MIAMI (AP) — Simon has strengthened into a powerful Category 4 hurricane as it barrels toward Mexico’s coast.

The National Hurricane Center in Miami said early Saturday Simon’s maximum sustained winds increased to 145 mph (230 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 center said.

The bulletin also urged residents to take immediate action to prepare, saying the hurricane will make landfall late Saturday or early Sunday, but tropical storm-strength winds could arrive much sooner.

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.

“This rainfall will produce life-threatening flooding and mudslides, especially in areas of steep terrain,” the NHC said.

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.