Severe bad weather arriving on September 17: downpours and temperature drop

An Atlantic disturbance, the second of September, is about to hit Italy, bringing a period of severe bad weather. On Thursday, September 17, numerous showers and thunderstorms, some of high intensity, are expected across much of the North and many areas of Central Italy, with a risk of cloudbursts and violent hailstorms. The most affected regions will be Liguria, Lombardy, and the Veneto areas.

The disturbance, arriving as early as Wednesday, September 16, will bring a widespread worsening of weather to the North before sliding down the Peninsula. The cool currents following it will cause a noticeable drop in temperatures, especially in the North-Central regions, with highs temporarily falling even below the seasonal average. In the South, however, more stable and warm weather will persist.

For Thursday, September 17, forecasts indicate showers and thunderstorms across almost all northern regions, Tuscany, Umbria, Marche, the Abruzzo Apennines, and northern Sardinia. Rainfall accumulations over 24 hours could exceed 100 millimeters in Friuli-Venezia Giulia and, locally, in Veneto and Trentino-Alto Adige.

The current weather situation is caused by the arrival of an Atlantic disturbance, a low-pressure system that brings cooler and more humid air from the Atlantic Ocean toward Europe. These phenomena are common in autumn, when the clash between different air masses (pre-existing warm air and incoming cool air) triggers instability and thunderstorms.

The disturbance in question, identified as the second of September, began its path toward Italy on Wednesday, September 16th, starting from the Alps and the Po Valley. The worsening weather gradually spread because the oceanic air mass, rich in humidity, meets the heat accumulated in previous days over our territory, creating ideal conditions for intense downpours.

This dynamic explains why the bad weather will mainly affect Northern and Central Italy, while the South will remain more protected, maintaining high temperatures. The expected temperature drop, up to 6-7 degrees lower, is a direct consequence of the disturbance's passage, which replaces warm air with cooler currents. The situation should gradually improve over the weekend.