The United Kingdom Environmental Change Network
Anticyclones (High Pressure)
High pressure systems have low pressure gradients (ie the air pressure doesn’t change rapidly). This means that the winds are gentle. As the air sinks, it warms up, leading to warm and dry weather.
Anticyclones are much larger than depressions and can lead to many days or weeks of settled and calm weather. Anticyclones often block the path of depressions, either slowing down the bad weather, or forcing it round the outside of the high pressure system. They are then called ‘Blocking Highs‘.
As air descends, air pressure increases. When air hits the ground, it has to go somewhere. The earth’s rotation makes the air change direction. In the Northern Hemisphere the air is pushed clockwise. In the Southern Hemisphere the air is pushed anticlockwise. This can be seen in the diagram below.
Air Direction in High and Low Pressure Systems
Weather conditions can vary between summer and winter anticyclones. Do you want to look at summer or winter anticyclones?
|Characteristics of Summer Anticyclones
||Characteristics of Winter Anticyclones