The satellite ia showing a clear sky over Romania (again a hot day) while radars (S band) intercept echoes from all kind of particles (dust, insects...) around some radar sites. Thunderstorms chasers love "bugs" because they can show the convergence lines in the wind field and other surface boundaries that can promote storms initiations. But, unexperienced forecasters can be tricked by these echoes, so is always good to first check with the satellite image.
