Catalonia is set for a final day of rain and cooler temperatures on Monday, 18 May, before a significant shift to summer-like heat later in the week. A new cold front has brought increased instability, with showers and storms affecting the northern and north-eastern parts of the region. Temperatures have remained cool for the season, particularly along the Girona and Barcelona coasts, where highs have been between 18 and 21 °C, more typical of April than May.
Monday will bring a final burst of showers and cool weather to eastern Catalonia. Some rainfall could be heavy and accompanied by violent phenomena or hail, according to meteorologists. However, a radical change is expected from Tuesday as an anticyclonic ridge moves in, bringing the first taste of summer heat to the Iberian Peninsula and much of Western Europe.
Monday's Forecast: Rain Continues East
The meteorological forecast for Monday, 18 May, indicates another day of precipitation and mild temperatures, especially in eastern Catalonia. This will conclude the unstable weather of recent days. Early morning will see initial showers across the central coast and pre-coastal areas, as well as parts of the interior and Pre-Pyrenees.
During the morning, the sky will be largely clear across the country, though central Catalonia and the coastal and pre-coastal strips of Barcelona and Tarragona will experience more low and medium clouds. Moderate to locally intense showers are expected along the Tarragona coast during the first half of the day. Bands of high and medium clouds will also cross the country from west to east, leaving the sky partly cloudy in the southern and western regions.
By midday, large clouds will develop in the northern third, across the Barcelona and Girona pre-coastal areas, and particularly in the north-east quadrant of Catalonia. These regions will remain heavily overcast in the afternoon. A new round of afternoon showers is expected in the eastern half of the region, with weak to moderate and localised precipitation. Showers will also occur in the Pyrenees and Pre-Pyrenees, mainly in the eastern sector. Some storms are possible in Ripollès, Garrotxa, Selva, and Gironès, among other areas. The heaviest rains will concentrate in Girona, where downpours could be abundant and accompanied by lightning, thunder, and hail. The atmosphere will stabilise towards night, with showers then limited to the Costa Brava. Some snow flurries are not ruled out at high altitudes on the northern slopes of the Western Pyrenees.
Light winds are generally expected throughout the day, with a gentle Tramuntana wind possibly blowing early towards the north of Cap de Creus. Along the coast and pre-coastal areas, a southerly sea breeze will prevail, with gusts not exceeding 30 or 35 km/h. In Ponent and parts of the interior, moderate westerly winds will blow. This will create surface convergence lines, where drier westerly winds and humid southerly sea breezes will allow cloud development in the eastern half of the country.
Temperatures will remain largely unchanged in the eastern half, with cool conditions for the season and highs often staying below 20 °C in Girona. It will be warmer in southern Lleida and inland Tarragona, with thermometers locally exceeding 25 °C. Coastal areas will be mild, with highs slightly above 20 degrees. Minimum temperatures could rise slightly.
Week Ahead: Anticyclone Brings Summer Heat
The anticyclone will rapidly gain ground from Tuesday, bringing a more stable atmosphere and a clear improvement in the weather. Early morning will still see abundant cloud cover across the territory, with intervals of high and medium clouds. However, clear spells will quickly open up, allowing for more sunshine. Some low clouds could also appear along the coast in the early hours.
From mid-morning or midday, convective clouds will develop in the Pyrenees, Pre-Pyrenees, and more locally in the pre-coastal areas, where the sky will become more overcast again. The rest of the country will experience clearer conditions. Weak to moderate showers are expected in the northern third and parts of inland Girona, as well as north of the central depression. These are expected to be light, with storms limited to mountain areas. Temperatures will rise notably, with highs in the eastern half potentially increasing by more than five or six degrees. Readings will align with seasonal averages: highs between 20 and 25 °C along the coast and pre-coastal areas, while Ponent and the Ebro valley could approach 28 °C.
Anticyclonic weather will consolidate from Wednesday. High surface pressures and warm air will create a very stable atmosphere, ensuring long periods of sunshine and rising temperatures. In the central and southern third, the sky might appear somewhat hazy due to high clouds. Along the Tarragona coast, advection sea fogs could form in both the morning and afternoon, caused by the thermal contrast between the land surface and the Mediterranean. Convective clouds will form across the northern third during the afternoon, but the lack of cold air at altitude will hinder their growth, leaving Catalonia free of precipitation.
Thursday will see a similar situation, with the sun as the sole actor in the sky. Stable, summer-like conditions are expected, as temperatures will continue to rise and be clearly above the climatic average. Warm weather is forecast for the coast and pre-coastal areas, with highs between 24 and 28 °C. Inland areas will experience the first taste of summer heat, with temperatures potentially reaching 31 or 32 °C. The anticyclonic monotony will continue into Friday, with long periods of sunshine and few clouds, apart from the usual afternoon cloud development in mountain areas. However, some weak and localised showers could occur in parts of the Pyrenees. Temperatures are expected to climb further, with inland areas potentially experiencing the first heatwave of the season, reaching up to 35 °C.
The first changes could arrive by the weekend, with a DANA (isolated upper-level depression) approaching the west or north of the Iberian Peninsula. This system could bring back showers and storms to Catalonia. However, as many days remain, the situation will require daily monitoring, according to El Nacional's weather reports.
