How the UK could have a heatwave this summer

By The Newsroom
Friday, 13 April, 2018, 15:05

With unseasonably warm weather this week, the UK is looking forward to embracing the sunshine.

However, every time there is an eagerly anticipated burst of sunshine, the inevitable question on everyone's lips is: how long will this last? And what will summer be like?

So could the UK have a heatwave this summer, and is this week's warmer weather forecast set to last?

The ways in which the UK could have a heatwave this summer

A heatwave, as the name suggests, refers to a prolonged period of hot weather, which is at times accompanied by high humidity.

Low pressure and high pressure are two of the main variables which control how much heat the UK receives, high atmospheric pressure being how a heatwave occurs.

Heatwaves are most common in summer due to high pressure developing across an area, and high pressure systems are slow-moving and can persist over an area for a prolonged period of time.

Last year, a heatwave occurred in the month of June into July.

Heatwaves can occur in the UK due to the location of the jet stream, which is usually to the north of the UK in the summer. This can allow high pressure to develop over the country, resulting in persistent dry and settled weather.

The weather forecast this week predicts bright blue skies and warm sunshine, but will summer be the same? (Photo: Shutterstock)

The warm weather forecast for the rest of this week, with temperatures set to reach the low 20s, also relates to this low and high pressure system, as the low pressure system, which brings cold and wet weather, is slowly moving away from the UK and settling down.

Grahame Madge from the Met Office explains that this week's weather is due to “warm air coming up from further South, from both Europe and the Atlantic”, which then brings the temperatures up, caused by a “ridge of high pressure”.

UK records

• The hottest temperature ever recorded by the Met Office in the UK was 38.5C (101.3 F) at Faversham in Kent on 10 August 2003.

• The Scottish record is 32.9°C (91.2°F), recorded at Greycrook in the Borders on 9 August 2003, while the Welsh record is 35.2°C (95.4°F), set at Hawarden Bridge on 2 August 1990.

Source: Met Office

With this ‘high pressure’ being the cause of a heatwave, is this month’s warmer weather a sign of things to come during the summer?

The answer to this question isn’t as simple as you may think.

Will this summer be a scorcher?

Although the whole of the UK is wishing for the answer to be yes, the forecasting of the weather is much more complex than a simple yes or no.

Mr Madge explains that although they are “making great strides in meteorological science”, continuously pushing the boundaries of longer and more advanced forecasts, making any weather predictions past a month is “too challenging”.

The vast amount of data which is required to be collected and analysed per second just for a 12 hour forecast means that any forecast past a seven-day period decreases in accuracy and becomes the “merest of indications”.

Are we set to have a summer scorcher? (Photo: Shutterstock)

Although the location of the UK means that we can experience warmer weather and perhaps a heatwave or two at times, Mr Madge explains that its location also means it is at a “crossroads for weather from all directions”, which makes it harder to predict the weather past a month, as our ‘atmosphere is “so chaotic”.

The past few years have been warmer in the summer generally, with last year setting a new record, but this unfortunately doesn’t guarantee the same for this year.

The UK can but hope that the high ridge of pressure triumphs over the low pressure, and that this week’s warm weather forecast continues, allowing us to have a summer scorcher and not a weather washout.

How has climate change affected UK temperatures?

The UK is already affected by rising temperatures due to climate change.

The average temperature in Britain is now 1˚C higher than it was 100 years ago, and 0.5˚C higher than it was in the 1970s.