Why do thunderstorms happen after hot weather? The weather bureau explains how it issues a yellow warning

After surviving two days of record temperatures, the British now have to prepare for an onslaught of thunderstorms and possibly even floods.

with office issued a yellow thunderstorm warning for much of the south east of England from today, including LondonEast Anglia and East Midlands.

A yellow storm warning means the weather will cause some “minor impacts”, including road closures and possible train cancellations.

Britain just experienced the hottest day on record this week when temperatures topped 104°F (40°C) for the first time.

Yesterday, the Met Office recorded a provisional reading of 40.3°C (104.5°F) at Coningsby in Lincolnshire at 15:00, a record high.

The Met Office issued a yellow warning for thunderstorms across much of the south of England on Wednesday afternoon and evening.

WHAT IS A YELLOW WARNING?

On Wednesday, the Met Office issued a yellow warning for thunderstorms across much of the south of England this afternoon and evening.

The Met Office issues color-coded weather warnings when severe weather could affect people in the UK.

A yellow storm warning means the weather will cause some low level impacts, including some traffic obstruction in several locations.

What to expect:

– Splashes and flash floods can lead to difficult driving conditions and road closures.

– In the event of flooding or lightning strikes, there may be delays and some cancellations of trains and buses.

– There is a small possibility that power outages may occur and other services for some homes and businesses may be lost.

Wednesday will be cooler overall, around 25°C in many places, but accompanied by thunder, lightning and heavy rainfall that could lead to flooding.

Members of the public have already seized some amazing photos thunderstorms that lasted from Tuesday evening to Wednesday morning.

But the yellow warning means the storms could cause “low-level strikes” starting Wednesday afternoon and continuing into the evening.

Thunderstorms tend to happen after hot weather, such as heat waves, because the atmosphere is “unstable,” according to the Met Office.

It defines an unstable atmosphere when warm air exists under much colder air, as in the case immediately after a heat wave, when there is a lot of heat near the ground.

Warm air naturally rises and in doing so cools and condenses to form small water droplets and a dense, towering vertical cloud called a cumulonimbus cloud.

As the warm air continues to rise, the water droplets combine to form larger droplets that freeze to form ice crystals.

“As a result of air circulation in clouds, water freezes on the surface of a drop or crystal,” explains the Met Office.

“Eventually, the droplets become too heavy to be supported by updrafts of air, and they fall in the form of hail.

“When hail travels inside a cloud, it builds up a negative charge by rubbing against smaller, positively charged ice crystals.

A thunderstorm has three stages in its life cycle.  In the first stage, the cloud is pushed upwards by an ascending column of air (updraft).  Further, precipitation begins to fall from the storm, creating a downdraft (a column of air pushing down).  When the descending and rain-cooled air spreads across the land, gusty winds are formed.  This second phase is the most likely time for hail, heavy rain, frequent lightning, high winds, and tornadoes.  Eventually, a large amount of precipitation falls and the updraft is overcome by the downdraft.

A thunderstorm has three stages in its life cycle. In the first stage, the cloud is pushed upwards by an ascending column of air (updraft). Further, precipitation begins to fall from the storm, creating a downdraft (a column of air pushing down). When the descending and rain-cooled air spreads across the land, gusty winds are formed. This second phase is the most likely time for hail, heavy rain, frequent lightning, high winds, and tornadoes. Eventually, a large amount of precipitation falls and the updraft is overcome by the downdraft.

“A negative charge forms at the base of the cloud, where hail accumulates, while lighter ice crystals remain at the top of the cloud and create a positive charge.

“Negative charge is attracted to the surface of the Earth, other clouds and objects.

“When the attraction gets too strong, the positive and negative charges combine or discharge to balance the difference in a lightning flash, sometimes called a lightning strike or thunderbolt.”

The rapid expansion and heating of the air caused by lightning is accompanied by loud peals of thunder.

We hear this pop a few seconds after the flash of lightning for the simple reason that light travels faster than sound.

Warm air naturally rises and in doing so cools and condenses to form small water droplets and a dense, towering vertical cloud called a cumulonimbus cloud (pictured).

Warm air naturally rises and in doing so cools and condenses to form small water droplets and a dense, towering vertical cloud called a cumulonimbus cloud (pictured).

In the UK, thunderstorms are most common in the East Midlands and South East, but are common worldwide.

They are most common in areas of the globe where the weather is hot and humid, such as the southeastern United States, including Florida.

The Met Office also lists ways to stay safe during a thunderstorm, as a lightning strike can be fatal.

Once outside, people should avoid water and find low-lying, open areas at a safe distance from trees, poles, or metal objects.

If you are in a car, close the windows and stay inside because the metal frame will act as a conductive cage, passing current around the passengers inside and to the ground.

Drivers should also slow down if possible, as this will shorten the distance you can travel when the wind shakes you.

“Vulnerable” road users, including cyclists, motorcyclists and pedestrians, should also be given more space than usual as they are more likely to be blown away by the wind.

It’s also a myth that lightning never strikes the same place twice – this often happens, especially if it’s a tall and isolated object like the Empire State Building.

The Met Office says, “Lightning strikes the best conductor on earth, whether it has struck before or not.”

LONDON IS BURNING! HOW FIRES START AND HOW TO EXTINGUISH THEM – HOW FIRES FLASH IN THE UK BECAUSE OF THE HEAT

Countries across Europe, including the UK, are battling a string of catastrophic wildfires that are flaring up due to the current heat wave.

Wildfires are starting all over southern Europe, including in Spain, Italy, France and south of England.

In the UK, the London Fire Brigade announced a “major incident” on Tuesday in response to a huge surge in fires across the capital.

Only about 15 fire engines and 100 firefighters are fighting a horrific blaze in the Essex village of Wennington that has destroyed entire houses.

Amid the surge in wildfires, MailOnline has delved into how they start and how they can be put out.

Wildfires are unplanned fires that burn in natural areas such as forests, grasslands, or prairies, although the term is increasingly being used for wildfires and human settlements as well.

They ultimately require three key ingredients to ignite and propagate: fuel, heat, and oxygen.

Read more