By 21z on Friday….a large positively tilted trough axis with a coupled upper jet structure will begin to eject eastward out of the Plains states and affect the Mid-South.  Of most concern is that the Mid-South will be in the left exit region of the subtropical jet streak.  Given this coupled structure, divergence will be remarkable over the region by early afternoon as wind profiles also become increasingly supportive of supercells and the potential for long track tornadoes given the kinematic environment coming into place. 

Step two in this game will be the potential energy available at the surface.  Each model run is consistently raising these numbers from Central LA into AR and W MS.  CAPE values of over 2000J/kg are likely.  Given that the model is projecting temperatures in the 70′s for most of the day, these could even be a little on the low side.  Very little forcing and a EML (elevated mixed layer), otherwise known as a capping inversion, across the area should keep junk convection at bay.  If this were to occur….the model could be low on temperatures and some areas could reach the lower 80′s across portions of LA/AR/W MS.  This would provide a “loaded gun” environment and be more like a time bomb waiting to go off.