Portugal: Heatwave forecast across much of the country through at least July 24

Forecast models indicate a heatwave will persist across much of Portugal through at least July 24. Temperatures of up to 42 C (108 F) are possible in interior parts of mainland Portugal over the coming days.

As of July 22, the Portuguese Institute of the Sea and Atmosphere (IPMA) has issued the following warnings across Portugal over the coming days:

• Orange high-temperature warnings (the middle level on a three-tier scale): Beja, Evora, Portalegre, Santarem, and Ssetubal districts July 22-24 and Braga, Braganca, Castelo Branco, Guarda, Vila Real, and Viseu district July 23-24.

• Yellow high-temperature warnings: Across the rest of mainland Portugal and Madeira July 22-24.

Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

The extended period of oppressive heat and dry conditions may produce ideal circumstances for additional wildfire growth throughout the region. Heatwaves also pose a threat to vulnerable groups - such as the elderly, children, pregnant women, and those with respiratory illnesses - due to the increased possibility of heat stroke or heat exhaustion during prolonged exposure to high temperatures. These health risks could also extend to relatively healthy individuals during significant heatwave events. In addition to significantly impacting athletes and those who work outdoors, high temperatures can cause problems for people using mass transit. The lack of air conditioning and cramped vehicles during rush hour may lead to some passengers being hospitalized for dehydration.

Very high temperatures may warp rail tracks and force passenger and freight trains to operate at reduced speeds. Road surface damage is also possible, and overheated vehicles may worsen traffic problems in urban areas where congestion is already a problem. Commercial trucking disruptions might occur, as very high temperatures put more stress on vehicles, making tire blowouts more common. Major flight disruptions are unlikely at regional airports, but general aviation disruptions are possible, and some airfreight carriers could reduce cargo loads. High temperatures could lead to an increased demand for electricity, which might trigger localized brownouts or blackouts, exacerbating hazardous conditions when air conditioning is no longer possible.