Updated

A tropical depression formed off Mexico's southern Pacific coast Wednesday, prompting authorities to issue a tropical storm warning for a coastal region popular with tourists.

The U.S. National Hurricane Center said the storm was centered about 100 miles (165 kilometers) south-southwest of Puerto Angel late Wednesday. It had maximum sustained winds of 35 mph (55 kph) and was moving northeast at 6 mph (9 kph).

The hurricane center's forecast said the depression was expected to strengthen into a tropical storm as it approached the coast of Oaxaca state in the coming days.

Heavy rain and flash flooding were likely along Mexico's southern coast, the center said.

The tropical storm warning was in effect from Puerto Escondido to Salina Cruz. That stretch includes beach communities such as the Huatulco region.