Causative Analysis of a Local Heavy Rainstorm Process in Weifang City

Based on the routine observational data,NCEP/NCAR data,FY-2E and radar data,an analysis is performed of a typical local heavy rainstorm process on 17 to 21 July 2010 in Weifang City.The result shows that the main influencing systems of the local heavy rainstorm are Prior Trough,shear line,Low level Jet and cyclone.K index of the rainstorm area is bigger than 36℃ and they are tallied each other.Intruding from the northwestward of Weifang,cold air triggers the release of unstable energy and produces convective rainstorm.The rainstorm occures in the warm air side.The area of powerful updraft is often accompanied with the heavy rainfall distribution.The mesoscale and microscale analysis of the heavy rainfall shows that the moving path of the surface low or surface convergence line is accompanied with the centre of the heavy rainfall.This has a good indicative effect for the precipitation area and the beginning and ending time in the short term forecasting and nowcasting.