Computer models take the current environment conditions which are gathered from observations, weather balloons, satellite, radar, and other instruments. Various models take this information and compute forecasts using different atmospheric formulas. Differences in resolution and the way formulas are applied can lead to different forecasts. While certain models have proven to be superior over others there is no one model that is right all the time. Best practices suggest looking at trends in models rather than exact tracks and look for consensus among the various models.