Speed
Diffluence/Confluence
Speed Diffluence
Speed Confluence
A
B
Point A shows an area of speed diffluence.  The winds are progressively accelerating upstream, which in-turn will result in the separation of the air parcels.

Point B shows an area of speed confluence, as the winds quickly decelerate as they approach the point.  This in-turn will result in the compression of the air parcels.