Surface pressure charts
These charts show the surface pressure pattern using isobars (lines of equal pressure) and indicate areas of high (H) and low pressure (L) along with their central pressure value. Isobars are represented by solid lines. Fronts are also displayed.
An actual analysis chart is issued along with forecast charts out to five days ahead. These are updated every 12 hours around 0730 and 1930, with the exception of charts for days four and five which are only issued once per day at 0730.