This is a pretty typical setup for January. In peak winter it is very difficult to get sufficient moisture over the MS Valley. Plus the jet stream tends to sag south and the lows that would normally track over northern Arkansas and MO are tracking over southern Arkansas or north Louisiana which limits the warm moist gulf air from getting much farther than southern MS. This low pressure system is just more potent than usual.
HiRes models are indicating a fast moving squall line and wind shift. There will be some embedded rotation but if a storm fires just out in front will have a tornado risk and with the low level shear in place any tornado that forms has a chance to be strong and storm motions will be so fast that any tornado that touches down will travel a long distance in a short amount of time. Strong tornadoes and long track tornadoes are both rare south of I-12 but they do happen as we've seen the last 18 months.