The latest weather synopsis showing the weather fronts and associated pressure is below – the image is updated very hour or so.
And if you prefer a more classical, static black and white version from the Met Office:
The numbers measure the atmospheric pressure in millibars. Usually isobars are drawn at intervals of two or four millibars (one thousandth of a bar). The closer the isobars are together, the windier it is.
If the lowest number is in the middle circle, this is a low pressure or depression. Often low pressures mean wet and windy weather.
If the highest number is in the middle circle, this is a high pressure or anticyclone. Often high pressures mean dry, sunny weather.
Air pressure tends to range from 890 mb (a hurricane) to 1060 mb (an anticyclone).