A weather forecasting system has weather forecasting logic that receives weather data from a satellite or other source, such as radar. The weather forecasting logic processes such data to identify cumulus clouds. For each cumulus cloud identified, the weather forecasting logic applies interest field tests and feeds the results into formulas derived based on measurements from current and past weather events. The model determines a score indicating the likelihood of the cumulus cloud forming precipitation and a score indicating the likelihood of the cumulus cloud forming lightning in the future within a certain time period. Based on such scores, the weather forecasting logic predicts in which geographic regions the identified cumulus cloud will produce precipitation and/or lightning during the time period. The predictions of the weather forecasting logic may then be used to provide a weather map thereby providing users with a graphical illustration of the areas.