U.S. weather forecasters say Tropical Storm Dora has become the fourth hurricane of the eastern Pacific season as it swirls in the open ocean off the coast of Mexico.

The National Hurricane Center in Miami says Dora is about 360 kilometers south-southwest of Acapulco, Mexico, with winds of 130 kilometers per hour. It is expected to move nearly parallel to the coast of southwestern Mexico but remain offshore. Dora is expected to pass the tip of Baja California by Saturday.

Forecasters warn that Hurricane Dora could generate swells that will affect the coast of southern Mexico and are likely to cause life-threatening surf and rip current conditions. Dora could strengthen into a major storm by Thursday.

In the Atlantic, Tropical Storm Bret is forecast to weaken as it moves northeast away from the Bahamas and well off the U.S. Atlantic coast. Forecasters say Bret has 85-kilometer-per-hour winds and is centered about 465 kilometers south-southeast of Cape Hatteras, North Carolina.