On August 9, an area of convection developed just south of Jamaica in association with a trough of low pressure. The system moved west-northwestward, and by August 10 it had a broad surface trough with minimal shower activity. Convection increased on August 11, and by August 12 a tropical wave and an upper-level low began to merge which resulted in a large area of disorganized thunderstorms extending from the western Caribbean Sea into the central Bahamas. Upper-level winds slowly became more beneficial for development, and on August 13 a large low pressure area formed about 90 miles (145 km) north-northeast of Cancún, Quintana Roo. Late on August 14, a reconnaissance flight into the system reported a small circulation center, but at the time was not well-defined enough to result in the initiation of tropical cyclone advisories. However, deep convection was found near the increasingly organizing center, and at 0300 UTC on August 15 the National Hurricane Center upgraded it as Tropical Depression Five about 425 miles (685 km) southeast of Brownsville, Texas.