MCS exercise. Ask forecasters questions about the various fields shown. For example, where would you expect strong upper level divergence based on slide 86. Why? On slide 87 there is small area in west-central Oklahoma where backbuilding appears to be occurring. This is a chance to explain that in early stages of MCS development that the Corfidi vector method does not always work. The method works best for mature systems. My own experience is that convection out ahead of the main MCS seems to have a better chance at having a period of backbuilding prior to organizing into a system.