Shuttle Weather Forecast Worse But Still "Go"

A storm front making its way toward central Florida is slowing down a bit, raising the probability that weather could prompt a delay in the planned launch Friday of shuttle Endeavour on its 25th and final flight.

But the overall probability of favorable conditions still is good: Meteorologists say there is a 70 percent chance conditions will be acceptablefor the scheduled 3:47 p.m. Friday launch Endeavour commander Mark Kelly and his five crewmates: pilot Gregory "Box" Johnson and mission specialists Greg Chamitoff, Andrew "Drew" Feustel, Michael Fincke and Roberto Vittori of the European Space Agency.

That 70 percent probability is down from an 80 percent forecast for good weather. Shuttle Weather Officer Kathy Winters issued a forecast today that calls for both a chance of stiff cross winds at the Kennedy Space Center shuttle runway and low cloud ceilings.

The crosswinds are expected to be at or above normal 15 knot limits. That could present trouble in the event that a system failure early in flight prompted an unprecedented emergency landing attempt.

Cloud ceilings at the runway also must be above 5,000 so mission commander Kelly could get a good view of the runway on final approach should an emergency landing attempt be required.

The storm front is expected to sweep into the area early this evening. NASA hopes to retract the Rotating Service Structure at launch pad 39A at 7 p.m.

The move can be delayed up to four or five hours without impacting the planned start of external tank propellant-loading operations at 6:22 a.m. Friday.

Cloudy conditions -- and potentially rain showers -- are expected during the three-hour propellant-loading operation. But skies are expected to clear as clocks tick toward launch at 3:47 p.m.