Formation of altocumulus after the first thunderstorm of the season and preceding a second round of rain showers in the afternoon. When such clouds form during morning, it normally indicates instability which generally increases during the day due to daytime heating hence thunderstorms. In this case, thunderstorms did occur. However, in Summer, this is generally not the case because Malta`s landmass is not big enough to generate thunderstorm clouds on its own unless weather conditions are really at an optimum for storm cloud formations. But having said this, during late Summer and Autumn, it is the warm sea surface that act as a trigger to the instability hence thunderstorms occur. For explanation of the day`s prevailing weather conditions click here.