In complex outdoor sound propagation meteorological effects as well as various absorbing properties and shapes of the boundaries need to be accounted for. This paper presents a hybrid GFPE-BEM method relying on the power of the BEM near obstacles and uneven topographies in order to compute the starting field which is then propagated thanks to the GFPE. The approach is firstly described. Then some numerical results are given for typical road traffic noise configurations with and without meteorological effects. The results show that this hybrid GFPE-BEM model can predict accurately the sound pressure levels in complex outdoor configurations.