The same closed upper trough as explained here had arrived over the Maltese Islands as evidenced in the 500mb chart. However, due its arrival over Malta during the early morning whereby the air is at its most stable in late Spring due to lack of surface heating, this low pressure was only able to produce nimbostratus clouds also given the relative stability of the airmass in the weather sounding. Should it have arrived in the afternoon, the resultant cloud formation would surely have been different in the form of cumuliform clouds. This cloud had produced steady rain for around 2 hours in the morning with an accumulation of around 15mm which is more than the average monthly rainfall for May in Malta. The first thumbnail shows an unusual soggy May morning.