ANN REALTIME UPDATE 06.30.06 1500 EDT -- With storm clouds gathering, the official word from NASA is that Saturday's launch of the space shuttle Discovery remains on as planned.

The countdown for the Discovery launch is currently in a built-in hold at the 11-hour mark, with the countdown scheduled to resume at 10:53 pm. The launch control team members are in Firing Room 4 of the Launch Control Center monitoring the system consoles.

Launch remains scheduled for 3:49 pm Saturday.

The STS-121 crew is relaxing and reviewing flight data files today. They will go to sleep at 8:15 pm at the Kennedy Space Center, and will be awakened at 5:15 am Saturday to begin final prelaunch preparations.

Meanwhile, at Launch Pad 39B, preparations continue for the launch. Fuel cell reactants were loaded Thursday night after a three-hour delay caused by lightning at the Kennedy Space Center. Crew module provisions are being stowed, and pad closeouts are under way. The rollback of the Rotating Service Structure is scheduled for 7 pm Friday night.

Despite the routine preparations, however, the prognosis for a Saturday launch does not look ideal. US Air Force weather officers are still forecasting a 60-percent chance of weather prohibiting the launch attempt, with the primary weather concerns being anvil clouds from inland thunderstorms and thundershowers within 20 nautical miles of the Shuttle Landing Facility.

If the launch is delayed Saturday, another attempt will be made Sunday afternoon... but the forecast isn't much better then, either. If the launch is bumped from Sunday, the next attempt would be made Tuesday, July 4.

FMI: www.nasa.gov