Chris Fawkes
BBC Weather presenter

Thunderstorms are made from air rising quickly through the atmosphere. The sun heats the ground strongly during our summer months and this heats the air up near the ground.

This bubble of warmed air will become more buoyant and will rise upwards through the atmosphere. As the air rises upwards, it cools down.

Moisture in the air can then turn into water droplets and ice crystals. These can sometimes make thunder clouds.

The ice is important for making lightning and the cracks of thunder we hear.

Summer thunderstorms have much more energy in them, so can give us impressive lightning displays, flooding rain or sometimes large hail.

Yellow warnings for thunderstorms are in place in northern England and Northern Ireland into this evening, and in Scotland into the early hours of tomorrow morning.

Danny Savage
North of England correspondent

Image source, BBC Weather Watchers/@LizzieMcK

Live weather radar is showing thunderstorms now developing over parts of northern England.

In western parts of North Yorkshire, where car thermometers have been showing 31C outside, permanent rolling thunder has been heard for a while.

Not the odd rumble with a gap, just constant.

The storm is drifting north-eastwards.

As we reported earlier, thunderstorms are expected to develop through the day in Scotland, Northern Ireland and northern England with the threat of flash-flooding and some large hail.

Sheffield’s tram network has been suspended due to the heat, its operator says.

"While we have experienced high temperatures throughout the week, this afternoon’s forecast is the highest we have seen, and we have therefore taken the decision to temporarily suspend tram services across the network," a spokesperson for Supertram says.

The operator says it will monitor temperatures throughout the afternoon, with services resuming "once conditions have improved".

The M5 in Somerset has reopened in both directions following a defect with overhead power lines.

National Highways warns that there are delays of 160 minutes and 10 miles of congestion in both directions, adding that this will begin to ease.

Image source, Getty Images

As the heatwave persists, a 'cool space' map in London is helping people find somewhere to take respite from the heat.

Through the map, external, those in England's capital can seek shelter in the cool spaces, ranging from the O2 and the Royal Opera House to the Imperial War Museum, churches, community centres and libraries.

Inside they will find cooler temperatures - some have air conditioning - free seating and water, and toilet facilities.

At a minimum, the spaces are open five days a week from 10:00 until 17:00, according to the website.

They can be found across the city, with the map also showing places covered by tree canopy, and areas where the surface temperature is generally cooler.

Michael Race
Business and economics reporter

Image source, Getty Images

Unsurprisingly, as temperatures have soared, sales of fans and air conditioning units have spiked as people seek to stay cool. A quick online search shows many retailers of portable air con units are out of stock.

Covid-era queues were seen outside some Lidl supermarkets ahead of opening hours on Thursday as shoppers flocked to the middle aisle before they sold out. The retailer Curry's told the BBC that it saw air conditioning sales increase 330% in the space of a week.

Lincoln Smith, managing director of Custom Heat in Warwickshire, says he is planning to change his company name due to a steady rise in his business fitting more air conditioning units in homes over the past five years.

"There is a significant demand coming for home comfort and air conditioning," he tells the BBC's Wake Up To Money, adding that because demand is so high, some of his suppliers are saying they won't be able to get units until after the summer.

"We are having to diversify and use other manufacturers to keep up with demand."

Image source, National Highways

The M5 in Somerset is closed in both directions between J22 and J23 due to a risk that overhead electricity cables could fall into the road.

There are currently delays of 115 minutes, with up to 8 miles of congestion both ways, according to National Highways.

National Grid engineers are carrying out "essential repair work" following the fault in the area between Highbridge and Puriton, and it will "reopen the road as soon as it is safe to do so", National Highways reports.

On Wednesday, more than 10 people were taken to hospital for "minor and heat-related conditions" after huge queues of traffic built up on the M25 during the red heat alert following a serious crash between a van and a lorry.

• Stay up-to-date with the M5 closure

As we've just reported, Wattisham, Suffolk has set a new provisional June record temperature of 36.9C.

Here are the highest temperatures recorded in the other UK nations so far today:

Scotland - Eskdalemuir, 28.6C

Wales - Hawarden, 34.0C

Northern Ireland - Katesbridge, 24.1C

Image source, BBC Weather Watchers/@DesM

Jacob Phillips
Live reporter

Image source, Reuters

The June heat record for the UK keeps getting pushed higher.

For the third day in a row the record has been broken for the hottest June day, and the Met Office has warned that temperatures are still rising.

Here's a reminder of the numbers behind the record-breaking heatwave:

Wednesday 24 June

The 50-year-old record was toppled when it reached 36.1C in Gosport, Hampshire, beating the previous highest temperature of 35.6C recorded in Southampton in 1976 and Camden in 1957.

Thursday 25 June

Temperatures of 36.7C were recorded at Merryfield, Somerset, breaking the previous day's record.

Friday 26 June

Temperatures reached 36.9C in Wattisham, Suffolk, setting another new provisional record.

There will be respite however by Sunday, with the Met Office forecasting that many areas will be at least 10C cooler than today.

Friday is the provisional hottest June day on record as 36.9C is recorded in Wattisham, Suffolk, the Met Office says.

This passes the previous record which was set on Thursday when 36.7C was recorded in Merryfield, Somerset.

Image source, EPA

Various museums and tourist attractions have had to make adjustments to manage the soaring temperatures.

Here's what we've seen so far:

Tower Bridge is closed to visitors. The Cutty Sark and Royal Observatory in Greenwich are also closed. The Victoria and Albert Museum has shut some galleries, and the Young V&A is closed until Sunday. The British Museum has warned it may have to close some galleries.

Marwell Zoo in Hampshire has closed its 140-acre site. Thorpe Park, Chessington World of Adventures and Legoland Windsor and are allowing people to swap their tickets for a different day.

Plus, some Greggs stores have also closed during the heatwave, with 11 sites shut since Wednesday.

This comes on top of school closures, with more than 600 shutting in England fully or partially today.

Vanessa Clarke
Education reporter

More than 600 schools in England have either closed or partially closed again today.

The Department for Education doesn’t publish a list of schools that have closed during the heatwave, so the figure is only an estimate and is likely to be much higher.

We’ve been looking at individual councils’ websites in areas most affected by the heatwave and counted 677 that have fully or partially closed, or that have offered parents the option to pick their children up early.

Most schools have stayed open, although many academy trusts are reporting lower attendance this week.

Catherine Burns
Health correspondent

A nurse working in a hospital in the Midlands who contacted the BBC through Your Voice says her ward has been transformed into a "wall of heat".

She also describes the ward as "terrible" and "intolerable" but is having to push on through for the patients.

Meanwhile, a midwife tells me there’s no air conditioning in the post natal ward - so mums and new babies are trying to cope with temperatures over 30C (86F).

An A&E doctor also tells me the heating is still on in some parts of their hospital, with no air conditioning and windows that do not open.

They say staff are getting irritable, while patients are in “hot, cramped and chaotic” conditions, and some are becoming abusive.

The hot weather has ushered thunderstorms into the UK, sparking dramatic displays of lightning around the country.

As of 10:00 this morning, more than 63,000 lightning strikes had been recorded in a 24-hour period, the Met Office says.

A second lightning storm in five days was in the west of England, with one strike causing a fire at a nursing home in Glastonbury.

Image source, Matthew Harris

Around 32,000 lightning strikes have been seen in Scotland in the last 24 hours.

The thundery weather came after Scotland recorded its hottest day of the year on Thursday, with temperatures peaking at 31.2C in Threave, Dumfries and Galloway.

Image source, BBC Weather Watchers - Alice E

Similar displays were also seen in the island of Ireland as many watched in awe as almost 9,000 strikes lit up the skies, during a "once-in-a-lifetime" experience, one resident said.

A dramatic lightning display lasted more than an hour and was witnessed mostly in Counties Londonderry and nearby Donegal, in the Republic of Ireland.

Image source, Patryk Sadowski

Over in Wales, lightning forked and tore across the sky in Pembrokeshire.

Wales recorded its hottest June day and highest temperature of the year so far on Thursday when 35.9C was recorded in Bute Park, Cardiff.

Image source, Debra Angel

Orange lightning strikes were also seen close to Mont Orgueil Castle in Jersey in the Channel Islands.

Image source, Andrew Battersby

As we've just told you Cavendish in Suffolk was the hottest place in the UK at midday, with a temperature of 35.8C.

Just behind that was Santon Downham, in Suffolk, which recorded 35.2C.

Elsewhere, Kew Gardens in London recorded 34C, as did Cambridge.

London's Heathrow Airport saw temperatures of 33.7C, and Bedford 33C.

Coventry recorded 32.5C and Nottingham 32.2C.

Chris Fawkes
BBC Weather presenter

The hottest place at midday is Cavendish in Suffolk at 35.8C

Some patches of cloud will probably cap the temperatures in south-east England at about 35C this afternoon.

The highest temperatures today look most likely in Norfolk or Suffolk this afternoon with temperatures perhaps going as high as 37C or even 38C.

The chase is on then for beating the all-time June temperature of 36.7C provisionally recorded yesterday at Merryfield, Somerset.

Police searching for a missing boy who was reported to have entered a lake in Leicestershire have recovered a body.

Officers were called to Meynell Lake, just after 13:30 BST on Thursday, after reports that a teenage boy had gone into the water, Leicestershire Police say.

Police divers were called in to assist with the search for the boy, who has not been named, alongside fire and rescue, and ambulance services.

Leicestershire Police said a person recovered from the water is confirmed to be the missing teenager and his family are being supported by specially trained officers. They say "there is no suggestion of any suspicious circumstances".

Image source, Chelsea Claw

If you're just joining us, or want a quick catch-up, here's the latest.

Thunderstorms have hit parts of the UK – with yellow warnings in place for more storms in northern England into the evening, and Scotland into the early hours of tomorrow morning. These alerts come with warnings about potential flash flooding and disruption to transport.

In London and south-east England, a red extreme heat warning is in place until 21:00 BST. We’ve heard warnings that pavements in parts of the capital have seen temperatures hit 57C. This morning, the London Ambulance Service said 999 calls had increased 50% during the heatwave.

The mercury had already hit 30.5C at Heathrow by 09:00 BST.

The hottest temperatures are still yet to come - our weather team expects that we could see 35-37C this afternoon, in East Anglia or south-east England.

Michelle Roberts
Health editor

Image source, Getty Images

After days of record-breaking temperatures around Europe, officials have warned people to adjust their behaviour - even fit, young people - as health services report a sharp rise in life‑threatening emergencies.

In London, the ambulance service faced its busiest day on record this week, with cardiac arrests up nearly a third, and is urging people to drink responsibly and avoid exercise outside.

Parisians, meanwhile, will be restricted from drinking alcohol in public from noon through the night on both Friday and Saturday.

Extreme heat puts immense physical strain on the body - made worse if you are dehydrated from drinking alcohol - with the heart pumping harder and faster to cool you off.

• Read more on this story