By means of analyzing the frontal rainstorm events in flood season in Guangxi,it is found that the significant frontal rainstorms are unimodal distribution.

Numerical simulation tests of three representative Meiyu front rainstorm processes of the Huai-he flood reason in July 2003 were conducted with WRF(weather research and forecasting) model for the intention of investigating the applicability of WRF model to research and forecast our country s rainstorm.

6") Meiyu front rainstorm are analyzed using the observed data and the high-resolution output from the numerical simulation.

The purpose is to investigate the influence of various moist physical schemes on the forecasted precipitation of Meiyu front rainstorm.

Through the diagnosis of a Meiyu front heavy rain process occurring from 1 to 3 June, 2000, this paper has studied the affection on the rainstorm caused by the ageostrophic wind, the unbalanced flow, low level jet (LLJ), and the generation and propagation of gravity wave after the abrupt change in large-scale circulations.

Using the wet Q-vector and combining with the intense data output of the modified MM4(MMM4) model simulation,a typical Meiyu front heavy rain process occurred during 5-6th July 1991 in the Changjiang-Huaihe Basin is diagnosed carefully in this paper.