MIAMI (AP) — Dangerous tropical weather brewed Friday in the Atlantic Ocean with Humberto intensifying into a major Category 3 hurricane and a system forecasters dubbed “Potential Tropical Cyclone Nine” striking the Caribbean and taking aim at the Southeast United States.

Hurricane Humberto had maximum sustained winds of 115 mph, the Miami-based National Hurricane Center said in an advisory. Humberto was expected to keep strengthening over the next several days and churned Friday afternoon about 430 miles northeast of the northern Leeward Islands.

Humberto could produce life-threatening surf and rip currents for the northern Leeward Islands, the Virgin Islands, Puerto Rico and Bermuda over the weekend, forecasters said.

Meanwhile, a tropical storm warning associated with Potential Tropical Cyclone Nine was issued for the Central Bahamas. The center of the tropical disturbance was about 55 miles north-northwest of the eastern tip of Cuba, forecasters said. It had top winds of 35 mph. A tropical storm watch was issued for portions of the northwestern Bahamas.

The hurricane center said the potential cyclone was likely to become a tropical depression — the next name in the alphabet would be Imelda — on Saturday. By Sunday, it could be a tropical storm. The forecast put the system on track to approach the Southeast U.S. over the weekend and into early next week.