Awwal 24, 1432 H/April 28, 2011, SPA -- Hundreds of thousands of spectators are expected to gather Friday on central Florida's Atlantic coast for the launch of the space shuttle Endeavour, and NASA officials say they expect the weather will cooperate, dpa reported. There is just a 30-per-cent chance of poor weather delaying the launch, said forecaster Kathy Winters. The tail of the violent thunderstorms that wreaked havoc across the south overnight will reach Florida late Thursday, but the weather system is expected to have weakened significantly and will have cleared Cape Canaveral before Friday's afternoon launch, she said. Traffic on Friday into the Kennedy Space Centre will be heavy, with 45,000 people viewing the launch on the site and some 700,000 watching from elsewhere in the area, said Jeff Spaulding, shuttle launch director. President Barack Obama and his family will attend the launch, which will be the final for the Endeavour as NASA prepares to retire the shuttle fleet. The last-ever launch is planned for late June. Endeavour is scheduled to blast off for its final mission at 3:47 pm (1947 GMT) Friday from Kennedy Space Centre at Cape Canaveral, Florida, carrying six astronauts on a two-week mission to the orbiting International Space Station. Endeavour is to deliver a particle physics detector to the station to allow scientists to measure cosmic rays in the search for dark matter and antimatter. It will also carry a host of supplies to keep the spacecraft operating once shuttles are no longer available to lift large items into orbit.