What is the reason for this unusual flight path? Last week, flight AA9675 flew from MIA to TUL. It took this very unusual flight path:



It's an ad hoc flight number, so it's not a regularly scheduled flight. You can see there was a line of thunderstorms moving across at the time. But that alone does not explain the route. FlightAware shows the flight plan that was filed.



After leaving Miami it skipped the first few filed waypoints. But after it left Florida it followed the plan as filed from one VOR to the next, in a big circle around the Midwest and finally landing in Tulsa. 

My only guess as to the reason for such an unusual route is that, due to the line of storms, it's some kind of contingency flight. Maybe they were anticipating delays and kept a plane airborne so that it could be quickly re-routed if necessary. I've been told that FedEx does this during peak season, but I've never heard of a passenger airline doing it. 

Does anyone have an explanation for such an unusual flight path?
My guess is the captain requested and the dispatcher approved an excessive amount of fuel to deal with the crossing of the long line of weather.  The flight plan would have to reflect being able to burn off that excess fuel to be able to land BELOW the maximum landing weight of the plane. The crossing consumed far less fuel than expected so the crew had to burn off the excess fuel by flying the filed flight plan.  Or they could have just wanted to fly the filed flight plan because flight crews get paid by the hour and they would have just about doubled their pay for that leg.