Abstract:Focusing on the thunderstorm gale process in Liaoning on 6 July 2023, based on the X-band phased array radar data, this paper analyzes the impact mechanisms of meso-γ scale vortex (MV) on merged bow echo and thunderstorm gales which occurred under the background of Northeast China cold vortex. The results show that the thunderstorm gale area in Liaoning Province was located in the southeast quadrant of the Northeast China cold vortex, influenced by low-level shear lines and low-level jet streams. The beneficial environment condition such as extreme temperature difference between 850 hPa and 500 hPa was conducive to the occurrence of thunderstorm gales. The relative humidity near the ground at night was close to 70%, which was not conducive to the formation of strong cold pools. Therefore, there was no bow-shaped pattern in squall lines and the thunderstorm gales were very scattered at this time. Subsequently, the squall line merged with the isolation storm, with shallow MV generated at the merging height, and the rear-inflow jet (RIJ) was weakened. The micro downburst near MV created a strong cold pool near the ground. Under the joint stretching effect of the rising airflow at the edge of the cold pool and the original rising airflow of the storm, the MV stretched upward and strengthened. The ZDR column formed over the MV, indicating the presence of strong updrafts in this area. Although the storm at the MV showed a bow-shaped pattern during this period, there were no thunderstorm gales below the MV. When the rotation of MV weakened, there was a rapid decrease in the scale and concentration of precipitation particles within the storm. The evaporation of precipitation led to the formation of even stronger and larger cold pools on the ground, and the fast development of RIJ below the MV, leading to the concentration of thunderstorm gales in the strong cold pool and RIJ below the MV. The ground strong winds were not caused by the strengthening of MV development, but rather the result of RIJ’s downward development and hydrometeor evaporation.