This photo taken by Julian Farrugia shows the dissipation process of an early advection fog over the Grand Harbour of Malta. Fog dissipates quicker over land because even in late Winter, the sun heats the land much quicker than the sea. In fact on the first thumbnail, another photo taken by Julian shows the fog patches retreating back towards the sea as it was cooler. This fog had formed suddenly just before dawn because of trapped moisture by an extensive subsidence inversion in which air is sinking (second thumbnail) and the presence of an upper high (third thumbnail). Under such conditions, sea-level airmass is inhibited from rising upwards. Therefore, upon arriving over slightly cooler sea surrounding the Maltese Islands, clouds begin to form at the surface causing the fog seen on the photos taken by my friend Julian Farrugia. Any type of fog is simply Stratus clouds at ground level.