2 Jun 2015

UK heatwave: fact or a load of hot air?

The howling of the wind and pounding of the rain last night were more reminiscent of a night in October, rather than June.

An unusually deep area of low pressure for the time of year passed across the far north of the UK, pushing heavy rain and gales from west to east.

Thankfully, it is moving away later today, with signs of warmer weather arriving later on this week.

Why so unsettled?

It’s not just the start of June that has been unsettled either. Provision statistics from the Met Office show that May (1-27th) was wetter and cooler than normal for the UK.

The mean temperature (a combination of day and night temperatures) was 0.8C below average, with a third more rainfall than would normally be expected for the month of May – most of that falling in the first two weeks of the month.

Our unsettled weather of the past month has been down to the position of the jet stream, which has been further south than normal for prolonged periods of time.


This has steered areas of low pressure and their associated cloud, wind and rain towards the UK, rather than Iceland and Scandinavia.

However, in the coming days, the jet stream is going to move northwards and weaken, which will direct wind and rain away from us. This will allow high pressure to build, bringing drier, sunnier and warmer weather.

Are we going to get a heatwave?

There have been headlines and stories in some of the newspapers in recent days that a heatwave is on the way, without any mention that the detail was always uncertain, as I tweeted last weekend.

sun_sky_g_wpThis happens relatively often, where everything quickly becomes a bit over the top, without any sense of the likelihood of a mentioned event actually happening – much to the frustration of those of us in the weather community trying to manage expectations of what weather lies ahead.

In a nutshell, no, we are not going to get a heatwave. Nor are we going to get a mini-heatwave.

The notion of the term mini-heatwave actually makes no sense, given that a heatwave by definition of the World Meteorological Organization, is a prolonged spell of heat;

“A heatwave is when the daily maximum temperature of more than five consecutive days exceeds the average maximum temperature by 5C.”

How warm will it get?

The warmest day will be Friday, when East Anglia and south east England will see temperatures reach 23-27C. However, while there will be some sunshine, there’s going to be some thunderstorms around as well.

In terms of the whole of the UK, what we’ll notice during the next five days, is a return to weather more typical for this time of year.

thunderstorm_summer_g_wpThis means that temperatures will sit in the range of 17-23C for England and Wales, with 14-19C for Scotland and Northern Ireland.

There’ll also be a trend towards drier, sunnier weather as high pressure dominates. Although, occasionally, there’ll be a risk of thunderstorms drifting up from France.

And finally, if you think we’re having a rough time with the weather today, on the 2 June 1975, the UK had sleet and snow showers as far south as London.

The snow was so heavy in some places that county cricket matches had to be called off!

Don’t forget, you can get the latest forecast on the Channel 4 Weather website. I’ll also be posting regular updates on Twitter – @liamdutton

Graphic: earth.nullschool.net

Tweets by @liamdutton