UPDATE 3-Hurricane Carlotta strengthens off Mexico's Pacific coast
* Hurricane Category 1, expected to gain strength
* Pacific oil refinery not affected
* Storm far south of Los Cabos, location of G20 summit
ACAPULCO, Mexico, June 15 (Reuters) - Hurricane Carlotta formed in the Pacific on Friday, strengthened quickly and traveled along a path that could bring it ashore on Mexico's southern coast later in the day or early Saturday, the U.S. National Hurricane Center said.
Carlotta, the third named storm of the Pacific hurricane season, escalated throughout the afternoon into a "rapidly intensifying Category 2 hurricane," the center said.
As it hurtled toward the coast, it reached maximum winds of nearly 105 mph (165 kph) with higher gusts. At 5 p.m. EDT/2100 GMT, it was about 65 miles (100 km) south-southeast of Puerto Angel and about 280 miles (450 km) southeast of the tourist city of Acapulco.
Officials expected it to move over or near the coast between the two beach resorts as early as Friday night. They expected a dangerous storm surge and significant coastal flooding across the area, though the hurricane could dissipate if it moves over the mountains of southern Mexico.
The Mexican government issued a hurricane warning from Punta Maldonado to Acapulco, where winds started to pick up on Friday afternoon. State oil company Pemex took preventative measures, but by late morning, the eye of the storm had passed north of its biggest refinery, the 330,000 barrel-per-day Salinas Cruz. The installation was operating normally.
The hurricane's path is far from the Baja California resort of Los Cabos, where the Group of 20 leaders of top economies are convening on Monday and Tuesday. Authorities said they did not expect Carlotta to make much of an impact and that the airport remained open.
In Acapulco, local government spokeswoman Maribel Helguera said they were preparing for heavy rains. In Acapulco, there was no sign of residents boarding up windows.
"Officials are visiting danger zones at risk from mudslides in the highlands to tell people the storm is coming and where to seek shelter if need be," she said.
Acapulco Mayor Veronica Escobar said there are 112 shelters in the state of Guerrero.
In neighboring Oaxaca, state weather officials reported moderate to heavy rainfall across the area. They said they had not yet ordered residents to evacuate or to suspend school.
The sun-drenched area last was hit by a hurricane in 1997, when Pauline made landfall near Puerto Angel, causing torrential rains, flooding and mudslides in two of Mexico's poorest states. Hundreds died and thousands were left homeless. The hurricane caused more than $400 million in damage.
In 2002, Hurricane Kenna hit south of Los Cabos while the city was hosting an international meeting of the 21-member Asia Pacific Economic Cooperation group. Strong winds from Kenna knocked over the main tent at the event where world leaders were set to attend a gala dinner. No one was injured.
Kenna hit land 300 miles (482 km) south of Los Cabos in 2002. Carlotta is expected to strike the coast much farther away.
