Afternoon storms have brought hail and powerful winds to multiple regions of Spain. Persistent heat and instability linked to low pressure at higher altitudes have helped trigger intense weather, particularly late in the day. The broader pattern was evident during a DANA episode from 17 to 19 October, when the Spanish State Meteorological Agency (AEMET) forecast very strong, persistent storms across the Mediterranean coast, southeastern Spain, Catalonia, the Balearic Islands, Andalusia, Murcia, Ceuta and Melilla. A DANA is an isolated upper-level depression. Cold air aloft interacting with warm, moisture-laden air near the surface can intensify atmospheric instability and fuel downpours, hail and strong gusts. The October episode brought heavy rainfall and abrupt weather changes, while forecasts indicated that afternoon storms would continue in a number of areas.
The current pattern stems from warm air rising rapidly, cooling as it ascends and forming cumulonimbus clouds. When upper-level cold air and abundant moisture add to that instability, these clouds can produce intense downpours and localized hailstorms. Strong wind gusts have also accompanied the storms, adding to disruption in affected areas. AEMET described the Mediterranean conditions during the October episode as very adverse, with persistent and potentially torrential rainfall.
On Tuesday, unstable weather is expected to return, following a pattern similar to previous days. Most regions will start the day with clear skies, while cloud cover is likely in the north from early morning. As the day progresses, clouds will build near major mountain systems, bringing renewed afternoon storm activity. The heaviest rainfall is forecast around the Central System, with additional storms likely in the Cantabrian Mountains, the Pyrenees, the Iberian System, Sierra Morena, Montes de Toledo, the Betic System and the interior of the Valencian Community. By late afternoon, storms are expected to spread across the northern and southern plateaus and Extremadura, with a chance of reaching urban centres such as Madrid. Heavy evening rain is expected in southern Badajoz. Wind gusts will be particularly strong in parts of the Iberian and Central Systems and in some towns in Castilla-La Mancha.
Forecasts during the October DANA episode pointed to the potential severity of rainfall in eastern Spain: totals could exceed 300 litres per square metre in 24 hours in the Pitiusas, Valencia and northern Alicante. Up to 200 millimetres in 12 hours was forecast in parts of the Valencian Community, with isolated 24-hour totals reaching 300 millimetres. AEMET issued a red warning for the Valencian Community from 10:00 on Sunday, 18 October, for exceptional rainfall. Orange warnings covered areas including Andalusia, the Balearic Islands and Murcia, while yellow warnings extended to Catalonia, Extremadura, Galicia, Ceuta and Melilla. The forecasts also included northeast winds of up to 70 kilometres per hour along the Valencian coast, with rough seas and waves of three to four metres in parts of the Valencia, Catalonia, Balearic and Galician coasts. Such intense or repeated rainfall can rapidly increase flash-flood risks.
From Wednesday, the distribution of storms is set to shift as high pressure returns to much of the peninsula. This will reduce the likelihood of widespread convection, confining storm activity mainly to the western half of the country and mountainous regions. Clear skies will prevail in the early hours, but by midday storms are expected to develop in the Cantabrian Mountains, the Iberian System, the Pyrenees, the Penibetic System and Montes de Toledo. In the afternoon, storms will extend across most of Castilla y León, Galicia and Extremadura, with isolated events possible on the southern plateau. The heaviest rainfall is forecast in the northwest, particularly in the Cantabrian Mountains and León province. On Thursday, afternoon storms are likely to persist in western regions such as Extremadura and Castilla y León, as well as in various mountain systems across the peninsula. During the October episode, instability shifted towards Catalonia, where AEMET forecast very heavy, persistent afternoon rain in Barcelona, Girona and Tarragona. The shift showed how storm hazards can move even as conditions ease elsewhere.
Spain's varied geography, with its extensive mountain ranges and contrasting climate zones, often brings rapid weather changes during the warmer months. Interactions between hot air masses and shifting pressure systems can produce sudden, intense storms, especially inland and at higher elevations. The storms have also unfolded against an unusually warm national backdrop: AEMET reported that mainland Spain had its hottest September on record and that June through August was the country's warmest summer. A warmer atmosphere can hold more water vapour, increasing the potential intensity of rainfall when instability and lifting are present, though the location and timing of storms depend on the weather system. The October forecasts also showed sharp regional temperature differences, including a decline of more than six degrees in maximum temperatures across parts of eastern Spain. Residents in affected regions are advised to follow local forecasts and prepare for abrupt weather changes, particularly in the afternoons, when storm activity tends to peak.
The emergency’s effects went beyond rainfall. Reports during the October episode described flooding, rescues and fatalities in eastern Spain, as well as school closures and accumulations exceeding 500 litres per square metre over 48 hours in some locations. AEMET maintained warnings for heavy rain and thunderstorms on 19 October as the DANA’s effects continued. Along with hail, strong winds and dangerous coastal conditions, the rainfall created a compound hazard that disrupted daily life across affected areas.
