A mass of hot and dry air over the Iberian Peninsula is expected to trigger a “gradual rise in temperature” starting Saturday, with maximum values reaching 38 degrees Celsius in Alentejo and the Tagus Valley, according to IPMA.
According to the Portuguese Institute for the Sea and the Atmosphere, the gradual rise in temperature from Saturday is due to “the influence of a high-pressure system located north of the Azores, which extends crest-like to the Bay of Biscay, promoting the transport of a continental (hot and dry) air mass over the Iberian Peninsula”.
“The maximum temperature is expected to reach values above 30°C across the majority of the mainland territory, approaching 38°C in some locations, notably in Alentejo and the Tagus Valley,” IPMA forecasts.
The minimum temperature, the institute adds, “will also register a small rise, not dropping below 20°C in some areas of Alto Alentejo, Beira Baixa, Tagus Valley and the Algarve’s south coast.”
According to IPMA, this episode of hot weather “will be essentially characterized by its duration, with a high probability of evolving into a heatwave across a large part of the territory.”
“Although the forecast maximum temperatures are lower than those recorded in some episodes this summer, they will be substantially higher than the averages for the second half of September,” it notes.
The institute notes that a heatwave is considered “when, over a period of six consecutive days, the air’s maximum temperature is above 5°C the average of the daily maximum temperatures for a given reference period.”
