On March 2 and 3, 2012, a large and deadly tornado outbreak occurred over a large section of the Southern United States into the Ohio Valley region, spawning up to 70 tornadoes in its wake. A moderate risk of severe weather was issued for March 2 a day in advance for a large area from near Tuscaloosa, Alabama to Dayton, Ohio as an intense storm system tracked across the region in a very high shear environment, and intense tornadoes were possible. On the morning of March 2, it was upgraded and a high risk of severe weather was issued for Middle Tennessee and central Kentucky, later extended into Central and Southern Indiana and southern Ohio. The Storm Prediction Center mentioned the potential for significant tornadoes. Multiple PDS tornado watches were issued shortly thereafter.
The outbreak began fairly early in the morning, with an initial round of storms and tornadoes associated with the incoming warm front attached to a rapidly deepening low-pressure area over the central Great Lakes. One of these early day storms produced a damaging EF3 tornado that impacted Harvest, Alabama. Discrete supercells developed in the afternoon along a corridor from the South to the Ohio Valley, producing multiple intense to violent tornadoes as a result. This included a long-lived EF4 that formed just north of the Ohio River, resulting in extreme damage to numerous communities in southern Indiana, including Marysville and Henryville. Another EF4 wedge tornado killed four people and obliterated homes near Crittenden, Kentucky, while a large EF3 killed three people and destroyed most of Moscow, Ohio. At around 6:00 pm EST, an EF3 tornado impacted downtown West Liberty, Kentucky, resulting in major damage and 10 deaths. A high-end EF3 tornado also caused major damage to many homes in businesses in Salyersville, Kentucky, killing two people along its path. Another high-end EF3 tornado touched down at 8:03 pm. This storm tracked into Haralson County, Georgia, and Paulding County, Georgia, where it caused major damage in the Dallas area before dissipating. Some scattered activity occurred the following day, though an EF3 tornado caused damge in Georgia before the outbreak came to an end and the associated system moved offshore.
The storms resulted in 41 tornado-related fatalities, 22 of which occurred in Kentucky. Tornado-related deaths also occurred in Alabama, Indiana, and Ohio. The outbreak was the second deadliest in early March for the U.S. since official records began in 1950; only the 1966 Candlestick Park tornado had a higher death toll for a tornadic system in early March.
One day prior on March 1, 2012, at approximately 12:30 PM EST (17:30 UTC), the NOAA Storm Prediction Center (SPC) issued a large, 45% hatched and level 4/5 moderate risk area for severe weather across the eastern United States. This large risk spanned across northern Mississippi and Alabama, into central Tennessee and Kentucky, towards southern Indiana and Ohio the following day on the 2nd. A very large mid- and upper level trough was stationed in northern Arkansas and southern Missouri, towards the Columbus, Ohio area. The trough moved slowly eastward from its position in the Ozark mountains, transporting a belt of fast southwesterly winds to the southeastern side of the storm system. This overlapped with a highly sheared region, resulting in a possibility of tornadic supercells forming and tornadoes in general, some strong per the SPC.
The following day on March 2 at around 8:00 PM EST (13:00 UTC), the SPC issued a Public Severe Weather Outlook (PWO), concerning a more hazardous risk for significant (EF2+) tornadoes than what was expected the day prior. A level 5/5 high risk, which corresponded to a 30% hatched tornado risk, was put in place over central Kentucky and north-central Tennessee. The moderate risk area widened to include portions of southeastern Illinois, northwestern Georgia and the western Virginias. Alongside the main tornado risk, 45% hatched hail and damaging wind risks were issued over parts of the Ohio and Tennessee River Valleys. At 11:30 PM EST (16:30 UTC), the SPC adjusted the outlooks to include southern Indiana and Ohio in the high risk. At the same time, the moderate risk extended more westward, with most of northern Mississippi encompassed by it but also a small portion in eastern Missouri. The 45% hatched wind risk extended south to northern Alabama and Georgia, where as the 45% hatched hail risk moved westward, with northern Mississippi included. The strong upper-level trough with a vorticity center moved from northern Missouri to the Ohio River Valley area. Strong wind shear with the trough created a large, unstable air mass (warm sector) that overlapped a massive region, conducive for a widespread and potentially destructive tornado outbreak.
On the morning of March 2, 2012, around 10:30 AM EST (15:30 UTC) a tornado watch was issued by the National Weather Service across east-central Tennessee, northern Alabama and northwestern Georgia. An initial squall line that formed along the Kansas–Missouri border moved eastward across the state and towards the Tennessee/Ohio River Valley area. Some of these storms within the line showed signs of rotation. These morning storms, including one that was responsible for a damaging EF3 tornado that impacted the northern Huntsville, Alabama metropolitan area, were associated with an incoming warm front that was linked to a low pressure area, located north at the Great Lakes. After many strong tornadoes occurred throughout the warm sector, the latest and final PDS tornado watch was issued at approximately 4:20 PM EST (21:20 UTC) that covered parts of Kentucky, Ohio, West Virginia and Virginia. Many of these supercells that had a history of producing destructive tornadoes, moved towards the Appalachian Mountains later into the evening. High vertical wind shear values were present within the warm sector of the expanding extratropical cyclone, giving way for storms to produce strong tornadoes.
The initial round of storms allowed for a strong warm air mass to enter the region, with temperatures rising to near-record levels for early March and instability combining with extreme wind shear, resulting in a highly volatile air mass. As a result, a second, much larger broken line of discrete supercells developed and followed the Ohio River, with additional storms developing farther south. During the afternoon, those cells tracked eastward across the Ohio Valley, passing north of Louisville, Kentucky and south of Cincinnati, Ohio with devastating results. One long-tracked EF4 tornado ripped through the Indiana towns of New Pekin, Henryville, Marysville, and Chelsea, killing 11 people. As isolated activity developed farther south, intense supercells also formed in central Kentucky in the late afternoon hours and tracked east into the Eastern Mountain Coal Fields region before weakening as they reached West Virginia later that evening. The town of West Liberty, Kentucky was devastated by a mile-wide EF3 tornado that killed 10 people.
The next day, on March 3, the cold front continued to push eastwards toward the United States East Coast, although the most severe activity took place near the Georgia-Florida state border. A slight risk of severe weather was issued for a small area extending from Cape Hatteras to the Mississippi Delta. A mesoscale convective system in South Carolina was responsible for hail reports in the area, although the threat for tornadoes was reduced with lower instability levels. Most tornado activity for the day was associated with an upper-level system in Florida, and mainly consisted of isolated, weak tornadoes touching down across the Southeastern United States. However, an EF3 wedge tornado caused significant damage near Moody Air Force Base in Georgia. On March 4, most of the cold front responsible for the outbreak had already moved into the Atlantic Ocean with only a small portion of thunderstorms extending into Florida. A slight risk was issued for a section of Florida. Some scattered activity lingered around the East Coast for the duration of the day, but no additional tornadoes were reported.