Hurricane Maria strengthened to a Category Two storm on Monday with maximum sustained winds of 175km/h as it menaced Caribbean islands already hard-hit by megastorm Irma.
The US National Hurricane Centre expected Maria to grow into a "major hurricane", a Category Three, later on Monday with the French territory of Guadeloupe - the staging area for relief operations for several islands battered by Irma - in the crosshairs.
Warnings were also triggered for Dominica, St Kitts and Nevis and the British island of Montserrat.
Earlier the forecaster said Maria was "expected to become a major hurricane as it moves through the Leeward Islands", marked by “rapid strengthening”.
Maria is approaching the eastern Caribbean less than two weeks after Irma hammered the region before overrunning Florida.
That storm, one of the most powerful ever recorded in the Atlantic with winds up to 298 km/h, killed at least 84 people, more than half of them in the Caribbean.
As of 2am local time on Monday, the centre of the storm was about 145 km north-northeast of Barbados and about 270 km east-southeast of the Leeward island of Dominica, moving to the west-northwest at about 20km/h.
Hurricane conditions were expected for Guadalupe, Dominica, Martinique and St. Kitts, Nevis and Montserrat, and the hurricane centre warned Puerto Rico to monitor the storm.
The British Virgin Islands and St. Martin, which was devastated by Hurricane Irma, were under a hurricane watch, as were the US Virgin Islands and Anguilla.
More than 1,700 residents of Barbuda, where Irma damaged nearly every building, braced for Maria on neighboring Antigua, now under a tropical storm watch, said Ronald Sanders, the country’s ambassador to the US.
Puerto Rico braces for Maria
Puerto Rico has already begun preparations for Maria, which by Tuesday was expected to unleash powerful winds on the US territory, already dealing with a weakened economy and fragile power grid.
Damage to Puerto Rico could also disrupt the disaster relief supply chain to other islands that were hit by Irma.
“Puerto Rico is our lifeline,” Judson Burdon, a permanent resident of Anguilla who has helped coordinate supply shipments to the island, said.
“We had two volunteer flights cancel because of the weather that is coming.”
The planned deliveries consisted of plywood, power tools and screws to close up windows and doors that remain open on the island, where 90 per cent of structures were damaged.
Tropical storm alert for Jose
The hurricane centre also issued a tropical storm watch for portions of the US mid-Atlantic and New England coast by Tuesday as a second hurricane, Jose, moved slowly north from its position in the Atlantic Ocean about 510 km southeast of Cape Hatteras, North Carolina.
The eye of Jose, with top sustained winds of 145km/h, should remain off the US East Coast, the NHS said.
Even so, by Tuesday it could bring tropical storm conditions from Fenwick Island, Delaware, to Sandy Hook, New Jersey, and from East Rockaway Inlet on New York’s Long Island to the Massachusetts island of Nantucket.
Up to 13cm of rain could fall over parts of the area, and the storm could bring dangerous surf and rip currents as well.
