For the second time there has been a ghost cloud over Germany for several hours drifting east. Ghost cloud meaning that the weather radar picks up a reading of a cloud without there being any visible cloud.
See the weather radar picture. The picture is an overlay of the colored weather radar picture (yellow) and a satellite picture of what is visible to the eye.
The lower big yellow area is an actual rain area (see the visible clouds). The long stretches yellow areas to the north are the readings of the weather radar, but there are no clouds to be seen.
See the article from the German "Spiegel" news magazine: Geisterwolke über der Elbe. An interview with a meteorologist at the German Weather Service Institute.
Birds and dumped Kerosen can be ruled out again for various reasons like, no bird migration being around or Kerosen dissolving within a much shorter time.
Jörg Asmus, meteorolgist, is guessing that this is some scientific or military experiment that we're wittnessing like maybe methods to confuse enemy radars or missile counter measures or spreading of aerosoles in the atmosphere.
Whatever it is, I don't like stuff that makes clouds of 400km length and that comes down somewhere where you breathe.