Nature Does Not Like Vacuuums Part I: At a given level, air tends to move horizontally from higher values of pressure to lower values of pressure (Note: due to Coriolis Effect the air really "spirals" from higher values of pressure to lower values of pressure).

Nature Does Not Like Vacuums Part II: Divergence in the upper troposphere is associated with rising air from beneath and convergence in the upper troposphere is associated with sinking air beneath.

Divergence aloft tends to be associated with falling surface pressures (formation of surface lows), whereas convergence aloft tends to be associated with rising surface pressures (formation of surface highs)