Why is the weather forecast inaccurate?

The general process of weather forecast is to obtain all kinds of relevant data from meteorological stations and observation points around the country, and then substitute these parameters into the mathematical model designed by meteorologists, and the forecast results are calculated by computers. This amount of calculation is quite huge, so it was completely impossible before the advent of computers. So whether the prediction is accurate or not depends largely on the mathematical model. Chaos theory holds that things like weather are unpredictable (see "butterfly effect"). Therefore, the money spent on weather forecast is also a waste. However, it is quite accurate to predict the recent weather situation in a certain area through satellite cloud images, but the specific weather or temperature in a certain place at a certain time is quite different. Why is the weather forecast so inaccurate? Yang Guiming, a senior engineer of the Central Meteorological Observatory of China Meteorological Bureau, explained: "The accuracy of weather forecast depends on the density of observation data. However, there are only 100 sounding stations in China, which is equivalent to only one sounding station every 200 kilometers. Cloud's life is very short. A large rain cloud may rain within 10 km, but it will not be observed if the rain does not fall on the observation point. Sounding stations are sparse not only in space but also in time. Only at 8 am and 7 pm every day, the sounding balloon is raised twice for observation, and only the ground observation station is used for observation at other times. It is unpredictable that the sounding balloon rises without encountering clouds. "