 A tropical wave moved into the Pacific Ocean from Central America on September 10. Convection along the wave became better organized as it moved westward, and a tropical depression developed on September 18. The depression moved generally west-northwestward before strengthening into Tropical Storm Marty on September 19. The storm entrained dry air into its circulation as it curved toward the northwest, disrupting the storm's convective structure and inhibiting further intensification for the next two days. Eventually, Marty fought off the dry air and intensified, reaching hurricane strength on September 21.
