Tropical Storm Dorian is threatening Puerto Rico with a direct hit containing near-hurricane force winds and forecasters say it could strengthen further as it approaches the US mainland.
The storm was expected to pass over or near Puerto Rico, with landslides, widespread flooding and power outages possible in what is expected to be the first major test of emergency preparedness since Hurricane Maria devastated the island in 2017. President Donald Trump declared an emergency Tuesday night and ordered federal assistance for local authorities.
"Practically the entire island will be under sustained tropical storm force winds," said Roberto Garcia, director of US National Weather Service San Juan, during a press conference late Tuesday.
However, he said the forecast could keep changing, adding that late shifts occur with storms such as Dorian that do not have a well-defined centre.
The storm earlier had been projected to brush the western part of the US territory and the change in the storm's course caught many off guard in the tiny island of Vieques just east of Puerto Rico, a popular tourist destination that now lies in Dorian's path.
"I'm in shock," Vilma Santana said in a phone interview, adding that she's relieved it's not a hurricane. "Thank God it's a storm."
A still-uncertain long-term forecast would have Dorian nearing Florida at hurricane strength by Sunday or Monday.
Trump sent a tweet assuring that "We are tracking closely tropical storm Dorian as it heads, as usual, to Puerto Rico. FEMA and all others are ready, and will do a great job."
He added a jab at Puerto Rican officials who have accused the government of a slow and inadequate response to Hurricane Maria: "When they do, let them know it, and give them a big Thank You - Not like last time. That includes from the incompetent Mayor of San Juan!"
Early Wednesday, Dorian was located about 95 kilometres southeast of St Croix, US Virgin Islands. The US National Hurricane Center said it had strengthened slightly, with maximum sustained winds of 96 km/h while moving northwest at 13 mph (20 kph).
The storm was expected to dump 10 to 15 centimetres of rain with isolated amounts of 20 centimetres.
It's a forecast that worries many in Puerto Rico because blue tarps still cover some 30,000 homes nearly two years after Hurricane Maria. The island's 3.2 million inhabitants also depend on an unstable power grid that remains prone to outages since it was destroyed by Maria, a Category 4 storm.
Australian Associated Press