Abstract: By using MM5 mesoscale numerical model this paper simulated a meteorological event of strong sandstorm,gale,snowfall and cold wave that occurred in the southern part of Xinjiang,northern part of Qinghai,largely part of Gansu,northern part of Shaanxi,Ningxia and largely part of Neimeng on 7~9 April 2001.The results show that(1) MM5 can simulate this disaster weather event and on small domain it can depict finely;(2) the strong and lasting gale led by special circulation and drastic mesoscale vertical convection under stable terrain and landform are responsible for this event;(3) this event can be forecasted 24 hours before by synthetical analysis on trough and ridge assembling and developing at high levels,terrain,surface temperature and pressure etc;(4) the correlation coefficient of surface gale with 24 h temperature difference and also with 24 h pressure difference can forecast this disaster weather event;(5) the speciality of this event is that the unstable weak level over 200 hPa and the updraft occurred before noon.

Key words: sandstorm, MM5 mesoscale numerical model, stable level