Hurricane Simon has strengthened into a powerful Category 4 system as it barrels toward Mexico’s Pacific coast.

Early Saturday, the National Hurricane Center in Miami said Simon’s maximum sustained winds increased to 140 mph (225 kph). A storm of that strength or greater is considered a major hurricane. Simon could bring as much as 10 to 20 inches (25-50 cm) of rain over parts of southwestern Mexico, with some areas receiving up to 30 inches.

The forecast was upgraded as Simon approached Mexico’s southwestern and west-central Pacific coast, one of the country’s most popular tourist regions.

“Simon could deliver the most significant hurricane impact to this stretch of the Mexican Pacific coast since Lidia in 2023, which damaged thousands of homes and devastated crops along the Jalisco coast,” said Tyler Roys, a senior meteorologist at AccuWeather.

At the very least, Simon is expected to bring heavy rainfall to parts of southwestern Mexico, possibly concentrated along Jalisco’s coast and in parts of Michoacan, Colima, and Nayarit.

On Friday, forecasters warned that Simon could bring life-threatening flooding and mudslides, with isolated rainfall totals reaching 30 inches (762 mm).

Simon is expected to make landfall on Sunday between Manzanillo — Mexico’s largest port and the main gateway for trade with Asia — and Puerto Vallarta, a popular beach destination and home to nearly 300,000 residents.

Jalisco suspended classes on Friday and Monday in 22 coastal municipalities and began evacuating dozens of people from at-risk areas. It also asked the tourism sector in Puerto Vallarta, a popular destination for U.S. tourists, to ensure that both workers and visitors are fully accommodated in shelters or safe zones by Friday afternoon.

In Manzanillo, fishermen were hauling their boats off the beach and authorities were putting up black flags along the coast to signal the beach was closed.

The Mexican Navy activated emergency response personnel in Colima and restricted maritime traffic along parts of the Pacific coast, closing ports to smaller vessels and barring larger vessels from operating in Michoacan.

Last week, Hurricane Polo made landfall on the Baja California Peninsula as a Category 2 storm, toppling trees and utility poles, flooding streets and causing other property damage.