Historical heatwave in May: Catalonia obliterates absolute heat record

Temperatures are rising even more today in Ponent and in the south of the country, setting new historical records. The mercury has already climbed to 39.5 °C in Vinebre (Ribera d'Ebre). This is the highest maximum ever reached in a May in all of Catalonia, shattering the absolute record in force until now: the 38 °C recorded in May 2022 in Castellbisbal (Vallès Occidental) and Anglès (Selva), equaled yesterday in Vinebre.

All this after a night that has been tropical in many parts of the coast and pre-coast, and even some torrid minimums, above 25 °C, have been recorded. This is the case of the Fabra Observatory in Barcelona, where the minimum of 25.3 °C recorded today is the new record for nocturnal heat in a May in 112 years of data, exceeding the previous record by 1.5 °C. Also noteworthy are the 25.7 °C minimum in Portbou (Alt Empordà), where yesterday the temperature did not drop below 28 °C, the new record for the highest minimum in a May in Catalonia. An extraordinary event very localized in this area due to the reheated tramuntana wind that blew there.

Therefore, this Friday has started with very warm conditions near the sea after temperatures peaked in many regions yesterday. We are experiencing the worst hours of this historic and premature heatwave, which on Thursday set many heat records for a May. The Lleida station, with 86 years of data, has also broken its own heat record for May, with 37.3 °C, and the centenary Ebre Observatory has also broken its own May ceiling, with 37.3 °C. The city of Girona has reached 37 °C in May for the first time since records began, and the Raval neighborhood of Barcelona has also reached its May heat record, with a maximum of 33.5 °C. Many other municipalities have also broken their own records.

We are under the effects of a powerful and long anticyclone that is causing what is known as the heat dome effect: the air does not circulate and we have strong solar radiation that heats the environment a lot, causing the heat to accumulate and be more intense day after day. Today the extreme heat will continue, and we could reach 40 ºC in Ponent and the Ebro valley, where we will see if new records are reached. But temperatures will already recede a little in the regions of Girona and Barcelona after yesterday's torrid peak. A decrease that will become generalized on the weekend, although we will be coming from so high up that the atypical mid-summer weather will continue for quite a few days, also in the first days of June. Afternoon showers will increase in the Pyrenees, and next week it could cool down more significantly.

Friday: very hot

Temperatures will remain very high and clearly above average for this time of year. Values between 8 and 12 degrees above average in many cases. After a tropical or torrid night in various locations, especially along the coast and pre-coast, today the maximums will again exceed 30 or 35 °C in most regions. It will approach 39 or 40 °C in Ponent and the southern interior, where we will see if new heat records are reached. On the other hand, in the regions of Barcelona and Girona, the mercury will not rise as much as yesterday. On the coast, intense sultriness will be the protagonist.

All this in a new anticyclonic day marked by brilliant sunshine. In the afternoon, clouds will grow in the Pyrenees and Pre-Pyrenees, which will leave some scattered showers. Nuances in a context of calm and very hot weather for the dates.

Some changes over the weekend

Temperatures will drop at the weekend, but the atmosphere will remain fully summery, with values clearly above average. We are coming from very high up, and it will be very difficult to normalize the thermometers. Throughout next week the maps indicate that we could have a cooling down, although the end of this exceptional situation is not yet at all clear.

This weekend, the center of the anticyclone will move to the Atlantic, which will favor the appearance of more afternoon showers and thunderstorms in the Pyrenees and Pre-Pyrenees. With so much accumulated heat, we will see if any local downpour, hail, or hailstorm occurs. Throughout next week, the showers could gain ground.