Abstract:Using the conventional ground and upperlevel synoptic charts and radar observation data, the cause of a local severe hail weather process in the Enshi mountain area of Hubei Province on 15 April 2017 is analyzed. The results show that the thermal effect of warm and low pressure systems on the ground before the front strengthened the convergence and the accumulation of the unstable energy on the ground, and made the warm and wet unstable stratification under the dry and cold condition more obvious. Under the action of the dynamic uplift of the mesoscale convergence line, the uplift of the lowlevel convergence triggered the release of convective unstable energy, and coupled with the uplift of the favorable bellshaped terrain of the mountainous area, the development of the severe convective weather was stimulated. In the process of the severe convective weather, the multicell storms had the feature of one’s strengthening companying with the weakening of another. Under the favorable atmospheric environment and terrain conditions, the development of multicell storms was strengthened and the strong storms were maintained for a long time, which were the important reasons for the local strong hail. The vertical structure of hailstorm cell reflects the typical characteristics of the lowlevel inflow, weak echo zone, highstrength echo overhang, etc., and the combined action of the middlelevel radial convergence and the divergence of the storm top made the storm cell maintain and develop, which is also an important cause of the local hailstorm. The monocell storm reflectance factor reflects that it maintained above 60 dBz for a long time and corresponded to a large VIL value. The strong hail weather had the characteristics of strong locality and small impact scope. The main reason is that the vertical wind shear of 0 to 6 kilometers was not large. At the same time, the middle and lowlevel wet layers were shallow, and the wet area on the ground was obviously southward.
