Autumn arrives and a strong equinoctial storm immediately breaks out. Friday 23 September at 3.04 the equinox falls that takes us into the new season, in less than 24 hours the first autumn Atlantic disturbance will threaten Italy with persistent and potentially alluvial rains. From Saturday on the North-West and part of the Tyrrhenian Center, even more so from Sunday 25 September, bad weather will hit a large part of Italy. But what does the name ‘equinoctial storm’ mean? In the period of the transition between Summer and Autumn (as well as between Winter and Spring) we find the first important differences in temperature between the polar and subtropical zones. In these last weeks of the summer, the sun has hardly warmed the areas north of the Polar Circle due to the increasingly long night and, on the contrary, has continued to warm the areas in the south of Italy. due to the inclination of the earth’s axis, every year causes strong storms to be unleashed in this equinoctial period: the cold air tries to balance the thermal difference by descending towards Italy, allying itself with warm ascents from the Sahara. In this way, meridian exchanges are activated, i.e. north-south and vice versa, which try to re-establish thermal equilibrium but which create extreme conditions of bad weather.Andrea Garbinato, Editor of the website www.iLMeteo.it, therefore confirms the possibility of a strong equinoctial storm from Saturday 24 September with at least 5 days of bad weather. In the next few hours, the isolation of a depression on Spain will favor the rise of hot and humid currents with possible accumulations on the western sector. On Saturday and Sunday these humid flows could cause storms, first in Liguria then in extension to the Tyrrhenian side of the central regions and to Sardinia. The rest of the North will also experience a very disturbed phase at least until Wednesday when it could even snow at low altitudes for the period in the Alps and the northern Apennines.In the meantime, the last hours of Summer 2022 will still be mild during the day and cool in the morning with the possibility of some strong thunderstorms on the Major Islands due to the still high temperature of the Italian sea: normally the Italian waters lose the heat accumulated during the Summer by the end of November. In this period of early autumn we must therefore expect and therefore prepare for storms, especially along the coasts. In fact, we know that more heat means greater probability of heavy rain. We will follow the expected evolution of the equinoctial storm, meanwhile we live the last day of summer with a prevalence of sun, but also some sudden storms. IN DETAIL Thursday 22. In the north: little sky cloudy. Center: sunny except for some thickening on the hills, intense showers in Sardinia. In the south: variable with strong thunderstorms in Sicily. Friday 23. In the north: sunny with haze coming from the west. Center: sunny except for showers in Sardinia. In the south: sunny, some showers in Sicily. Saturday 24th. In the north: bad weather in the North-West, in the evening also in the Northeast. Middle: bad weather in Tuscany and Sardinia towards Lazio and Umbria. South: sunny and warm. Trend. Widespread, persistent, incessant rains and a significant drop in maximum values over most of Italy for at least 4-5 days.