An amber weather warning for extreme heat has been extended by the Met Office, with forecasts suggesting temperatures could reach 38C (100F) in parts of England later next week. The updated warning will be in force from Monday morning through to Thursday evening, reflecting growing confidence in exceptionally hot and humid conditions persisting.

Large swathes of England and Wales are covered by the warning. The heat is spreading from continental Europe, where an intense heat spell has developed, with temperatures in parts of western France predicted to climb to 43-44C and Paris potentially reaching an unprecedented 40C for June.

The Met Office anticipates daytime temperatures exceeding 30C widely across the warning area, with the hottest spots potentially hitting 38C. Overnight temperatures are also forecast to remain unusually high, with some urban areas expected to stay above 20-21C, leading to "tropical nights."

Population-wide impacts are likely, including serious health risks, disruption to daily routines, and increased pressure on infrastructure. The Met Office states that adverse health effects are probable not only for vulnerable groups but for the general population.

For a hot spell to officially be classified as a heatwave, temperatures must exceed a varying threshold (25-28C) for three consecutive days. An amber warning was already in place for Monday and Tuesday across parts of England and Wales, where temperatures were expected to reach the low to mid-30s. This warning will now extend further north and west for Wednesday and Thursday.

Substantial changes to working practices and daily routines may be necessary. Heat-sensitive systems and equipment could be affected, and concerns exist about increased demand on transport and energy networks. The UK Health Security Agency has also issued heat-health alerts across parts of England.

There is also a heightened risk of water safety incidents as more people seek to cool off at beaches, rivers, and lakes. High UV and pollen levels are anticipated in many areas.

Very hot conditions are expected to continue until at least Thursday across much of England and Wales. Temperatures above 30C could persist for several consecutive days, with overnight temperatures remaining exceptionally high.