Bad weather in the North: heavy rain and thunderstorms expected on September 17

A vast North Atlantic disturbance will hit Northern Italy on Thursday, September 17th, bringing widespread rain and intense thunderstorms with expected accumulations between 10 and 50 mm. The first signs of bad weather will already be felt on Wednesday, September 16th in the Northwest, before extending to most of the northern regions. The areas most at risk, where accumulations could exceed the general average, are central-eastern Liguria, upper Tuscany, Lombardy, Veneto, Friuli, and Trentino.

In addition to heavy rainfall, the unstable front will be accompanied by strong wind gusts and the risk of more violent local phenomena, including the possible formation of waterspouts along the coastal sectors of Tuscany and Liguria. While the North will be hit by the bad weather, Southern Italy will remain stable and dry with maximum temperatures that could reach around 30-31 degrees, in stark contrast to the northern conditions.

The severe weather forecast for September 17th marks a sharp change from the previous meteorological situation, characterized by the stability brought by the Azores anticyclone over the Mediterranean. This shift toward autumnal conditions is fueled by residual energy in the Mediterranean Sea, which interacts with the incoming North Atlantic disturbances. The phenomenon is not isolated but is part of a seasonal transition where different air masses vie for control over the Italian peninsula.

The disturbance will develop progressively: it will begin to manifest with intensity in the Northwest as early as Wednesday, September 16th, then reach the peak of its development the following day. The central regions (Tuscany, Marche, and Lazio) will find themselves in a transitional position, with a gradual worsening of conditions and a risk of scattered showers in the afternoon and evening of September 17th. The true, marked onset of severe weather in the Center is, however, expected for Friday, September 18th, thereby completing the progression of the disturbance along the entire peninsula.