Per CNN
Southwest is using the flights to fly out 500 stranded passengers on 5 aircraft out to Love Field.
That will leave 10 aircraft at Hobby.

"The airline received clearance from the Federal Aviation Administration to operate out of the closed airport, according to the two sources. Hobby Airport is expected to remain closed to all non-emergency air traffic until August 30 at the earliest, according to the FAA.

Without working airport lights at Hobby Airport, the Southwest aircraft are going to have to move quickly."