Kenna's 160 mph winds made it a Category 5 hurricane, the strongest category for hurricanes considered capable of causing catastrophic damage.
The hurricane was roaring toward land and forecasters said it could threaten the shrimp-rich coasts of Nayarit state but would likely miss the Baja California Peninsula, where world leaders were gathering for a summit.
"Based on the records, which go back 40 or 50 years, this would be one of the two or three strongest" hurricanes to hit Mexico's Pacific coast, said Ed Rappaport, deputy director of the National Hurricane Center in Miami.
Kenna was centered 195 miles southwest of Cabo Corrientes, the tip of land that juts into the Pacific south of the tourist resort of Puerto Vallarta.
A hurricane warning was posted for the coast from Mazatlan, another tourist resort, southward to the port city of La Fortuna. Nayart's coastline sits near the middle of that swath of territory.
Kenna was churning northeast at 12 mph just before midnight Thursday but was expected to pick up speed before slamming into the coast Friday afternoon. The hurricane center said some weakening was expected before it hit land, but "Kenna is expected to be an extremely dangerous hurricane at landfall."
