Formation of a mature cumulonimbus capillatus incus cloud with a large widespread anvil that developed locally in Malta as per visible satellite imagery on the fifth thumbnail. This cumulonimbus cloud was the result of extreme contrast between the unseasonably cold Wintry airmass flowing into the Central Mediterranean from the Arctic moving along the large kink in the jet stream as per sixth thumbnail and the very strong May sunshine leading to considerable heating of the landmasses below it. A waterspout underneath the base of this cloud was reported to local weather facebook pages hence classifying it as a severe thunderstorm. In fact, part of its base was very diffused due to localized heavy precipitation. The prevailing wind was not strong as the Maltese Islands were situated well inside this very unusual jet stream setup for late meteorological Spring. The weather sounding on the fourth thumbnail confirmed this cold airmass and instability despite indicating only a modest wind shear. The temperature anomaly map is on the final thumbnail highlights the unseasonable temperatures over the Central Mediterranean and the Arctic.

The first thumbnail is another photo of distant cumulonimbus capillatus incus clouds lined together on the horizon. These developed over the Sicilian landmass due to the same weather mechanisms in which the strong sunshine lifted the overlying cold air. The second thumbnail shows a decaying anvil precipitating itself out whilst the third thumbnail is a small timelapse of rising cumuliform clouds due to instability. Finally, the SLP chart on the seventh thumbnail indicated a cold occluded front over the Maltese Islands acting as a foci around which bad weather could form inside the trough.