Abstract:A warm-sector severe convective event dominated by short-time severe precipitation occurred in southern Anhui in the early morning of 27 May 2023. The train effect formed by a number of north-south parallel meso-β scale short convections resulted in 123.2 mm sudden local severe precipitation in 100 min. The numerical simulation of this event was carried out by using WRF-EnKF, a rapid update assimilation system for meteorological service operation in Anhui Meteorological Observatory. The results show that the interaction between large-scale environmental field and mesoscale convective system led to the increase of horizontal scale and intensification of several short convections. In terms of dynamic action, after the occurrence of convection, a meso-γ scale cyclonic vortex formed between the short convection and the low-level jet core, causing the development of eastward convection. Meanwhile, the surface convergence line formed between the outflow of thunderstorm and the ambient wind triggered new convection in the south side of the short convections, making the short convections continuously development linearly to the south. For the environmental conditions, multiple parallel low-level jet cores provided favorable dynamic and thermal conditions for the development of convection. Inverse secondary circulation in the middle and upper levels occurred due to the strong development of convections resulted in the significantly enhanced atmospheric instability on the south side and the development of convections strengthened the deep vertical wind shear. In addition, the interaction between the convections contributed to the maintenance of the short convection structure. Parallel convection formed parallel thunderstorm high pressure, and the interaction between the outflow of adjacent thunderstorms caused the formation of multiple parallel positive and negative divergence pairs, thus bringing about multiple parallel zonal-vertical circulations between adjacent convections in the vertical direction. These were conducive to the maintenance and development of the multiple short convections.