The U.S. National Hurricane Center said the storm could bring dangerous flash floods and mudslides through the weekend as it parallels the coast, likely moving just off the point below the Puerto Vallarta region on Saturday and then possibly hitting the Los Cabos resort region on Monday.
The storm was centered about 270 miles 435 kilometers) south of the port city of Lazaro Cardenas on Thursday night and it was heading to the west-northwest at 12 mph (19 kph).
Nora had maximum sustained winds of 45 mph (75 kph) and it was expected to reach hurricane force on Saturday. It was a big system, with tropical storm-force winds extending as far as 205 miles (335 kilometers) from the center.
The hurricane center said the storm could dump 8-12 inches (20 to 30 centimeters) of rain over the central Mexican coast, with isolated maximums of up to 20 inches (50 centimeters.
It was also kicking up heavy surf.