How to

15 August 2016

What’s the Deal with the Spanish Plume?

There has been some confusion as to whether the high temperatures predicted for the following fortnight in Britain constitute a ‘Spanish Plume’.

Img source:
The words ‘insane’, heatwave’ and ‘rocketing temperatures’ are being flung around by media outlets like there’s no tomorrow. They say it’s set to be a ‘sizzling’ August, a real scorcher. Some forecasters seem adamant that the Plume will strike, and it will strike hard: prepare yourself for over 35 degree heat. Others are not so sure.

The most recent reports suggest that a change in wind direction might have shifted the plume off course, so does that mean no heatwave for Brits? The weekend delivered a somewhat disappointing show: none of the blistering rays we were warned to bulk-buy sun cream to protect against.

Alex Burkhill, a forecaster from the Met Office, is among the August Spanish Plume deniers:

‘A Spanish plume is looking very unlikely. It is not a Spanish plume set up, it would be wrong to use that term.’

He says the temperature rise is due to warm air coming in from France, instead.

So, what exactly is a Spanish Plume, what causes it, and how do we recognise one?

A Spanish Plume in simplest terms is hot dry air from Spain that spreads upwards through France and across to Britain. This is caused when a high pressure builds up over Scandinavia, north-east of the UK, and the pressure drops over the Bay of Biscay.

As we know, hot air rises. But hot air rising through cool air can cause the type of instability that leads to thunderstorms. The warm air from Spain ascends and forms a sort of lid or cap, a layer in the sky, which makes the air near the surface heat up.

At first, this actually blocks any more hot air from rising, but eventually, the energy builds up enough to break through. This upward push is the source of further instability in the air, and can lead to outbursts of energy that translate into extreme weather outbreaks.

Characteristic weather activity during a plume includes high temperatures, thunderstorms, lightning strikes, heavy downpours, hailstorms, and even, in severe cases, dangerous winds and tornadoes.
Notable plumes have also occurred in Germany, France, Belgium and The Netherlands, caused by this particular type of air current. 

For example, in July 1968, a plume led to severe flooding in Somerset, and a tornado in the Southern town of Pforzheim, Germany. In 1995, the Rhine Valley was afflicted by another significant tornado.

More recently, in August 2011, festival-goers at Pukkelpop in Belgium were caught by a sizeable storm which hit the region. A gust of wind travelling at 102 mph was recorded in July 2013, when a complex of thunderstorms swept across parts of France, the Netherlands and northern Germany.

Sadly, these storms sometimes cause a lot of damage to power lines, and a July storm in 2014 left at least two fatalities in France, as it brought floods and power cuts to regions of France and the UK.

This is by no means a uniquely European phenomenon. Plumes in Mexico similarly affect the south west of the US, but on a bigger scale. Parts of Scandinavia are also affected by air from the continent, which comes across from Russia and Belarus. 

Naomi Pyburn

Naomi is an English graduate with an itch to write. Her free time is spent blogging, reading feminist writing, cycling, cooking and managing her food Instagram account. Her not-so secret talent is the ability to nap anywhere.