The Azores anticyclone releases its grip. After days of sun and unseasonal heat, from Wednesday 16 September Italy will enter a more autumnal phase, with an Atlantic disturbance that will bring rain and thunderstorms to much of the peninsula over the course of three days.
Wednesday 16th: the worsening starts from the North
The day still opens with fair conditions across a large part of the country, but between the afternoon and evening the situation changes rapidly in the northern regions. The first showers affect the Alpine and pre-Alpine arcs, and then extend to central-northern Lombardy, where the phenomena could be more intense, accompanied by episodes of hail, and in the evening also to central-eastern Liguria. In the rest of Italy the weather remains stable, with the exception of Calabria and Sicily, where a cyclone forming in the lower Mediterranean, slowly moving towards Greece, is fueling local showers along the Ionian and Tyrrhenian coasts.
Thursday 17: the most unstable phase
It is the culminating day of the disturbance. The storms spread throughout the North, with peaks of greatest intensity between Triveneto and the North-West, while the rains are also starting to reach the central regions, in particular along the Tyrrhenian side, Tuscany, upper Lazio and western Umbria above all. Temperatures drop sharply in the North, with drops of up to 6-8 degrees in the most affected areas. The South still remains on the margins, but the first signs of change are already being felt in the evening, starting from Campania.
Friday 18th and weekend: the disturbances slide towards the South
The disturbed front reaches the southern regions on Friday 18th, with a cyclonic vortex that digs between the Center and the South and which tends to persist for the entire weekend. At the same time, from the west, the Azores anticyclone is making itself felt again, bringing stability to the North and the northern Tyrrhenian belt. It is not excluded that, once this phase has been overcome, the good weather will return in the last ten days of September, therefore the real autumn, the one that is not satisfied with a disturbance, will still be able to wait.
