Tropical Storm Pilar has formed just off western Mexico and is expected to brush its Pacific coast near the resort of Puerto Vallarta.
The U.S. National Hurricane Center said Pilar had winds of 40 mph (65 kph) and was located about 70 miles (110 kilometers) west-southwest of the port city of Manzanillo. It was moving north at about 5 mph (7 kph).
The hurricane center said late Saturday that Pilar was expected to move over or very near the coast of Jalisco on Sunday as a tropical storm.
The center warned of heavy rains over southwest Mexico through Monday.