Within the past decade, very few three-dimensional numerical investigations of hurricane intensity change have been conducted. Most previous investigations have focused on the effects of a variety of background flows on hurricane motion and of vertically sheared background flows on hurricane intensification. The present investigation addresses the effect of uniform zonal background flows on the intensification of tropical-cyclone-like vortices using a numerical three-layer shallow-water model that includes parameterizations of convection, sea surface energy exchange, and boundary-layer friction. Calculations on an f-plane showed that, during the intensification phase, an intially weak vortex intensified more rapidly in the presence of a uniform zonal background flow, regardless of its direction. Compared to an environment at rest, the uniform zonal background flow resulted in increased boundary-layer convergence colocated with increased boundary-layer mixing ratio due to surface moisture fluxes, producing stronger convection and more rapid intensification. After the vortex reached hurricane strength, however, a sequence of internal processes resulted in a decrease in convective activity in the region of boundary-layer convergence surrounding the vortex center, which translates into a reduction in the maximum strength of the hurricane compared with an experiment involving a resting environment. On a beta-plane, it was found that a uniform westerly background flow was more favorable for intensification than an easterly background flow of the same strength. This dependence of intensification rate on background flow direction is attributed to differences in the position of a region of convectively unstable air relative to the trajectory of the vortex in these respective cases