IT WAS a foreboding sight - storm clouds gathering over the North Sea at Spurn Point yesterday as Britain braced itself for the arrival of the ‘Spanish Plume’.
Residents in the east of England were issued with a severe weather warning for today, as hot, unstable air is expected to push up from France into the UK.
The so-called Spanish Plume could bring temperatures into the low 30s - but could also trigger torrential thunderstorms, with the risk of more than 30mm in less than an hour.
The weather phenomenon commonly causes flash flooding and fierce storms, and has even been known to spark tornadoes.
MeteoGroup forecaster Matt Martin said Yorkshire and the Humber should escape the worst of the Plume’s effects - although high temperatures will see the region swelter in muggy heat before thunderstorms hit tonight.
He said: “Between 6pm and midnight on Saturday is the period with the highest risk of thundery downpours.
“It’s going to be quite muggy with temperatures around 24 or 25 degrees and staying warm overnight.
“On Sunday the rain will push back westwards, so it will become dry late morning, but the risk of rain will return in the evening and overnight.”
The coast will see the best of the weather, with “some sunshine across the eastern region,” Mr Martin said.
“During the afternoon it could be dry towards Scarborough with periods of hot sunshine, but there is still a risk of thunderstorms on Saturday evening and overnight, but it certainly has more chance of drier weather.
“We can’t be too specific with these plumes.
“They happen two or three times a year and can result in some extreme outcomes.”
The Met Office issued yellow ‘be aware’ warning for rain in the east of England, East Midlands, London and the South East.
A spokesman said isolated heavy thunderstorms could break out on Saturday afternoon and last into the evening.
“Whilst most will miss these, the public should be aware of the risk of localised surface water flooding, strong gusts, lightning and hail,” he added.
A Spanish Plume occurs when a large southwards dip in the high altitude jet stream develops to the west of Europe, encouraging a deep southerly wind flow. This pushes hot and humid air from Iberia north and north-east into northern Europe, including the British Isles.
The Spanish Plume can create a risk of tornadoes, although there is a low risk of that this weekend.
The warning comes after US scientists found that July was the warmest month on record worldwide and 2015 is likely to be the hottest year.
This week officials at the National Oceanic and Atmospheric Administration in Washington DC said July’s average global temperature was 16.5C (61.86F), beating a previous record set in 1998 and 2010.
The first seven months of this year were also the hottest January-to-July span on record.
With the final days of the summer holiday and a bank holiday weekend approaching, Mr Martin said Yorkshire can expect unsettled weather next week, with temperatures coming back down to the average for this time of year, with a mixture of showers and longer spells of rain.
There are some signs of high pressure which could mean a good bank holiday weekend, and it will “more than likely” be more settled, he added.