Divergence aloft tends to be associated with surface low pressure area development.
There are two ways, one of which is related to the heating and cooling patterns over the globe. For example, during the summer the surface of the continent is the site of low pressure. We can trace this from divergence aloft which can, in turn, be traced to heating of the air columns over the continent which causes the development of upper tropospheric high pressure areas initially. Since according to our rule of thumb, at a given elevation air tends to move from high pressure to low pressure, air diverges out of these high pressure areas aloft moving towards the low pressure areas at either Pole, which lowers the pressure on the surface directly underneath the high. Examples of Thermal Lows and Highs During the summer, the continents at a given latitude aremuch warmer than the oceans.