18z NAM appears a little faster and not quite as deep with the trough as the 12z. According to the FWD AFD this afternoon, the 12z Euro has sped up a little bit too, relative to previous runs. Euro still shows pretty substantial storms back into N/NE Texas though. The level of severity on Friday is going to have a lot to do with just how fast that dryline mixes east, and how much the trough will dig and hang back out west. It would seem that the faster this system plows through, the less favorable the shear profiles are overall, and the less instability for storms to capitalize on.