Tropical storm Juliette was about 40 miles (65 km) southeast of the Mexican Pacific beach resort Cabo San Lucas, where it is now heading, the U.S. National Hurricane Center said on Wednesday, as authorities there prepared for the prospect of evacuations.
The tropical storm was blowing at 45 miles per hour (72 km per hour) and heading northwest toward the tourist resort in the state of Baja California Sur at 25 mph (40 kph), the NHC said.
Authorities said that up to 15,000 people who live in the storm's path could be evacuated and taken to temporary shelters.
"We're currently on orange alert and tonight we'll be on red alert. We've prohibited sailing for all small vessels," said Carlos Enriquez, head of Baja California Sur emergency services.
Juliette is due to make landfall in the next few hours and produce rainfall of up to 3 inches (8 cm), the NHC said, although it said the storm should weaken by Thursday morning.
Mexican state oil monopoly Pemex has no major oil installations or refineries nearby.