Two inches of rain are set to lash the UK within hours as thundery downpours are forecast to descend on Britain after the hottest day of the year.
A ‘danger to life’ warning is in force across much of England and Wales, with the Met Office saying parts of the country could be hit by flooding and power cuts.
Meteorologists warned heavy showers and thunderstorms are on their way in southern England, where between two and four inches of rain could fall in an hour.
Torrential downpours are set to be accompanied by ‘gusty winds, frequent lightning and large hail’ – and could continue throughout the night.
While rain from the morning has partially cleared, a yellow warning for thunderstorms still covers the majority of England and Wales for the whole day.
But the weather is set to be muggy as high temperatures persist, predicted to reach highs of 29C around London.
It comes after the country was beset by scorching weather – with the mercury soaring to highs of over 31C yesterday in Brize Norton, Oxfordshire.
The Met Office said: ‘Scattered slow-moving heavy showers and thunderstorms are expected to develop through this afternoon and evening, particularly across parts of central and southern England, and perhaps also east and southeast Wales.
‘Whilst not all areas will see them, where they do occur torrential downpours could produce 50 mm or more in 1-2 hours, with a small chance of isolated 100 mm accumulations where multiple showers/storms move over the same area during the course of a few hours, leading to the risk of surface water flooding.
‘In addition, thunderstorms may be accompanied by gusty winds, frequent lightning and large hail.
‘Showers and thunderstorms will only slowly fade through the evening hours, and may persist or even re-develop during the overnight period in parts of eastern England.
Tuesday was the UK’s warmest day of 2024 so far with a temperature of 32.0C (89.6F) recorded in London at both Kew Gardens and Heathrow Airport.
There is a small risk of more than two inches of rainfall in two to three hours which could be accompanied by frequent lightning, the Met Office added.
The Met Office predicts heavy and thundery showers across parts of Wales, the Midlands and northern England which will ease towards midday.
Scattered heavy showers and thunderstorms are expected across this afternoon and evening across parts of central, southern and eastern England and South Wales which could produce two inches of rain or more in one to two hours as well as gusty winds, large hailstones and the risk of flooding.
Met Office meteorologist Simon Partridge said: ‘The problem is that the winds are very light as well, so where you see those heavy thundery showers, there’s not really much wind to blow them through as often as when you have showers and it’s a fairly breezy day – you don’t get much of the rain from one particular shower.
‘Where those thunderstorms occur, that local area will probably get pretty much all of the rain that that thunder cloud is holding – so there could be very locally heavy downpours which bring along the risk of localised flooding and surface water problems for transport networks.’
Among the storms, there will be ‘a lot of fine, dry and sunny weather’ and Thursday will feel ‘very warm, very humid and very muggy’, he added.
Highs of up to 30C are expected from Hampshire up to north London while western Scotland is predicted to experience the coolest temperatures of the day of between 17C and 18C.
Friday is forecast to be ‘mostly dry with plenty of sunny spells’ with temperatures of up to 28C followed by ‘generally dry and still quite warm’ weather over the weekend, Mr Partridge added.
Dan Holley, a Met Office deputy chief forecaster, said yesterday: ‘The Met Office has issued a thunderstorm warning over a broad geographical area but not all locations will see impacts.
‘The most intense impacts are likely to be focussed on central, southern and southeast areas of England. Here some locations will witness torrential downpours, large hail and frequent lightning. A few places could see 50-100mm of rainfall in a few hours.’
The average August rainfall in England is 2.95 inches.
Forecasters said there could be road closures, train delays and power cuts due to the storms.
They also said in tomorrow’s warning that there is ‘a small chance that homes and businesses could be flooded’ and cause ‘a danger to life.’
But the heat is not set to last into the weekend with temperatures set to return to the mid-20Cs in the South as a band of rain moves through the country on Saturday.
The Met Office has also confirmed that Britain is currently experiencing an official heatwave and that it is likely to remain very warm for the next few days.
Met Office meteorologist Becky Mitchell added that the heatwave began on Monday, and ‘we’re in the midst of it now as we expect temperatures to continue to be high in the coming days’.
Heatwave criteria is when a location records a period of at least three consecutive days with daily maximum temperatures meeting or exceeding the heatwave temperature threshold, which varies by region but is 28C (82F) in London.
Yesterday, a fire broke out in Orpington, South East London, with four fire engines and around 25 firefighters called to a field where four hectares of straw were ablaze.
The UK Health Security Agency has issued yellow heat health warnings for all areas of England, except the North East and North West, until 9am on Friday.
It warned the expected hot weather may have ‘significant impacts’ on the health and social care sector across the south east and London, with minor impact elsewhere.
Conditions are likely to impact the ‘vulnerable’, such as the elderly and those with multiple health conditions.
To cope with warm evenings, the Met Office has urged Britons to keep their homes as cool as possible.
It said: ‘Overnight temperatures are going to be very high so it’s quite hard to cool houses down in that situation because you don’t have the relief overnight and temperatures dropping.
‘If you can open your windows at night, try to let some of the cooler air in and keep curtains or blinds shut during the day’.
The UK’s hottest day of the year before yesterday was July 19 when a temperature of 31.9C (89.4F) was recorded at St James’s Park in London. The previous record high for 2024 before that was 30.5C (86.9F) in Wisley, Surrey, on June 26.
Aldi expects to sell 12million ice creams and lollies this week, and shift 1.7million individual ice cream sticks, lollies and cones per day during the hot weather spell.