Weekend temperature spikes before autumn weather settles in

 ROME - Due to the rise of an African anticyclonic ridge towards southern Europe, this week will be characterised by the return of hot weather, with temperatures reaching peaks that are quite high for this time of year. Those who love the cold will therefore have to wait a little longer before putting on their jackets and jumpers. But not for long because from 22 September bad weather could return.

 According to 3BMeteo forecasts, the arrival of cold polar air from Labrador towards the European Atlantic will form a deep depression west of England, which will cause a gradual rise towards southern Europe of an African anticyclonic ridge during the week. Its arrival will be preceded by a very brief phase that will bring unstable weather, causing some disruption in some northern regions, and in part of central Italy, but with only minor effects.

 Towards the beginning of the week there will be some disturbances in the north due to weak western humid infiltrations: these will mainly consist of scattered irregular cloud cover, more persistent in Liguria and the pre-Alpine areas in general. There will also be some cloud cover in upper Tuscany. During the night, showers will affect the Alpine areas, especially those near the border. The rest of the peninsula will be mainly sunny. Temperatures will remain stable, within the average range.

 On Wednesday, there will be residual cloud cover in the north-east but no precipitation, with mainly sunny weather over the rest of the peninsula and slightly higher temperatures in the south.

 Between Thursday and Saturday, the African anticyclone will gradually move up towards the Mediterranean. A late and significant heatwave will affect the Iberian Peninsula, where temperatures could reach 38°C. Stable conditions and above-average temperatures will also affect Italy, but with lower values.

 During the day on Sunday, the approach of a disturbance associated with the Atlantic vortex, which will tend to move towards the United Kingdom, could bring a gradual increase in clouds in the north with the arrival of some rain at the end of the day over the western Alps.

 Warm air from the south-west will cause temperatures to rise to summer levels, particularly in central and southern Italy. Maximum temperatures could reach, and in some areas exceed, 30°C. Peaks of up to 33-34°C are expected, especially in the southern regions, where the weather will be more in line with August than September.

 But the calm of this phase could be just a prelude. Attention is already focused on the end of the month, when a radical change in the scenario could be in the offing. Between Monday 22nd and Tuesday 23rd, coinciding with the arrival of astronomical autumn, there is a growing risk of a so-called “equinoctial storm”. If this event were to occur, it would bring a marked wave of bad weather, with heavy rainfall and a sharp drop in temperatures across most of Italy.

 This is a typical phenomenon during this transition period between summer and autumn, but its potential intensity and spread requires constant monitoring. The “equinoctial storm” is a term used to describe an intense and often violent disturbance that typically occurs around the equinoxes, i.e. the times of year when day and night are of equal length. At this juncture, the contrast between warm summer air and the first cold autumn air masses can give rise to extreme and widespread weather phenomena.

rs