3 days ago
UK heatwave expected as temperatures climb to 33C on longest day of the year
After a toasty 29 C last Friday, the mercury is on the move again - climbing day by day this week and expected to reach a scorching 33 C by Saturday.
With a heat health alert now in place for the coming days, we're officially stepping into heatwave territory.
The heat will build slowly, peaking through the weekend and into early next week as a warm and humid air mass blows in from Europe.
Expect sun-soaked days, sticky evenings and warm nights that feel close to Mediterranean-living.
What is the reason for it warming up again?
This week's heating is the result of 'home-grown' heat, where the sun is strong enough this time of year to allow temperatures to naturally rise in combination with another area of high pressure.
The high pressure - our dominant system over the record-breaking sunny spring - has returned and keeps wet weather at bay.
This, together with the clear, cloudless skies, the sunshine really gets to work.
This time of year we see the highest UV levels with the sun at its highest in the sky.
The summer solstice, the longest day of the year, will also arrive on Saturday and allows for maximum heating with such long daylight hours.
Expect to see temperatures peak close to 30C in the next few days with very warm evenings and 'tropical ' nights - it'll feel stuffy and uncomfortable for sleeping.
By late Friday into Saturday, we'll draw in hotter and humid air from the near continent, boosting temperatures to nearer 33C or so by the weekend.
The humid air will initially be more of a feature across central and western areas, with a little more of an onshore breeze along the south-east of England, offering some relief from the heat.
What is a tropical night?
The Met Office definition of a tropical night is a night that doesn't fall below 20C. With such high temperatures and long daylight hours, we get maximum solar heating by day and with such short nights, it'll stay remarkably warm and increasingly muggy by the weekend.
Expect it to stay stuffy and mild overnight beyond the weekend across some south-eastern areas.
Where will we see the highest temperatures?
The highest temperatures will initially be across the south east and into central and western England today and Thursday.
By Friday, the heat will be more spread into the far north of England, Scotland and parts of Northern Ireland, with temperatures way above average - we'll be near heatwave conditions for many parts of the UK.
A breeze will develop along the south-east coasts as the high pressure repositions itself, as it feels increasingly muggy further west with hot, humid air from Europe.
By Saturday, as temperatures peak and we have more influence of humid, muggy air from Europe, there'll be a risk of thunder downpours developing but details will become clearer in the coming 24 hours.
How long will the heat last?
Temperatures will slide a few degrees towards the end of the weekend and early next week, making for a more comfortable and manageable feel, but parts of the south-east will keep the hot air for a few more days with temperatures not far from 27-30C, ensuring another hotter than average week ahead in places.
Since 2015, we've reached 30C for eight out of ten years during the month of June - previously, we were more likely to see 30C+ temperatures in July and August.
