A storm brewing in the eastern Atlantic became the fourth named storm of the 2015 hurricane season and could become a hurricane by Thursday, National Hurricane Center forecasters said.
Roughly 1,600 miles off the west coast of Africa, the slow-moving disturbance strengthened to a tropical storm with sustained winds of about 40 mph Tuesday afternoon. It is expected to continue to gain strength as it moves west and turns toward the northwest Wednesday.
Forecasters said the storm was moving about 12 mph -- giving forecasters plenty of time to track its progress -- with tropical storm-force winds extending 45 miles.
The system is still too far away to speculate what risk it might pose to Florida or the United States, said NHC spokesman Dennis Feltgen.
"This is a slow mover across the Atlantic. Even in our five-day forecast, it's not even at the Windward Islands," he said. "So we have plenty of time to watch this."
On average, the fourth storm of the Atlantic season forms Aug. 23, said Feltgen.
"We're going into the peak of the season, so we're right on target," he said.
So far, the 2015 season has produced just three tropical storms, Ana, Bill and Claudette. Preseason forecasts predicted fewer storms than average with just six to 11 named storms, three to six hurricanes and up to two major storms. Earlier this month, hurricane center meteorologists scaled back the forecast to six to 10 named storms, one to four hurricanes and up to one major storm.
The slow season is being steered by a fierce, record-breaking El Niño heating waters in the Pacific and fueling upper-level winds that keep storms from strengthening.
TS Danny is expected to keep building in intensity over the next 72 hours.