The foundation of all weather forecasts is observational data. Thousands of permanently installed and mobile weather stations (i.e. ships, buoys, and aircrafts) and the Meteomatis Meteodrones are delivering weather parameters, like temperature, relative air humidity, precipitation, cloud coverage, wind direction and –speed on a regular basis.

Besides different model physics, also differences in assimilated observational data can cause strong deviations in the weather forecasts of individual weather models. This became clear in the thunderstorm, which crossed Switzerland last Thursday. Swiss1k, the Meteomatics weather model with a resolution of 1km for whole Switzerland, has already shown this front on Wednesday. The precise forecasts have enabled early warnings by the SRF, which in some cases could lead to considerable damage being avoided.