By Sunday night, Isaac became the fifth hurricane of this year's Atlantic season, but that only lasted until the next day.
Tropical-storm-force winds extend outward up to 105 miles (165 km) from the center.
The government of Antigua has issued a tropical storm watch for Barbuda.
"My staff and I will continue to monitor Tropical Storm Isaac", said VITEMA Director Mona L. Barnes.
Hurricane Florence, now a Category 2 storm, is slowly approaching the USA coast, and the storm's massive fury is on full display in video footage taken from the International Space Station. "Intermittent rain bands are expected on St. Croix as Isaac passes south of the big island".
Friday's expected landfall near the NC/SC border will cause Florence to weaken as it interacts with the coast.
Florence is now 485 miles from Wilmington, North Carolina.
Sustained winds on Tuesday afternoon approached 105 miles per hour, making it a very strong Category 2 storm, though it was expected to gradually weaken over cooler waters.
Residents of the Carolinas and neighboring states should consult local authorities for any evacuation orders and other preparation guidelines. Flash flooding is possible over low-lying and flood-prone areas. Florence is huge in size, and even though there will probably be some minor fluctuations in strength, it's likely to hit as a major hurricane.
The storm is now around 530 miles southeast of Cape Fear, North Carolina, and is moving west-northwest at 17 mph.
The Met Office said a Tropical Storm Warning was in effect for Guadeloupe, Dominica and Martinique but was expected to be discontinued by Thursday evening. Satellite images show very little left as a recognizable tropical storm.
A trough of low pressure over the western Gulf of Mexico is also producing disorganised showers and thunderstorms this morning, which the NHC had a 50% chance of becoming a storm.