Heatwave: Is it coming to the UK?
- Published
While the intense heatwave continues across southern Europe, the United Kingdom has been much cooler and wetter.
Weather patterns have been stuck in the same position and there is no real sign of that changing.
The UK therefore is not likely to see any of that extreme heat in the coming days or weeks.
So when are we likely to see any warmth return?
After the UK's warmest June on record, the weather patterns took a significant shift.
We said goodbye to high pressure which brings generally settled weather and a feed of warmer air from the south and replaced it with low pressure bringing rain and cooler weather.
This change was due to movement of the jet stream - a fast wind high in the atmosphere.
To the north of the jet stream you have the cooler Arctic air with rain-bearing weather systems being formed. To the south is where the warmer tropical air sits.
The north-to-south movement of the jet stream dictates, therefore, how warm or cool it might be in any location.
Right now, the jet stream is stuck in a position through central Europe and we call this a blocked weather pattern.
A blocked weather pattern currently sits across Europe
In these situations, weather systems tend to get stuck in the same place for a long time and so changes only come about very slowly.
Depending on where they develop, blocked weather patterns can bring extremes of weather - heatwaves and cold spells, floods and drought.
The heat across southern Europe has been intensifying in this pattern with temperatures widely above 40C, peaking at around 46C in Sardinia on Tuesday.
Where has summer in the UK gone?
Weather patterns across Europe and the UK over the next week to 10 days don't show much change.
The UK has seen lots of rain in July, though much needed in some parts
The hot air remains to the south while the UK remains under the influence of the cooler Arctic air and rain-bearing weather systems.
This is of course in stark contrast to this time last year when the UK had an intense heatwave with 40C being exceeded for the first time on record.
The longer-term weather models show the jet stream moving further north into August, which could bring the UK higher temperatures - but an intense heatwave like they are experiencing in southern Europe isn't expected.
Is El Ni帽o or climate change to blame for the current heatwaves?
El Ni帽o is the natural climatic pattern that brings an increase in sea surface temperature to the eastern Pacific. Forecasters in the US have declared that we are now in El Ni帽o conditions.
This will affect weather systems around the world and ultimately, with the extra heat in the Pacific, raise global average temperatures.
However, El Ni帽o has only just started and we would therefore expect the warming associated with it later this year and into 2024.
The current heatwaves across the northern hemisphere therefore cannot be attributed to El Ni帽o.
While temperatures in the summer can reach over 40C in certain locations, the size and length of the current heatwaves is more unusual than "just summer".
We are currently seeing all sorts of local and national records not only for the maximum temperatures observed but also for how long the heat has been around for.
For example, in Phoenix, Arizona the temperature on Monday went above 43C (110F) for the 18th consecutive day, equalling a record from 1974. Not only will it break this record on Tuesday but temperatures above 43C are forecast to continue through into next week.
Whether climate change is having an impact on blocked weather patterns responsible for the current heatwave is complex and not entirely clear.
However, when we do get weather patterns like this, scientists are clear.
Extremes of weather such patterns bring - such as heatwaves - are likely to become more frequent, more intense and last for longer. It is therefore something people will need to adapt to happening more often in the future.
- Published17 July 2023
- Published13 July 2023
