 A tropical wave emerged into the Atlantic Ocean from the west coast of Africa on September 12 . The wave moved westward across the Atlantic basin with minimal deep convection . By September 23 , it reached the eastern Pacific Ocean and began increasing in shower and thunderstorm activity over the next few days . While located near Acapulco another burst in convection occurred on September 25 , likely due to interaction with the Intertropical Convergence Zone ( ITCZ ) . Around that time , the National Hurricane Center began Tropical Weather Outlooks ( TWOs ) on the system , which is information issued every six hours on significant areas of disturbed weather and their potential for development out to 48 hours . The tropical wave split on September 26 , with the northern portion moving northwestward near the southwestern coast of Mexico . By September 27 , the system had organized deep convection and was producing tropical storm force winds , but data from scatterometers indicated that it lacked a closed circulation . Although TWOs issued on September 27 predicted a high probability for development , the chances for tropical cyclogenesis was decreased later that day , due to the system 's close proximity to land . 
