AMS STAC Mesoscale Processes Awardee Keynote Talk: The Role of Mesoscale Environmental Variability in Determining Supercell Evolution

Mesoscale environments supportive of supercellular convection are well-established. Yet, severe convective storm environments are known to exist on a spectrum from nearly homogeneous to highly complex and heterogeneous in time and space; terrain, surface boundaries, diurnal effects, other nearby convection, and even the storm itself can induce changes in the surrounding environment. The presence of such environmental variability can result in challenges in accurately predicting storm intensity, longevity, organization, and severe weather production.

Previous work using idealized models has demonstrated that accounting for shifts in the near-storm environment, regardless of their origins, produces more accurate depictions of supercell evolution. Yet, questions remain regarding the timescale at which supercells respond to changes in their environments, the influence of the magnitude of the heterogeneity, the dependence of the storm’s maturity when variability is imposed, as well as the relative importance of internal storm processes versus environmental variability in determining storm evolution and severe weather production. This presentation will review what is currently understood about the role of environmental variability on supercell evolution through synthesis of recent observational and idealized modeling studies investigating heterogeneity in the inflow environment. Additionally, results from new idealized simulations will be shown to compare and contrast the effects of variability due to terrain, surface boundaries, and diurnal processes on supercell characteristics. Suggested avenues for future work will also be provided