18z HRRR was definitely a worst case scenario for DFW. The 00z and especially the 06z have backed off a fair bit, with somewhat stronger capping and somewhat slower timing
That said, one thing which stands out (and while I'm not entirely convinced on the upscale growth part) is all the drier air above 850mb. This could allow for a few things, which is the cells remaining discrete for a longer period (which would be concerning as low level shear really picks up during the early evening hours), but also for outflow boundaries (with there no longer being a stable surface layer unlike the past 48-72 hours) to either trigger more numerous storms further SE than what the CAMs are currently depicting or cause them to propagate further SE than currently depicted on the CAMs given the negligible capping in place.