CAPS Storm-Scale Ensemble Forecasts and Ensemble Consensus Techniques for the 2018 Hydrometeorology Testbed FFaIR Experiment

The Center for Analysis and Prediction of Storms (CAPS) at the University of Oklahoma (OU) ran an extensive set of real-time CONUS-scale convection-allowing ensemble forecasts to support operations in the the Hydrometeorology Testbed (HMT) Flash Flood and Intense Rainfall (FFaIR) Experiment. For 2018 FFaIR, CAPS produced a 15-member ensemble using 3-km grid spacing over the full CONUS. The ensemble included 13 members of WRF-ARW with mixed microphysics, land-surface models, and PBL parameterizations as well as perturbations to initial and boundary conditions. In addtiona, the CAPS ensemble contained two FV3 forecasts, also at 3-km grid spacing over CONUS. The FV3 model forecast differ from each other in that one used the Thompson microphysics scheme and the other used the NSSL microphysics scheme. Recent statistical verification will be shown for the ensemble forecast system including the FV3 models.

As part of our testbed effort CAPS is developing unique methods of producing ensemble consensus products, including the Localized Probability Matched Mean (LPM) and the Spatially-Aligned Mean (SAM). The LPM method uses localized statistics with the probability matched mean method and the SAM accounts for phase or position differences among the ensemble members by first adjusting the members spatially to a consensus location, then computing the mean. Recent tests and verification of these ensemble post-processing techniques will be shown.