Michael,
I recall Chuck Doswell during a discussion on inflow into supercells that it varies significantly. Of course it could differ in different environments as well but the supercell itself enhances inflow. You may note that towards the end of the footage wind picks up dramatically and I think changes direction. I guess being so close, the chasers (Reed and Joel) were near the surface based mesocyclone. Being northeast of the tornado, they would probably experiencing the RFD. Reed may have a little more to say about this.
I also get the impression that the tornadic storm developed in extreme CAPE (>4000)with lots of upmotion - vortex stretching. Lapse rates in the area were also extreme and in the region and likely superadiabatic from memory (something we lack in Australia within zones of moist air and low bases). The storms initiated along the dryline. An upper trough would have been approaching this region by this point. Perhaps further clarification by Reed or Joel can correct me otherwise:) I would not mind seeing some of the available data for this day.
Regards,
Jimmy Deguara