The cold tonight will not be any different than previous nights this week. Tempreatures will drop from 40s to 30s by 6 PM and then to below freezing by around 9 PM. Temperatures will drop to the mid-to-upper 20s by Saturday morning.
Saturday afternoon will warm into the 40s again, but that is the last warm(ish) day before dangerous levels of cold take over the Tennessee Valley. The initial introduction of that extreme cold can come with snow flurries for a small few of us within the Tennessee Valley. Most of us will be snow-free.
Temperatures will drop below freezing Saturday night and will not warm back above freezing until Wednesday afternoon. Highs temperatures will range from upper 20s to lower 30s through Tuesday. Nights and mornings will be the most brutal with temperatures dropping into the teens. Single digits are possible in our coldest spots. Wind will increase to 15-30 mph, which will likely bring wind chills down to as cold as ten degrees below zero.
Air this cold is dangerous, especially to areas not accustomed to it. If you have to be out in the cold, dress in layers topped with a heavy coat. Multiple layers are more effective at keeping you warm than a coat alone. Wear multiple pairs of socks, and don't forget to wear gloves. The outer extremities of your body can freeze quickly. Cover as much bare skin as possible if you are exposed to the cold wind. Outdoor pets need shelter from the wind and a way to stay warm. If possible, bring them inside. It not, prepare them for the cold. Make sure they have plenty of food and water