Sensitivity of Supercell Behavior to Artificial Airmass Boundaries in High-Resolution CM1 Simulations

Supercells frequently produce hazardous weather phenomena, and their behavior is strongly influenced by the environment in which they form and propagate. Numerous previous studies, based on both observations and numerical simulations, have demonstrated that supercells often interact with external features (outflow boundaries, differential heating boundaries, storm interactions etc.) prior to hazard production. In this study, we used the Bryan Cloud Model (CM1) to conduct high-resolution supercell simulations in which an artificial cold air mass, following Fischer and Dahl (2020, 2022), was introduced into the model domain along the path of the simulated storm. A series of simulations were conducted where the storm-relative distance, depth, and cooling intensity of the artificial cold air mass were systematically varied. A total of 27 perturbed simulations and one control run were analyzed, focusing on right-moving supercells, with particular attention to surface hail production, near-surface vertical vorticity maxima (Tornado-Like Vortices, TLVs), and midlevel mesocyclone strength. The results suggest that, similar to observations, the behavior of the simulated supercell is influenced by the physical characteristics of the cold air mass, favoring either more prolific hail production or stronger near-surface vorticity generation. In some cases, however, the cold pool interaction weakens the storm intensity, highlighting the complexity of storm-scale processes.