A temporary advance of the anticyclone guarantees large spaces of clear weather in the Central-Northern regions, while weak rains in the Southern regions. However, this interlude of stability will be short-lived: over the next week we will in fact witness the return of Atlantic disturbances.
Mattia Gussoni, meteorologist at iLMeteo.it, confirms that during Sunday 8 November, generally light rainfall will be recorded in Puglia, Basilicata and Calabria, with accumulations estimated between 5 and 10 mm/24h. At the same time, the expansion of western high pressure towards central Europe will guarantee large spaces of clear and prevailing atmospheric stability over the central-northern regions.
The thermal regime will see maximum values between 11 and 15°C in the North, between 13 and 18°C in the Center, and between 18 and 20°C in the South and on the Major Islands. Ventilation will remain weak or moderate, with reinforcements of Scirocco and Libeccio on the Ionian sectors capable of reaching gusts of 30-40 km/h, resulting in a wave motion with wave height between 1 and 1.5 metres.
New unstable phase from Monday: the Atlantic flow
Starting from Monday 9 November, the European synoptic picture will undergo a change, triggered by the entry of unstable currents. From a technical point of view, the Atlantic perturbed flow represents an atmospheric channel of westerly currents at mid-latitudes which, driven by the thermal gradient between the tropics and the poles, conveys moisture-laden extratropical systems directly towards the Mediterranean basin.
The arrival of this first disturbance will lead to precipitation in the northern regions, with accumulations estimated between 10 and 20 mm/24h, associated with snowfall along the Alpine arc at altitudes on average between 1500 and 1700 metres, where snowfall contributions of 5-10 cm are estimated.
The evolution between Tuesday 10th and Wednesday 11th November
During Tuesday 10 November, the arrival of a further Atlantic-based disturbance on the western Mediterranean basin will lead to a progressive increase in cloud cover associated with weak or at most moderate intensity precipitation. The phenomena, with accumulations estimated between 5 and 15 mm/24h, will affect Liguria and the central regions. On the following day, Wednesday 11 November, the instability will be concentrated only along the central Tyrrhenian side, with accumulations estimated between 10 and 20 mm/24h, guaranteeing instead a temporary dry variability over the rest of the country.
The peak of instability expected on Thursday 12 November
The markedly dynamic phase will undergo further accentuation during Thursday 12 November, due to the deepening of a marked depression system. This configuration will trigger extensive and persistent rainfall, particularly concentrated in the Central-Northern regions. Model projections indicate significant rainfall accumulations, with peaks estimated at or above 80-100 mm/24h. This baric dynamic will be associated with a decisive reinforcement of ventilation: gusts of Scirocco and Libeccio capable of reaching 70-90 km/h are expected along the exposed coasts, generating a rough wave motion with wave heights between 3 and 4 meters offshore.
The heavy rainfall will also favor significant amounts of snow across the entire Alpine range, with snow levels above 2000-2100 meters (with accumulations on the ground estimated at between 30 and 50 cm above 2200-2300 metres). With the entry of the strong ventilation of the Scirocco and Libeccio on Thursday, a marked thermal contrast will be activated between the North (cold air in the lower layers) and the South/Adriatic side: maximum values estimated at 10-13°C in the North and peaks of up to 20-23°C in the South.
The possible activation of warning procedures for hydrogeological and hydraulic criticalities will be evaluated in the official Civil Protection bulletins close to the event, if the trend is confirmed.
IN DETAIL
Sunday 8
In the North: stable and sunny conditions; maximum values between 11 and 15°C. In the Center: clear or slightly cloudy skies, highs between 13 and 18°C. In the South and on the Islands: residual instability with weak rainfall (5-10 mm/24h) on Puglia, Basilicata and Calabria; maximum between 18 and 20°C.
Monday 9
In the North: rapidly increasing cloud cover with scattered rain (10-20 mm/24h); snow in the Alps at 1500-1700 meters. Maximum values of 10-14°C. In the Center: increasing clouds starting from the Tyrrhenian side, in an initially dry context. Maximum values of 13-17°C. In the South and on the Islands: stable conditions with large clearings; maximums around 18-21°C.
Tuesday 10
In the North: increase in cloud cover with weak or moderate precipitation in Liguria (5-15 mm/24h), dry elsewhere. In the Center: intensifying cloud cover with scattered rain (5-15 mm/24h). In the South and on the Islands: dry variability, stationary temperatures.
Trend
On Wednesday, instability limited to the central Tyrrhenian side (10-20 mm/24h), a prelude to a marked worsening expected for Thursday 12 November with rainfall exceeding 80-100 mm/24h in the Centre-North and gusts of wind up to 70-90 km/h.
