Abstract:By using the Doppler radar data and the conventional observation of 29 torrential rain processes from 2004 to 2010 the velocity field characteristics in rainstorms in south central Hebei Province are analyzed. It is found that the characteristics can be divided into five categories, including the meso β scale convergence line, the meso β scale convergence, the meso γ scale convergence, the upper level jet and the long lasting and deep low level jet. The last one is one of the main velocity field features of large range severe rainstorms. The upper level jet is the characteristic of both large range heavy rainstorms and regional heavy rainstorms. The meso β scale convergence line, the meso β scale convergence and the meso γ scale convergence are common features and main meso scale systems of all the three types of severe rainstorms. In addition, train effects is a key cause of local severe torrential rains.