Abstract:Because of the influence of Taihang Mountain topography, there is steady wind direction convergence in lower layer in the south central region of Hebei Province, and the local convective weather often occurs near the surface convergence line (SCL). Based on the dense surface observational data from May to September in 2007 and 2008, the relation between evolution characteristics of hourly SCL and local convective rainfall is analyzed. The results show that the SCL gradually expands along the Taihang Mountain after it emerges at dusk in the southwest of Baoding, slowly moving from west towards east with intensity steadily strengthened. In the early morning the next day a cyclonic circulation is almost shaped. The SCLs are classified into 7 types according to the wind fields at the hour with strongest rainfall in each process. Generally, the SCL caused simply by topography cannot generate rainfall, and the intensity is small even if rain falls. That is to say, the SCL caused by topography generally does not produce convective weather, but will result in severe convective weather on the advantageous condition of weather system. By analyzing the daily SCL in the cases of a cold eddy weather system in the last ten days of June 2008, it is indicated that the convective weather first appears, near the convergence line no matter what type of SCL is generated. The time, location and intensity of convective weather can be qualitatively determined according to the evolution of hourly wind and temperature fields under the large scale atmospheric circulation.