Wind energy is the world's fastest-growing renewable energy source. Thus, the number of people exposed to wind farm noise is increasing. Due to its broadband amplitude modulated characteristic, wind turbine noise (WTN) is more annoying than noise produced by other common community/industrial sources. Aerodynamic noise on the blades is the dominant noise source of modern large wind turbines. Physically accurate methods for the prediction of acoustic noise produced by wind turbines and farms are crucial for their environmental impact assessment, including their amplitude modulation behavior. The state-of-the-art approach to model the aerodynamic noise from wind turbines is to divide the blades into a number of radial segments. A noise source is then associated to each element. From the wind profile, blade geometry and aerodynamic parameters (e.g. angle of attack, etc.), the strength and directivity of each of the sources are estimated. Finally, the noise from each source is coupled to a propagation code to account for weather conditions. This process has to be performed at each angular position of the blades as it completes a full rotation. This approach results in hundreds of noise sources needed to model a single turbine. The result of this process is extremely computationally intensive calculations, unfeasible to model realistic wind farms. We propose a novel method for modeling wind turbine's noise and its atmospheric propagation. The approach consists of computing an equivalent noise source placed at the turbine hub with a strength and directivity that is a function of the rotor angular position. This single equivalent source is then coupled to a curved ray tracing propagation code. The approach is demonstrated for a 5MW modern wind turbine over a flat acoustically soft terrain. The results show the proposed modeling approach to be computationally efficient and accurate.