Southwest Connecting Flights

[pamjb]

Is there anyway to tell where a flight may be connecting from? DH's aunt is flying from MCO to PHL today. I know her flight going to Orlando was delayed due to flight problems in Nashville. I was keeping her up to date on the flight status online, as it usually is more up to date than what the gate agents know. She told me the flight was originating in Nashville, but that was when she was already in the airport. From that I was able to tell when the Nashville flight was leaving for PHL.
I want to try to do the same thing for her return flight. Anybody know?