Gray-bluish feautureless, widespread and transparent cloud through which the sun was dimly shining through as shown in the first thumbnail photo. It seems to have formed at an altitude of about 4km. In this case, a system of upper-level fronts was clearly shown in the surface pressure chart between Tunisia and Algeria about 12 hours earlier when the photo was taken in mid-afternoon. Such weather situation is very ideal for such cloud to form. In fact, it was followed by an isolated mid-level thunderstorm during late afternoon which is typical after the passage of such cloud. Click here for more details.