Stratus: a prototype expert advisory system for terminal weather forecasting

The methodology used to develop an expert system to predict low clouds is described. The expert system is based on the fundamental physical rules that govern the existence of clouds and is therefore location-independent. The first prototype, built using an expert system shell, confirmed the feasibility of the approach but showed that a much more efficient implementation would be required in order to validate the system statistically. Thus, in the development of the second prototype there was emphasis on conventional programming. The database management utility, which allowed fast and flexible access to the meteorological data, was the key factor enabling validation of the second prototype. A sensitivity analysis of the system´s performance has provided the experts with invaluable objective feedback to improve their ability to model the physical phenomena involved in forecasting low clouds