 A tropical wave moved off the northwestern coast of Africa into the Atlantic Ocean on August 11 . After moving across the Atlantic and Caribbean Sea without development , the system moved through the Intertropical Convergence Zone of the northeastern Pacific Ocean . The cloudiness moved northward toward the Gulf of Tehuantepec on August 22 . The thunderstorm activity organized sufficiently for the system to be upgraded to Tropical Depression Fifteen @-@ E on August 23 while 298 mi ( 480 km ) southeast of Acapulco , Mexico . The depression moved west @-@ northwestward and strengthened into a tropical storm 217 mi ( 350 km ) south @-@ southwest of Puerto Vallarta on August 25 . The storm began to turn more westward due to a strengthening high pressure system to its north and was upgraded to a hurricane on August 27 while 286 mi ( 460 km ) southwest of Cabo San Lucas . As the high to the north continued to strengthen , the hurricane turned west @-@ southwest . 
