Although computer models are a standard part of weather forecasting, existing models operate at a much larger scale than ARPS. Models at the National Meteorological Center, for instance, predict atmospheric structure over the entire United States every 12 hours. These regional-scale models can't predict movement and severity of individual storms.
ARPS, on the other hand, is scaled to the size and duration of a storm. It predicts over a smaller area (up to 1,000,000 square kilometers) and gives detailed readings on key storm parameters -- rainfall, wind direction and velocity, temperature and pressure, among others. It also predicts in time increments related to the way storms actually develop -- every few minutes rather than every 12 hours.