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The following image is an example of a UK plotted weather chart.
Plotted surface charts are made up of individual 'station circles'.
Each individual stations observation is put into graphical format
so that it is simple to understand, can be put on a chart and
be compared to its neighbours.
| The diagram opposite shows the basic station circle, including
temperature, pressure, weather, cloud cover, wind speed and
direction. Some elements, e.g. weather and cloud cover, are
put into a graphical code to make them more obvious. The Met
Office uses a much more complex station circle but the one
below is a simplified version using the main weather elements. |
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Wind speed and direction
Wind direction is indicated by a line coming from the centre
of the station circle. The line indicates the direction from which
the wind is blowing.
On the end of the wind direction line are 'feathers', these indicate
the wind speed. Half feathers represent 5 knots whilst whole feathers
indicate 10 knots. A wind speed of 50 knots is indicated by a
triangle. Combinations of these can be used to report wind speed
to the nearest 5 knots.
The table below shows the symbols used to indicate different
wind speeds.
Cloud cover
Cloud cover is indicated by the shading of the centre of the
station circle. The table below shows the meanings of the different
symbols.
Temperature
Temperature is plotted to the nearest degree and is located in
the top left-hand corner of the station plot.
Pressure
Pressure is plotted in the top right-hand corner of the station
plot.
Weather
In total the Met Office has 99 codes for recording the current
weather at the time of the observation. However these can be simplified
down. Different types of weather are represented using different
weather symbols, a key to which can be found below.
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