Night and early morning of downpours with a rainy and cooler Sunday

BarcelonaThe DANA 'Adam' and the arrival of humid maritime winds are already causing the first storms and some intense downpours (61 l/m² in Cabrils, 39 l/m² in Caldes de Montbuí or in Santa Coloma de Farners). The contact of the cold pocket, with temperatures at 5,500 m of up to -18 ºC - and the warmer and more humid air that we have over our territory - will help the clouds to develop rapidly and violent storms to form.

During the evening, night, and early hours of Sunday, the rain will be intense and will be accompanied by torrential downpours that will leave significant accumulations in a short time. For this reason, Meteocat has activated an alert for intense rain in many regions, which can leave more than 40 l/m² in just half an hour or more than 90 l/m² in three hours. The warning is red –danger level 5 out of 6– in Vallès Oriental, Vallès Occidental, Selva, Maresme, Baix Llobregat, Barcelonès, and Garraf.

This episode, typical of autumn, is the result of a combination of factors. On one hand, the anticyclone will settle over northern Europe and a low-pressure system will form in the Mediterranean. All of this will open up a corridor of winds coming from central Europe and will facilitate the arrival of a pocket of cold air at high altitude in the north of the Iberian Peninsula. It is a DANA that has been christened with the name of Adam, the first on the official list of DANAs and storms for this season. This will reactivate instability and cause temperatures and the snow level to drop.

In addition, moist maritime winds will be reinforced from a sea that remains very warm and that can fuel the intensity of the precipitation. It is a situation that we will have to monitor very closely, since, depending on the final position of all these pieces, the rain will be more or less widespread and intense.

Sunday: gray and cold day

What we will notice most on Sunday will be a sharp drop in temperatures. The atmosphere will be cold in general, with many maximums only from 13 °C to 17 °C, but clearly lower in mountain areas. On the coast, they will not reach 20 °C. An atmosphere of advanced autumn suddenly and values below what would be expected for this time of year. The decrease in maximums can be in some cases of up to 10 degrees compared to days ago.

All this with weather that will continue to be quite unsettled. A gray sky is expected throughout the territory, with a risk of rain anywhere. There is still some uncertainty about the final distribution of the precipitation, a classic in these Mediterranean autumn situations. There will be a risk of some downpours repeating, especially between Tarragona and Barcelona, while towards Ponent, the Costa Brava, and the western Pyrenees, rain will be less likely.

Attention to the Valencian Community and the western half of the Balearic Islands, where rainfall will be heavy and abundant, with a risk of torrential downpours and significant accumulations. AEMET has issued a red warning for the southern coast of Valencia and the north of Alicante for 24-hour accumulations of between 200 and 300 mm. There are also alerts activated for intensity (60 mm in 1 hour).

Here, there will be tramontane in the Empordà and northeasterly wind along a large part of the coast that will accentuate the feeling of cold, with a very rough sea state.

In the Pyrenees, the snow level will drop to 2,000 m or, locally, below. Therefore, the high peaks of the mountain range may become snow-covered. Next week the weather will remain unsettled, with a risk of further precipitation and an atmosphere that will continue to be fully autumnal. Between Monday and Tuesday, an average of 5 to 10 cm may accumulate above 2,000 m in the High Pyrenees and the Aran Valley.