Based on the vertically integrated liquid (VIL) water, a statistic analysis of the evolvement and development of VIL before the disastrous winds is made by using the volume scan data of Tianjin CINRADSA Doppler weather radar in combination with the reports of disastrous wind and observational data. The results show that a VIL value of 30 kg/m2 can be regarded as the threshold of disas trous winds and 40 kg/m2 as the forecasting index. The rapid decreasing VIL after the maximum indicates the beginning of disastrous winds， and the subsequent jumping change can be acted as the symbol of the beginning of disastrous winds. The verification suggests that these warning indexes are not only practicable but also adjustable with time. Before the beginning of disastrous winds， orecasters have 12 to 18 minutes to issue shorttime,nowcasting weather forecast.