The U.S. National Hurricane Center said Maria had maximum sustained winds of 145 kph late Sunday. It was centered about 270 km east-southeast of Dominica and heading west-northwest at 20 kph.

A strengthening Hurricane Maria swirled toward the eastern Caribbean early Monday, with forecasters warning it probably would be a major storm by the time it passed through the already battered Leeward Islands later in the day.

Maria grew into a hurricane on Sunday, and forecasters said it was expected to become much stronger over the next 48 hours following a path that would take it near many of the islands wrecked by Hurricane Irma and on to Puerto Rico, the Dominican Republic and Haiti.

The U.S. National Hurricane Center said Maria had maximum sustained winds of 145 kph late Sunday. It was centered about 270 km east-southeast of Dominica and heading west-northwest at 20 kph.

The hurricane center said hurricane conditions should begin to affect parts of the Leeward Islands by Monday night, with storm surge raising water levels by 4 to 6 feet (1.2 to 1.8 meters) near the storm’s center. The storm was predicted to bring 6 to 12 inches (15 to 30 centimeters) of rain across the islands, with more in isolated areas.

Maria could make a direct hit on Puerto Rico, which was spared the full brunt of Irma although much of the island had its power knocked out.

Governor Ricardo Rossello said officials had prepared about 450 shelters with a capacity for nearly 68,000 people or even 125,000 in an emergency. He said schools were cancelled for Monday and government employees would work only a half day.

Officials in the Dominican Republic urged people to leave areas prone to flooding and said fishermen should remain in port.

Farther north, long-lived Hurricane Jose continued to head northward off the U.S. East Coast, causing dangerous surf and rip currents. It wasn’t expected to make landfall but tropical storm watches were posted along the coast from Delaware to Massachusetts’ Cape Cod.

Jose was centered about 465 km southeast of Cape Hatteras, North Carolina, and was moving north at 15 kph. It had maximum sustained winds of 150 kph.

In the Pacific, Tropical Storm Norma’s threat to Mexico’s Los Cabos resort area at the southern end of the Baja California peninsula seemed to ease as forecasters said the storm’s center was likely to remain offshore.

Norma had winds of about 85 kph and it was centered about 225 km southwest of Cabo San Lucas. That area was hit two weeks ago by Tropical Storm Lidia, which flooded streets and homes and killed at least four people.

The Baja California Sur state government prepared storm shelters and canceled classes for Monday.

Meanwhile, Tropical Storm Lee weakened into a tropical depression far out in the Atlantic while Otis strengthened into a hurricane out in the Pacific. Neither threatened land.