| The heavy convective storm is one of the primary disastrous weather in summer in North China, such as thunder, windstorm, hail and heavy rain etc, which often cause great hazards. It has been the hotspot for the meteorologists all the time to monitor, forecast and study this system. Based on observed data and NCEP reanalyzed data, a case of strong convective storm occurring in North China on June 8,2009 was analyzed, furthermore, the process of the storm was simulated using WRF model, discussing the feature and mechanism of the system and getting the following conclusions:(1) Under the favourable weather situation, Mongolian vortex moved towards east and spreaded to south, cold air moved towards south with the moving of high frontal zone. Accompanied by the spreading towards north of West Pacific Subtropical high, the low-level jet came into being, which provided the delivery of strong vapour and strong convergence climbing movement for heavy convective rainstorm.upper-level jet provided strong vertical wind shear and positive vorticity advection for the rainstorm, this resulted in powerful ascending motion.Rainstrom occurred in the left side of low-level and upper-level jet, and the coupling of them may be the dynamics mechanism of this process.(2) Better thermal condition,high temperature and humidity ridge of low-level, better vapour transmission, convective unstable stratification and symmetrical unstable stratification,led to strong unstable energy. This convective storm took place nearby the zero line of MPV, MPV1 and MPV2, the combination region of convective instability and barocline instability and downstream of the middle of CAPE. It is advantage to the development of the strong convective rainstorm that plus MPV1 zone above 600 hPa just over minus one at lower levels.(3) For WRF model has a great simulation capability, this process has been successfully simulated by using WRF model through simulated tests of several different microphysical process parameterization, new Thompson hail scheme was adopted in exp7. Model results showed very well all the occurrence and development of this convective rainstorm of North China, it also can be used to reveal the rules and mechanisms of development of the strong convection.(4) Two main precipitation period has different occurrence mechanisms, which was confirmed by analysing model results. In the first session, at 6-9 am,in June 8,2009, with West Pacific Subtropical high and low-level jet moving towards north, plentiful vapour delivered northword and convergence at lower level strengthened, at the same time, the low-level west-south warm and moist flow was lifted by cold air accompanied by suface northeasterly winds, thus a convective storm was triggered, following with strong rainfall and gale wind. In the second period, at 14-18pm,the main reason of the occurrence of this process was upper-air trough moving towards south and cold air spreading southward,which led to frontogenesis in North China, dynamic action of jet at low-level or upper-level was also an incentive.
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