a data-driven system that uses a built-in set of rules to predict the results of a process or to simulate how a given set of conditions will change over time. By comparing the model’s predictions to experimental and observational results, scientists can refine the underlying rules to make the model itself more accurate. The AWIPS, seen in action during the field trip, is an example of a computer model of the atmosphere. As data about current wind conditions, precipitation, cloud cover, temperature, and other variables is fed into it from various places around the world, it uses sophisticated built-in theories about how those variables interact to predict how the atmosphere will respond over the next seven days.