On September 16, 2000 a tropical wave – an elongated area of low air pressure moving from east to west – exited the west coast of Africa. It moved westward across the Atlantic Ocean without development due to the presence of upper-level wind shear. After moving across the Caribbean Sea, a disturbance along the wave started to become better organized on September 27. The next day, a Hurricane Hunters flight indicated a closed circulation and winds of ; upon receiving the data, the National Hurricane Center (NHC) initiated advisories on Tropical Depression Fifteen at 2100 UTC. The NHC later estimated the depression had formed three hours earlier, about north-northeast of Cabo Gracias a Dios. Upon forming, the depression had good outflow, although the convection was not as organized. With an anticyclone over the system, the depression was expected to gradually intensify while moving slowly to the west-northwest, a motion caused by weak steering winds. Late on September 28, the NHC upgraded the depression to tropical storm status and named it Keith, after another Hurricane Hunters mission reported flight-level winds of .