The Met Office has warned that parts of England will be hit by thunderstorms and heavy rain as it revealed August is on track to be another dry month.
The yellow warning issued for Thursday from midnight to 3pm for south and eastern England, says driving conditions could be affected by spray, standing water and even hail and there may be delays to train services, power cuts, flooding and lightning strikes.
But while the forecast rain and downpours last week make it unlikely this summer – June, July and August – will see record dryness, forecasters warn there needs to be a period of above average rainfall to ease the drought.
So far this month the UK as a whole has had only 46% of the average total rainfall for August, the Met Office said.
Much of the country has seen even drier conditions, with only 35% of the total expected rainfall for the month so far in England, 34% in Wales and 39% in Northern Ireland.
And in southern England there has been just 29% of the month’s average from 1991 to 2020.
Bedfordshire has had only 13% of its average August rainfall so far, recording just 7.7mm (0.3 inches) this month.
The ongoing dry weather has seen drought declared across swathes of England, with parched grass and struggling crops, streams drying up and river, reservoir and aquifer levels low, and hosepipe bans brought in for millions as heatwaves pushed up demand for water.
Heavy rain is expected for some areas of the UK on Thursday and Friday, with parts of the South East potentially seeing 5-15mm of rain fall over three hours.
The Environment Agency issued six alerts for areas where “flooding is possible” on Thursday, adding: “Heavy rain and thunderstorms, bringing the potential for locally intense rainfall, are forecast to affect the London area.
“While uncertainty remains around exact timings and which areas will experience the heaviest rain, there is a possibility that rivers could respond quickly and overtop their banks.
“Flooding to low-lying land, roads and riverside gardens is possible.
“Surface water flooding may also affect low-lying areas.”
But the bank holiday is expected to be largely dry with warm sunny spells, though possibly wetter in the North West.
Temperatures could climb to 30C or into the mid-20s depending on how the high pressure builds, the Met Office said.
Spokesman Grahame Madge said: “We’ve definitely switched from the hot and dry regime to something that has rain in the forecast.
“There’s some heavy rain for the next 24 to 36 hours, providing some relief to gardeners more than helping to top up long-term resources.”
We've had below average rainfall for such a long time, it's going to take a period of above average rain to make it up— Grahame Madge, Met Office
While the forecast rain for this week will mean this month will “catch up a bit” with rainfall totals, he said: “It’s certainly going to be a dry August for the whole of the UK.”
And he said some areas had gone without any significant rainfall from the middle of June until last week.
“We’ve had below average rainfall for such a long time, it’s going to take a period of above average rain to make it up,” he warned.
Whether that period of above average rainfall is looming remains to be seen, with the Met Office set to bring out its seasonal forecast for the likely conditions over the next few months next week.
It is possible for the weather to turn around: the severely dry summer of 1976 was followed by rain that meant that rainfall levels had caught up with the average by the end of autumn.
But scientists warn that climate change is making weather extremes more likely, increasing heatwaves, droughts and heavy rain events that can lead to flash floods.
