According to Weather Underground, hurricane path projections are the result of multiple computer modeling programs taking into account large amounts of atmospheric data about the storm. Some models use only the current atmospheric conditions in their calculations, while others take into account historical data about past storms and the ways they moved in order to anticipate possible storm paths.
Hurricane forecasting begins with data collection. Satellites, ground- and sea-based weather stations, and aerial overflights of hurricanes provide meteorologists with regularly updated data about the conditions in and around the storm. In addition, meteorologists can take into account regional data such as the movement of the jet stream and high and low pressure fronts that may impact the storm's path.
There are more than three dozen computer models the National Hurricane Center may use to plot a hurricane's path. Due to each model's variances, such as how heavily its weighs certain variables, the data provided by these models can vary significantly. Most models give a reasonably accurate picture of the next 24 to 48 hours of a hurricane's activity, but beyond that threshold, the variables can cause the models to disagree and suggest very different paths for the storm. The National Weather Service compares all these tracks, considering the ones that have been most accurate in the past. The result is a cone-shaped projection showing the most likely position of the storm's eye at any given point in the next five days.