A parameterization of slantwise convection in the WRF model

Abstract In this study, we introduce a parameterization scheme for slantwise convection (SC) to be considered models that are too coarse resolve explicitly (with horizontal grid spacing coarser than 15 km or less). This SC operates in locally defined 2D cross section perpendicular the deep-layer-averaged thermal wind. It applies momentum tendency adjust environment toward neutrality with prescribed adjustment time scale. Condensational heating and associated moisture loss also considered. To evaluate added value of scheme, implement it Weather Research Forecasting (WRF) Model supplement existing cumulus schemes upright test two different numerical setups: idealized, unforced release conditional symmetric instability (CSI) an initially conditionally stable environment, 3D real-data precipitation event containing both CSI along cold front cyclonic storm near United Kingdom. Both cases show significant improvements coarse-gridded (40-km) simulations when parameterizing convection. Compared 40-km only counterparts additional exhibit larger extent neutralization, generate stronger grid-resolved circulation, produce greater amounts precipitation, all better agreement corresponding fine-gridded reference simulations. Given importance midlatitude weather systems, our results suggest there exist potential benefits general circulation models.