A tropical storm formed off Mexico's west coast Saturday and forecasters said it could turn into a hurricane and the country's mainland within a few days.

Tropical Storm Paul was located over the Pacific Ocean about 315 miles (500 kilometers) south-southwest of the coastal city of Cabo Corrientes, said Lixion Avila, a meteorologist at the U.S. National Hurricane Center in Miami.

The storm rapidly gained strength and had maximum sustained winds of 50 mph (80 kph) by mid afternoon Saturday. It could intensify into a hurricane within three days, Avila said.

Paul was moving northwest at 7 mph (11 kph) but it was forecast to gradually shift to the northeast, passing by the tip of the Baja California peninsula and hitting mainland Mexico around the state of Sinaloa early in the week.

Mexico was hit by two Pacific hurricanes last month. Hurricane John battered a remote section of Baja California, killing five people and destroying 160 homes, while Hurricane Lane struck the Sinaloan resort town of Mazatlan, causing relatively minor damage.