Residual Outflow Boundary Impacts on CAPE versus Shear Contributions to Tornadic Supercells: the F-5 Barneveld, Wisconsin Tornado Revisited

The impact remnant outflow boundary over the Upper Midwest from early morning convection on maximized afternoon and evening CAPE values is examined through the use of Geostationary Operational Environmental Satellite (GOES) data and available surface observations. Satellite imagery and surface analyses conveyed that a residuum deformation structure provided the focus for further convective development over southern and eastern Wisconsin. Thus, the prevalence of widespread cloud debris over southern Wisconsin prohibited excessive boundary layer instability from reaching high values during the window of maximum diurnal diabatic heating. The combination of reduced CAPE values and ambient high shear profiles is investigated for priming Barneveld, Wisconsin with low Bulk Richardson Numbers (BRN) conducive for a nocturnal tornadic supercell. Furthermore, it is hypothesized that the presence of the deformation zone itself led to an augmentation of streamwise vorticity, enhancing low-level rotation such that the F-5 Barneveld tornado could materialize. _______________________________________