A 30C heatwave set to scorch the UK has led to the year's first heat health alert.
Issued by the Health Security Agency (UKHSA) and the Met Office, the alert covers six regions in England: London, East Midlands, West Midlands, East of England, South East and South West.
It will be in place from 9am on Friday to Monday morning.
Parts of England are predicted to be hotter than Marbella, Ibiza, and Tenerife over the weekend as a "plume of warm air" moves in from the south.
Cloud, rain, and thunderstorms are also set to sweep in, with the nights becoming humid.
Dr Agostinho Sousa of the UKHSA said: "In the coming days we are likely to experience our first sustained period of hot weather of the year so far, so it is important that everyone ensures they keep hydrated and cool while enjoying the sun.
"Forecasted temperatures this week will primarily impact those over the age of 65 or those with pre-existing health conditions such as respiratory and cardiovascular diseases.
"If you have friends, family or neighbours who you know are more vulnerable to the effects of hot weather, it is important you check in on them and ensure they are aware of the forecasts and are following the necessary advice."
The threshold for a heatwave is different across the UK, but in some areas, it is classified as hitting highs of 25C to 28C across a three-day period.
From tomorrow, Storm Oscar, which is currently across the Canary Islands, will push the high pressure further east, causing the mercury to rise to 25C or 26C.
Dan Harris, deputy chief meteorologist at the Met Office, said: "Temperatures will rise later this week and into the weekend, with a plume of warm air being drawn in from the south.
"Coupled with the rise in temperatures is an increase in the likelihood of some potentially heavy and thundery showers, which could bring some localised disruption for some from late on Friday and into the weekend."
So far, the hottest temperature in the UK was 25.1C in Porthmadog, North West Wales, on 30 May, but Simon Partridge, forecaster for the Met Office said the country is "certainly" going to see higher temperatures.
He also said the humidity at night will become "uncomfortable" as some areas will not get below 15C or 16C, compared to about 3C at the start of the week.
Most of Wales is set to see "long sunny spells" on Friday, before temperatures climb to 25C over the weekend when there will be "thundery" showers, the Met Office said.
Northern Ireland and large parts of Scotland will be breezier and cooler than other areas on Friday and Saturday, before heavy rainfall moves in on Sunday.
