Simplify the following text for a Grade 11 native English-speaking person.
Original: The system , thoroughly disrupted by the mountainous terrain of Mexico , dissipated on the July 1 after moving back over water just south of Puerta Vallarta .
Simplified: The system was disrupted by the mountainous terrain of Mexico and dissipated on the July 1 after moving back over water just south of Puerta Vallarta .