Temperatures above 40C and tropical nights this week, warns IPMA

From Monday, central and southern inland districts are on yellow alert, extending to Trás-os-Montes on Tuesday and the rest of mainland Portugal on Wednesday. By week’s end, temperatures could reach 43 °C in the Tagus valley and Alentejo. The start of July will bring mainland Portugal a prolonged heatwave, with tropical nights, sending temperatures soaring to 43°C in some parts of the country. According to the Portuguese Institute for Sea and Atmosphere (IPMA (source in Portuguese)), the cause is an 'anticyclone located to the north/northwest of the Azores archipelago' that will pull in a 'very hot, dry air mass'. Average temperatures are expected to run between 3°C and 7°C above normal across the mainland, the IPMA added, highlighting increases of 5°C to 7°C in the central region and Alentejo. The 40°C mark will be exceeded from Wednesday in the Alentejo districts, with the high temperatures then spreading to parts of the remaining regions by the end of the week, meteorologists warn. In inland Alentejo, daytime highs will remain above 40°C from 1 to 7 July, at least. Unlike during the late-May hot spell, the coast is also expected to be affected by the high temperatures, especially from Wednesday, with highs between 35°C and 38°C. 'The afternoon sea breeze along the coast will be weak, allowing unusually high temperatures to be recorded in places where they are not common,' the IPMA noted. The situation will be compounded by tropical nights. Minimum temperatures will range between 12°C and 17°C at the start of the week, but are expected to exceed 20°C in inland areas from Tuesday and in the other regions from Thursday. Yellow warnings issued In view of what it describes as 'a prolonged spell of hot, dry weather', the IPMA has issued yellow warnings for the districts of Guarda, Castelo Branco, Portalegre, Évora and Beja from Monday. On Tuesday, these warnings will be extended to Bragança and Vila Real, coming into force in the remaining mainland districts from Wednesday. This weather pattern is, however, expected to be reviewed. Because of the 'long duration of this hot spell', the IPMA warns, 'it is highly likely that the warning level will be raised in several districts in updates over the coming days'.