Thunderstorm warnings expire but rain continues to bring risk of floods for UK

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

A Met Office yellow thunderstorm covering parts of northern England and north Wales expired at 13:00 BST, with focus of heavy downpours shifting southwards across England and Wales.

Drivers are still being warned that wet weather could lead to slippery conditions and flooded roads.

The Environment Agency has issued one flood warning, external for Walverdon Water in Nelson, Lancashire.

Temperatures are also dropping 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.

After a wet morning in parts of northern England and north Wales, the most intense downpours will continue to ease during Thursday afternoon.

However, parts of mid and south Wales, the Midlands, East Anglia and south-east England will continue to see frequent heavy showers, some accompanied by hail and thunder.

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

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.

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 plant oils and soil-dwelling bacteria.

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

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.

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.