Editing Surface weather analysis (section)

==== High pressure ====
High-pressure systems, also known as [[anticyclone]]s, rotate outward at the surface and clockwise in the northern hemisphere as opposed to outward and counterclockwise in the southern hemisphere. Under surface highs, sinking of the atmosphere slightly warms the air by compression, leading to clearer skies, winds that are lighter, and a reduced chance of precipitation.<ref>BBC Weather. [http://www.bbc.co.uk/weather/features/understanding/highpressure.shtml High Pressure.] Retrieved on 2007-05-05.</ref> The descending air is dry, hence less energy is required to raise its temperature. If high pressure persists, air pollution will build up due to pollutants trapped near the surface caused by the subsiding motion associated with the high.<ref>United Kingdom School System. [http://atschool.eduweb.co.uk/radgeog/metlink/ppt/highs/Press-System.ppt Pressure, Wind and Weather Systems.] {{webarchive|url=https://web.archive.org/web/20070927190000/http://atschool.eduweb.co.uk/radgeog/metlink/ppt/highs/Press-System.ppt |date=2007-09-27 }} Retrieved on 2007-05-05.</ref>