ABSTRACT
Zollinger, M. and Williams, G.J., Jr., 0000. Impact of ambient conditions on the longevity of quasi-linear convective systems crossing the southeastern U.S. coast.
A climatological study was conducted to investigate the synoptic, mesoscale, and boundary layer factors that governed the longevity of warm-season quasi-linear convective systems (QLCSs) as they passed through the southeastern U.S. Atlantic coastline from 2013 to 2023. QLCSs were classified into three categories (decaying, slowly decaying, and sustaining) based on their longevity once they entered the U.S. southeastern Lowcountry and based upon their evolution when encountering the southeastern Atlantic coastline. Results show that 95% of QLCSs (88 out of 93) dissipated within 100 km of the Atlantic Coast. Although cold pool strength and convective instability were not clear discriminators between the three categories of QLCSs, the two distinguishing features for the five sustaining systems were the presence of surface fronts (along with the ambient vertical wind shear and the synoptic-scale forcing associated with them) and anomalous warmer sea-surface temperatures relative to land. These results indicate that the marine environment of the southeastern Atlantic Ocean serves as a deterrent to QLCS maintenance, and sustaining QLCSs are driven primarily by external forcing mechanisms (such as frontal boundaries and upper-tropospheric jet streams) rather than internal forcing mechanisms (such as lifting along the cold pool boundary).
