Synoptic charts and weather
A synoptic chart is a more detailed weather map which shows what type of weather system is moving over Britain.
Low and high pressure
The main weather element shown on a synoptic chart is air pressure.
Isobar lines which join up areas of equal air pressure are drawn on these maps. The pattern these lines make shows areas of low or high pressure.
Charts and symbols
Be sure to examine the information on the chart carefully. In the example below the date tells you the likely weather conditions of a high pressure system.
Synoptic chart for 14 November 2010
Synoptic charts often have weather circles shown on them.