After forming, the system, which was located in an environment of easterly vertical shear, strengthened slowly. By September 22 the organization of the cloud pattern improved to the extent that tropical storm strength was estimated to have been reached. Kiko turned from a northwestward to a west-northwestward heading that day. Although some easterly shear continued to affect the system, very deep convection persisted near the center, and based on Dvorak intensity estimates, Kiko strengthened into a hurricane around September 23. A little later on September 23, deep convection decreased in coverage and intensity and Kiko weakened back to a tropical storm.