Abstract:

Based on the conventionally meteorological data and GFS reanalysis data with 0.5°×0.5° resolution, a heavy rainstorm on June 19, 2010 caused by a southwest low vortex in Hebei procince and Shandong province were analyzed, including its forming conditions and evolution of isentropic potential vorticity. The results show that the southwestern low vortex, high jet, low jet and surface low pressure are the main weather systems of this process．The evolution and forming of isentropic potential vorticity are indicative to activity status of cold air. Convergence of airflow on both south and north sides of the isentropic potential vorticity center is favorable to development of surface low pressure. High potential vorticity moves downward, which leads to the heavy rain. Precipitation area has a better corresponding relationship with area of large isentropic potential vorticity values and its moving direction.

Key words: Southwestern low vortex, Heavy rain, Isentropic potential vorticity, Vertical structure