The Met Office has issued a yellow thunderstorm warning for large parts of England as temperatures hit 30C for the first time this year.
The map shows where thunderstorms are likely to hit this weekend, based on forecasted heavy rain and heat.
Heathrow recorded 30.5C on Saturday as warm air from the south sent temperatures soaring.
Two thunderstorm warnings are in force on Saturday and Sunday, covering the cities of Manchester, Cardiff, London and Glasgow.
The Met Office has warned that there is a “high risk” that homes and businesses in the affected areas will be flooded by the heavy rain.
Warnings for much of England on Saturday
(UK Met Office)
The second warning came into effect on Sunday, covering large swaths of Scotland and England
(UK Met Office)
Spray and excess water on roads could also cause delays in car travel, it added. There is also little chance of power outages and rail service cancellations.
Authorities have issued heat warnings for the weekend, with temperatures set to peak at 31C in south-east England.
Large swaths of the UK are expected to be hotter than Marbella, Ibiza and Tenerife over the weekend as a “thermal air” blows in from the south.
The scorching forecast prompted the Met Office and the UK Health Safety Agency to issue their first heat warnings of the year.
Dr Agostinho Sousa, from the UKHSA, said: “Over the next few days we are likely to experience our first sustained hot weather so far this year, so it is important that everyone ensures they stay hydrated and cool while enjoying the sun.
“This week’s temperature forecast will mainly affect people over the age of 65 or those with pre-existing medical conditions such as respiratory and cardiovascular disease.
“If you know friends, family or neighbors who are more likely to be affected by hot weather, it’s important to get to know them and make sure they know the weather forecast and follow the necessary advice.”
A 30C heatwave set to scorch the UK, leading to the first Heat Health Alert (PA) of the year
(PA line)
According to the Met Office, warm air from the south is expected to raise temperatures but also bring the possibility of thunderstorms with hail and gusty winds.
Chief meteorologist Frank Saunders said temperatures could reach 31C in parts of central and south-eastern England on Saturday, with heavy rain possible.
“Thundershowers will continue into Saturday afternoon as the heat builds up in the south,” he said. “While not everyone in the warning area will experience the heaviest showers, or even rain at all, some will bring downpours.
“In the case of heavy showers, there is a risk of surface water flooding that could cause some damage.”
