Formation of stratocumulus clouds due to very weak convection currents despite the cold North wind moving over a still warm sea. The very dry airmass at higher altitudes as indicated by the weather sounding, made sure that no instability could develop within this cold, dry airmass other than such specific clouds. In fact, the photographed clouds are very flat-looking with no real vertical development and light could easily pass through them hence the sub-species perlucidus meaning light goes through. The visible satellite image shows a swirl of clouds over the Ionian Sea despite this very cold air having produced no cyclogenesis. Exactly the same clouds were observed the following days due to more or less of the same weather features.