Precipitation assimilation has previously been found to be useful for improving regional climate model simulations of the surface water and energy cycles. Here we show that upper‐level dynamical features are also better simulated. In particular, noticeable improvements in the intensity and location of the subtropical upper‐level westerly jet and associated transverse circulations were found in a regional climate model simulation of the 1993 heavy summertime precipitation over the midwestern United States. We suggest that the increased rainfall directly over the upper Mississippi River Basin during the 1993 summer was linked with the location of the upper‐level jet, and its associated transverse circulation, in addition to increased low‐level summertime meridional moisture transport from the Gulf of Mexico.