 A poorly organized tropical wave emerged off the west coast of Africa on September 23 and quickly developed into Tropical Depression Seven on September 25 , while centered 775 miles ( 1 @,@ 247 km ) southwest of Cape Verde . Because the depression was tracking over warm SST 's , it was predicted to intensify into a tropical storm . However , wind shear exposed the center as indicated by visible satellite images on September 26 , and the National Hurricane Center noted on September 26 that " the depression could be downgraded to a tropical wave later today " . Early on September 27 , the center of the depression became difficult to locate on satellite imagery . 
