Formation of cumulonimbus cloud due to a cut-off low with an associated cold pool of air sitting over the Central Mediterranean and Malta generating lots of convective currents high into the atmosphere. This cloud is a resemblance of such convective current reaching high into the atmosphere and ready to form its anvil. Isolated rain showers were observed throughout the first part of the day as indicated in the first thumbnail. The visible satellite image (2nd thumbnail) depicts the same cumulus and cumulonimbus clouds rotating inside the upper low (3rd thumbnail) and cold pool. In the surface pressure chart, this weather was indicated as line of bad weather (solid black line). For further weather details on the day kindly click here.