 A tropical wave exited the west coast of Africa on September 7 and spawned a low pressure area by the following day. At 18: 00 UTC on September 8, a tropical depression developed about 225 mi (360 km) west-southwest of Dakar, Senegal. The depression moved steadily westward and intensified into Tropical Storm Humberto early on September 9. Despite moderate wind shear, Humberto continued to strengthen while passing south of Cape Verde, due to a moist atmosphere and warm ocean temperatures. The storm brought squalls to Cape Verde. The southwestern islands experienced wind gusts exceeding 35 mph (55 km / h) which downed several trees. Heavy rains in many areas triggered flooding that washed out roads and damaged homes. Offshore, the freighter Rotterdam went missing with a crew of six amid 10 to 16 ft (3 to 5 m) swells. The vessel eventually reached São Tomé and Príncipe, though that country's port institute and coast guard denied her entrance. Later on September 10, the storm's deepening briefly halted as it curved northwest in response to a developing mid-level trough over the central Atlantic.
