Combination of numerous weather data in real time
With the nowcasting systems developed by MeteoSwiss, factors such as the position and strength of thunderstorms, heavy rain and hail cells can be forecast for up to six hours ahead. For this purpose, radar, satellite and lightning measurements in real time are combined with model data to produce as detailed and precise predictions as possible on the development and path of thunderstorm cells. Initial nowcasting systems were restricted to the use of weather radar data, however, the new generation includes additional monitoring data in order to further improve the forecasting. Together with those from radar, measurements from satellites, lightning and meteorological stations, and the forecasts from the COSMO weather model are also used. Algorithms that amalgamate numerous information sources are known as expert systems. These allow the characteristics and the path of thunderstorm cells to be tracked over a period of time. On the basis of changes in the storm cell, estimates can be made as to the potential for hazards within the coming hours.
The expert systems TRT and COALITION developed by MeteoSwiss have now been in operation for several years. The forecasters obtain information from these systems about the current and future developments of thunderstorms, and can thus convey warnings promptly to all the relevant official institutions and the media in the case of a prevailing or impending hazard.