In lecture I said that CYCLONES and ANTI-CYCLONES occur in sequence in the middle latitude atmosphere. That is they occur in succession; LOW - HIGH - LOW - HIGH etc. As evidence of this fact I offer the sea-level pressure map from 1200 UTC April 1, 1997.
We then concluded that, since the CYCLONES and ANTI-CYCLONES are associated with regions of DIVERGENCE and CONVERGENCE aloft, respectively that there should be alternating regions of upper divergence and convergence directly above the surface positions of the cyclones. As evidence of this fact I offer the 500 MB map from 1200 UTC April 1, 1997.