Formation of dense cirrus clouds taken through panorama settings. The photographed clouds passing over the Maltese Islands were in relation with a large upper-level trough over the Iberian Peninsula confirmed against the infra-red satellite imagery as evidenced by the 5th and 4th thumbnails respectively. Though the visible satellite imagery on the 3rd thumbnail, seemed to indicate that this photographed thick high-level clouds have been arranged similar to a front, no fronts were observed at the surface. Furthermore, from the infrared satellite imagery, no thunderstorms were observed seemingly contradicting recent WMO cloud atlas of this particular cloud that it generally forms out of cumulonimbus clouds. Furthermore, through the same satellite it seemed that the cirrus spissatus developed abruptly very near the southwest of Malta triggered by an upper-level instability whose source could not be established from my end and it was moving quite swiftly northeastwards due to upper-level wind from the SW. The first thumbnail is a photo of a patch of cirrus spissatus taken later on the same day whilst the second thumbnail is the weather sounding depicting lots of upper-level moisture with effectively little wind shear at the cloud level.