Diagnosis Analysis of a Gale and Sandstorm Weather Case

Using data of basic observation and numerical forecasting product HLAFS, we analyzed the synoptic causes and forcing mechanism of a gale and sandstorm weather process in March 2nd of 2004 in Wuwei city of Hexi corridor. This weather process was formed under the Siberian Cold Trough moving towards southeast and developing greatly. The involvement of very cold air made the Siberian Cold Trough develops further, which provided the forcing condition for sandstorm. The vertical structure of Siberian Cold Trough provided the mechanism of momentum transmitting downwards for sandstorm. The gale at rear of ground cold front created the basic condition for sandstorm. Accordingly, we got the starting point of forecasting sandstorm.