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The 1987 Atlantic hurricane season was a below-average hurricane season that was limited by an ongoing El Niño. The season officially began on June 1, 1987, and lasted until November 30, 1987, although activity began on May 24 when a tropical depression developed in the east central Bahamas. The June through November dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin. The first cyclone to attain tropical storm status was an unnamed tropical storm which formed on August 9, nearly a month later than usual. The final storm of the year, Tropical Depression Fourteen, merged with a weak extratropical low on November 4. The season marked the first year tropical storm watches and warnings were issued; previously, gale watches and warnings were used for tropical storms, and this season was one of only a few seasons with no deaths in the United States; the last time this happened was in the 1981 season. During this season, 14 tropical depressions formed of which seven attained tropical storm status. One tropical storm was operationally classified as a tropical depression but was reclassified in post-analysis. Three tropical cyclones reached hurricane status of which only one became a major hurricane, which is a Category 3 or greater on the Saffir-Simpson Hurricane Scale. Hurricane Emily was the costliest storm of the season, causing $80.3 million in damage (1987 USD) as it ravaged the Dominican Republic and Bermuda. Tropical Depression Fourteen was the deadliest storm of the season, causing six deaths as it passed across Jamaica. Of the seven cyclones that attained tropical storm status, three did not affect land. ==Seasonal forecasts and activity== Forecasts of hurricane activity are issued before each hurricane season by hurricane expert Dr. William M. Gray and his associates at Colorado State University. An average season, as defined by NOAA, has 6 to 14 named storms, with 4 to 8 of those reaching hurricane strength, and with 3 hurricanes becoming major hurricanes. The June 2, 1987 report suggested that eight tropical storms would form during the 1987 season, five of them becoming hurricanes.〔 〕 The forecast anticipated more tropical activity than what ultimately occurred. During the season, 14 tropical depressions formed from May 25 to November 5. Seven of the depressions strengthened into tropical storms, six of them named.〔 Tropical Depression Two was upgraded into a tropical storm in post-season analysis, and as a result has no name. Tropical storms Arlene, Emily and Floyd all reached hurricane status during their durations, of which only Emily reached major hurricane status.〔 〕 The United States was affected by four tropical cyclones in 1987, of which three struck Florida. The unnamed tropical storm struck Texas and affected much of the Gulf Coast of the United States.〔 〕〔 〕 The season's activity was reflected with a cumulative accumulated cyclone energy (ACE) rating of 34, 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「1987 Atlantic hurricane season」の詳細全文を読む スポンサード リンク
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