Long-term weather forecast: persistent anomaly, no way out

The week between September 16 and September 23 is expected to be characterized by rather unstable weather, with temperatures dropping below the seasonal average and intermittent widespread precipitation, especially in the regions of Central Italy and Southern Italy.

The ECMWF weather maps indicate that Italy will be influenced by a persistent negative pressure anomaly, triggered by a depression vortex that will remain over the eastern sectors of Europe, affecting the climate on our Peninsula as well.   This particular configuration will lead to a general drop in temperatures, not only in Italy but also in France, Germany, and much of the Mediterranean area.

Negative thermal anomalies between 2°C and 4°C are expected, marking the beginning of a cool week.

Although the meteorological summer technically ends at the end of August, these climatic conditions indicate that summer is now definitively behind us.   The analysis of the weather maps for the week shows Italy still under the influence of a depression vortex that will keep the weather unstable. Northern Italy, while remaining in a relatively more stable situation compared to Central Italy and Southern Italy, could see cooler weather, especially in the alpine and pre-alpine areas, where temperatures will remain below the seasonal average.   In Central-Southern Italy, however, rain is expected to be more frequent and concentrated along the Adriatic side and in the regions of Southern Italy, including the Main Islands. Sardinia and Sicily could experience isolated thunderstorms and cooler weather compared to previous days, with temperature values lower than the average for September.

The risk of intense rain will be higher along the Adriatic coasts and in the internal Apennine areas, while the Tyrrhenian coastal areas could remain relatively drier, although the possibility of showers cannot be ruled out.   Another interesting aspect concerns the 500hPa geopotential height map, which suggests a continuous presence of low pressure that will affect the climate in much of Europe.

This means that, despite the presence of some sunnier days, the weather will remain cool and unstable.

During the week, in fact, the alternation of rain and clear spells will be a constant, with the risk of extreme weather that could particularly affect the most vulnerable areas.   The weekend will mark a further drop in temperatures, bringing values well below the seasonal average.

In some areas of Northern Italy, such as the alpine and pre-alpine regions, there could be a thermal excursion that will bring very low minimum temperatures, while Central Italy and Southern Italy will experience humid and cool days, with possible thunderstorms and showers along the Adriatic side and in the internal regions.   However, it is essential to emphasize that this is a weather trend.

Conditions can vary, and forecasts will need to be confirmed and updated in the coming days, particularly regarding the distribution of rain.

While the general outlook predicts a cool and intermittently rainy week, the situation could evolve, influenced by meteorological factors not yet entirely predictable.

This is typical of September weather, when meteorological instability marks the boundary between summer and autumn.

The weather outlook for the week of September 16-23 therefore invites us to pay attention to the daily evolutions of the weather, especially for those in areas most exposed to storm phenomena, such as Central-Southern Italy and the Main Islands.