By using the method of ensemble sensitivity analysis,this paper investigated the sensitivity areas of major circulation systems associated with the torrential rainfall of typical Meiyu front during 11-12 June 2017 over Zhejiang,and their evolution processes during short and medium ranges. Then, the possibility of prediction for error distribution and its evolution characteristics in the future by using early forecast errors were evaluated. Results are as follows: (1) it is showed that in medium range the major sensitive weather systems associated with torrential rainfall location are the lower trough nearby the Balkash Lake and the upstream vortex in the region of Ural Hill,while in short range the development of the lower trough has significant impact on the evolution of the downstream ridge,which further influences the movement of the deeper vortex in front of the blocking high. Also torrential rainfall location is substantially influenced by the eastward movement and development of the trough in the south-west Tibet Plateau and by the intensity changes in different parts of the subtropical high. It is also found that signal of sensitivity is strong in short range but weak in medium range,which mainly correlates with the vortex located in the upstream region of the Balkash Lake,so is the analysis of torrential rainfall intensity. In addition the interaction between the subtropical high and the tropical depression in lower latitude,and the depression's track have effects on the intensity in west side of the subtropical high. (2) The difference of forecasted precipitation between two adjacent runs are correlated with,near the time approaching torrential rainfall,the intensities of the blocking high and the subtropical high,the development of the low trough and ridge in the south-central and eastern Tibet Plateau,and in medium range,the vortex in the region of Ural Hill,the troughs in the Balkash Lake and the south-west Tibet Plateau. In addition,the evolution of the sensitivity areas in the subtropical high shows obvious features of discontinuous. (3) The result from the sensitivity experiment of Forward Ensemble Regression (FWD) indicates that the positive and negative regression areas coincide well with the error evolution of geopential height, which indicates the possibility of prediction for model future errors with the early forecast ones.