The parameterization of surface roughness is necessary in order to determine surface exchange coefficients and subsequently surface fluxes. Surface fluxes then provide the bottom boundary conditions for the atmospheric boundary layer scheme in a parent atmospheric model. Surface roughness is explored in the NCEP operational WRF-NMM (mesoscale model) with a number of approaches tested for both momentum and heat roughness related to land-use (i.e. vegetation) and terrain (i.e. height, variation, orientation with respect to wind direction), and for different seasons and stability conditions. Model results are compared with low-level observations (i.e. 2-m temperature and humidity, and 10-m winds) and observed vertical profiles of wind, temperature and humidity, and where available, with surface fluxes and surface skin temperature.