How long will rainy weather and thunderstorms continue? Met Office issues an update

Severe weather warnings replace heatwave alert as up to 80mm of rain set to fall in just a few hours

Maidenhead street flooded as thunderstorms hit England (PA)

Large parts of the UK are being lashed by heavy rains and thunderstorms as the Met Office’s latest forecast showed more intense wet weather to come.

Saturday was a warm and humid day for most in the country with some sunshine that soon turned to showers and thunderstorms.

And these showers are set to intensify on Sunday as the Met Office forecast “very intense rainfall” ahead with a risk of flooding in some parts.

A yellow warning for thunderstorms is in place for most of England and Wales with lightning, strong winds and hail all expected on Sunday.

The Met Office has said London through to the Midlands as well as eastern England, east Wales and lower areas of northern England are most likely to experience disruption.

The current humid weather comes after several days of heatwave conditions which has seen much of the country bask in temperatures up to and including 30C.

The high temperatures have put a strain on some water supplies, prompting a hosepipe ban for up to 2 million people, and the NHS warning it could lead to its busiest day ever.

The Met Office’s yellow warning states that while some places may miss the rain, others could see 30mm fall in an hour or less and a few spots may even see 60 to 80mm within three to six hours. The warning is in place from noon to midnight on 18 June.

Motorists have been warned spray and sudden flooding could lead to difficult driving conditions and possible road closures.

Forecasters also warn flooding of homes and businesses “could happen quickly, with damage to some buildings from floodwater, lightning strikes, hail or strong winds”

The Met Office has also warned of potential power cuts and disruption to transport services in the event of flooding or lightning.

This change comes as warmer and moist air from the Atlantic moves in, making the conditions more humid, explains Grahame Madge, a spokesperson for the Met Office.

“Heat and humidity are the key ingredients for thunderstorms,” he said, adding that “thunderstorms can unleash very intense rainfall and even hail.

The thunderstorm warning extends to essentially the whole of England and Wales, apart from some areas around the Lake District.

Large parts of England and Wales and under yellow warning (Met Office)

“Some of the storms have the potential to be quite intense, with high rainfall rates,” Mr Madge adds.

“Some locations may well miss them altogether but all we can do now is indicate that there is a risk across both countries.”

“We will keep the yellow warning closely monitored and if we need to escalate that for local areas then we will,” he added.

Rainfall forecast for UK (Met Office)

This week's humid heatwave has also caused some people to experience heavy hay fever and even worsened asthma attacks.

Members of the public have taken to social media to complain that their hay fever symptoms are worse than usual this year. Mr Madge put this down to the hot, dry weather over the last few weeks.

“Pollen season is certainly with us,” he said. “The fact we've had very dry conditions means that grasses can release pollen on mass into the air column.

“Around 70 per cent of hay fever sufferers are allergic to grass pollen, and will likely have symptoms continuing from mid June into July during grass season.”

The heat and humidity have also led to a surge in the number of people presenting at hospitals with lung problems. More than five million people in the UK have asthma, leaving them more vulnerable to the weather conditions.

“People with asthma who have hay fever can experience much more severe symptoms during thunderstorms,” said Emma Rubach, head of health advice at Asthma + Lung UK.

“This is because thunder breaks pollen into smaller particles, which can then be inhaled deep into the lungs, causing wheezing, coughing, a tight chest and shortness of breath.

“If there is also higher pollution in the atmosphere – which tends to be the case when the weather is warm - this is an added threat.”