With engineers gearing up to load the shuttle Discovery's external tank with rocket fuel, forecasters with the Spaceflight Meteorology Group at the Johnson Space Center in Houston have added a chance for rain showers to an already cloudy forecast.

But as of 9:30 a.m., shuttle forecasters in Florida were sticking with a 60 percent chance of a launch delay due to weather, the same probability announced Wednesday when rain wasn't part of the SMG forecast. Forecasters may update the outlook following a final pre-fueling management review that begins within the hour. Updates will be posted as warranted.

The latest SMG forecast for a return-to-launch-site - RTLS - abort calls for a chance of showers within 30 nautical miles and broken cloud decks at 3,000, 6,000 and 20,000 feet in the wake of a cold front. Winds will be out of 340 degrees at 15 knots peaking to 22, resulting in a peak crosswind component of less than 5 knots.

The forecast for two emergency runways in Spain calls for low clouds, turbulence and showers within 20 nautical miles. At an emergency runway in France, high tailwinds are a concern. All three sites are predicted to be "no-go" and at least one is required for a launching to proceed.

Hoping for the best, engineers are gearing up to pump a half-million gallons of liquid oxygen and liquid hydrogen into Discovery's external tank starting at 11:40 a.m. The three-hour procedure should be complete by around 2:40 p.m. NASA television coverage begins at 3:30 p.m. and the astronauts will begin strapping in around 6:15 p.m.

Here are countdown highlights for the rest of the day (in EST):

EST...........EVENT

09:40:00 AM...Begin 2-hour built-in hold (T-minus 6 hours)
09:50:00 AM...Safe-and-arm PIC test
10:30:00 AM...Mission management team tanking meeting
10:40:00 AM...External tank ready for fueling
11:10:00 AM...Orbiter ready for fueling
11:40:00 AM...Resume countdown (T-minus 6 hours)

11:40:00 AM...Liquid oxygen, liquid hydrogen transfer line chilldown
11:50:00 AM...Main propulsion system chill down
11:50:00 AM...LH2 slow fill
12:20:00 PM...LO2 slow fill
12:25:00 PM...Hydrogen ECO sensors go wet
12:30:00 PM...LO2 fast fill
12:40:00 PM...LH2 fast fill
01:55:00 PM...LH2 topping
02:35:00 PM...LH2 replenish
02:40:00 PM...LO2 replenish

02:40:00 PM...Begin 3-hour built-in hold (T-minus 3 hours)
02:40:00 PM...Closeout crew to white room
02:40:00 PM...External tank in stable replenish mode
02:55:00 PM...Astronaut support personnel comm checks
03:25:00 PM...Pre-ingress switch reconfig
03:30:00 PM...NASA TV coverage begins
03:56:00 PM...Astronaut photo opportunity (time approximate)
05:05:00 PM...Final crew weather briefing
05:15:00 PM...Astronauts don pressure suits
05:40:00 PM...Resume countdown (T-minus 3 hours)

05:45:00 PM...Crew departs O&C building
06:15:00 PM...Crew ingress
07:05:00 PM...Astronaut comm checks
07:20:00 PM...Hatch closure
08:05:00 PM...White room closeout

08:20:00 PM...Begin 10-minute built-in hold (T-minus 20m)
08:30:00 PM...NASA Test Director countdown briefing
08:30:00 PM...Resume countdown (T-minus 20m)

08:31:00 PM...Backup flight computer to OPS 1
08:35:00 PM...KSC area clear to launch

08:41:00 PM...Begin final built-in hold (T-minus 9m)
08:51:45 PM...NASA Test Director launch status verification
09:26:47 PM...Resume countdown (T-minus 9m)

09:28:17 PM...Orbiter access arm retraction
09:30:00 PM...Launch window opens (actual: 9:30:47 p.m.)
09:30:47 PM...Hydraulic power system (APU) start
09:30:52 PM...Terminate LO2 replenish
09:31:47 PM...Purge sequence 4 hydraulic test
09:31:47 PM...Inertial measurement units to inertial
09:31:52 PM...Aerosurface profile
09:32:17 PM...Main engine steering test
09:32:52 PM...LO2 tank pressurization
09:33:12 PM...Fuel cells to internal reactants
09:33:17 PM...Clear caution-and-warning memory
09:33:47 PM...Crew closes visors
09:33:50 PM...LH2 tank pressurization
09:34:57 PM...Booster joint heater deactivation
09:35:16 PM...Shuttle computers take control of countdown
09:35:26 PM...Booster steering test
09:35:40 PM...Main engine start (T-6.6 seconds)
09:35:47 PM...SRB ignition (LAUNCH!)

Video coverage for subscribers only:
VIDEO: POST-ARRIVAL COMMENTS FROM THE CREW PLAY
VIDEO: ASTRONAUTS ARRIVE IN WAVE OF T-38 JETS PLAY
VIDEO: BIOGRAPHIES OF THE DISCOVERY ASTRONAUTS PLAY
VIDEO: NARRATED STS-116 MISSION PREVIEW MOVIE PLAY

VIDEO: WEDNESDAY'S SHUTTLE BRIEFING IN ITS ENTIRETY PLAY

BRIEFING SOUNDBITES:
VIDEO: THE ISSUES DISCUSSED AT FRR PLAY
VIDEO: NOT YOUR FATHER'S FRR PLAY
VIDEO: READY TO RESUME NIGHT LAUNCHES PLAY
VIDEO: LAUNCH PREPS PROCEEDING WELL PLAY
VIDEO: YEAR-END ROLLOVER CONCERNS PLAY
VIDEO: REASSESSING TANK FOAM RISK PLAY
VIDEO: STATION SOLAR ARRAY DRIVE SYSTEM PROBLEM PLAY
VIDEO: PRESSURIZATION PRECAUTIONS AT THE PAD PLAY

VIDEO: OVERVIEW OF STS-116 MISSION PLAY
VIDEO: SHUTTLE/ISS PROGRAM PERSPECTIVE PLAY
VIDEO: PREVIEW OF MISSION'S SPACEWALKS PLAY
VIDEO: ASTRONAUTS' PRE-FLIGHT NEWS BRIEFING PLAY

VIDEO: COVERAGE OF PRACTICE COUNTDOWN ACTIVITIES PLAY

VIDEO: DISCOVERY ROLLS TO THE PAD PLAY
VIDEO: DISCOVERY MATED TO TANK AND BOOSTERS PLAY
VIDEO: SHUTTLE HOISTED VERTICALLY INSIDE VAB PLAY
VIDEO: DISCOVERY HAULED FROM HANGAR TO VAB PLAY
VIDEO: PORT 5 TRUSS PAYLOAD PACKED UP PLAY
VIDEO: CREW VISITS KENNEDY SPACE CENTER PLAY
VIDEO: EXTERNAL FUEL TANK MATED TO BOOSTERS PLAY
MORE: STS-116 VIDEO COVERAGE
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