Formation of cumulonimbus capillatus incus clouds during late afternoon forming ahead of an approaching vigorous cold front with big temperature difference as indicated by the surface pressure chart on the third thumbnail. If one looks at left-hand side of the photo, a small cloud clearly formed an anvil upon reaching the anvil of a much bigger cumulonimbus cloud perhaps indicating the stable level at 7.8km as shown by the weatrher sounding. On this day, plenty of cumulus and cumulonimbus clouds formed well ahead of the cold front itself hence it was possible that the anvil of one cloud inhibited further growth of the cumulus congestus clouds forming underneath it. As the cold front itself passed, a very localized whirlwind was reported vide https://www.timesofmalta.com/articles/view/20171113/local/cars-buried-under-debris-as-whirlwind-demolishes-wall-in-mosta.663023 This was probably a small tornado. Although little wind shear was present, it was possible that a cumulonimbus cloud moving towards the NE suddenly met a NW wind from the cold front itself causing a spin within the cloud structure hence spawning a mini-tornado. Drivers noticed a sudden drop in temperature of about 5C (from 20C to 15C) within just few minutes making the described event likely. The first thumbnail shows a common primary rainbow now classified under a photo-meteor being an optical phenomena produced by the refraction of light of direct sunlight inside falling rain drops. The fourth thumbnail is the visible satellite image clearly showing a mid-latitude cyclone with its cold front about to reach the Islands and a mass of clouds that formed over the Maltese Islands well before the actual cold front which was photographed.