While the impacts of the parameterization of convective processes in a mesoscale model are expected to be on the local scale and generally limited to warm-season convective precipitation forecasts, there can be significant impact on synoptic-scale features as well. Stable regions, in which convective processes will not play a role, can still be affected by upstream convective processes. This study examines two cases in which the evolution of a major synoptic feature differed greatly when the model was run with a different convective parameterization.

The cases involve precipitation events in the mid-Atlantic states, one a winter storm case and the other a heavy, warm-season overrunning precipitation event. The focus will be on Eta model cases run with the Betts-Miller-Janjic and Kain-Fritsch convective schemes. If time permits, modifications to each scheme will be tested as well.