Polar air mass and trough to bring 10 °C temperature drop and severe storms across Spain

Incoming polar front and atmospheric shift

Spain is preparing for a pronounced meteorological shift as an Atlantic trough and a cooler polar air mass move across the Iberian Peninsula starting Wednesday. The State Meteorological Agency (Aemet) issued a special advisory detailing how the incoming system will displace the anticyclonic ridge responsible for recent high temperatures across the country. As the cooler air penetrates through the Cantabrian region, daily temperatures will drop below seasonal averages for late August. Forecasters expect the most persistent and abundant rainfall to concentrate across the northern third of the mainland. The change represents a transition from widespread heat warnings to unstable autumn-like conditions.

The passage of a trough that will quickly cross the Iberian peninsula, accompanied by the entry of a cooler polar mass.

Sharp regional temperature drops

Maximum temperatures will drop by 6 °C to 10 °C within a 24-hour period between Wednesday and Thursday, with northern and southeastern provinces seeing the steepest reductions. León will register a drop of 10 °C, moving from 33 °C on Wednesday to 23 °C on Thursday, while Burgos declines by 9 °C to 26 °C and Lugo falls from 30 °C to 22 °C. In the Ebro Valley, Logroño will move from 38 °C to 31 °C, Pamplona will decrease from 34 °C to 28 °C, and Vitoria will drop from 30 °C to 25 °C. Zaragoza will experience one of the sharpest contrasts, falling from approximately 43 °C on Wednesday to 37 °C on Thursday and 32 °C on Friday. Southern provincial capitals will also see cooling, with Albacete and Murcia falling to 32 °C and 37 °C respectively, while Granada drops to 30 °C and Seville falls from 39 °C to below 32 °C.

Severe storms, downbursts, and flood warnings

Atmospheric instability will trigger intense convective storms across multiple mountain systems and inland valleys beginning Wednesday afternoon. Forecasters anticipate strong thunderstorms accompanied by hail and severe wind gusts across the Pyrenees, the Baetic systems, the northern Iberian system, and the Cantabrian mountains. The Pyrenean area faces elevated risks of localized flooding in valleys and mountain ravines due to heavy precipitation rates. In southeastern Spain and the Balearic Islands, storm cells could generate sudden downbursts and destructive gusts of wind. Precipitation will also spread into Andalusia on Thursday, where Seville, Huelva, and Cádiz face rain probabilities of up to 80% during the morning hours.

Pre-frontal heat spikes and weekend outlook

Before the arrival of the cold front, several regions will experience a final surge in heat on Wednesday. In the Valencian Community, westerly winds will push coastal temperatures upward by up to 10 °C in 24 hours, sending local thermometers past 42 °C. Similar pre-frontal highs will reach 42 °C in Ourense and 38 °C in Madrid, while Meteocat maintains heat warnings in Catalonia through Wednesday night. The incoming weather pattern will consolidate over the weekend as a cut-off low (DANA) transforms into a broader trough stationed west of Portugal. A slow-moving front will sustain rain across the northern third of Spain through at least Monday, 24 August, while night temperatures in Seville fall to 14 °C.

The establishment of a broad trough to the west of the peninsula and the passage of a slow-moving front, which will contribute to destabilizing the atmosphere, especially in northeastern areas of the peninsula.