“Tropical nights” also expected in the Algarve
Maximum temperatures in mainland Portugal will be above 30ºC from Friday and could reach 37ºC, around 5 to 8º C above the average for the month of September.
This generalised rise in temperature accompanied by a decrease in relative humidity will contribute to a worsening of the danger of rural fires, especially in the Algarve and inland regions, according to meteorologist Ângela Lourenço, from the national meteorological institute, IPMA.
From Friday, the weather on the mainland will be influenced by an “intense anticyclonic ridge localised over Western Europe, associated with the transport of a mass of hot, dry air originating in North Africa”.
“This episode of hot weather in mainland Portugal will be felt mainly on Friday and Saturday. So far, maximum temperatures close to or over 30ºC have been recorded in some regions of the country,” she said.
However, Ângela Lourenço emphasised, from Friday and Saturday there will be a significant rise, which means that maximum temperatures, particularly in the south and the Tagus Valley, could reach between 35 and 37ºC.
“These figures are higher than normal for the month of September. Although absolute maximum temperature levels are not expected to be comparable to episodes that occurred during the warmer months, the predicted figures correspond to anomalies of up to around 5 to 8ºC above the usual averages for this time of year,” she emphasised.
As far as minimum temperatures are concerned, Ângela Lourenço said that they will rise and nights of 20ºC or more may be recorded, which the IPMA characterises as tropical nights in some places, especially on the coast of the Algarve region.
“This hot weather situation should persist until the beginning of the week, until October 3. From then on there is some uncertainty as to whether this persistence of high temperatures will continue or not. In any case, even if there is a drop in temperature, the figures will remain above average for the time of year,” she said.
According to Ângela Lourenço, if the scenario of the influence of the anticyclonic ridge persists and the episode of hot weather continues for more days, especially in the south, a heatwave could occur.