Anticyclones

Anticyclones are the opposite of depressions - they are area of high atmospheric pressure, where the air is sinking.

Anticyclones: high pressure over the U.K and northern Europe (left) brings settled weather with clear, bright skies.

• As the air is sinking, not rising, no clouds or rain are formed. This is because as the air sinks it warms - meaning it can hold more water.
• The absence of fronts means winds may be very light.
• Consequently, high pressure areas are often associated with settled, dry and bright conditions.
• In summer, anticyclones bring dry, hot weather. In winter, clear skies may bring cold nights and frost.
• In cold conditions anticyclones may also bring fog and mist, as the cold forces moisture in air to condense [Condense: A substance condenses when it changes from a gas to a liquid, e.g. from water vapour to water. When this happens it will reduce in size and become more dense. ] at low altitudes.

Exam tips

Watch tv weather reports for the British Isles with the sound / subtitles off to see if you are able to understand and predict the weather forecast (you can always video the report and play it back afterwards to see if you got it right).

Look at the synoptic charts on weather websites such http://www.bbc.co.uk/weather/world/. See if you can spot any patterns in air pressures shown? Where are the high pressure fronts originating from? Where are the low pressure fronts coming from?

Studying synoptic charts on a larger scale will help you develop your skills and understanding of weather systems, and of how global weather systems interrelate.