The mercury will nosedive with easterly winds and chilly downpours pushing temperatures around 10C below those seen over the past week. High-pressure responsible for the blazing sunshine and blue skies will weaken allowing unsettled conditions to move in, experts say. A huge storm threatening to batter Europe at the end of this week will in part drive the wind and rain set to hit the UK, they warn.
However another u-turn after the weekend will see a return to blue skies and sunshine by the middle of next week week.
The weather will turn later on Thursday as bands of rain start to move across the country as the powerful high which has kept Britain sunny breaks down.
Met Office meteorologist Greg Dewhurst said: “Thursday will be a generally fine day although the breeze will pick up a little bit and temperatures will be down from the middle of the week.
“As we move into the afternoon we could see some showers and some of these could be heavy and thundery.
UK weather forecast: A barrage of rain will hit Britain at the weekend
“The trend is for the weather to become more unsettled through Friday and into the weekend.
“Most of the rain will be the result of home-grown low pressure, however Scotland will see some bands of showery rain coming off the North Sea with some showers also coming up from France.”
Northern Britain will cool down faster than the rest of the country with southern England in for a relatively pleasant weekend, he said.
Temperatures across the region will remain in the low 20Cs although there will be a risk of showers into the start of next week, he added.
The good news is the wet and miserable weather is likely only to hold out for around five days before the nation welcomes a return to sunshine.
Mr Dewhurst said: “After an unsettled weekend and start to the new week, things will settle down again as we go through the week.
“It might not be quite as nice as we have seen over the past couple of days, but all in all it doesn’t look bad at all.”
Weather charts show a near-nationwide risk of storms this weekend while rain charts highlight heavy showers sweeping across the UK.
Maximum temperatures of 20C (68F) are possible across southern Britain while thermometers will struggle to rise much out of low single figures elsewhere.
Temperatures may lift back above the seasonal average after a wet and chilly few days ahead, according to The Weather Company.
Britain’s weather will remain largely dry and settled into the second half of the month, their meteorologists claim.
They said: “It will remain largely dry with sunny spells on Thursday although temperatures will fall slightly below the seasonal average as high pressure drifts to Scandinavia setting up a cool easterly breeze.
UK weather forecast: Weekend storm risk
“There will be showers or longer spells of rain on Friday and during the weekend with a fair amount of cloud around.
“There are signs of high pressure rebuilding next week with temperatures recovering marginally above the May average with highs possibly reaching 20C.
“It will be predominantly dry with a mixture of cloud and sunny spells.”
Bookies have slashed the odds for this summer entering the record books after temperatures hit the mid-20Cs this week.
Coral is offering 6-4 from 3-1 on the hottest May ever with 4-5 on summer records falling and 1-2 for thermometers to hit 25C (77F) next week.
Spokesman Harry Aitkenhead said: “We’re getting towards summer now and the sun is finally here to stay by the looks of things.
UK weather forecast: Rain moving in from France
“We’ve slashed our odds on this month going down as the hottest May since records began and the future looks warm.
“There’s every chance that this summer will top the sweltering heights of last year and if it does it will almost certainly go down as the hottest summer the UK has ever seen.”
Rain will start to dampen spirits across northern parts of the UK on Thursday as a major storm sweeps into Europe, according to AccuWeather meteorologists.
Showers will set in through the rest of the week before turning heavier on Saturday and Sunday as temperatures fall.
AccuWeather Meteorologist Maura Kelly said: “The dry pattern will come to an end across western Europe by the end of the week as a large storm system moves in from the Atlantic.”
UK weather forecast: A heatwave is expected by the end of the month
Colleague Eric Leister added: “Following a string of dry, sunny days across western Europe, showery weather will make a return later this week.
“The unsettled weather pattern will also help to reinforce the cool weather pattern that has been in place this month from the United Kingdom through France and Germany.
“Showers will be possible across Ireland, Northern Ireland and Scotland on Thursday before spreading throughout Wales and England on Friday.
“There will continue to be a threat for showers throughout Ireland and the United Kingdom on Saturday and Sunday.”