How common are cyclones in the UK?

Strong winds, hail and thunderstorms possible this week as two pressure systems meet

The UK faces the unusual prospect of having to brace for the possible arrival of a cyclone later this week, according to the Met Office.

The whirlwind could reportedly appear once the jet stream drops south from Friday and drives a band of low pressure to our shores, which, should it meet a dominant high pressure centre over western Europe, might mean torrential rain, hail and thunderstorms following in its wake.

Of the two pressure centres, Met Office meteorologist Jonathan Vautrey told The Independent: “We have got one that’s going to try to push in from the northwest, and there’s also one from around the Bay of Biscay that’s going to try and push in from the south.

“Friday is when we might see the first signs of the low pressure centres, particularly the northwestern one spreading across western Scotland and into Northern Ireland. Even where there is rain coming through, it could feel warm.”

A cyclone is a large air mass rotating counterclockwise in the northern hemisphere (and clockwise in the southern) that sends inward winds spinning around a central low pressure zone, typically over the tropical waters of the equator where the north east and south east trade winds meet over sea with high temperatures of 27C and above.

For that reason, they are far from common in the UK and cannot form in our latitudes, even in summer.

That said, the British Isles can be affected by deep depressions that were previously tropical cyclones and that have since shifted to higher latitudes, according to the Met Office, a process known as extratropical transition, an example of which was Hurricane Ophelia in 2017.

“Intense mid-latitude depressions can produce near surface winds of hurricane strength, even those which do not originate from a tropical cyclone,” the forecaster states.

One of the most notorious examples of that happening took place on 16 October 1987, an event that became known as The Great Storm and is best remembered for the embarrassment it caused BBC weather forecaster Michael Fish, who took to the air to assure viewers that Britain was not about to be hit by a hurricane, just before it was.

While that storm brought 100mph winds that caused widespread havoc and uprooted trees, it was another front two years later that actually brought Britain’s fastest-ever winds, which were recorded at Fraserburgh in northern Scotland on 13 February 1989 and topped 142mph.