Hurricane Darby formed Thursday off the coast of southwestern Mexico, as Hurricane Celia strengthened further out in the Pacific to a Category Three storm.

Neither of the first two hurricanes of the 2010 Pacific storm season were expected to make landfall, according to the Miami-based National Hurricane Center.

Packing winds of around 75 miles (120 kilometers) per hour, Darby was located about 235 miles south-southwest of the Mexican town of Puerto Escondido and moving west-northwest at around nine miles per hour, the forecast said.

"Darby is a Category One hurricane on the Saffir-Simpson scale," the center said in a statement. "Some additional strengthening is forecast over the next day or two."

Way out in the Pacific, Hurricane Celia strengthened overnight into a major Category Three storm, packing sustained winds near 185 kilometers (115 miles) per hour with higher gusts.

Celia was some 1,230 kilometers south of the Baja California peninsula at 1500 GMT Thursday, with no threat posed to coastlines, experts said.

The other major storm to strike the Pacific so far this season was Tropical Storm Agatha, which slammed into Guatemala in May, unleashing heavy rains and floods that left some 275 people dead or missing across Central America.