The OC is going to hear the booms today

From Flame Trench here:

Conditions are not expected to improve at KSC after another orbit of Earth. If the bad conditions remain, entry flight director Norm Knight already has said he would take his first good-weather opportunity to bring Atlantis down at Edwards.

The weather looks better for two subsequent landing opportunities at the California desert military base. The first landing chance at Edwards is 3:49 p.m. A second chance comes at 5:23 p.m. The weather forecast calls for acceptable conditions during those first two passes at the California site, but strengthening winds later in the day.

The Science Dude says:

NASA says it might land the space shuttle Atlantis at Edwards Air Force Base in the Mojave Desert today if weather conditions don't improve at Kennedy Space Center in Florida, where thunderstorms are expected. If Atlantis does set down here, it will produce a double sonic boom that will likely be heard across Orange County.

NASA has booked three possible landing times for Edwards: 12:49 p.m., 2:23 p.m., and 3:59 p.m.

Why does the shuttle make two sonic booms? Here is the explanation:

"The Cause"
"Sonic booms are created by air pressure. Much like a boat pushes up a bow wave as it travels through the water, a vehicle pushes air molecules aside in such a way they are compressed to the point where shock waves are formed."

"These shock waves form two cones, at the nose as well as at the tail of the vehicle. The shock waves move outward and rearward in all directions and usually extend to the ground. As the shock cones spread across the landscape along the flightpath, they create a continuous sonic boom along the full width of the cone's base. The sharp release of pressure, after the buildup by the shock wave, is heard as the sonic boom."

"The nose and tail shock waves are usually of similar strength. The time interval between the nose and tail shock waves is primarily dependent on the size of the aircraft and its altitude. Most people on the ground cannot distinguish between the two and they are usually heard as a single sonic boom. As the time interval increases, two booms are heard. A small fighter-type aircraft about 50 ft long will generate nose and tail shock waves of less than a tenth of a second (0.1 sec). The ear usually detects these as a single sonic boom."

"The interval between nose and tail shock waves on the Space Shuttles, which are 122 ft long, is about one-half of a second (0.50 sec), making the double boom very distinguishable."