With well-established outflow and low levels of wind shear, Erika became stronger as the circulation became better defined. A high pressure system covered over the south-central United States, forcing the storm to move just south of due west at 25 mph (40 km/h). On August 15, convection were made into bands, and as its winds were turning into hurricane strength, an eye developed within the storm. The storm quickly weakened over the Sierra Madre Oriental, and Erika was calming down early on August 17. After entering the Gulf of California on August 18, It led to the formation of a tropical disturbance. It went to the northwest and weakened on August 20.