Great question!  Changes in the polar vortex winds can transfer energy downward and impact the winds at lower levels, which in turn, can impact winds at even lower levels. Sometimes these changes can propagate all the way through the stratosphere and troposphere to the surface. Other times, these changes stop near the stratosphere-troposphere boundary (called the tropopause).  There is active research to understand which factors are most important for this this downward propagation to occur. Amy is going to cover these ideas in much more detail in the next post. Thanks for reading!