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

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