Disappointing November, Snowy December? Weather hypotheses
November has been disrupted by warm weather phases, dictated by frequent Anticyclones, which have brought temperatures well above seasonal averages in Italy.
This phenomenon has transformed the typically autumnal climate into a sort of spring preview, with temperature peaks reaching and sometimes exceeding 20°C, especially in the southern and central regions of Italy.
Early October values, indeed! The persistence of this weather pattern is keeping stable weather conditions over much of the Peninsula, limiting the arrival of disturbances and leaving the sky clear, except in some southern areas that have been hit by incredible rains.
Conversely, in the Po Valley, this situation has favored the formation of dense fog during the night and morning hours, a typical phenomenon of the autumn months but accentuated by thermal inversion. Weather projections for the coming days suggest that this phase of abnormal warmth may have its days numbered.
Polar currents in a couple of weeks?
Despite the current dominance of the Anticyclone, a sudden change is not ruled out.
The High Pressure dominating the central Mediterranean could weaken in the coming weeks, paving the way for disturbances from Northern Europe.
If this happens, towards the end of November and the beginning of December, our country could be hit by cold currents of polar or Siberian origin, bringing a drop in temperatures and the possibility of snow even at relatively low altitudes. Meteorologists are closely monitoring the behavior of the jet stream and atmospheric pressures on a continental scale.
A possible southward shift of the jet stream could allow the entry of cold and humid disturbances, thus interrupting the period of atmospheric stability.
However, at the moment, the subtropical Anticyclone maintains a firm grip on southern Europe, preventing the arrival of cold air and keeping temperatures well above normal.
Abnormal heat: negative effects
The high temperatures and lack of rain are prolonging the growing season for many plant species, affecting the natural cycles of plants.
In the agricultural areas of the Center-South, for example, some crops are benefiting from this mild climate, while others could suffer from prolonged drought if rain does not arrive by the end of the month. From a health perspective, the gloomy weather and stagnant air are contributing to the accumulation of pollutants in urban areas, especially in the major cities of the North, primarily Milan and Turin.
Thermal inversions, in fact, trap pollutants in the lower layers of the atmosphere, worsening air quality.
This can have a negative impact on people with respiratory problems, especially the elderly and children.
A sudden change is needed
The baric configurations that establish themselves in Autumn can have a decisive influence on the course of Winter.
Currently, the subtropical Anticyclone is dominating the scene, but sudden changes are not uncommon.
A strengthening of the Azores Anticyclone, for example, could push colder air masses towards the Mediterranean, leading to a harsh Winter, especially in the northern regions. The temperature trend in the coming weeks will be crucial to understand which direction the weather in December will take.
Long-term forecasts indicate that we could see a drop in temperatures as the Christmas holidays approach.
In particular, a weakness of the Anticyclone would allow the entry of cold disturbances that could cross the Alps, bringing snow even to the plains.
Winter: will it follow in autumn’s footsteps?
Seasonal forecasts often indicate the possibility of a mild and dry Winter, but it should be noted that these projections are subject to many uncertainties.
Even though High Pressure and abnormal warmth seem to dominate at the moment, it cannot be ruled out that these conditions could change rapidly.
A possible shift in atmospheric currents could lead to a very different Winter than expected. According to some models, starting from the second half of December, we could see a change in the scenario, with the possibility that cold currents descend from the North Atlantic or Russia.
In that case, the northern and central regions of Italy could see a return of snow, especially in the Apennine and Alpine areas.
The subtropical Anticyclone in full Autumn: drought nightmare
The phenomenon of the subtropical Anticyclone influencing the European climate is not new, but its persistence at this time of year is unusual, although already experienced in past Autumns. This situation is aggravated by the lack of precipitation, which could have repercussions on water availability in the coming months. The absence of significant rains, in fact, is already putting the water basins of Northern Italy under stress, and if the situation does not change, we could face drought problems even during Winter.
Fog and thermal inversions: the downside of High Pressure
A side effect of the current High Pressure configuration is the intensification of fog in plains and valleys, especially during the night and early morning hours.
The thermal inversions that form in these conditions prevent air exchange, favoring the accumulation of humidity and pollutants.
This phenomenon is particularly accentuated in the northern regions, such as the Po Valley, where the combination of fog and smog creates a real blanket of haze. Thermal inversions, typical of transitional seasons like Autumn and Winter, not only limit visibility but can also have negative effects on health, increasing the risk of respiratory problems, especially among the most vulnerable people.
Prospects for December: is the cold really coming? Or are they just flashes in the pan?
Looking ahead, weather projections for December indicate that the dominance of High Pressure could give way under the push of colder currents.
If atmospheric configurations change, we could see a drastic drop in temperatures right during the Christmas holiday period.
In particular, the European ECMWF model suggests the possibility of a trend reversal with the arrival of cold air from the Arctic.
But it is still to be verified
