Exact reason why thunderstorms happen after hot weather

Exact reason why thunderstorms happen after hot weather Parts of the UK will stop seeing the sunshine and start experiencing thunder, lightning and rain This week has seen some crazy temperatures with highs of almost 40C across the UK. While some parts of the UK, like London, are still seeing sunshine, other areas are now experiencing thunder and lightning. But why is it that we experience thunderstorms after hot weather? According to the BBC, "thunderstorms start inside a cloud when it's high up in the atmosphere where the air is cooler than the air below it. Bits of ice move up and down and bump into each other inside the cloud. This builds up an electric charge. "If the charge builds up enough it can suddenly flow as a huge current of electricity - either between the cloud and the ground, or between different clouds. We see this as a really big spark and it's what we call lightning." When lightning flashes, it heats the air around it to about 10,000C - almost twice as hot as the surface of the Sun. The air gets hot so quickly that it expands with a bang, creating a huge vibration in the air. That vibration is what we hear as thunder. You may think that thunder and lightning happen at the same time. But it does not. In fact, because light travels around a million times faster than sound, you will always see lightning before you hear thunder. Why does thunder and lightning happen after a heatwave? The experts explain that thunderstorms begin with warm air. This often happens after a long spell of hot weather, such as a heatwave, when the Sun has heated both the ground and the air above it. As the warm air rises through the atmosphere, it cools and condenses into tiny water droplets. These droplets start moving in the cloud, and if the atmosphere is cold, they will start rising even further up into the atmosphere. When the atmosphere is unstable, thunderstorm clouds, known as cumulonimbus clouds, develop. Cumulonimbus clouds are the only type of cloud capable of producing thunder, lightning and hail. Met Office thunderstorm tips The Met Office has forecast thunderstorms across parts of the UK, bringing thunder, lightning and heavy rainfall. In response, experts are urging people to take precautionary measures to protect both themselves and their property from potential damage and disruption. It advises: - Check if your property is at risk. If you are at risk, prepare a flood plan and prepare an emergency flood kit - Check the flood advice in your area to know when and where flooding will happen - Charge mobile phone devices - Park your car outside the flood zone - Prepare a flood kit to help you cope in the event of flooding to your home and business - Store valuables up high, including electrical devices, important documents and furniture - Turn off gas water and electricity supplies - It is safer not to drive in thunderstorms but if you must drive you can do this more safely by slowing down, using main roads and dipped headlights, giving yourself more time to react on slippery surfaces and keeping a bigger gap between vehicles - Prepare for powercuts - Protect your property and your neighbour's too by checking for loose items outside your home and if you can, secure them. Items you should think about include bins, plant pots, garden furniture (bring inside or secure in place) , trampolines (turn upside down or secure with tent pegs) and sheds (ensure doors are locked). The Met Office warns: "Don't go outside to repair any damage during the storm." For more tips on how to stay safe during a thunderstorm, visit the Met Office website.