The first tropical depression of the Atlantic hurricane season formed Friday in the Western Caribbean, but forecasters can't yet say if it will pass over the massive oil spill in the Gulf of Mexico.

Forecasters at the National Hurricane Center in Miami said Friday the storm has winds of about 35 mph (55 kph). Most storm prediction models show it traveling over the Yucatan Peninsula of Mexico over the weekend and into the southern Gulf by Monday, hurricane center specialist Michael Brennan said. It was expected to strengthen to a tropical storm sometime Saturday.

A tropical storm warning is in effect for the east coast of the Yucatan Peninsula, which separates the Caribbean Sea from the Gulf of Mexico.

It's too early to tell if the storm will hit the northeastern part of the Gulf, where the spill has spread over the past 10 weeks, Brennan said. Somewhere between 69 million and 132 million gallons of crude have spewed into the water since the rig Deepwater Horizon exploded April 20, killing 11 workers.

The storm raises concerns over what might happen to efforts to contain the oil if BP is forced to abandon the area for a while. An armada of ships is working in the Gulf.

A cap has been placed over the blown-out undersea well and it is carrying some of the oil to a surface ship where it is being collected. Some of the oil is being brought to the surface and burned. Other ships are drilling two relief wells, projected to be done by August, and are the best hope to stop the leak.

Some models have the storm heading toward the spill, but others do not, and forecasters can't speculate about what rough weather would do to oil in the water, Brennan said.

The depression is on track to reach the peninsula by late Saturday. It is about 345 miles (555 km) east-southeast of Chetumal.

Meanwhile in the Pacific, two major hurricanes are swirling but don't pose an immediate threat to land. Darby is a Category 3 storm, with maximum sustained winds near 115 mph (185 kph).

The hurricane is located about 265 miles (425 kilometers) southwest of Acapulco, Mexico. It's heading west-northwest near 6 mph (9 kph).

Hurricane Celia has weakened to a Category 3 storm farther out in the Pacific. Celia's maximum sustained winds have decreased to near 120 mph (195 kph). The hurricane center says Celia is approaching cooler waters and is expected to continue weakening.