A tropical wave moved off the coast of Africa on September 10, with evidence of a low-level circulation and convective banding. It moved west-northwestward, located south of a subtropical ridge. Based on satellite imagery, it is estimated the system organized into Tropical Depression Nine by 1200 UTC on September 11 to the south of the Cape Verde islands. Upon its formation, the center was poorly defined, with restricted easterly outflow due to easterly wind shear. After about 24 hours of remaining somewhat disorganized, the convection became more concentrated on September 12 as banding features and outflow improved. Consequently, the National Hurricane Center (NHC) upgraded the depression to Tropical Storm Gert, the seventh named storm of the season.