 A tropical wave exited the west coast of Africa on September 24 . Interaction with a mid- to upper @-@ level low pressure forced the wave to split , with the southern portion spawning Tropical Storm Octave in the eastern Pacific Ocean on October 12 . As evidenced by scatterometer wind data , the northern portion moved north @-@ northwestward and transitioned into a low pressure area early on September 28 . After convection gradually became better organized , a tropical depression developed early on September 29 , about 910 mi ( 1 @,@ 460 km ) east @-@ northeast of the Leeward Islands . The depression moved northeastward and initially struggled to intensify due to the presence of dry mid @-@ level air . 
