An abundance of cirrus clouds which gradually thicken to lower level clouds on the horizon for example, is a typical indicator of an approaching depression . Historically, such observations have led to the development of weather folklore, although many have little sound basis in fact. When the morning Sun illuminates clouds to the west, this may be an indication of an approaching front and depression . In the evening, the setting Sun in the west will illuminate clouds to the east that may have already passed by. Better predictions of weather require an understanding of the isobaric patterns associated with fronts and depressions , anticyclones and high-pressure ridges.
Meteorologists plot isobaric patterns on synoptic charts .
Meteorologists used to plot all their synoptic charts by hand. Since the advent of fast powerful computers however, this task has become much easier. Nevertheless, although organisations like the UK Meteorological Office use supercomputers to predict the weather, television weather presenters still use the isobaric patterns of pressure to describe the movement of depressions and other weather phenomena. BBC Weather Weather Dude Weather Dude WW2010 Met.