Is the weather forecast for more than 7 days accurate?

The accuracy rate is 70% to 80%. The accuracy of weather forecast is relatively high for conventional weather forecast, such as three-day forecast, which can reach 70% to 80% globally. If it is a three-day forecast in a certain area, such as South China, the accuracy can be higher than 80%.

The accuracy is higher within 24 hours, close to 92%. For special weather, such as typhoon, rainstorm, hail and local heavy precipitation, the forecast accuracy is relatively low. The validity of international weather forecast has been increased from the early 1-3 days to 5-7 days. "At present, it is impossible for the weather forecast to achieve' ten reports and nine accuracy' or even' ten reports and ten accuracy'.

Ideally, observation stations of the order of 106 to 107 are needed in different geographical locations and different altitudes around the world. In fact, this value is only 103 to 105. Moreover, the distribution of observation stations is extremely uneven. For example, there are few meteorological observation stations on the Qinghai-Tibet Plateau in China.

At the same time, this is not a matter of a country, because the atmosphere is mobile, even if the domestic observation points are dense and the surrounding countries can not meet the requirements, it will also affect the initial data. Besides the data limitation of the observation station, the observation error and calculation error of the instrument are also quite large.

In the processing program, because the numerical prediction model is based on the solution of fluid mechanics equations, the difference calculation method will inevitably lead to calculation errors when solving equations.