On September 30, a tropical wave off of the coast of Africa began to show signs of an organized circulation, though convection remained limited. The disturbance moved generally west-northwest over the following two days, and increased markedly in thunderstorm activity. The circulation remained slightly elongated into October 3, but the system was sufficiently organized to be designated Tropical Depression Fifteen.
The cyclone had internal structure issues ab initio; at its formation, convection was displaced to the east and south of the circulation, and the center featured multiple vortices that only gradually consolidated. A trough descending into the central Atlantic had displaced the Bermuda high by this time, and Fifteen began to turn northward.
Overnight, winds increased slightly, and the system was upgraded to Tropical Storm Oscar. Strong upper-level winds kept the center of the cyclone exposed all through October 4, but deep convection moved a little closer to the center, and the winds within the area of shower activity increased. This brought Oscar to its peak intensity of 50 mph winds and a pressure of 997 mb.
By October 5, the trough was encroaching on the circulation of Oscar, and the rapidly deteriorating cyclone was accelerating to the northeast. By late that morning, the cyclone's elongated circulation combined with the trough of low pressure, and the system was announced dissipated.
Oscar as a strongly sheared cyclone over the far east Atlantic.
Track of Oscar.
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