Today (Friday) could be the hottest day on record, according to experts.
The Met Office has said temperatures could peak at a sweltering 38C in London, bordering on the 38.7C UK record.
And hot air travelling from the Sahara could potentially push the mercury closer to 40C.
Last week, forecasters predicted no more than 35C for Friday, before temperatures soared to 37.8C, smashing this year's record in what turned out to be the third hottest day ever documented.
And with that in mind, the Met Office's Marco Petagna told the Daily Star : "Forecast models show up to 37C in south-east England on Friday.
"Remember computer models underplayed Friday’s heat.
"But 35C or 36C is most likely, with still in the mid-30s on Saturday."
He added: "It’s scorchio. A heatwave is coming."
While The Weather Outlook forecaster Brian Glaze claims there is a 10 percent chance of Friday beating the 37.8C recorded on July 31.
A 700 mile-wide mass of hot air from Africa’s Sahara Desert has sparked possible highs of 45C in Spain, which could help push Britain up a few notches.
Mr Gaze said: "Blowtorch heat is coming from the Sahara, with around a 10% chance of over 37.8C.
"Computer models show 36C or 37C highs, but often understate extreme high temperatures, as they did by several degrees when last Friday reached 37.8C."
Bristol is set to bake in 28C today, some 2C lower than experts had predicted earlier this week. Tomorrow, temperatures will climb even higher, peaking at a sweltering 29C.
UK weather forecast
Friday:
Cloudy across some western areas with rain moving eastwards across Northern Ireland and Scotland. Periods of hot sunshine elsewhere, and becoming very hot in the southeast.
Outlook for Saturday to Monday:
The weekend will be dry for most with sunny spells. Increasing risk of the odd thunderstorm by Monday. Remaining very warm or hot in the south. Fresher for the north.
