The weather agency warned of the risk of life-threatening flash floods and mudslides for the area, especially in higher terrain.
Lorena was centered Wednesday about 120 miles (195 kilometers) south-southwest of Cabo San Lucas, Mexico. The tropical storm had maximum sustained winds of 75 mph (120 kph) and was moving northwest at 14 mph (22 kph).
Those living in southwestern Mexico and the Baja California peninsula were urged to monitor the progress of the storm.