London - A powerful heatwave is forecast to sweep across Europe's western flank this week.
"It looks like heat will start to build across Iberia later this weekend and spread northwards across France early next week," Britain's weather forecasting Met Office said yesterday on its website.
Temperatures across Portugal and Spain and southern France could reach 40 deg C or more by mid-week and almost that level in northern France.
"The UK is likely to be near the boundary between this tropical continental airmass and a tropical maritime airmass over the Atlantic, but we do expect to see temperatures rise across the whole of the UK for the start of July," the Met Office said. Temperatures in southern Britain could rise to more than 30 deg C at the start of the week - relatively high for this time of the year.
London's revered Time Out magazine thought it best to issue a series of warnings to city residents, including to people tanning in their underwear in the capital's parks.
The authorities in Portugal, meanwhile, increased the alert level to orange, the second highest on a scale of four, for five regions, cautioning the public about increased temperatures and the risk of forest fires.
France was bracing itself for possibly the worst heat for this time of the year in more than 60 years. "Minimum and maximum temperatures will be very high, sometimes reaching records" in south-western regions of France until the end of the week, Meteo-France said.
The forecast heatwave has prompted concern about increased pollution risks and strains on healthcare. Airparif, the organisation which monitors air quality in the Paris region, has warned that levels of ozone in the atmosphere could be higher than recommended.
The French Health Ministry has also warned of the risks from dehydration and heat strokes. In 2003, a heatwave in Europe led to 70,000 deaths above the normal rate, mainly among the elderly.