This document discusses disease forecasting models that use weather data to predict outbreaks. It provides examples of models for rice blast, potato late blight, wheat yellow rust, and more. The potato late blight model for India, JHULSACAST, is specifically discussed. Disease forecasting is useful for giving advance warning to apply protective chemicals before infection starts and help control economically important crop diseases. Both empirical and fundamental forecasting systems are covered, along with their components and requirements for developing useful forecasting.