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The 1983 Atlantic hurricane season was the least active Atlantic hurricane season in 53 years, during which only four tropical storms formed.〔 〕 The season officially began on June 1, 1983, and lasted until November 30, 1983. These dates conventionally delimit the period of each year when most storms form in the Atlantic basin. The season had very little activity, with only seven tropical depressions, four of which reached tropical storm strength or higher. This led to the lowest Accumulated Cyclone Energy count since 1950, but not since 1900. The season began later than normal; the first tropical depression formed on July 29〔 and the second on July 31. Neither tropical depression strengthened and they dissipated soon thereafter. Hurricane Alicia formed as Tropical Depression Three on August 15, quickly intensified into a hurricane on August 16 and made landfall in Texas on August 18. Alicia caused over $3 billion in damage in Texas. Hurricane Barry formed on August 25, crossed Florida and strengthened into a hurricane. Barry made landfall near Brownsville, Texas and dissipated over land on August 30. Hurricane Chantal, the third of three hurricanes in 1983, formed on September 10. It strengthened into a hurricane, but stayed out at sea, and became absorbed by a front on September 15. Tropical Depression Six formed on September 19 and caused heavy rains in the Caribbean before degenerating into a wave on September 21. Tropical Storm Dean was the final storm of the season, forming on September 26. It originally tracked to the north, peaking at winds (85 km/h), and made landfall in the Delmarva Peninsula on September 29. It dissipated over the coast of Virginia on September 30. ==Seasonal forecasts and activity== Forecasts of hurricane activity are issued before each hurricane season by noted hurricane experts like Dr. William M. Gray, and his associates at Colorado State University. A normal season, as defined by NOAA, has six to fourteen named storms, with four to eight of those reaching hurricane strength, and one to three major hurricanes. The July 23, 1983 forecast predicted that after the slow start to the season, that a total of eight storms would form, and five of the storms would reach hurricane status. The forecast did not specify how many of the hurricanes would reach major hurricane status.〔 However, the predictions proved to be too high, with only four named storms forming by the end of the season and three of those reaching hurricane status.〔 The season, which began on June 1 and ended on November 30, was very inactive because of strong upper-level wind shear.〔 The wind shear was unusually strong throughout the Caribbean and open Atlantic, and disrupted convection in areas of disturbed weather so they could not develop. Over sixty African systems had formed and made it westward, but when they reached the Lesser Antilles, they were dissolved easily. The only area where the shear was minimal—a region encompassing the Gulf of Mexico and the Atlantic north of the Bahamas and east of Florida—was where the four named storms developed. This makes the 1983 season the least active season since the 1930 Atlantic hurricane season which had only two storms.〔 1983 and the prior season became the first example of two consecutive years to have no storms form in the Caribbean Sea since 1871, when reliable record began.〔 1983 also proved to be the first season since 1871 that a storm did not form south of 25°N latitude.〔 1983 was the first season for which the National Hurricane Center issued numeric landfall probabilities. Probabilities had been calculated for prior storms for use in the issuing of hurricane watches and warnings, but this was the first time the raw numeric probabilities were released to the public.〔 The probabilities issued were accurate during Alicia, indicating that Galveston and surrounding portions of the upper Texas coast were the most likely area to be struck. The season's activity was reflected with a low cumulative accumulated cyclone energy (ACE) rating of 17, which is classified as "below normal". ACE is, broadly speaking, a measure of the power of the hurricane multiplied by the length of time it existed, so storms that last a long time, as well as particularly strong hurricanes, have high ACEs. ACE is only calculated for full advisories on tropical systems at or exceeding 34 knots (39 mph, 63 km/h) or tropical storm strength. Subtropical cyclones are excluded from the total. 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「1983 Atlantic hurricane season」の詳細全文を読む スポンサード リンク
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