Formation of cirrocumulus due to an upper-level cold pool between Tunisia and Malta that was in the process of being cut off by the upper trough. In the following several hours, this cold pool moved very slowly across the Maltese Islands triggering unusual heavy thunderstorms two days later. Click here for further details. As per weather sounding, instability extended towards the upper reaches of the atmosphere hence instability was the main trigger for such formation. The tendrils are actually falling precipitation being blown by Force 11 upper winds as per sounding on the first thumbnail. The second and third thumbnails indicate a close-up of the upper-level cold approaching the Maltese Islands and clouds wrapping around the same trough.