A tropical depression that developed over the east-central Atlantic strengthened to Tropical Storm Danny Tuesday and was expected to become a hurricane.
Tropical Storm Danny had maximum sustained winds of 40 mph but was expected to gradually strengthen over the next 48 hours, forecasters at the National Hurricane Center in Miami said.
Danny is expected to become a hurricane by Thursday, forecasters said.
The system was moving to the west at about 13 mph but it was expected to turn toward the west-northwest later Tuesday or Wednesday.
There were no watches or warnings in effect.
Danny is the fourth tropical storm of the 2015 Atlantic season, which ends November 30.