Necessity of Convective Parameterization in Simulating MCS Precipitation at High Resolution

The need for a convective parameterization when simulating a Mesoscale Convective System (MCS) at high resolution is investigated using the Grell-Freitas (GF) moist convection scheme, the Grell 3D (G3D) convection scheme, and a control without convective parameterization. The Weather Research and Forecast ARW was run between Oct. 2, 2013 0000 UTC and Oct. 4, 2013 0000 UTC in three (27-9-3 km) two-way nested domains over the Great Plains to simulate an MCS. As grid spacing decreased, the G3D and GF schemes produced less parameterized precipitation. The G3D scheme produced less total precipitation than either the GF or control experiments and less explicit precipitation than the GF scheme at 3 km resolution. The GF and control runs better utilized water vapor at low levels that allowed for a stronger MCS. The final precipitation totals between the GF and control schemes are similar, demonstrating that at fine grid spacing a convective scheme is unnecessary when simulating precipitation in an MCS.