Computers are an integral part of our home and work lives, and that's certainly true in the weather business. Weather forecasting is really just a huge math problem that can't be solved with pencil and paper. The earliest electronic computers were invented in the 1940s, and some of the first scientists to use them were meteorologists. It was because of a computer developed at the University of Pennsylvania's Moore College of Electrical Engineering that "weather forecasting by computer" became a reality.

The software packages that produce computerized weather forecasts are called computer models, or just "models" for short. A typical model has hundreds of thousands of lines of code. Those computerized instructions input weather observations, apply the physical laws that govern how the atmosphere works, and then produce forecasts that meteorologists use to guide their predictions. The farther out the prediction, the more meteorologists rely on computer guidance.

This week we'll look at the history of computer weather modeling, how a computer actually makes a forecast, why computer models don't always get it right, and where you can get the model forecasts yourself.