Severe disturbance in the South, September-like weather returns with the Azores High

The first September disturbance completes its passage over Italy today, Saturday, September 12, bringing the last showers and thunderstorms to the southern regions and Sicily. The phenomena, most likely in Abruzzo, Molise, Puglia, Basilicata, Irpinia, Calabria, and Sicily, are expected to dissipate throughout the day.

Meanwhile, the arrival of cooler air definitively ends the heatwave even in the South, with maximum temperatures dropping in the South, Sicily, and the mid-Adriatic. Values mostly settle between 25 and 30 degrees, with a more pleasant climate everywhere, close to the mid-September averages.

The weather will become more stable over the weekend thanks to the expansion of the Azores High, which will ensure a prevalence of sunshine and mild temperatures, with highs generally below 30°C. However, forecast models indicate a possible new worsening in the latter part of next week, with uncertainty still regarding its extent and location.

The heatwave that affected Italy in recent weeks has been interrupted by the arrival of the first autumn disturbance of September. This low-pressure system, typical of the change of season, has brought rain and thunderstorms, especially to Central and Southern Italy, marking the transition from intense summer heat to milder and more variable weather conditions.

The protagonist of the improvement is the Azores High, an area of high pressure that forms in the Atlantic Ocean. When it expands towards the Mediterranean, as is happening now, it brings stable weather, clear skies, and pleasant temperatures, typical of the September period. This phenomenon is cyclical and common in this season, following the peak of summer heat.

However, the stability may be short-lived. The main forecasting models, such as the American GFS and the European ECMWF, show conflicting scenarios for the second part of next week. The weakening of the high pressure could open the door to a new trough (an incursion of low pressure) of Atlantic origin, with the risk of a return of bad weather, especially in the North according to some projections. The uncertainty is high, and the forecasts will require updates in the coming days.