Measuring Pressure at the surface - the surface pressure chart

Surface pressure chart - isobars (lines of constant pressure) are plotted every 4 mb

Maps of surface pressure are very important:

- give positions of highs and lows

- can give information about the direction and strength of the surface winds

Q: How is a surface pressure chart created from observations around the country???

- remember that the station elevation will dramatically affect your pressure reading.....

Sea-Level Pressure Chart (Constant Altitude)