Tropical Storm Debby in US will elevate UK temperatures above 30C

Britons are set to enjoy a return to hot weather from this weekend with temperatures soaring above 30C (86F) thanks to the influence of Tropical Storm Debby in the US.

The Met Office said an ‘increasingly hot and humid air mass’ will push across the UK’s southern half this weekend following an unsettled week for many areas.

The storm hitting the eastern US is helping to strengthen the jet stream and make it ‘meander’ over the Atlantic which will allow hot air to move into the UK from Sunday.

Temperatures are expected to get to at least 30C (86F) in the South and South East of England and there is even a 30 per cent chance of the mid-30Cs (mid-90Fs).

This would bring the hottest day of 2024 so far, which is currently July 30 when 32.0C (89.6F) was recorded at both Kew Gardens and Heathrow Airport in London.

However forecasters also warned of thunderstorms or heavy showers falling further north and west within the warm air mass, and in eastern areas on Monday.

A very warm night is expected on Sunday night into Monday – although by Tuesday the hot air mass will likely become displaced by fresher conditions. 

The weather will then become unsettled again, with occasional Atlantic frontal systems or showers – but it will also feel pleasant in between these systems.

Before that, the picture for the rest of this week remains fairly changeable, with influxes of rain from the west on Thursday, fine weather for many on Friday and then a more mixed picture on Saturday when conditions will start to feel more humid.

Met Office chief meteorologist Dan Suri said: ‘Tropical Storm Debby in North America is helping to strengthen the jet stream, and is causing it to meander over the Atlantic.

‘This will allow hot air to move into the UK later this weekend, and early next week. Temperatures are likely to reach the low 30Cs in places, notably in the South and South East.

‘Further north and west within this warm air, outbreaks of heavy showers or thunderstorms are possible. As well as the hot daytime temperatures, a very warm night is also expected on Sunday night into Monday.’

Debby made landfall along the Gulf Coast of Florida on Monday morning as a Category 1 hurricane and has already dropped up to 400mm (15in) of rain over parts of the state.

At least six people have died due to the storm, five of them in traffic accidents or from fallen trees.

Debby will continue to impact eastern and southeastern parts of the US over the coming days, with areas of Georgia and North and South Carolina set to bear the brunt.

Its centre was about 90 miles east of Savannah in Georgia this morning with maximum sustained winds of 45mph, according to the US National Hurricane Center.

Debby is then likely to weaken and gradually break up later in the week and into the start of next week, but its influence will play a part in the UK’s conditions.

Met Office deputy chief meteorologist Nick Silkstone said: ‘While Debby itself won’t reach the UK, the system and its remnants does play a role in the UK forecast next week, but chiefly as background influence on the shape and strength of the jet stream, which often plays a significant role in the weather we experience in the UK.

‘Debby in North America will help to strengthen and veer the direction of the jet stream and this means this ribbon of air is likely to shift further to the south.’

‘This southwards dip in the jet stream will likely be located across the mid-Atlantic this weekend and early next week, allowing south-westerly flow across the UK.

‘During this time a hot and perhaps very hot airmass could develop and be advected into the South East of the UK. 

‘On balance it now looks likely that temperatures will reach 30C, with around a 30 per cent chance that temperatures could reach the mid-30Cs early next week. Debby plays a role in developing this forecast hot spell.’

But before the summer sunshine returns, Britain is set for an unsettled few days as parts of the country are hit by heavy rain.

Much of the UK could face showers at times today with the heaviest rain expected in Scotland, although conditions should turn drier and clearer into the evening.

Temperatures are expected to reach 23C (73F) in southern England this afternoon, 20C (68F) in the North and 18C (64F) in Scotland, Wales and Northern Ireland .

Met Office meteorologist Amy Bokota said: ‘A brighter and fresher start if you’re in the South East today, but it will be a fairly damp start across the far North West.

‘And that’s due to an area of low pressure and associated occluded front giving some fairly heavy and frequent showers through the morning.

‘But as we head into the afternoon there’s a ridge of high pressure extending across the South and we will see some drier conditions through the afternoon.’

Most places will remain dry this evening but the North West will endure scattered showers and outbreaks of rain could fall over the South West by dawn.

Ms Bokota said: ‘Heading through this evening any showers remaining will slowly start to die out but we will still see them continue to feed into western Scotland and in the far South West.’

She said cloud would thicken as a new frontal system brings ‘rain, drizzle and quite murky conditions to start the day on Thursday’.

Cloud and rain will move in from the West tomorrow which could turn heavier in the afternoon amid highs of 23C (73F) in the South and 21C (70F) in the North.

Ms Bokota added: ‘Underneath the cloud and rain we’re going to see a return some more humid, muggy conditions but under the clearer skies further east it’s going to be a bit of a fresher start to the day.

‘So there will be some early morning sunshine for parts of the South East and North East England and North East Scotland.

‘But we do have an area of rain and drizzle slowly moving north-eastwards and there will be some heavier outbursts as well at times particularly for northern Wales and North West England.

‘So there could be some isolated surface water flooding in these few spots.’

She also said that ‘with the cloud, the rain and that strong wind it’s probably not going to be feeling too summer-like’, although the best of the sunshine tomorrow will be across the far South East and for parts of Shetland.

Ms Bokota said it would be a ‘grey and wet night’ tomorrow but conditions are then set to improve in the South by the end of the week.

She added that ‘much drier and brighter’ weather was on the way for Friday with highs of 26C (79F), although showers will continue in the North.

The top temperature in Britain yesterday was 26.4C (79.5F) at Neatishead in Norfolk.