Tropical Storm Henriette formed off the Pacific coast of Mexico on Friday and is expected to move parallel to Mexico's mainland over the course of the day, the National Hurricane Center said.

The Miami, Florida-based center issued a tropical storm warning for Mexico's southern coast from Lagunas de Chacahua to Punta San Telmo, and a tropical storm watch northwest to Manzanillo.

At 800 a.m. EDT, the center of the storm was 85 miles south of Acapulco in Guerrero state with maximum sustained winds of 40 mph. It was moving west-northwest at near 10 mph and is expected to continue on this path for the next 24 hours.

The center said Henriette is expected to move near and parallel to Mexico's Pacific coast over the course of Friday and into the evening. It is expected to 4 inches to 8 inches of rain along the southern coast and flooding and landslides are possible.