"On the 9th and 10th [Saturday and Sunday], maximum temperatures will rise and remain high until the 11th [Monday], potentially ranging between 30 and 38 degrees Celsius across most of mainland Portugal and reaching 43 degrees Celsius in some locations, particularly in the interior south and in the Tagus and Douro river valleys," the Portuguese Institute of the Sea and Atmosphere (IPMA) said in a statement.

According to the IPMA, the minimum temperature will continue to exceed 20 degrees Celsius in the interior of the North and Central regions, "extending to the interior of the South during the coming weekend."

Between today and Friday, the IPMA states that there should be a "slight drop in maximum temperature values," which will be more significant on the west coast, "while maintaining the highest values in the interior of the North and Central regions."

"The maximum temperature values, already recorded in previous episodes of hot weather, have been contributing to a heat wave that may continue in some inland areas" the note reads.

The IPMA states that the weather in mainland Portugal is being influenced by an anticyclone located north of the Azores region that is moving "gradually east/northeastward, intensifying and positioning itself southwest of the British Isles" on Friday.

This situation, "together with a depression region between North Africa and the Iberian Peninsula, causes a mass of hot, dry air from North Africa to be transported over mainland Portugal," adds the IPMA.