Diagnostic Analysis of Mesoscale System and Environmental Conditions During Hebei Severe Rainstorm
The severe rainstorm process which occurred in the central part of Hebei on 1 July 2013 was analyzed by using the conventional sounding data, NCEP reanalysis data, automatic stations data, FY2E satellite data and radar data. The results show that: (1) The rainstorm can be divided into warm sector rainstorm and cold shear rainstorm. During the process of warm sector rainstorm, lowlevel moisture flux convergence was dramatically enhanced. (2) Strong ageostrophicwet〖WTHX〗Q〖WTBZ〗 vector convergence took place before the warm sector rainstorm, and it has good performance in forecasting the warm sector rainstorm. Large value area of ·〖WTHX〗Q〖WTBZ〗* only with convective condensation heating in warm sector can be used to indicate the heavy rainfall area. Furthermore, condensation heating plays an important role in ageostrophicwet〖WTHX〗Q〖WTBZ〗 vector convergence. (3) Warm sector rainstorm occurred in the developing stage of warm mesoβ scale convective clouds, influenced by the surface mesoscale vortex. Then, cold shear convective clouds incorporated with warm sector convective clouds formed PECS, which worked in with the surface convergence line causing rainstorm again. (4) The radar echoes show that mesoγ scale convergence lines in the mesoβ scale cyclone flow field creates a favorable dynamic condition for banded strong rainfall echo in Sizhilan Area.