Heatwave continues, but a change is on the way
Author: Press Office
13:51 (UTC+1) on Thu 7 Sep 2023
September’s warm weather will continue into the weekend for much of the UK, though there’s a chance of some thundery rain to come for some.
Official heatwave criteria has been met for much of England and Wales, with temperatures likely peaking around 32C in the south or southeast in the next few days, though there’s an increasing signal for a thundery breakdown for some later in the weekend.
There’s a chance the highest temperature of the year so far of 32.2°C on 10 and 25 June could be exceeded this week.
Met Office Chief Meteorologist Steven Ramsdale said: “High pressure is situated to the southeast of the UK, which is bringing more settled conditions and temperatures well above average for the time of year. While the highest temperatures are expected in the south, heatwave conditions have already been met for much of England and Wales, with parts of Scotland and Northern Ireland also likely to continue to see some unseasonably high temperatures.
“An active tropical cyclone season in the North Atlantic has helped to amplify the pattern across the North Atlantic, pushing the jet stream well to the north of the UK, allowing some very warm air to be drawn north. It’s a marked contrast to the much of meteorological summer, when the UK was on the northern side of the jet stream with cooler air and more unsettled weather.”
As our climate changes due to human influences, hot spells like this are becoming more frequent and severe. By 2070, the chance of exceeding 30°C for two days or more throughout the year increases. Projections show that over southern parts of the UK exceeding 30°C for two days or more becomes sixteen times more frequent than it is today.
Chance of tropical nights
In addition to high daytime temperatures, it will remain uncomfortably warm overnight, especially in the south, with a chance of tropical nights for some, which is when overnight temperatures remain in excess of 20°C.
The highest UK overnight minimum temperature for September on record is 21.7°C, and this record could be threatened in the coming nights.
There have never been consecutive tropical nights recorded in the UK in September. This could change this week, most likely in southern parts of the UK. The Met Office previously completed an attribution study examining the influence of human induced climate change on tropical nights in the UK, which is explored in this newly-published blog.
Heat Health Alert
The UK Health Security Agency, which provides alerts for the health and social care sector in England, has issued an Amber Heat Health Alert which highlights increased risks to those more vulnerable to heat.
The Met Office has not issued an Extreme Heat Warning, which covers the UK and aligns with the wider national severe weather warning service and looks at more widespread potential impacts for the public.
Help to protect the vulnerable people that you know including older people, those with underlying conditions and those who live alone; they may need support to keep cool and hydrated. For more advice click here.
Dr Justine Shotton, Senior Vice President or the British Veterinary Association, said: “We may be past the peak summer months but it’s important to remember that this September sun and heat is also dangerous for animals. Pets can be extremely susceptible to heat-related illnesses such as heatstroke, and can also suffer sunburn, heart conditions and breathing difficulties, many of which can sadly be fatal. Make sure all pets have access to fresh drinking water, good ventilation and shade from direct sunlight at all times.”
Thundery breakdown on the way
Many areas will remain very warm or hot until at least Saturday, with the heat becoming more confined to southeastern areas on Sunday and Monday. Temperatures could reach 32°C in the southeast of England on Saturday, before easing off on Sunday and Monday.
By the weekend there’s also an increasing chance of some intense thundery downpours developing for some.
Met Office Deputy Chief Meteorologist Nick Silkstone said: “A cold front will begin to influence things as it arrives from the northwest over the weekend, though it’ll remain very warm or hot to the southeast of this front.
"There’s a chance the thunderstorm risk for some central and western areas from Friday, but more especially Saturday onwards may require a warning response, with some potentially impactful downpours, though exact details on the likely positioning of these downpours are still being determined, and indeed many places may see little if any rain on Friday and Saturday.”
By the early part of next week, a return to westerly weather regime, with a mix of sunshine and showers is most likely, with temperatures returning towards average for the time of year.
You can check the latest forecast on our website, by following us on Twitter and Facebook, as well as on our mobile app which is available for iPhone from the App store and for Android from the Google Play store. Keep track of current weather warnings on the weather warning page.