Improved parameterizations of urban boundary layer flow are being incorporated into the MM5 and WRF meteorological models. In the case of MM5, the first urbanized version included a canopy structure and a set of gridded urban canopy parameters (UCPs) to reflect the influence of urban surfaces. It has successfully undergone testing and evaluation, and it has been linked to the Community Multiscale Air Quality (CMAQ) modeling system. In WRF, sets of gridded urban parameters that represent surface features have been introduced and have also undergoing testing and evaluation. Plans for WRF include the implementation of a canopy version. To improve the characterization of urban influences in CMAQ, we have recently modified the Meteorology-Chemistry Interface Processor (MCIP) to link with the urbanized versions of MM5 and WRF. Parameters used in both urbanized versions of MM5 and WRF are provided from the National Urban Database and Access Portal Tools (NUDAPT) prototype system. Initial simulations from MM5, WRF, and CMAQ will be presented for the Houston, Texas area. Results of two sensitivity studies will also be presented, one examining the impact of introducing fine-scale gridded anthropogenic heating rates and the other showing how mollification of the heat island intensity can be achieved by varying the values of the gridded urban parameters.