Analysis of the Regional Heavy Rain Caused by a Cooling Shear Line

By using conventional data,automatic weather station rainfall data,the regional heavy rain in Shandong Province during May 9th-10th,2009 was analyzed.The results showed that the main system caused the heavy rain was low-level cooling shear line,the rainstorm mainly placed on the left front of low-level jet,on the right of low-level cooling shear line,as well as the northeast quadrant of the vortex.Southwest jet of the west side of the subtropical high established the water vapor channel from the South China Sea to the North Central China,which provided the adequate warm and moist air and energy for the heavy rain of the development,that was also a necessary condition for the low-level shear line a long stagnation.Ground frontal cyclone was the mechanism of the heavy rain beginning,after front the northeast wet and cold air and the Southwest warm and wet over the intersection of Shandong,prompt the development of convection and instability and instability energy released that produce rainstorm.