Approaching cirrus spissatus cumulonimbogenitus clouds still in their anvil shape of former isolated cumulonimbus clouds surviving towards the Maltese Islands due to lots of upper-level moisture and an upper-level WNW wind directing them towards Malta as per weather sounding on the second thumbnail. Under dry conditions, such clouds tend to evaporate quite rapidly. The third and fourth thumbnails depict the visible satellite image and the surface pressure chart respectively. The thunderstorms themselves that caused the formation of the photographed clouds had developed due to a level pressure field over the Mediterranean causing cumulonimbus clouds to form over land by convection. Once over cooler waters, such clouds tend to quickly decay due to lack of instability and weather features leaving behind high clouds. The first thumbnail is another photo of cirrus clouds that developed later that evening.