Formation of high-level clouds ahead of an approaching upper-level trough towards the Maltese Islands which was still over the NW Mediterranean as indicated by the 500mb chart on the fourth thumbnail. The cloud species if analyzed only through the main photo was clearly cirrus fibratus being composed of nearly straight curved white filaments and of the variety radiatus as strong upper-level west-northwest winds have arranged the cirrus into parallel bands that are converging inside the tree in the background. It is very important to look at the weather sounding on the third thumbnail in order to explain the rather large cirrus cloud observed. First of all, it showed plenty of upper-level moisture at altitudes between 7km and 12.3km. My thinking is that the clouds formed at the upper range of the altitude, that is at circa 12km in which the bitterly cold WNW wind was blowing at over 100kmh aligning the cloud from west to east exactly as the photo alignment. The first thumbnail is an arm of the cirrus cloud in the main photo extending towards the opposite side of the sky in Valletta which is terminating into a hook making that part of the cirrus an uncinus species whilst the second thumbnail is a panoramic photo of the whole cirrus that highlights its widespread coverage in the sky hence difficulty in fully photographing it. The weather created by the mentioned upper-level trough is explained here.