John packed maximum sustained winds of 75 miles per hour (120 km per hour) and was expected to strengthen into a major hurricane by late Tuesday or early Wednesday, the Miami-based NHC said.
There are currently no coastal watches or warnings in effect.
John was located about 320 miles (510 km) southwest of Cabo Corrientes, Mexico, and 435 miles (700 km) south of the southern tip of Baja California as of 0300 GMT. It was moving toward the northwest at 8 mph (13 kph).
"Swells generated by John are expected to begin affecting the coasts of southwestern Mexico and the southern portion of the Baja California peninsula during the next day or so," the NHC said.
The swells are likely to cause "life-threatening surf and rip current conditions," it added.
Hurricane-force winds extend outward up to 25 miles (35 km) from the center of the storm and tropical-storm-force winds extend outward up to 105 miles (165 km).
More about: #Hurricane
