The 06z GFS is rather different than other models, and even it's own previous runs, as it shows the western 500 mb energy not digging as much, closing off up in Nebraska instead of the southern plains. It's hard to buy that unless we see something from other models.
I don't know what's going on with the HRRR. The 00z run had heavy snow through northern Iowa. The 06z run was weaker and through central Iowa. The 12z run is weaker and through southern Iowa.