How to predict heavy rains in Aba, Sichuan? What kind of meteorological conditions can cause heavy rains?

Predictions of heavy rains are all predicted by professional equipment from the National Meteorological Observatory, and the accuracy of the prediction results is difficult to say. The United States can only achieve an accuracy of 25%. Next, let’s talk about heavy rain.

Heavy rainfall is usually caused by mesoscale weather systems. Rain with an hourly rainfall of more than 16 millimeters, or a 12-hour rainfall of more than 30 millimeters, or a 24-hour rainfall of 50 millimeters or more is called "heavy rain." According to the intensity of precipitation, it is subdivided into "heavy rainstorms", "heavy rainstorms" and "extremely heavy rainstorms".

Generally speaking, the formation of heavy rain requires three conditions, namely sufficient water vapor supply, strong vertical rising conditions and a certain duration of precipitation. In the process of heavy rainfall forecasting, forecasters need to fully consider these three conditions to determine the magnitude of the possible heavy rains caused by the precipitation process. Forecasters' heavy rain forecast work mainly relies on observation data and numerical model forecasts. On this basis, forecasters use their own knowledge and experience to judge and correct the forecast results.

Heavy rainfall forecasting cannot completely rely on numerical forecasting and must give full play to the subjective initiative of the forecaster. Through the theoretical knowledge, experience, data and information mastered by forecasters and other forecasting methods, the numerical forecast results can be effectively revised and even changed when necessary. The final forecast results may have smaller deviations and be closer to reality.

Let’s talk about the formation of heavy rains. The formation process of heavy rains is quite complicated. Generally speaking, the main physical conditions for producing heavy rains are sufficient and continuous water vapor, strong and persistent upward movement of air currents and the structure of the atmosphere. of instability.

The water vapor sources of heavy rains in my country come from the South China Sea and Bay of Bengal in the south direction, and the western Pacific Ocean. In addition, rivers and lakes are also sources of water vapor.