Summer finds it hard to say goodbye to Spain, despite the fact that the astronomical autumn began last Saturday and the meteorological one, on September 1. This week "stable weather will predominate, with generally cloudy skies and absence of rainfall in most of the territory," Rubén del Campo, spokesman for the State Meteorological Agency (Aemet), said Monday. This stability will trigger temperatures, which "will experience a progressive rise" and that, especially from Thursday, will be clearly higher than usual for the time of year, "with daytime values that could exceed 30 ° in large areas and even 32 ° to 34 ° in points of the southern half of the peninsula.
Is it the usual last blow of the heat, popularly known as veranillo de San Miguel? No, it's worse. "It is a very warm situation for the time, with values between 5° and 10° above normal, more typical of late August than late September or early October," contextualizes Del Campo. Thus, the episode will be "more powerful" than a normal summer, "especially on the weekend and until Monday or Tuesday." It is also possible that it will last longer than usual, which is usually only a few days, although at the moment it is not clear how long it will last. "As it began last weekend and will last until the beginning of next week, it will have been 10 days of summer," says the expert. "As projected by climate models, the new summers of San Miguel arrive, exacerbated by anthropogenic climate change," says Aemet researcher Juan Jesús González Alemán.
This is the day-by-day prediction
This Monday will be a quiet day, with some weak rain only in the northwest of Galicia and with temperatures rising in most of the country. "In Badajoz, Cordoba, Granada and Seville values of 33 ° to 35 ° will be reached," exemplifies the spokesman.
On Tuesday, another day of stable weather, with "skies in general little cloudy, although they will be somewhat cloudier in the Cantabrian, where there could be some weak and scattered precipitation." Temperatures will not vary too much, except for a slight drop in the northwest. The maximum will exceed 25° in most of the territory and 30° in the southern half. In the interior the dawn will still be cool: in areas of the northern plateau and moors of the center such as Palencia and Teruel will be around 10 ° in the early hours.
This #VeranilloDeSanMiguel will last at least 10 more days, until the first days of October:
➡️ Little cloudy or clear
➡️ 🌞skies Maximum temperatures typical of summer 🌡️ pic.twitter.com/qk5gucW0hL
— AEMET (@AEMET_Esp) September 25, 2023
On Wednesday, more of the same, although a front will brush Galicia and leave weak rains in the northwestern end of this community. In addition, strong wind will blow there and in the Strait. In the rest of the country, "morning fog banks, also intervals of low clouds in the morning in inland areas, but in the afternoon it will be clearer" are expected. The winds will blow from the southwest, which will raise temperatures in the eastern Cantabrian Sea to 30°, with a very high risk of fires in much of the Cantabrian coast. It will also exceed 30° to 32° in cities in the northeast of the peninsula such as Zaragoza or Lleida, and in the southern half, with points of the Guadalquivir such as Seville and Córdoba at 34°.
During the second half of the week the temperatures will continue to climb "slightly but progressively" and the atmosphere "will be very warm for the time in most of the country, especially in the peninsular interior and during the central hours of the day". Thus, the 25° will be widely exceeded and in the northeast and the southern half, the 30°, even the 32° to 34° in the Guadalquivir. The skies will be little cloudy and "an almost total absence of precipitation, although the passage of fronts could entangle the skies in the far north", with some weak rain in Galicia.
To know the thermal character of an air mass, its temperature is usually analyzed at about 1500 meters of altitude. Well, at the end of this week and the beginning of the next, warm record values could be reached over the Peninsula. pic.twitter.com/rNHIqGPdcz
— AEMET (@AEMET_Esp) September 25, 2023
As of Thursday, it will be "an episode of high temperatures for the time" because of an atmospheric stability propitiated by a high pressure ridge that guarantees little cloudy skies and, also, that there is no mixture in the air mass, so that the sun effectively heats the surface. " At the same time, "within this ridge subsidence phenomena occur, which consist of a descent of air from the middle and high levels of the troposphere to lower areas. This causes the air to compress and heat up in its path.
In addition, these mechanisms "will happen within a mass of very warm air for the time, which will reach Spain from lower latitudes," explains Del Campo. This mass could "reach record values" for the date, according to Aemet. "There is a high probability that a historic anticyclonic ridge will develop in the coming days," adds González Alemán. And how long will it last? In principle, this episode will last throughout the weekend and "would last until Monday or Tuesday of next week, but there is still a lot of uncertainty," details the Aemet spokesman.
Meanwhile, in the Canary Islands will predominate during the next few days "a regime of moderate trade winds with some strong intervals, especially in exposed areas". There will be cloudy intervals in Lanzarote and in the north of the islands of greater relief, without ruling out some weak rain in the north of the more mountainous islands. Temperatures will remain unchanged, although they could also rise for the weekend.