC on August 11, about 980 mi (1,565 km) west of the Azores.〔 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「Tropical Storm Emily (2011)」の詳細全文を読む スポンサード リンク
|