The paper considers the possibility of increasing of the nonstationary wave (similar to Tollmin-Schlichting (T-S) wave) growth by striped stationary structures of eigen-problem of stability of the supersonic boundary layer stability. The problem is solved within the framework of three-wave resonance interaction in local-parallel approximation. In this work the pumping wave is the stationary almost striped structures. Studies have shown that even in a stable area under the influence of longitudinal structures there is an increase of T-S waves. At sufficiently high amplitudes of stationary perturbations their effect on T-W waves is noticeable even in unstable area.