Rain to continue for UK with risk of flash flooding

Heavy showers and thunderstorms will continue to affect large swathes of the UK on Thursday, bringing the threat of flooding and travel disruption.

A Met Office yellow thunderstorm covering parts of northern England and north Wales has been extended until 13:00 BST on Thursday.

The downpours will drift southwards and eastwards during the day, affecting other parts of Wales, the Midlands, East Anglia and southern England.

Drivers are being warned that the return to wet weather could lead to slippery conditions as well as the risk of flooded roads.

Temperatures are also forecast to drop with some places expected to remain below the August average over the next few days.

After a summer that has largely been dominated by high pressure, low pressure has now taken control.

Unstable air underneath the low has allowed big storm clouds to develop, capable of delivering torrential downpours accompanied by hail and thunder.

During Thursday morning, northern England and north Wales will continue to bear the brunt of the thunderstorms.

Within the Met Office yellow warning area, 15-20mm of rain could fall in just an hour, with 30-40mm possible over several hours.

Flash flooding is possible, especially in areas where the ground remains very hard after the prolonged hot, dry spell.

Lightning and hail will bring additional hazards and there is a chance of power cuts.

Showers are expected to ease from the north during the morning, migrating southwards into other parts of Wales as well as central and southern England where a few downpours could still be heavy and thundery.

As ever with showers, some places will see more rain than others.

Scotland and Northern Ireland will also have showers but they should be less intense, with a lower chance of thunder.

Motoring experts warn that wet weather after a prolonged dry spell can cause dangerous driving conditions.

RAC road safety spokesperson Rod Dennis says: “Oil, fuel and rubber deposits that have built up over many weeks will now have been mixed together by the light rain, instead of being washed away, which means drivers are at greater risk of skidding on greasy roads.

“If heavier rain arrives, motorists may have to contend with the danger of flash floods in some areas.”

Drivers are being advised to reduce their speed and leave extra space between them and the vehicle in front.

You may have noticed that rain produces a particular smell.

This smell is called petrichor – from the Greek words petri, meaning stone, and ichor, which refers to the golden fluid that flows through the veins of the gods in Greek mythology.

In reality this smell is caused when raindrops disturb the dry dusty ground, releasing the scent of chemicals – which come from a combination of plants oils and soil-dwelling bacteria.

The scent is most noticeable when wet weather returns after a prolonged dry spell.

Even as rain has returned, experts are warning that the drought gripping large swathes of the UK will not immediately come to an end.

It will need a sustained period of persistent rainfall to replenish water stocks and we are unlikely to know whether this has happened until late in the upcoming winter.

However, it is worth adding that while most areas have seen rainfall well below normal this summer – with some locations having a two month dry spell – that has not been the case everywhere.

Aultbea in the Scottish Highlands has recorded 389.6mm of rain so far this summer – more than one and a half times the seasonal norm, and only 10.2mm short of its wettest summer on record.

As northerly winds develop across the UK, temperatures are set to drop.

Thursday afternoon is expected to bring highs of 13-23C.

It is expected to be the first day since 29 June when temperatures will fail to reach 25C anywhere in the UK.

Friday is set to be cooler still with temperatures widely remaining below the August norm.

Friday night will also be the chilliest for quite some time with temperatures widely dropping into single digits.

Parts of Scotland and northern England could see lows of 3 or 4C.

Chilly nights will continue to feature over the weekend although daytime temperatures will rebound a little as high pressure tries to build – meaning less rain and more sunshine.

You can keep up to date with your local forecast on the BBC Weather website and app.