The storm is expected to gradually intensify and turn into a hurricane on Sunday before making landfall on the southern coast of Mexico on Monday. Mexico issued an hour of hurricanes for the south coast from Salina Cruz to Punta Maldonado.

“Mass storms can cause coastal flooding near and east from where the center passes the coast in areas with onshore winds,” the National Hurricane Center said. “The tide can be accompanied by large and destructive waves.”

In addition to storms, heavy rain from Agatha will hit parts of southern Mexico from Sunday through Tuesday evening.

“Heavy rain is expected in the Mexican state of Oaxaca, with 10-16 inches expected, but the isolated total is likely to be 20 inches,” the hurricane center said.