Hurricane Simon strengthened into a Category 4 storm off Mexico’s Pacific coast on Saturday, with maximum sustained winds of 240 km/h, the U.S. National Hurricane Center (NHC) reported.

The NHC said the storm was located about 185 km south‑southwest of Manzanillo and is expected to approach the west‑central coast late Saturday or early Sunday, with possible further strengthening before landfall.

A hurricane warning now covers the Pacific coast south of Puerto Vallarta, including Manzanillo, while a tropical storm watch extends toward Lázaro Cárdenas, according to the NHC.

The centre of Simon could bring 10‑20 inches of rain across southwestern Mexico, and isolated totals of up to 30 inches in parts of Michoacán, Colima and Jalisco, the NHC warned, raising the risk of life‑threatening flooding and mudslides.

The NHC also forecast a storm surge and large destructive waves near and east of the expected landfall area, creating dangerous surf and rip‑current conditions along the coast.

"Strong winds could damage homes and businesses, while flooding and mudslides could wash out roads and make it difficult for emergency crews to reach some communities. Even after the storm passes, power outages and damaged infrastructure could make recovery challenging," said AccuWeather meteorologist Dan Pydynowski.

The NHC urged residents in the warning zone, which also includes the Islas Marías archipelago, to rush preparations to protect life and property.