THE INFLUENCE OF STRATIFORM PRECIPITATION ON SHALLOW CONVECTIVE RAIN - A CASE-STUDY

An event where light, uneven stratiform precipitation and strong but s hallow convective cells moved through each other is studied. While the stratiform rain was moving rapidly from the west, the convective cell s were almost stationary, as if the two types of precipitation were dy namically independent. Using a scanning radar, a vertically pointing r adar, a wind profiler, and standard meteorological instruments, it is shown that the shallow showers were initiated and then destroyed by th e stratiform precipitation. The initiation was caused by the combinati on of the moistening of the boundary layer by a rainband, followed by the seeding of convective clouds by very weak rain or drizzle. The des truction of the convection was provoked by the washout of the convecti ve clouds by moderate stratiform rainbands.