The FCO is advising against all travel to the British Virgin Islands and all but essential travel to Anguilla, Montserrat and the Turks and Caicos.
It comes after Hurricane Maria caused widespread flooding and an island-wide power cut in Puerto Rico, just weeks after Hurricane Irma devastated the region.
Although peak winds had dropped from 175mph to 110mph before the storm made landfall on the island, it was the torrential rain that proved to be the real problem with rivers swelling to record levels and “catastrophic” flash flooding.
The hurricane has since left the island but has regained strength as a category three storm and could last in this state for the next 48 hours.
The storm is forecast to scrape the north coast of the Dominican Republic on Thursday before arriving in the Turks and Caicos and Southeast Bahamas on Friday.
It will then turn north with the US East Coast potentially vulnerable to further damage.