Why is it so hot? Your questions answered
Experts explain why the UK is sizzling as it prepares for the hottest day of the year.
Why is it so hot?
In the short term, the current weather phenomenon can be attributed largely to the position and the strength of jet streams – fast moving air typically five to seven miles above the Earth’s surface. Such jet streams are crucial to bringing in new weather systems.
What does that mean?
Becky Mitchell, meteorologist at the Met Office in Exeter, said: “The jet streams are not very strong to the north of the UK. When the jet stream is like that, it means we’re under a period of high pressure, currently drawing up hot and humid air from France.”
What causes a low jet stream?
Sometimes it is just a feature of the weather at the time. However, this prolonged period of dry and very warm weather will inevitably cause scientists to look at the long-term impact global warming is having on the planet.
What would ordinarily be happening across the UK at this time of year?
Again, when the jet stream is further south it means cooler weather systems are able to come in from the Atlantic. That is not happening at the moment, hence the extended period of hot temperatures.
Will we have to endure much more of this?
In short, yes. It is probably fair to say that things will get worse (that is to say, hotter) before they get better. And it’s all building towards Friday being the hottest day of the year, with temperatures expected to hit 36C (96.8F) in the south east before dropping back to the high 20s again. Interestingly, despite the driest start to summer since 1961, the previous three years have each had a top temperature exceeding 33.3C (91.9F), the record high for 2018 so far.
Any chance of rain?
Succour is on its way. Thunderstorms are expected in parts of eastern and northern England on Friday, according to the Met Office, with a chance of hail and strong winds alongside the torrential downpours.
But will it actually make any difference?
The volume and persistence of the rainfall will have a variable impact on the overall temperature. Extended periods of very hot and dry weather mean the ground has itself been heated – a light shower is going to do little to change that. Nor is it likely to fill the reservoirs, which are in desperate need of a top-up. But many gardeners and farmers are crying out for rain. Any cooling of the temperatures will be particularly welcomed by dog walkers, who have been forced to take their pets out very early in the morning or late at night when the temperatures have dropped to something less punishing.