Can weather models be helpful for astronomers? In this talk, I do a revision of the state-of-the-art in numerical weather prediction models and its specific applications for astronomical observatories. In the context of flexible scheduling, the weather prediction models, and the mesoscale models in particular, can give a significant contribution in the management of the observing nights based on the forecasted atmospheric conditions. A prototype for the operational forecasting of the Precipitable Water Vapour above ORM for observations in the Infrared, currently under development, is presented and discussed.