Bad weather in Florida could force NASA to postpone the launch of the space shuttle Endeavour scheduled for Saturday, officials said.

Weather Officer Kathy Winters said thunderstorms were predicted for the area around the Kennedy Space Center. She said there was a 60 percent chance the launch, scheduled for 7:39 p.m., will have to be delayed.

Otherwise, NASA officials said everything was on track.

"Everybody is 'go' for launch; we have no major issues at all," said Mike Moses, chairman of the mission management team, after a final review Friday.

The STS-127 mission is scheduled to last 16 days.

Five spacewalks are planned, along with construction of the Japan Aerospace Exploration Agency's Kibo laboratory. Astronauts will attach a platform to the outside of the Japanese module, allowing experiments to be exposed to space.