A model is developed to investigate the effects of far field flow on the solidification of a spherical particle from the melt, under the influence of thermal and solute flow. The stability of the spherical interface is studied and the growth rate of the interface perturbation is calculated. The perturbation to the maximum growth rate becomes larger when the spherical radius increases. The downwind side of the interface is more unstable than the upwind side. The effect of far field flow reduces the critical radius of the spherical crystal.