A tropical disturbance in the Caribbean Sea, now known as Potential Tropical Cyclone 18, is likely to become Tropical Storm Rafael by Monday and is forecast to become a hurricane later this week, the National Hurricane Center said Sunday night.

Potential Tropical Cyclone No. 8 has formed in the southwestern Caribbean this afternoon. This system will likely strengthen further and soon become Rafael as it makes its journey to the north. A hurricane is possible as it nears Cuba and sits underneath an upper-level anticyclone,