| a chart showing the distribution of meteorological conditions over a wide region at a given moment. |
synoptic chart
any map or chart that shows the meteorological elements at a given time over an extended area. The earliest weather charts were made well before 1835 by collecting synchronous weather reports by mail. The first telegraphic collection of synoptic meteorological reports and their mapping for forecasting was accomplished by Urbain-J.-J. Le Verrier during the mid-1800s.
Learn more about synoptic chart with a free trial on Britannica.com.