The first eastern Pacific hurricane of the 2012 season, named Bud, has formed off the southwestern coast of Mexico, the US National Hurricane Center said early Thursday.

The category one storm was 385 miles (620 kilometers) southwest of the coastal town of Manzanillo, with maximum sustained winds of 75 miles (120 kilometers) per hour, according to the US monitors.

There was no immediate threat from the storm, though the center issued a tropical storm watch for the coastline from Punto San Telmo to La Fortuna, indicating that storm conditions were possible within the next 48 hours.

The storm was moving to the north at a speed of six miles (nine kilometers) per hour and was not expected to approach the Mexican coast until late Friday, at which point the storm was expected to weaken slightly.

Storm swells causing "life-threatening surf and rip current conditions" were expected along portions of the southern and southwestern coast of Mexico later on Thursday, the hurricane center said.