By using the observational data,satellite product and NCEP reanalysis data,the two convective rainstorm weather processes in central and southern areas of Guizhou from May 25 to 27,2008 and from June 4 to 5,2011 were analyzed.The results show that under the relatively stable circulation situation on 500 hPa,there were small trough moving eastward continuously over the Qinghai-Xizang plateau with low vortex shear at the middle and low level,which resulted in the two torrential rain processes,and two rainstorm processes were caused by MCC in Guizhou.During the first weather process (May 25 to 27,2008),the atmospheric stratification was extremely unstable,and the upward movement was very strong,but during the second process (June 4 to 5,2011),there was stationary front maintaining in the central line on the ground in Guizhou,the atmospheric was neutral or stable stratification,but low-level jet condition was better than that of the first process.There were some differences in moisture condition,instability condition and uplift mechanism during two rainstorm processes,which associated with the location of the subtropical high.The mesoscale low pressure convergence line or the stationary front existed on the ground,which strengthened convergence movement and resulted in mesoscale convective complex generation in the south region of Guizhou Province.Based on the analysis results,this kind of rainstorm forecast index was discussed in this paper.%应用常规观测资料、卫星产品和NCEP 2.5°×2.5°逐6h再分析资料,对2008年5月25 ～ 27日和2011年6月4～5日贵州中南部对流性暴雨天气的成因及异同点进行了分析.结果表明,2次连续性暴雨过程都是在500 hPa相对稳定的环流形势下,青藏高原有小槽不断东移,配合中低层的低涡切变等中尺度系统产生的.2次暴雨过程均为MCC反复在贵州生成所致.第一次过程(5月25～27日),大气不稳定能量很高,层结极不稳定,上升运动非常强；而第二次过程(6月4～5日)地面上贵州一直有静止锋维持在中部一线,大气为中性或稳定层结,但低空急流条件明显优于第一次过程.2次过程在水汽条件、不稳定条件和抬升机制等方面均有一定差异,而这些差异与副热带高压的位置有关.地面中尺度低压中的辐合线或静止锋的存在,加强了辐合上升运动,从而在贵州中南部反复生成中尺度对流复合体.根据分析结果,尝试探讨了这类暴雨的预报指标.
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