New cloud cell on a back-building thunderstorm. A back-building thunderstorm is a multi-cell storm in which new cloud cells develop at the back of the storm. In fact, this pictured cloud is actually a new developing cell within the thunderstorm that was actually moving AWAY from the Maltese Islands. Such cells give the false impression that a storm is heading towards the area while that would not be the whole truth. Such storms tend to produce heavy rainfall. I was able to confirm that it was a back-building thunderstorm by looking at the lightning satellite loop whereby the `+` sign indicating lightning were moving towards Malta while the clouds themselves were moving northwards.