The cloud is an extensive thin sheet (species stratiformis) with merged cloud elements. The darkening sky was easily visible through the layer, identifying the variety as translucidus. In fact, the photo in the first thumbnail shows that the upper altocumulus clouds could hardly be seen as the photo was taken at dusk. The dark lower altocumulus clouds is exactly the same species but not transparent as it is blocking more light making it visible. In combination, it could also be classified as altocumulus stratiformis translucidus duplicatus clouds. The Maltese Islands were situated in between cold fronts being affected by a pre-frontal Libecchio winds bringing a warm airmass before the arrival of the proper cold front. The weather sounding confirmed strong upper-level SW winds along with thin mid-level clouds. Kindly click here for a related weather photo during the passage of this cold front.