MIAMI (AP) — Tropical Storm Imelda formed Sunday and is expected to become a hurricane on a forecast track that could take it away from the U.S. East Coast early this week. The storm was causing disruption in the Bahamas and Cuba on Sunday, and a tropical storm watch was posted in parts of Florida.

Meanwhile, Hurricane Humberto weakened very slightly but remained a strong Category 4 storm in the Atlantic, threatening Bermuda.

At about 2 p.m. EDT, Imelda was located about 95 miles (152.89 kilometers) west-northwest of the Central Bahamas and about 370 miles (595.46 kilometers) southeast of Cape Canaveral in Brevard County, Florida, the National Hurricane Center in Miami said. It was headed north at 7 mph (11 kph) and its maximum sustained winds were 40 mph (65 kph).

The center said the system was expected to move across the central and northwestern Bahamas Sunday and Sunday night and turn east-northeastward, away from the southeastern U.S., by the middle of the week.

A tropical storm watch was in effect for the east coast of Florida from the Palm Beach-Martin County Line to the Flagler-Volusia County Line, the center said, urging residents along the southeast U.S. coast to monitor the system. A tropical storm watch means tropical storm conditions are possible within 48 hours.

South Carolina Gov. Henry McMaster urged people to monitor the weather closely and stay alert, although coastal Georgetown County said it was returning to normal operations with an improved forecast for the area. And in North Carolina, Gov. Josh Stein declared a state of emergency before Tropical Storm Imelda formed.

“What we learn every time is we never know where they are going to go,” McMaster said during a news conference to discuss the storm. “This storm is deadly serious. Not just serious. Deadly serious.”

The storm could bring high winds and heavy rain, which could produce flooding, he said. The state was prepositioning search and rescue crews over the weekend.

Humberto weakened slightly on Sunday but still had maximum powerful sustained winds of 150 mph (240 kph), according to the hurricane center, making it a Category 4 hurricane. It was located about 535 miles (861 kilometers) south of Bermuda and was moving west-northwest at 13 mph (20 kph).

A tropical storm watch could be required in Bermuda later in the day, forecasters said, and swells could reach the U.S. East Coast on Monday.

Alison Dagostino moved to Myrtle Beach, South Carolina, six years ago with her four children and husband. She experienced her first hurricane within days of moving into the area.

She said that other than basic storm preparation — like buying batteries and storm-proofing windows — people in the area were living life as normal on Sunday.

“People are still out and about. People are still walking on the beach,” Dagostino said, adding that school and sporting events haven’t been canceled.

Imelda was threatening parts of Cuba and the Bahamas with heavy rainfall and flash flooding, with portions of the Bahamas under a tropical storm warning.

The Bahamas’ Department of Meteorology said moderate to heavy rains would continue over the northwest and central islands, which include Nassau, Andros Island, San Salvador and Long Island. Rainfall could reach between 6 inches (15 centimeters) and 12 inches (30 centimeters), with some isolated areas seeing up to 10 inches (25 centimeters).

“Residents in low-lying areas should take actions to mitigate property damages due to flooding,” the department said in a statement.

Sunday’s storm surge was expected to raise water levels up to 3 feet (.9 meters) above normal tide along the coasts of the Abaco Islands, the north and east coasts of Grand Bahama, and all nearby cays.

The National Weather Service in Puerto Rico warned inexperienced mariners and those operating smaller boats against navigating the hazardous waters on Sunday, with swells from Humberto forecast to reach between 7 feet (2 meters) and 8 feet (2.4 meters) in Atlantic waters.

In the Dominican Republic, where weather conditions on Friday forced the evacuation of hundreds of people, meteorologists on Sunday expected moderate showers, thunderstorms and gusts in some inland areas. The Dominican Institute of Meteorology said in a statement that other areas including the capital, Santo Domingo, would only see scattered showers.

The agency added that while Humberto was not threatening the country Sunday, fragile and small- to medium-sized vessels should only “operate near the coastal perimeter, avoiding venturing out to sea due to abnormal waves.”

Tropical Storm Narda is rapidly weakening and is expected to become a post-tropical storm by Sunday evening or Monday.

Narda, formerly a hurricane, is affecting coastal Mexico and Baja California Sur, forecasters said, and life-threatening surf and rip current conditions are possible in Southern California. No coastal watches or warnings were in effect midday Sunday.

Associated Press writers Safiyah Riddle in Montgomery, Alabama, Regina Garcia Cano in Caracas, Venezuela and Dorany Pineda in Los Angeles contributed.