Leeds Festival campers warned to secure their tents as Storm Lilian sweeps in

Gusts of up to 80mph are expected, with travel disruption, flooding, power cuts and dangerous conditions near coastal areas all likely.

The forecaster has issued two yellow weather warnings for rain in south-west Scotland and the Aberdeenshire coast from 9pm on Thursday to 9am on Friday.

There is the possibility of thunder, while 20-30mm of rainfall is expected widely across both areas – with a chance of 40-50mm over higher ground.

A yellow wind warning has also come into force covering northern England and north Wales until 11am on Friday, with the storm widely expected to bring gusts of 50-60mph in the region.

The official X account of the Met Office posted at 5am on Friday: “Winds are now strengthening in many areas with the strongest winds occurring during the next few hours across northern England and north Wales

“Damaging gusts are possible in places so ensure you stay #WeatherAware.”

The impact of the severe weather has already been felt outside the expected regions, with National Highways warning the M48 Severn Bridge in Gloucestershire has been closed in both directions between J1 (Aust) and J2 (Chepstow) due to the strong winds.

Road users are advised to use the M4 Prince of Wales Bridge as an alternate route.

Met Office forecaster Greg Dewhurst said: “The strongest winds are likely to start forming through the early hours initially across parts of north Wales into the Liverpool, Blackpool area, and then crossing over the Pennines and into the east and north-east England – Yorkshire, up to Northumberland before then clearing out into the North Sea.

“So it’s really quite quick.”

Warning campers at Leeds Festival, Mr Dewhurst added: “The wind will pick up in that area through the night, particularly strongest towards dawn and then first thing in the morning, before then easing through the morning.

“So there could be potentially some impacts from those strong winds, of 50 to 60mph in the area so it’s worth making sure your tents are secured.

“There could also be disruption first thing to the transport networks for those travelling first thing.”

Lillian’s influence would “wane” by Friday afternoon as it reduced in intensity and pushed off into the North Sea, with scattered showers for most of the rest of the day, Mr Dixon said.

After the possibility of some heavy showers early on Saturday, settled conditions were likely to develop across southern and eastern England and Wales with sunny spells and dry conditions mixed with the odd chance of scattered showers.

The North and North West would continue to see “a fairly unsettled weekend”, with various fronts moving in and bringing more persistent rain, particularly for parts of western Scotland and Northern Ireland, the forecaster said.

Temperatures will reach highs of 21C on Saturday and Sunday and 23C on Monday in the South East, slightly below average for the time of year.

A New Order music concert set to take place in Cardiff on Thursday has been cancelled, with organisers citing the “severe winds” and a bad weather forecast.

The RAC estimated that 19.2 million leisure trips by car would be made over the weekend, with 3.2 million on Friday alone.

This is highest since the motoring services company began recording data for the summer bank holiday in 2015.

RAC Breakdown spokeswoman Alice Simpson said the adverse weather and large volume of expected trips represented “a perfect storm” for drivers.

She said: “Anyone driving in areas impacted by Storm Lilian should try to avoid exposed coasts and higher routes where there’s a greater chance of fallen branches and trees. It’s vital to lower your speeds and leave plenty of extra stopping distance to allow yourself time to react quickly.

“Drivers should keep a firm grip on the steering wheel and take extra care when passing high-sided vehicles which can cause an unnerving buffeting effect when you’re suddenly hit by the wind on the other side.”

A Network Rail spokeswoman said: “We are closely monitoring the potential impact that the storm might have on the rail network.

“We have teams on hand to put in appropriate measures, if necessary,  to ensure that we can continue to run trains safely and as reliably as possible.”

Lilian is the 12th named storm of the season – the furthest the Met Office have got through the list since it was introduced – and the first since April.

Storms are named when they have the potential to cause disruption or damage which could result in an amber or red warning, the Met Office said.

This is primarily based on impacts from strong winds but other weather types will also be considered, including rain if flood warnings are advised by national agencies, or snow.