Parts of south-east England have recorded the hottest day of the year after dramatic electrical storms.
Temperatures in Gravesend, Kent, nudged above 32C (90F), beating the previous high of 29.5C, recorded on Thursday, as much of the country enjoyed the sun.
The sweltering heat came after lightning struck the UK more than 3,000 times in the early hours of Friday.
But the Met Office is warning of more storms and, in England and east Wales, flash flooding is on the way.
BBC Weather said storms developing in France on Friday night would move north across the UK but that where exactly would be affected was difficult to predict.
The Met Office has issued a heat health alert for southern England and the Midlands, warning that "heavy thunderstorms in eastern areas on Saturday will lead to slightly lower maximum temperatures, but it will still be very humid".
Public Health England said elderly people and those with long-term illnesses should take particular care.
An amber rain warning issued by the Met Office for England and eastern Wales into Saturday means people should be prepared for possible flash floods.
Environment minister Dan Rogerson said the Environment Agency was working with local councils to prepare for any localised flooding.
"Our priority is public safety," he said. "I urge people to be prepared and act on the advice from the Environment Agency and local emergency services."
John Curtin, the agency's director of incident management, added: "Flooding can happen very quickly and the public are urged to keep checking local weather forecasts and the Environment Agency website for information on a regular basis."
In Gravesend it reached 32.3C.
Over the weekend, the storms forecast could affect the second Test between England and India at Lord's, with spectators warned to expect interruptions.
Public Health England has renewed its advice to people to take care in the heat.
Dr Paul Cosford, director for health protection, said: "While many people enjoy hot weather, high temperatures can be dangerous, especially for people who may be particularly vulnerable, such as older people, young children and those with serious illnesses."
People should stay out of the heat during the hottest time of the day and have plenty of cool drinks, he said.
Meanwhile, London Fire Brigade warned of an increase in grass fires and reminded people not to drop cigarettes in grassland.
The Fire Brigade Union is continuing its strike action across England and Wales, with a further stoppage scheduled from 23:00 BST on Friday until 01:00.
During this period, crews will not attend grass fires unless they present a risk to life or property.
How are you coping with the recent heatwave and thunderstorms? Please share your experiences by emailing email@example.com using the subject line "Heatwave alert".