Tropical Storm Danny formed in the Atlantic Ocean on Tuesday, August 18, and additional strengthening is forecast during the next 48 hours. Danny is expected to become a hurricane by Thursday.
The storm is forecast to continue to strengthen as it moves slowly to the west-northwest.
By as soon as Thursday, the National Hurricane Centre in Miami says, Danny could become the first hurricane of the 2015 Atlantic season.
It says Danny should to a Category 1 hurricane by then, and intensify further into a Category 2 with sustained winds of 98 miles per hour by Sunday.
Maximum sustained winds presently have increased to near 40 mph (65 km/h), with higher gusts. Tropical-storm-force winds extend outward up to 45 miles (75 km) from the centre.
There is no immediate threat to land and Danny is expected to track west toward the Caribbean over the next week.
Tropical Storm Danny is the fourth storm of the 2015 Atlantic hurricane season following on the heels of Ana, Bill and Claudette which hit the US east coast.
Earlier this month, the National Oceanic and Atmospheric Administration Climate Prediction Center said there was a 90 per cent chance of this season being a fairly quiet one, with just one major hurricane predicted even though there could be as many as 10 named storms.