Arrival of autumn and bad weather in Italy: storms in Sicily and temperature drops

Today, Wednesday 23 September, astronomical autumn officially begins. The Sun is perpendicular to the Earth's equator, giving the entire planet an equal distribution between hours of light and hours of darkness. But the transition is not just on the calendar: the Azores high pressure is giving way to decidedly colder easterly currents. The atmospheric circulation in our latitudes suddenly became dynamic again, literally splitting Italy in two and inaugurating a phase of strong meteorological instability.

While Western Europe still benefits from a strip of high pressure that guarantees stable weather in the northern and Tyrrhenian regions, on the opposite side - between Eastern and North-Eastern Europe - a deep cyclonic circulation dominates. It is precisely this enormous depression "spinning top" that pushes masses of fresh air and strong winds from the Balkans towards the Mediterranean basin. The air exchange has already led to a general and significant drop in temperatures, which began on Tuesday with a decrease in maximum temperatures between 3 and 4°C in the North and along the Adriatic side. The thermometers have finally returned to the climatic averages of the period, giving sunny but breezy days, with clear or slightly cloudy skies.

The scenario changes radically if we move towards the South, where a residual and tenacious cyclonic circulation persists. Since the early hours of today, irregular clouds and intense showers have hit southern Calabria and eastern Sicily. The greatest critical issues were recorded in Sicily: a violent storm hit the province of Catania, dumping up to 140 mm of rain on the ground and submerging roads and service stations. In Acicatena the situation is made even more difficult by the waste accumulated on the drains, which are blocking the regular flow of rainwater. During the afternoon, the strong daytime warming and the thermal contrast with the fresh air at high altitude will fuel new thunderstorm accumulations. The most intense phenomena will affect Ionian Sicily, Calabria and, locally, the western areas of Sardinia and Cilento.

Given the intensity and persistence of the phenomena, the Civil Protection has issued a yellow alert for hydraulic, hydrogeological and storm risks across large sectors of Sicily, Calabria and Sardinia. The authorities recommend maximum caution when traveling, especially in areas subject to sudden flooding and near registry offices or mountainous areas at risk of mud.

The truce foreseen for a large part of the country will however be short-lived. If Thursday will see a temporary attenuation of the bad weather, experts confirm that between tomorrow evening and Friday 25 September, Italy will be crossed by a new and more incisive nucleus of cold air of Northern European origin. This second disturbed system will slide rapidly along the Peninsula, particularly affecting the Adriatic side and the South. Friday will therefore be a day marked by widespread rain, thunderstorms of moderate or strong intensity and a further, decisive reinforcement of ventilation from the northern quadrants, which will definitively consolidate the face of the new autumn.