The country will shut down at 10:00 a.m. instead of the previously announced noon.
Prime Minister Mia Mottley made the announcement moments ago citing the strengthening of Tropical Storm Dorian overnight.
At 5:00 a.m Tropical Storm Dorian was centred near 11.9N, 56.3W or about 225 miles (365 km) east-southeast of Barbados.
Maximum sustained winds have increased to 60mph (97km/h), with tropical-storm-force winds extending outward up to 45 miles (75km) from the centre.
The minimum central pressure is 1002mb (29.59 inches)