A tropical wave emerged into the Atlantic from the west coast of Africa on August 17. Tracking steadily westward, the wave remained devoid of significant convection until August 21, when associated shower and thunderstorm activity increased a few hundred miles northeast of the Leeward Islands. Over the course of the next two days, the development of a low-level circulation was noted, though a reconnaissance aircraft failed to locate the presence of a surface low-pressure area on August 23. Subsequent surface observations indicated the formation of a circulation at the surface, and the wave acquired enough organization to be designated as a tropical depression at 00:00 UTC on August 24, while centered 220 mi (355 km) east of Turks Island. Data from a secondary reconnaissance aircraft and ship reports indicated intensification, and the depression was upgraded to Tropical Storm Dennis at 12:00 UTC that same day accordingly. Located at the tail-end of a stationary trough and in an environment of unfavorable wind shear, the system was ill-defined and asymmetric. Despite the unfavorable environment, data from the Hurricane Hunters indicated that Dennis had intensified into a Category 1 hurricane by 06:00 UTC on August 26.