Updated

MEXICO CITY (AP) — Hurricane Darby formed in the Pacific off Mexico's southwest coast Thursday, while Hurricane Celia strengthened farther out at sea.

Neither hurricane posed an immediate threat to land.

Darby, a Category 1 hurricane with winds of 80 mph (130 kph), was located about 250 miles (400 kilometers) south-southwest of Puerto Escondido on Thursday afternoon, according to the National Hurricane Center in Miami.

It was expected to strengthen over the next two days as it heads west-northwest, well away from land.

The hurricane center projected the storm could take a sudden eastward turn early next week, putting it on a path toward Mexico's southern Pacific coast.

That prediction is tentative and depends on a tropical wave of pressure forming in the western Caribbean, said John Cangialosi, a hurricane specialist at the center. Otherwise, Darby could continue on its northwestern path out to sea.

"It's a low-confidence forecast at this point," Cangialosi said. "It's not going to have great impact on land over next few days so there is certainly time to watch it."

Meanwhile, Celia became a Category 4 hurricane as it headed west across the open Pacific. Its maximum sustained winds increased to 135 mph (215 kph).

It was located about 765 miles (1,230 kilometerw) off the southern tip of Mexico's Baja California peninsula.