“Upper Air Charts”

by Caleb, KE0FOE

As we continue with our series covering JetStream, The National Weather Service’s new Online School for Weather, the topic this time is: Upper Air Charts.

In meteorology, changes in temperature, humidity, and air pressure across relatively short distances are usually associated with active weather. Forecasters plot these changes, also known as gradients, by using upper air charts.

Among all upper air charts, the 500 millibar constant pressure chart is the one referred to more often among meteorologists. This is because, at an elevation ranging from 16,000 to 20,000 feet, the 500 millibar level (which is half of the 1,000 millibar average sea level pressure) is considered the “middle” of the atmosphere.

All weather is caused by inequalities in air pressure, temperature, and humidity. These upper air charts compiled by meteorologists provide the daily numerical data needed by computer weather models in order for them to forecast our weather.

There are a lot of amazing facts and projects about earth’s atmosphere that you and your family can discover on the National Weather Service’s new Online School for Weather called JetStream. Visit their website: weather.gov/jetstream