Weather, Civil Protection: orange alert in Puglia and Basilicata. Weak polar vortex

So says Mattia Gussoni, a meteorologist at ilMeteo.it.

“The bad weather really set in during the course of Sunday 1 November (All Saints’ Day). The influx of cold air over the Mediterranean will encourage the formation of a low-pressure system. This low-pressure vortex,” continues Gussoni, “will trigger thunderstorms that are particularly active, fuelled by the energy accumulated from a Mediterranean Sea that is still mild (warmer-than-average waters will result in higher humidity in the lower layers and a surplus of potential energy).”

The weather systems are affecting Romagna, Marche, Abruzzo, Molise, Puglia, Campania, Calabria, Sardinia and Sicily, with rainfall totals locally reaching up to 50–60 millimetres within a few hours, particularly along the Adriatic coast. The weather is more stable across the rest of Italia, albeit in rather cool conditions.”

“The drop in temperature will also bring snow back to the Apennine mountain range.

In the central-southern Apennines, snowflakes fell as low as 800–1,000 metres, particularly between Sunday evening and the early hours of Monday, blanketing the inland areas of the Marche, Abruzzo, Molise and Lazio, whilst in the remaining southern mountains the snow line will be at higher altitudes. Some snowfall is also expected in the central-eastern Alps, generally above 1,000 metres. These conditions of marked atmospheric activity and decidedly cold weather will persist into the start of next week, with precipitation continuing to affect the central and southern regions in particular,” concludes Gussoni.

A low-pressure system, moving down from the Balkans towards the Tyrrhenian Sea, is causing unsettled conditions in central and southern Italy, with scattered showers and thunderstorms. On 2 November, the deepening of the low-pressure system over the southern Tyrrhenian Sea is causing a marked deterioration in conditions along the central Adriatic coast and across much of the south, with widespread rainfall – including thunderstorms and heavy downpours – accompanied by a general increase in wind speeds.

On the basis of the available forecasts, the Department of Civil Protection, in consultation with the regions concerned – which are responsible for activating civil protection systems in the affected areas – has issued a new advisory on adverse weather conditions. These weather events, affecting various parts of the country, could lead to hydrogeological and hydraulic risks, which are summarised in a national overview in the national risk and alert bulletin available on the Department’s website.

The forecast predicts, from the early hours of today, 2 November, scattered to widespread rainfall – including showers and thunderstorms – over Abruzzo, Molise and Sicily, extending to Campania, Calabria, Puglia and Basilicata, with persistent rainfall in the latter and along the eastern Apennine slopes of Abruzzo and Molise.

These conditions will be accompanied by heavy showers, strong gusts of wind, localised hailstorms and frequent lightning. Furthermore, from early tomorrow morning, strong to gale-force northerly winds are forecast for Lazio, particularly in the northern areas, Campania and Sicily, with strong gale-force gusts in the southern parts of the island, subsequently extending and veering from the east towards Basilicata and Puglia.

Based on the forecast conditions, the following has been assessed for today, Monday 2 November: an orange alert has been issued for today, Monday 2 November, due to meteorological and hydrogeological risk in Puglia and Basilicata. A yellow alert is in place in Calabria, Campania, Molise, Abruzzo and Sicily.