This Friday marks the official end of the summer's second heatwave in Catalonia, but a third is already brewing. Although thermometers have begun to drop slightly, the atmosphere remains very hot, with highs still potentially reaching 40 °C in Ponent. Meteocat maintains yellow alerts for intense heat in Ponent, Baix and Alt Penedès, Garraf, and Baix Llobregat for Friday.
Saturday is expected to see a more significant drop in temperatures, marking the end of the second heatwave. However, this respite will be brief, as temperatures are set to climb again from Sunday and are expected to continue rising throughout the following week. The arrival of a new mass of very warm air from North Africa, driven by a low-pressure system west of the Iberian Peninsula, will particularly affect the western Mediterranean, including Catalonia.
Initially, the Servei Meteorològic de Catalunya (Meteocat) considered this new surge as a continuation of the second heatwave. However, it has now been decided to classify it as the summer's third heatwave, forming part of a prolonged period lasting at least twelve days. The third heatwave will officially begin on Sunday, July 12th, and extend until at least Thursday, July 16th. Saturday will be the only day without intense heat alerts across the region, but by Sunday, the first warnings for intense heat have already been issued for Ponent, the Pyrenees, and the Pre-Pyrenees.
The new North African warm air mass will be even more intense than the previous one, with temperatures at 1,500 meters altitude ranging between 26 °C and 28 °C, about two degrees higher than during the second heatwave. This could lead to exceeding some of the records recently achieved, especially in the country's interior. Nevertheless, several factors might moderate the thermal escalation. Increased maritime humidity will heighten the feeling of mugginess on the coast, although it may slow the mercury's rise. The most significant factor will be the presence of suspended Saharan dust, which will haze the sky and could reduce the impact of solar radiation.
Despite these factors, forecasts point to highs between 36 °C and 41 °C, potentially exceeding 42 °C or 43 °C in Ponent and the Ebro Valley. The peak of the heat is expected between Wednesday and Thursday, with widespread tropical or torrid nights along the coast. Medium-term forecasts suggest a possible temperature drop from next Friday and the following weekend, entering the second half of July, with a gradual normalization, although the heat will continue.
