Megers between isolated supercells and quasi-linear convective systems: a preliminary study

Past research within the convective storms community has often viewed supercell thunder-

storms and larger-scale quasi-linear convective systems (QLCSs) as distinct entities to be

studied in isolation, with a majority of studies focusing purely on one phenomena or the

other. For instance, many studies investigating the dynamics and structures of supercell

thunderstorms conclude their analysis once the supercell has merged with other storms, or a

larger QLCS. In addition, most studies have focused on cases characterized by the archetypal

environments that favor a given mode rather than those that would permit both supercell

and intense QLCS organizations, which are not uncommon. While this has lead to immea-

surable advances in the understanding of supercells and QLCSs, an unintended result is that

there is a gap in the knowledge base surrounding what happens when these organizational

modes merge and interact. These interactions occur quite regularly in nature as multiple

storms, and multiple modes, are often evolving concurrently within the same region. This

is of particular importance to the severe storms forecasting community, given an ongoing

debate within the literature as to whether storm mergers (often referring to isolated, cellular

storms) may help or hinder tornadogenesis. With this in mind, the goal of the present study

is to begin to address the problem of QLCS/supercell mergers through a preliminary study

focusing on observations from several cases of QLCS/supercell mergers in the central United

States. The longer-term aim of this study is to set the stage for future numerical simulations

that will delve into dynamical processes at work during these events.