The tropical storm had maximum sustained winds of around 65 mph (100 kph), the Miami-based center said. It was moving northwest at 7 mph (11 kph).
The storm's projected path would take its center near the resort of Acapulco, which was devastated in October 2023 by Hurricane Otis, a Category 5 hurricane that rapidly intensified and caught many unprepared.
At least 52 people died in Otis and 32 were missing, after the storm severely damaged almost all of the resort’s hotels.
Guerrero state Gov. Evelyn Salgado said Tuesday that lessons were learned from that storm. She said all schools in the state would close Wednesday and said 582 shelters were prepared to receive people who might evacuate their homes.
A hurricane warning was in effect for Acapulco to Puerto Ángel. A hurricane warning means hurricane conditions are expected in the area, and preparations to protect life and property should be rushed to completion, according to the National Hurricane Center advisory.
Heavy rainfall up to 20 inches (51 centimeters) was forecast for parts of Oaxaca and Guerrero, with as much as 8 inches (20 centimeters) set to fall in Chiapas, Michoacan, Colima and Jalisco states.
The rainfall may produce flooding and mudslides, the center said, and storm surge could produce coastal flooding.