Mechanism Analysis of a Strong Convective Weather in Hebei Province

An analysis for the heavy rain and strong convective weather at night on 8 June 2009 in Hebei Province was performed using conventional data,surface intensified observational data,rainfall of automatic weather stations,physical quantity and satellite image,etc.Results indicated that the vast vorticity advection and cold air of the Mongolian vortex provided dynamical condition for the strong convection;Southerly and easterly jet stream provided rich water vapour,while the confluence of northwesterly jet stream of the low vortex with two warm jet streams facilitated the formation of the torrential rain,hailstone and gale.Strong rain districts were all located in the top part of lower-level energy field,the profile of energy field had a col structure,which had large energy in upper and lower layers,neutral in middle-level,which provided an initial thermal condition for the deep convection.Intensified observational data of wind field showed that the extended meso-microscale wind field convergence enhanced the lifting convergence of surface air,resulting in this mesoscale system and triggered condition of the local torrential rain.