Abstract: Based on the meteorological data from a Doppler radar and intensive automatic weather stations, and the GPS precipitable water vapor data, a local heavy rain process in the west of Shijiazhuang area was analyzed. The results show that the weak shear line moving westward and stretching northward are trigger mechanism and forecasting focus of this process under high temperature and high humidity atmospheric environment. The location of shear line is its main circulation background. Atmospheric water vapor is accumulated rapidly before the severe convective weather occurs, and the curve of the GPS precipitable water vapor contents has two peaks.  The maximum peak value corresponds to the starting time of precipitation exactly, and the second one is ahead of 16 hours before the heavy rain. An echo of the strong precipitation is generated by the combined development of the main echo, the gust front and the newborn echo. The peak values of combine reflectivity (CR), vertically integrated liquid (VIL) and echo top (ET) are 61 dBz, 55 kg.m^-2 and 17 km, respectively. Under the high temperature and high humidity atmospheric environment, a newborn echo, the gust front, convergence and cyclone or inversion wind area on the speed map are of indicative to the development of convective weather.

Key words: Heavy rain, Doppler radar, precipitable water vapor from GPS