Complex sentence: A broad area of low pressure formed over the western Caribbean Sea on October 8, and it persisted until October 11, when a tropical wave reached the area and caused the convection to organize, resulting in the development of a low-level circulation.
Split into simpler sentences: A broad area of low pressure persisted across the western Caribbean Sea on October 8. It remained disorganized until a tropical wave reached the area on October 11, resulting in the development of a low-level circulation.