Meteorologists say Tropical Storm Isaac is forecast to enter the central Caribbean Sea this weekend.
At 4:00 p.m., the centre of Isaac was located 667 miles east of the Lesser Antilles.
Isaac is moving toward the west near 17 miles per hour.
This general motion is expected to continue through the next few days.
On the forecast track, Isaac will move near or over the central Lesser Antilles on Thursday.
Maximum sustained winds remain near 68 miles per hour with higher gusts.
Isaac is expected to be near hurricane strength when it moves through the Lesser Antilles, with some weakening forecast afterward on Friday and Saturday.
The Meteorological Service says Tropical Storm Isaac is not a threat to Jamaica.