In order to promote the levels of shortterm forecasting and nowcasting of severe convective weather, the extremes of WPR (Wind Profiler Radar) data observed ahead of the occurrence of severe convective rainfall during rainy season from 2008 to 2012 in Dali are analyzed on the basis of large sample of related data. The results show: The maximum detection height of WPR reached its maximum 0 to 1 hours ahead of the appearance of heavy rainfall. The intensity of severe convective rainfall was positively associated with the maximum detection height and its increased range. Meanwhile, the negative vertical speed increased to maximum and its corresponding height decreased to the lowest 1 hour prior to the beginning of strong rainfall. The greater the negative vertical speed, the bigger the intensity of heavy rainfall was. Furthermore, the peak value of the extreme SNR (Signal to Noise Ratio) appeared 1 hour ahead of the appearance of strong rainfall. The intensity of strong rainfall was positively correlated with the peak value. The mesoscale lowlevel jet appeared 3 to 4 hours ahead of the occurrence of strong rainfall.