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1999 PRELIMINARY
REPORTS |
Cindy had a long track across the Atlantic with no direct impact on land. a. Synoptic HistoryThe origin of Cindy can be traced back to a tropical wave that crossed the west coast of Africa early on the 18th, accompanied by 4.5 mb 24-hour surface pressure falls and a 58-mph 700 mb jet as seen in Dakar, Senegal rawinsonde data and Shortly after entering the eastern tropical Atlantic, deep convection began to gradually become better organized. By the evening of the 18th, satellite imagery and ship reports indicated that shower and thunderstorm activity became more consolidated near the center of a broad circulation. It is estimated that a tropical depression formed from this system around 0000 UTC on 19 August, centered about 250 nautical miles east-southeast of the Cape Verde Islands. Persistent 23 to 35 mph easterly vertical shear, as shown in analyses from the University of Wisconsin Cooperative Institute for Meteorological Satellite Studies, prevented the system from becoming significantly better organization during the next 36 hours. By the afternoon of the 20th, the shear relaxed and the center of the depression became more co-located with the deep convection. The system is estimated to have become Tropical Storm Cindy by 1800 UTC 20 August, in agreement with Dvorak satellite classifications from the Tropical Analysis and Forecast Branch (TAFB), the Satellite Analysis Branch (SAB), and the U.S. Air Force Weather Agency. Cindy continued to become better organized on the 21st as banding features developed and a CDO formed over the center. Cindy reached hurricane strength at 0000 UTC 22 August, about 390 nautical miles west of the Cape Verde Islands. Further intensification was arrested as easterly shear became more pronounced. Cindy weakened to a tropical storm at 1800 UTC 22 August. By the afternoon of the 25th, the easterly shear slackened and Cindy re-strengthened to hurricane intensity at 0000 UTC 26 August, while located about 1100 nautical miles southeast of Bermuda. Cindy continued to intensify during the next several days as banding features became more prominent and the upper tropospheric outflow improved. A ragged eye first appeared in visible satellite imagery on the morning of the 27th, and by that afternoon a 25 nautical miles diameter banding-type eye became evident. The hurricane continued to strengthen and reached an estimated peak intensity of 138 mph at 1200 UTC 28 August, while centered about 375 miles east-southeast of Bermuda. On 29 and 30 August, Cindy began to weaken in response to increasing westerly, then southwesterly shear. The overall cloud pattern gradually degenerated and the eye became indiscernible, the cloud tops warmed, and the deep convection became displaced north, and eventually mainly east, of the center. For its first five days Cindy had a motion toward the west-northwest at 7 to 14 mph. The motion was northwestward at 14 to 21 mph from late on the 24th through the 26th under the influence of the subtropical anticyclone over the north Atlantic. On the 27th, a mid-to upper-level low located southwest of Cindy helped steer the hurricane more to the west. By late on the 27th, the tropical cyclone began to decelerate when an upper-level trough along 55W-60W began to pull Cindy on a more northwesterly, then northerly heading. Cindy reached its westernmost longitude, about 58.5W, on the afternoon of the 28th. On 29 August, the system turned northeast and it began to accelerate late on the 30th. Cindy's closest approach to Bermuda, about 325 nautical miles, occurred at 0600 UTC 29 August. Cindy was downgraded to a tropical storm at 0600 UTC 31
August as the system continued to accelerate northeastward into progressively
cooler waters. By that afternoon, Cindy became indistinct when it merged
with a large extratropical cyclone over the north Atlantic about 850 nautical
miles west of the Azores.
b. Meteorological StatisticsSatellite-based intensity estimates on 28 August are the main basis for the peak intensity estimate of 138 mph in the best track; the objective-based Dvorak intensity estimate is the basis for the minimum central pressure of 942 mb at 1200 UTC 28 August.
c. Casualty and Damage StatisticsNo reports of casualties or damage due to Cindy have been received at the National Hurricane Center.
Maximum
Intensity For Hurricane Cindy
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