Within a few days, Tropical Storm Dorian could develop into a Category 1 hurricane.
This would be the first major tropical storm to hit Puerto Rico after the island was devastated by Hurricane Maria in 2017. The island is still recovering from the damage.
The island of Barbados is also under a tropical storm watch, meaning storm conditions are possible within 48 hours.
Dorian is the fourth named storm for this hurricane season.
Additional reporting Newsy affiliate CNN.