Formation of very large nimbostratus cloud with continuous light to moderate rainfall lasting all day due to a warm conveyor belt over the Maltese Islands extending from central Africa as can be seen in the satellite image. It was noted that the cloud seem to have been driven in parallel with the sub-tropical jet stream from Africa. The first thumbnail shows the featureless nimbostratus clouds as it clears a bit in some layers and the second one shows the weather sounding indicating absolutely no instability but various layers of very humid air close to 100% forming the nimbostratus clouds producing drizzle like precipitation on that day.