On December 23, 2015, an outbreak of supercell thunderstorms produced tornadoes across northern Mississippi and middle Tennessee, resulting in 13 tornado-related deaths and numerous injuries. Other tornadoes occurred as far north as Indiana and Michigan. Scattered tornado activity continued over the next two days before the outbreak ended. This was the first of two deadly tornado outbreaks to impact the southern United States during December 2015 with the other occurring just a day after this one ended.

On at December 23, 2015, the Storm Prediction Center discussed the probabilities for severe weather to materialize in the Mississippi Valley, encompassing regions in northern Louisiana, eastern Arkansas, northwestern Mississippi, western Tennessee, the Missouri Bootheel, and extreme southwestern Kentucky. A cold front ejecting from the Texas Panhandle and a warm front coming from the lower Ohio River valley, intersected by a stationary front placed over western Kansas, led to the creation of a triple point over northwestern Missouri. This set up the environment for an atmosphere conductive to severe weather. As the evening progressed, further certainty arose for the possibility for an outbreak, as Convective Available Potential Energy values of around 1,000–2,000 J/kg and effective wind shear were present for the aforementioned areas of the upper Mississippi Valley. Daylight heating in these areas gave way for effective buoyancy in the area, further improving the conditions for supercells and to develop. Given the favorable parameters, the SPC, alongside its Convective outlook, introduced a 15% hatched area for tornadoes, indicating the probability for a few strong tornadoes to occur, as discrete supercell thunderstorms were expected to develop in the area.^[2] As such, the SPC issued a PDS tornado watch, the first of multiple tornado watches that day, for northern Louisiana, western Arkansas, northwestern Mississippi, and western Tennessee, highlighting the elevated threat for strong tornadoes in the area.^[3] At 2000 UTC, the SPC introduced an increased area for the concern of strong tornadoes, extending the existent area to reach central Tennessee, northwestern Alabama, and central portions of Kentucky.^[4]

The first tornadoes of the day occurred in the Midwest, where an EF1 tornado that touched down in Greenwood, Indiana, where several homes sustained damage. Another tornado caused damage to homes in the Indianapolis suburb of Noblesville. In Illinois, a tornado destroyed multiple outbuildings and downed trees near the town of Sciota.^[5] The outbreak also spawned the only known tornado to touch down in Michigan during the month of December, an EF1 that struck the Detroit suburb of Canton, causing considerable damage to vehicles, an industrial park, and a gas station.^[6]

In the area with the greatest risk for tornadoes, multiple supercells developed by noon, soon becoming tornadic. A strong EF2 tornado occurred near Marianna, Arkansas, completely destroying mobile homes, tearing roofs off of frame homes, and damaging cabins in the area. A large EF3 tornado eventually touched down south of Clarksdale, Mississippi, killing two people and severely damaging or destroying about 15 homes in that area. The tornado continued to the northeast, later snapping trees and destroying homes near Marks and Como before dissipating. The same parent supercell produced another tornado further east of Como, a violent EF4 that devastated 6 counties on Mississippi and Tennessee along a 75.09 miles (120.85 km) mile long path, killing 9 people.^[7][8][9] Another destructive EF3 tornado struck the small community of Lutts, Tennessee after dark, destroying multiple homes and a church, and completely leveling the town's post office.^[10] Significant tornado activity continued through parts of Mississippi and Tennessee overnight, including an EF2 that killed an elderly couple in their small, unanchored home near Linden, Tennessee.^[11][12] In total, the outbreak produced a total of 13 tornado-related deaths and numerous injuries.^[13] Additional scattered tornado activity occurred on the 24th and 25th, including a high-end EF2 that caused heavy damage in the southwestern part of Birmingham, Alabama on Christmas.^[14]

• December 2015 North American storm complex
• Tornado outbreak of December 16–17, 2019
• Tornado outbreak of December 10–11, 2021