Upper Air Charts

Introduction to the Upper Air

What we experience as weather at ground level is the end result of what takes place over our head. So, to determine the forecast, and therefore the impacts, of weather we will need to determine the weather patterns in the upper air before looking at the surface weather.

Any time there is a rapid "change in" any particular weather element we will say the "gradient" is large. It is near these large gradients where the weather is most active.

A common example is found near cold fronts. The "change in" air pressure is typically rapid near a cold front and therefore the pressure "gradient" is large. The greater the pressure gradient is near a front the stronger the wind. This is just as true for the upper atmosphere.

While the information a skew-t chart provides is invaluable, it will only tell us what is happening in the atmosphere at that location. To paint a complete picture of the atmosphere as a whole we need to view radiosonde data from many upper air observations.

We do this by creating constant pressure charts that let us see changes, and gradients, in atmospheric conditions across the country and around the world.

A sample 500 millibar upper air chart
A sample 500 millibar upper air chart. The gradient is the largest where the brown lines are closest together.