I’m at the Kennedy Space Center in Florida for the launch of Discovery tomorrow at 3:48 pm EDT, and took this photo at 9 pm this evening from launch pad 39-B. There’s a 60% chance that the weather will violate launch constraints. The main concern is that anvil clouds from inland thunderstorms over central Florida may be blown towards Cape Canaveral. The launch window lasts only 10 minutes, because the shuttle needs to fly while Cape Canaveral passes through the space station’s orbital plane.