Tornadoes in High-Shear, Low-CAPE Environments: A Review of The 9 January 2024 Claremont, North Carolina, Tornado

A powerful storm system impacted the National Weather Service Greenville-Spartanburg County Warning Area on 9 January 2024 bringing a myriad of hazards, including winter weather, flooding, and severe thunderstorms. A line of thunderstorms, some of which were severe, moved across the Upstate of South Carolina during the morning hours and into the North Carolina foothills and Piedmont by early afternoon. Numerous reports of wind damage were received, and one tornado was confirmed in the Claremont community in Catawba County, North Carolina. A subsequent damage survey determined that an EF-1 tornado touched down at 1727 UTC and tracked for 14.5 kilometers from south of the city of Claremont to Interstate 40 in Iredell County, just on the east side of the Catawba River. The tornado was 229 meters wide and had estimated peak winds of 49 m/s. Tragically, the tornado struck a mobile home community, resulting in one fatality and four injuries.

Unfortunately, no tornado warning was issued for this storm, with the tornado forming north of the tornado watch that was in effect. The Storm Prediction Center had a marginal risk for severe thunderstorms across Catawba and Iredell counties, with a 2% chance of a tornado within 40 kilometers of a point. Forecaster analysis based on available data during the event determined a high-shear, low-CAPE environment was in place across the region, with no surface-based instability in the area where the tornado occurred. Thus, the environment was assessed to not be conducive to the formation of tornadoes. This presentation will review the synoptic and mesoscale environments, along with radar data, to determine how a deadly tornado was able to form in an otherwise unfavorable thermodynamic environment. Several hypotheses for the tornadic development will be discussed, along with recommendations for future severe weather events.