The new tropical cyclone moved quickly west-northwestward away from South America, and on August 30 reconnaissance aircraft recorded winds of 45 mph (75 km/h). Based on the observation, the depression was upgraded to tropical storm status and given the name Francelia. Strengthening continued to near hurricane-force, but the fast-moving circulation outran the convection, causing brief weakening as it passed south of Jamaica. Although initially forecast to continue to the west-northwest, Francelia slowed and turned to the west-southwest on September 1 due to a ridge to its north. Concurrently, the storm intensified into hurricane status after its winds reached 75 mph (120 km/h), and late on September 1 Francelia passed over Swan Island. During its passage, an atmospheric sounding occurred in its eye; a sounding is a measurement of the physical properties of the atmosphere, and the process had only occurred four times previously.