In less than 24 hours, Hurricane Patricia strengthened from a tropical storm to a Category 5 juggernaut, the strongest cyclone the National Hurricane Center has ever measured.
The storm is threatening to make a "potentially catastrophic" landfall on Mexico's Pacific coast by Friday night, with sustained winds up to 200 mph and even stronger gusts, according to the hurricane center.
"Confidence is high that Patricia will make landfall in the hurricane warning area along the coast of Mexico as an extremely dangerous major hurricane this afternoon or evening," forecasters wrote Friday morning. "Preparations to protect life and property in the hurricane warning area should be completed as tropical storm conditions are beginning to affect the area."
The hurricane was about 145 miles southwest of the Pacific resort of Manzanillo early Friday. A hurricane warning was in effect for the Mexican coast from San Blas to Punta San Telmo, a stretch that includes Manzanillo and Puerto Vallarta.
Patricia's winds accelerated by more than 100 mph Thursday, going from one end of the Saffir-Simpson Scale of tropical cyclone intensity to the other. The storm is the most intense the hurricane center has ever measured in its area of responsibility, which includes the Atlantic and eastern Pacific basins.
"This is a remarkable feat, with only Linda of 1997 intensifying at this rate in the satellite era," hurricane center forecasters wrote.
Patricia's power is comparable to that of Typhoon Haiyan, which left more than 7,300 dead or missing in the Philippines two years ago, according to the U.N.'s World Meteorological Organization. More than 4 million people were displaced and over 1 million houses were destroyed or damaged in 44 provinces in the central Visayas region, a large cluster of islands that includes some of the country's poorest provinces.
Both typhoons and hurricanes are tropical cyclones. Cyclones in the western Pacific basin are known as typhoons, while in the Atlantic and eastern Pacific they are known as hurricanes. In the Indian Ocean and the southwestern Pacific, they are known simply as cyclones.
Residents of a stretch of Mexico's Pacific Coast dotted with resorts and fishing villages on Thursday had already boarded up homes and bought supplies ahead of Patricia's arrival. Some evacuations were reported in Puerto Vallarta.
In Mexico, officials declared a state of emergency in dozens of municipalities in Colima, Nayarit and Jalisco states that contain the bustling port of Manzanillo and the posh resort of Puerto Vallarta. The governor of Colima ordered schools closed on Friday.
After striking Mexico, Patricia also poses problems for Texas. Forecast models indicate that after the storm breaks up over land, remnants of its tropical moisture will likely combine with and contribute to heavy rainfall that is already soaking Texas independently of the hurricane.
The Associated Press contributed to this article.