The National Weather Service expects the phenomenon to land in Sinaloa.
It's a Category Five plus hurricane, according to meteorology expert.
Landfall is expected this afternoon in Jalisco.
Patricia's maximum sustained winds had increased Thursday to 130 mph (215 kph) - already Category 4 strength - and forecasters said it could grow even stronger before slamming into land.
The State Council of Civil Protection has prepared 400 shelters.
The yellow alert has been activated in Guerrero, Michoacán, Colima and Jalisco.
The phenomenon is on the Pacific.
The phenomenon will cause strong rains.
The hurricane is located 2,605 kilometers (1,618 miles) west-southwest of Cabo San Lucas, Baja California Sur.
The Tropical Depression Five-E was formed on Saturday morning and is currently located about 426 kilometers (265 miles) south-southeast of Acapulco, Mexico.