New Delhi, Oct. 22 -- Tropical Storm Melissa began dumping heavy rain on Hispaniola on Tuesday as forecasters warned of a significant flood risk in parts of the Caribbean region later this week.

The rains snarled traffic in the Dominican Republic's capital, Santo Domingo, and at least one traffic light was downed as winds whipped around the city. Games in the country's professional baseball league were canceled.

People in Haiti grew concerned over the possibility of heavy flooding, which has devastated the country during past storms given widespread erosion.

Melissa was about 325 miles (520 kilometers) south-southwest of Port-au-Prince, Haiti, with maximum sustained winds of 50 mph (80 kph) as of Tuesday night, the U.S. National Hurric...