Bad weather on the major islands And mists in the Po Valleywith a drop in temperatures expected for the weekend between 9 and 10 November: according to forecasts, theanticylon which has been dominating Italy and central Europe for several days, bringing with it clear days and temperatures well above the average for the period (even above 20 °C in Northern Italy) is starting to show i first signs of failure. There Eastern Sicily has already received heavy rains up to 60 millimeters in the Etna area, the result of the meeting between currents coming from the east and an infiltration of cold and humid air of Atlantic origin, transported by the same low pressure system produced by DANA that caused the recent floods in Spain . In the meantime the weather remains stable in the rest of the Peninsula, but in the North the “good weather” is only apparent: fog and absence of snow at high altitude are in fact the symptoms of the so-called “anticyclonic bad weather” which in recent days is affecting the northern regions.
Bad weather in Southern Italy: where bad weather could hit and what the Spanish DANA has to do with it
The instability in Sicily it could extend as early as today Wednesday 6 November on Calabria And Campania southern, where variable weather is expected, and on Sardinia southern. In the major islands, showers, including thunderstorms, are expected for Thursday and Friday, as well as clouds in Calabria. According to the models, a worsening is possible for the weekend following the arrival of one pocket of cold, low-pressure air coming from the Balkans. This could lead to instability in Puglia and the lower Adriatic, with possible cloudiness also in Central Italy (where variability is expected as early as Friday).
The dynamics of the bad weather forecast in Southern Italy is different from that of the rainfall caused by DANA in Spain, although between the two events there is a indirect link. In the case of Valencia, the storms were generated by the meeting of the DANA (therefore a low pressure and cold system) with warm air on the ground and a warm sea. This low pressure system, moving progressively eastwards across the Balearics and the Mediterranean, now effectively constitutes a “border edge” for the European anticyclonetherefore an area of potential instability that can produce thunderstorms.
What is the “anticyclonic bad weather” that is affecting Northern Italy
While the low pressure will disturb the European anticyclone in the southern regions, the weather in the North will remain stable and characterized by even thick fogs in the plains, especially in the Po Valley. However, clear skies and mild temperatures do not necessarily mean “good weather”, and this is one of those cases. In fact, we are talking about anticyclonic bad weather when atmospheric stability is accompanied by an increase in smog and pollutants in the air.
These days, the high pressure that brings clear skies and comfortable temperatures also has the effect of press the air more to the groundfavoring its stagnation especially in the plains and valleys. Without adequate air recirculation, particulates and fine dust such as PM10 hey PM2.5with negative consequences both at an environmental and social level human health. If to this we add a already very moist soil due to the very abundant rainfall in October, the water vapor condenses around the suspended particles, thus creating thick fog.
A similar situation occurred last autumn, when in October the African anticyclone brought record temperatures and a smog crisis to the Po Valley.
All this worsens in the presence of the phenomenon ofthermal inversionwhich is typical of periods of high pressure in the autumn and winter months in the lowlands. In a reversal situation, the air near the ground is colder than that at altitudecontrary to what normally happens. This favors the formation of fog and accumulations of particulate matter in the plains, while in the mountains there is no snow due to high pressure and high temperatures.
In fact these days snow accumulations in the Alps and Apennines are practically absent if not at the highest altitudes. If the situation were to persist, there would be a risk of winter drought in the Po Valley basin, as happened in 2022 with a water crisis that continued into the summer.
Now, many may ask “But why, isn’t the good weather good after all the floods in September and October?”. The answer is simple: Anticylic bad weather disguised as “good weather” is never positive. Just as the frenetic alternation between record rainfall and record heat that we are witnessing in Italy is not positive, since it is one of the clear symptoms of climate crisis caused by anthropogenic global warming.
