Otis was expected to come ashore on Wednesday morning, bringing high winds and heavy rain. It was already a Category 4 hurricane late on Tuesday afternoon, blowing maximum sustained winds of 233 kph, the US National Hurricane Center said.

By 6pm local time Otis was about 137km south-southeast of Acapulco and would continue strengthening before making landfall, the Miami-based NHC added.

Once Otis comes ashore, it should weaken rapidly, it said.

Hurricane conditions were expected within 12-24 hours for the stretch of coastline between the beach towns of Zihuatanejo and Punta Maldonado in the state of Guerrero, which is home to Acapulco, the NHC said.

The storm could bring up to 38cm of rain in parts of Guerrero and neighbouring Oaxaca state, possibly causing flash flooding and mudslides, a “life-threatening” storm surge, and surf and rip current conditions, the centre added.

Schools across Guerrero cancelled classes for Wednesday ahead of Otis’ arrival, Governor Evelyn Salgado said on social media.

Over the weekend, Hurricane Norma left at least three dead as it passed along the northwest coast of Mexico. Days before, the powerful Hurricane Lidia left one person dead and several more injured after battering Mexico’s Pacific coast.