During previous experiments, mixed physics approaches have shown potential for providing spread within a convection-allowing ensemble. These mixed physics approaches, however, are more difficult and costly to maintain in an operational setting. The stochastic physics approach, in which stochastic parameter perturbations (SPPs) are applied within physics parameterization schemes, is one potential method to provide ensemble spread while being part of a more sustainable unified system. The single physics approach will provide a performance baseline, which the mixed and stochastic physics approaches can be compared against.
Objective verification metrics detailing the utility of each ensemble for severe weather forecasting will be explored by generating surrogate severe probability forecasts (SSPFs) from updraft helicity (UH) fields, and verifying against observed severe probabilistic fields (OSPFs) generated from storm reports. Additionally, daily subjective evaluations from experiment participants for each ensemble will be presented, along with an examination of differences in the ensemble guidance for days in which noteworthy features are indicated by the subjective evaluations.