It had 45 miles per hour maximum sustained winds and was moving west at 6 miles per hour, the NHC's 11 a.m. EDT update said.
It was about 555 miles (895 kilometers) south of the Baja California Peninsula.
Forecasters said Aletta is now a Category 3 hurricane.
Hurricane Aletta has quickly intensified in the eastern Pacific Ocean, but still poses no direct threat to Mexico or the United States.More news: Deaths of famous by their own hands highlight troubling trend
The centre said Friday morning that swells generated by Aletta will begin to affect portions of mainland Mexico and the west coast of Baja California Sur later in the day. The outlook calls for 14 to 20 named storms, including 7 to 12 hurricanes, of which 3 to 7 become major hurricanes (category 3 or higher). The speed of the wind is 65 mph, and it will increase in less than 24 hours which is more than the criteria for the rapid intensification. The National Hurricane Center is giving the tropical wave a good chance to develop into a tropical depression this weekend south of the Mexican Riveria.
The average date when the first named storm forms in the Eastern Pacific Basin is June 10, according to NHC data from 1971 to 2009.
The Eastern Pacific hurricane season runs from May 15 through November 30. Out in the Pacific, there are two tropical storms we're watching.