Different mechanisms of atmospheric dynamics occurring during the Blazhko cycle. They cause rapid loops of a few tens of days (Blazhko period) with an appreciable amplitude around 500 K and a few solar luminosities when the star in Blazhko phase crosses the instability band of the Herztsprung-Russell diagram. The fundamental mode edges of the instability strip are plotted as solid lines and first overtone mode edges as dashed lines.