High-shear, low-CAPE (HSLC) supercells are a phenomenon in which an anomalously high wind shear makes up for a lack of convective available potential energy (CAPE). These events are not very common, but when they do occur they generate high wind speeds and spawn numerous tornadoes. The initial conditions, severity, and longevity of HSLC supercell cases differ depending on their location in the United States. This study aims to quantify that difference by assessing and comparing HLSC cases in the Southeastern United States to HSLC cases in the Great Plains.
A total of 10 HSLC cases were observed between 2016 and 2021. 5 cases were from the Southeastern United States, and 5 cases were from the Great Plains. Each case was analyzed individually in order to determine the length of time and observe the presence of embedded supercells within the convection. Specific tornado, wind, and hail events were also observed for each case to further quantify their severity. Initial analyses of the longevity and severe weather events suggest that HSLC cases in the Southeastern United States are more impactful than those in the Great Plains.
To better understand how the convection of these cases developed over time, the National Centers for Environmental Information (NCEI) reflectivity radar was used. Additionally, the Storm Prediction Center (SPC) storm reports were observed in order to compare the amount of severe weather events for each case. These two sets of data, along with observations of embedded supercells from each case, will show the variations of HSLC cases between the Southeastern United States and the Great Plains.
Presented at the 2022 UNC Charlotte Undergraduate Research Conference.