Hurricane Carlotta strengthened to a category two storm Friday as it barreled toward Mexico's Pacific Coast, US monitors warned.

The storm was packing winds of 105 miles (170 kilometers) per hour and was moving northwestward at 12 miles (19 kilometers) per hour, the Miami-based National Hurricane Center said in a bulletin.

"Some additional strengthening is possible this evening, followed by weakening as the center of Carlotta moves along the coast of Mexico," the NHC said after Carlotta became a category two storm on the five-point Saffir-Simpson scale.

The eye of the storm, set to move over or near the southern Mexican coast between Puerto Angel and Acapulco later Friday and Saturday, was located about 65 miles (105 kilometers) south-southeast of Puerto Angel at 2100 GMT.

US meteorologists predicted total rainfall of three to five inches (7.5 to 12.5 centimeters) in the Mexican states of Chiapas, Guerrero and Oaxaca, and up to 15 inches (38 centimeters) along the Oaxaca coast.

"These rains could cause life-threatening flash floods and mudslides," the NHC said, adding the hurricane was forecast to take a turn toward the west-northwest on Saturday.

"A dangerous storm surge is expected to produce significant coastal flooding to the north and east of the center," it added, warning of "large and destructive waves."

But the storm was not expected to affect a G20 summit happening in Los Cabos, Mexico, as delegates began gathering for the Monday and Tuesday meetings.

Photo of Hurricane Frank off the Pacific coast of Mexico in 2010 by Moderate Resolution Imaging Spectroradiometer (MODIS) Terra Satellite [Public domain], via Wikimedia Commons