Bologna, August 20, 2026 — After days of intense heat and humidity, the scenario is changing in Emilia-Romagna. The storm front is ready to enter the region and the most critical day will be tomorrow, Friday, August 21, when showers and thunderstorms of strong intensity are expected, locally accompanied by hail and gusts of wind.
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For this reason, Arpae, in agreement with the Civil Protection, has issued a yellow alert for thunderstorms, to which are added, in several areas, criticalities for wind, landslides and flooding of minor watercourses.
‘Yellow’ weather alert in Emilia-Romagna for Friday, August 21
The alert is valid from midnight on Friday and depicts a passing disturbance that could produce effects especially in the Apennine areas and in the territories affected by the most persistent thunderstorms.
Intense and concentrated precipitation could indeed cause runoff on slopes, localized flooding and landslide phenomena, as well as rapid rises in the water levels of watercourses, particularly those in the western sector and those reached by thunderstorm cells.
Wind represents another hazard of the day. An intense south-western flow will increase ventilation on the Apennine ridge and in Romagna, with possible moderate gale winds, between 62 and 74 kilometers per hour, and locally even stronger gusts.
On the Romagna coast, the wave motion will increase especially offshore, while sudden gusts may accompany the thunderstorms.
When will the rain arrive? Expert Roberto Nanni speaks
But when will the rain actually arrive? This is the central point of the forecasts for Friday. According to Roberto Nanni, meteorological technician at Ampro, the first signs of instability will arrive already today, Thursday, August 20, especially in western Emilia and the Apennines. The real worsening, however, is expected “between the night and the morning of Friday 21,” when showers and thunderstorms will advance from the hills towards the plains and, progressively, from west to east.
The most active phase could therefore begin already in the early hours of the night. The phenomena will initially involve the Apennines and the western provinces, then move towards the rest of the region during the morning. It will not necessarily be continuous rain: the greatest risk is linked to locally intense thunderstorm phenomena, capable of dumping a lot of water in a short time.
The Atlantic disturbance and thermal contrast
Nanni explains the reason for this sudden change of pace: “After the long hot and stable phase, between today and tomorrow we will witness a sharp increase in instability over Emilia-Romagna. In the lower layers there is still a very warm and humid air mass, while the approach of an Atlantic disturbance will bring cooler air aloft, increasing the thermal contrast.”
An important ingredient is represented by the energy available for convection. “The Cape, index of the energy available for convection, locally reaches very high values over the Mediterranean, even in the order of 3000-5000 J/kg,” the meteorologist observes.
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A high value, he specifies, “does not automatically mean violent thunderstorms, but indicates an environment potentially favorable to the development of intense convective phenomena, if adequate triggering mechanisms are present.”
Winds: the region between Garbino and Libeccio
Today will therefore be a sort of preview of the worsening. The first thunderstorms may affect western Emilia and the Apennines, while between Modena, Bologna and Ferrara the Garbino could still push temperatures up to 35-37 degrees. On the hills, the Libeccio will tend to strengthen, with locally strong gusts.
Weather forecast and temperatures for Friday, August 21
According to Amap, the picture will change radically tomorrow.
The forecast indicates very cloudy skies and thunderstorm precipitation already from the night, moving from the hills towards the plains and from west to east during the morning.
In the afternoon, the phenomena should progressively weaken, giving way to residual instability on the hills and, subsequently, to increasingly wide clearings, especially in the central-eastern sector.
Temperatures will also undergo a sharp drop. On Friday, the minimums will fall around 20-21 degrees in the western inland areas and remain around 23-25 in Romagna. The maximums, instead, will generally range between 25 and 29 degrees in the central-western sector, with values around 30 in Romagna. After the peaks of recent days, therefore, the air will change significantly.
Weather forecast for Saturday, August 22
Saturday, August 22, the day when the visit of Pope Leo XIV to Rimini is expected, will be a transition day. In the morning there will still be some irregular clouds, especially on the hills, but the situation will quickly improve, with wide clearings during the day. Temperatures will rise slightly again: maximums up to 29 degrees in western Emilia and around 33 in Romagna. Winds will remain moderate on the hills and coast, but easing.
The next disturbance at the beginning of next week
On Sunday, instead, the return of the sun and more stable conditions are expected, with a gradual thermal recovery. The cool spell, in short, could be brief.
And the next change could already be around the corner: between Monday 24 and Tuesday 25 August, models indicate the possibility of a new disturbance impulse.
However, the time distance does not yet allow to precisely determine its trajectory and intensity.
