A large, slowly-spinning system across the northern Caribbean and southern Gulf of Mexico could develop into something serious, forecasters said.

The National Hurricane Center says there's a 40 percent chance of a storm will form in the Caribbean over the next week. These odds may increase in the coming days.

A​ tropical storm is expected to form in the northwest Caribbean or southern Gulf of Mexico late in the week ahead, but details on its potential intensity, track and timing remain uncertain. Interests along the entire U.