A tropical wave moved off the coast of Africa on August 14, 1998. It traveled westward, and on August 19 spawned the tropical depression that eventually became Hurricane Bonnie. The wave continued westward across the Atlantic Ocean and Caribbean Sea, and crossed Central America into the eastern Pacific Ocean on August 25. The wave decreased its forward speed while approaching a large low-level circulation over southern Mexico. A broad area of disturbed weather formed in association with the wave and the low-level circulation, and after persisting for several days developed a smaller low-level circulation on August 29 about 575 miles (925 km) south-southeast of Cabo San Lucas. On August 31, the two primary areas of convection were well-removed from the center. By early on September 1, despite a lack of convective organization, the low-cloud circulation was sufficiently well-defined that the National Hurricane Center designated it as Tropical Depression Ten-E, or the tenth tropical depression of the season, about 350 miles (565 km) south of Cabo San Lucas. In real time, the National Hurricane Center first upgraded the system 21 hours later.