Abstract:The causes of a strong convective storm in the lower Yellow River in early summer on June 25, 2008 are diagnosed by using routine observation data, Doppler weather radar data and the NCEP/NCAR reanalysis data. It is shown that the joint effect of the high-level cold air and low-level warm air leads to the convective unstable atmosphere in knots. The shear line at 850hPa plays an important role in trigger and enhancement of convective systems over Anyang. It is also revealed that the vapor come from the Bohai Sea and Yellow Sea. The vapor convergence comes into existence in Anyang. They play a crucial role in the maintenance of strong convective storm. In the period of convective storm development, the strong convergence below 850hPa and divergence over 800hPa and below 600hPa are characteristics of divergence distribution. There exists convective ascending movement. The stronger updraft is below 600hPa. These provide favorable dynamic condition. There is high sufficient energy of Qse in the convective storm region. The energy frontal zone exists in the west of convective storm area. Doppler radar data show that the convection echo generates in Hebei Province and develops during moving to Henan. The reflectivity at 3.4° elevation of the strongest convection echo of Puyang is more than 50dBz. In the velocity field. The meso-scale convergence in Anyang is studied by analyzing the Doppler radar data also.