The National Hurricane Center says Tropical Storm Don has formed in the Atlantic Ocean.

Forecasters say the storm is about 485 miles east-southeast of Barbados and 595 miles east of Trinidad on Monday afternoon. It has maximum sustained winds of 40 mph and is moving west at 17 mph.

CLICK HERE FOR THE FOX NEWS HURRICANE CENTER.

A tropical storm warning is in effect for Grenada. A tropical storm watch is in effect for Barbados, St. Vincent and the Grenadines, and St. Lucia.

An Air Force Reserve crew found the storm small and well-defined but not particularly well-organized. Don is expected to dissipate within 72 hours.