Widespread formation of dense cirrus clouds covering the whole sky giving it a mare’s tails appearance signalling the approach of an unseasonable mid-latitude cyclone over the Maltese Islands in an unusually very clear way. Isolated patches of such clouds would not have normally signified anything particular weather though. In this case, the variety intortus may be added to the photographed cirrus spissatus since it looks like a messy accumulation of individual cirrus clouds. The first thumbnail is a view of the same cloud taken about an hour earlier. The second thumbnail is a view of individual high clouds over the other side of the sky seemingly cirrocumulus floccus virga in the foreground composed of precipitating ice crystals. The third thumbnail shows approaching high clouds from the north horizon taken around mid-afternoon corresponding with the visible satellite image of the fourth thumbnail. From the weather sounding, the clouds formed at heights of between 8.5km and 13.2km at temperatures of below -32°C.

The weather situation is explained in detail here.