From Dr. Roy Spencer:
The coast-to-coast cold that will be spreading across the U.S this week will be be accompanied by the development of a Gulf Coast low pressure center that will threaten the South and Southeast with substantial snowfall by the weekend.
The low is just now approaching N. California and will intensify as it travels across the Inter-mountain region, the Texas panhandle, then travel eastward along the Gulf coast by the weekend.
The latest GFS model forecast total snowfall by midday Sunday shows the possibility of 6-12 inch snowfalls across about ten southern states, including Oklahoma, Missouri, Arkansas, Tennessee, Mississippi, Alabama, Georgia, the Carolinas, and Virginia (graphic courtesy of Weatherbell.com):