First, the general circulation situation is stable. The unusually strong western Pacific subtropical high first extends westward and then rises northward, and then stably maintains in Huanghuai area, forming a stable circulation situation in Shanxi with the low-value system of westerly belt, which is conducive to the long-term precipitation weather in Shanxi.
Second, the water vapor condition is abundant. The southerly airflow on the west side of the subtropical high and the low-level southwest jet continuously transport the water vapor from the South China Sea and the Bay of Bengal northward through the southwest region to the central and southern parts of Shanxi, providing abundant water vapor sources for continuous precipitation in Shanxi.
Third, the low-rise conditions are maintained for a long time. Under the stable weather situation, the low-level shear line convergence system is maintained for a long time and the precipitation echo repeatedly passes through the central part of Shanxi, and the complex topography of Luliang Mountain and Taihang Mountain in Shanxi has increased the precipitation of the easterly airflow, resulting in the appearance of extremely heavy precipitation in the central part of Shanxi Province and the northern part of Linfen.