Forecasters say Tropical Storm Hernan has gained strength since forming far off Mexico’s Pacific coast.

According to the National Hurricane Center in Miami, the storm’s maximum sustained winds have increased to near 50 mph. Additional strengthening is expected and the storm could become a hurricane within the next few days.

As of 5 a.m. EDT Thursday, Hernan’s center was located about 640 miles south-southwest of the southern tip of Baja California, Mexico. The storm was moving toward the west-northwest near 14 mph.

Hernan is the eighth named storm of the Pacific hurricane season.