Vertical Structure of
Cyclone
If lows and highs aloft were
always directly above lows and highs at the surface, the surface systems would quickly dissipate.
When the surface pressure
system does not directly beneath the upper-level trough and ridge but toward
the west, surface cyclone and anticyclone can intensify and, steered by the winds aloft, move away from the
region of formation.
(from
Meteorology Today)
In order for cyclones to
develop, there must be upper-level divergence above the surface storm.