Air Masses and Fronts

It is not uncommon in Missouri to hear folks say, "If you don't like the weather, wait a few minutes and it will change". This statement can be very true. Weather can change in a big hurry. An example of this occurred while this lesson was being written. In the afternoon of August 17, 2000 temperatures across Missouri reached 100 degrees at many locations but the following day was 20 degrees colder. Click on the August 17, 2000 link below. Look at the surface map. Compare the temperatures of St. Louis and Kansas City, Missouri.

***August 17, 2000 6PM***

A cold front moved through Missouri on August 17, 2000. Temperatures dropped more than 30 degrees in some location in just a few hours. We will investigate the cause of the cool-down within this lesson.

Air Masses:
An air mass is a widespread body of air with similar temperatures and dew points. Air masses can be compared to the story about Rodney the cowboy. He developed his characteristics in one place and carried them along when he traveled. Air masses also develop their characteristics in one location and are capable of carrying these characteristics to other locations.