Above is the NearCast imagery at 22Z.  Utilizing this imagery, a pretty apparent boundary is evident across portions of MO into northwest Arkansas.  Along this boundary, convection was much more widespread than it was further south.  Further south, despite better instability, there is no indication of any boundary which likely explains the more scattered nature of the convection.  Operationally, seeing this boundary on the nearcast model would give me higher confidence in convective coverage further north versus further south.