Published: Oct 21, 2010 4:32 PM EDT
Updated: Oct 21, 2010 1:32 PM EDT

MIAMI (AP) - Tropical Storm Richard has formed in the Caribbean, becoming the 17th named storm of the Atlantic hurricane season.

Richard's maximum sustained winds Thursday are near 40 mph (65 kph). Additional strengthening is forecast and Richard could become a hurricane over the weekend.

The National Hurricane Center in Miami says the tropical storm could dump 4 to 8 inches of rain on Jamaica with possible isolated amounts of 12 inches. These rains could cause life-threatening flash floods and mud slides.

Richard is located about 220 miles (355 kilometers)

south-southeast of Grand Cayman and is moving southeast near 6 mph (9 kph).