Weather Iffy; Endeavour Still Waiting

Afternoon and evening thunderstorms are a summer staple in Florida. And they're expected tomorrow, meaning space shuttle Endeavour may have to wait a little longer before blasting off for the international space station.

NASA says today's forecast continues to give only a 40 percent chance of acceptable launch weather tomorrow evening. Conditions improve to 60 and 70 percent "go" for Sunday and Monday.

The mission already has been put off twice. Both of last month's delays were caused by hydrogen gas leaks that have since been fixed.

Endeavour and its seven astronauts are set to deliver and install the last piece of Japan's space station lab.