Abstract Results of a modeling study of the 24 May 1989 dryline are presented. A nonhydrostatic, two-dimensional version of the Colorado State University Regional Atmospheric Modeling System (CSU-RAMS) is used to deduce the impact of east-west variability of soil moisture and vegetation on convective boundary layer evolution and dryline formation. The effects of the initial moisture and wind fields and the impact of the Coriolis force on the model results are also examined. Model output is compared with special airborne and sounding observations of the 24 May dryline. Several findings of an earlier observational study of the 24 May dryline are supported in the present study. The modeled drylines are broadly comparable to the observed dryline with respect to the following properties: 1) width, 10 km; 2) strong horizontal moisture and virtual potential temperature gradients, >4 g kg−1/10 km and 2 K/10 km; 3) strong horizontal convergence, updraft, W–E shear of N–S wind component, 8 × 10−4 s−1, 1 m s−1, 10 m...