Formation of huge vertical cloud just above the Valletta shore (capital city of Malta) due to low pressure over the Maltese Islands (can be seen on both the surface pressure and 500mb charts). Another pic of the same cloud is attached. The weather sounding showed unstable airmass over all atmospheric levels and clearly shown that `Thermal` (in Malta`s case induced from the sea`s warmth) was clearly the cause of storm cloud initiation under the low pressure system.