Tropical Storm Beryl has moved toward the southeast Caribbean as forecasters warn it is expected to strengthen into a dangerous major hurricane before reaching Barbados.
A major hurricane is considered a Category 3 or higher, with winds of at least 178km/h.
Hurricane watches were in effect for Barbados, St Lucia, Grenada and St Vincent and the Grenadines while a tropical storm watch was issued for Martinique, Dominica and Tobago.
"It's astonishing to see a forecast for a major (Category 3+) hurricane in June anywhere in the Atlantic, let alone this far east in the deep tropics. Beryl organising in a hurry over the warmest waters ever recorded for late June," Florida-based hurricane expert Michael Lowry posted on X.
Beryl's centre is forecast to pass about 45km south of Barbados, said Sabu Best, director of the island's meteorological service's director.
On Saturday, Beryl was located about 1260km east-southeast of Barbados, with maximum sustained winds of 100 km/h.
It was moving west at 37km/h.
"Rapid strengthening is now forecast," the Miami-based National Hurricane Center said.
Warm waters are fuelling Beryl, with ocean heat content in the deep Atlantic the highest on record for this time of year, according to Brian McNoldy, University of Miami tropical meteorology researcher.
Beryl is the strongest June tropical storm on record that far east in the tropical Atlantic, noted Philip Klotzbach, Colorado State University hurricane researcher.
"We need to be ready," Barbadian Prime Minister Mia Mottley said in a public address late on Friday.
"You and I know when these things happen, it is better to plan for the worst and pray for the best."
She noted that thousands of people are in Barbados for the Twenty20 World Cup cricket final.
Meanwhile, St Vincent and the Grenadines Prime Minister Ralph Gonsalves said in a public address on Saturday that shelters will open on Sunday evening as he urged people to prepare.
He ordered officials to refuel government vehicles, and asked grocery stores and petrol stations to stay open later before the storm.
"There will be such a rush … if you keep limited hours," he said as he apologised ahead of time for government interruptions on radio stations with storm updates.
"Cricket lovers have to bear with us that we'll have to give information ... this is life and death."
Beryl is the second named storm in what is predicted to be a busy hurricane season, which runs from June 1 to November 30 in the Atlantic.
Earlier this month, Tropical Storm Alberto came ashore in northeast Mexico with heavy rains that resulted in four deaths.