The people of Bremen are used to all kinds of weather. But what happened in the summer of 1985 in Bremen exceeded the proverbial composure of most inhabitants. On the 24th of July the telephone in the weather office was running hot. Angry callers complained about the weather forecast which they had read in the morning in the Weserkurier. There, a day later, you can read a lengthy article on the summer weather:

What happened to make the meteorologists go so wrong, and what does it have to do with complex systems and the concept of chaos?

The starting point for any weather forecasts is the synopsis, that is, a survey of the current weather over a large area. The basis for this is measurements and observations from weather stations on land or at sea. For example, every day radiosondes climb into the atmosphere, and during their climb to almost 40 km in altitude they measure temperature, humidity, and pressure. A whole series of parameters such as pressure, temperature, dewpoint, humidity, cloud cover and windspeed are collected in this manner and input into a forecasting model, which is calculated with the aid of high-speed supercomputers.