Catalonia is preparing to face an exceptional meteorological episode that the officials of Meteocat qualify as exceptional. The rains that are already affecting different points of the territory could intensify rapidly in the coming hours due to the formation of a mesoscale convective system, a large structure of organized storms capable of dropping enormous amounts of water in very short periods and generating strong gusts of wind. The Generalitat places the period of greatest risk between 8:00 PM this Saturday and 2:00 PM on Sunday and asks to avoid during that time frame activities and movements that are not essential.
The director of the Meteorological Service of Catalonia, Sarai Sarroca, has warned that the situation "can complicate a lot," while the models handled by the meteorologists point to the possibility that a large-scale storm system may organize.
Demano màxima prudència davant les previsions meteorològiques: es podria formar un minihuracà mediterrani a Catalunya. Les pluges ja estan afectant gran part del territori. Aquesta tarda anunciarem mesures importants que caldrà respectar.
— Salvador Illa Roca (@salvadorilla) October 3, 2026
Seguiu sempre les indicacions i… pic.twitter.com/vlUHhRJccX
The people responsible for Meteocat have used the expression "Mediterranean mini-hurricane" to explain the potential of the episode, although technically it is advisable to distinguish the phenomena: a mesoscale convective system is an organized grouping of storms and does not automatically equate to a tropical cyclone or a hurricane like those that form in the Atlantic.
More than 200 liters and risk of flooding
The main concern lies in the amount of water that may fall on areas that are already very saturated after the precipitation of the last few days. The forecasts contemplate accumulations that may exceed 200 liters per square meter in some points, in addition to torrential episodes concentrated in a few hours. The storm has already left this week amounts exceeding 200 liters in areas of southern Tarragona and records of 162 liters in just six hours in Tortosa.
This starting point increases the risk that new rains will cause rapid rises in rivers, streams, and ravines, urban flooding, and mobility problems. Salvador Illa has warned that Catalonia is facing a "very complex" situation and has asked to follow the instructions of the emergency services. "This is not a joke," the president has pointed out, who plans to participate this Saturday in monitoring the INUNCAT plan from the Operational Coordination Center of Catalonia.
Seventeen counties on red alert this Saturday
The highest level of danger affects this Saturday 17 counties of the Catalan coast and pre-coast: Alt Empordà, Baix Empordà, Pla de l'Estany, Garrotxa, Gironès, Selva, Maresme, Vallès Oriental, Vallès Occidental, Barcelonès, Baix Llobregat, Garraf, Alt Penedès, Baix Penedès, Alt Camp, Tarragonès, and Baix Camp. The alerts will continue on Sunday and will change territorially as the system progresses.
The red alert represents the maximum degree of meteorological danger and activates additional protection measures. The INUNCAT plan itself establishes that, in the event of rain alerts of level 5 or 6, an alert may be sent to the phones of the affected areas with instructions to avoid mobility and outdoor activities. Civil Protection plans to use the ES-Alert system this Saturday to directly convey those recommendations to the population.
Tornadoes, waterspouts, and strong gusts of wind
The threat is not limited to rain. The most intense storms can be accompanied by hail, strong gusts of wind, downbursts, tornadoes, and waterspouts, especially near the coast. Civil Protection reminds that this type of phenomenon is difficult to predict accurately and can develop very quickly, so it recommends seeking shelter immediately if a rotating column of air or an especially violent storm is observed.
Waterspouts are, in general terms, tornadoes that form over the surface of the sea. If they reach land, they can maintain their ability to generate strong winds and material damage for a time. The combination of torrential rainfall, wind, and possible severe convective phenomena explains why authorities have increased surveillance along the entire Catalan coast.
Civil Protection asks to limit movements
The main recommendation from the Generalitat is to avoid unnecessary movements, especially during the hours of greatest intensity expected from Saturday evening to night. Civil Protection asks not to approach rivers, streams, and ravines, never to cross flooded areas, and to avoid parking vehicles in places likely to be covered by water. It also recommends suspending outdoor activities during times of greatest risk and staying alert to official warnings.
Illa has asked citizens to respect the preventive measures adopted by Civil Protection and has insisted on the need to act with caution in a scenario that can change rapidly. The evolution of the storms will determine in the coming hours which areas ultimately receive the greatest accumulations, as this type of system can concentrate extraordinary rainfall over relatively small areas.
What is a mesoscale convective system
A mesoscale convective system (MCS) is a structure formed by multiple storms that end up organizing and behaving like a single large system. It can remain active for several hours, constantly regenerating precipitation and dumping large amounts of water over the same area. This type of configuration is behind some of the most intense rainfall episodes historically recorded along the Spanish Mediterranean coast.
For this reason, the term "Mediterranean mini-hurricane" used during the explanations this Saturday should be interpreted with caution. A medicane or cyclone with Mediterranean tropical characteristics is a concrete phenomenon with a cyclonic structure similar to, although smaller in size and intensity than, tropical hurricanes; an SCM, for its part, mainly describes an extensive organization of storms. Both can produce very adverse weather, but they are not identical concepts.
With Catalonia still recovering from the rains of the last few days, attention is now focused on the afternoon and night of this Saturday. The interval between 8:00 PM and 2:00 PM on Sunday appears to be the most delicate period, with 17 regions on red alert, the possibility of torrential rainfall, and the risk of violent phenomena. The recommendation from the authorities is clear: reduce mobility, stay away from waterways and flood-prone areas, and pay attention to the ES-Alert messages that may arrive on mobile phones.