Meteorologists measure the atmospheric pressure because it is helpful when analysing and predicting winds and weather. The pressure is measured using a barometer, in units of millibars (mb), hectopascals (hPa), or inches of mercury. A correction is applied to calculate the equivalent sea-level pressure.
On a weather chart, lines joining places with equal sea-level pressures are called isobars. Charts showing isobars identify features such as anticyclones (areas of high pressure), depressions (areas of low pressure), troughs and ridges.
Surface pressure charts
Charts of surface pressure are available from analysis (T+0) in 12-hourly steps out to the 84-hour forecast (T+84). The charts are also available as an animation.
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Surface
pressure charts Updated once per day around 0730 UTC |
