8 Dec 2014

Stormy weather midweek: winds up to 80mph expected

A spell of stormy weather is expected to hit the UK during Wednesday into Thursday. Northern areas at risk from severe gales, with wind gusts of up to 80mph possible.

It will be the first notably deep area of low pressure that we have seen this winter season and will have the potential to cause some damage and disruption.

The Met Office has already issued a yellow “be prepared” warning for the northern half of the UK, although even further southwards, there’ll be brisk winds too.

stormy_coast_g_wp

Powerful jet stream

The cause of the change to a spell of stormy weather is a powerful jet stream over the mid-Atlantic, travelling at around 220mph, 30,000ft up in the sky.

storm_pressure_MO_wpAt the moment, warm sub-tropical air is colliding with cold arctic air, which is causing a huge temperature contrast – something that drives the jet stream.

The larger the temperature contrast, the faster the jet stream moves; and the faster the jet stream moves, the more active the weather tends to be.

Such a fast-moving jet stream acts as a vacuum in the sky, sucking up air from the surface, causing pressure to fall and a storm to form.

The jet stream is not only responsible for spawning these storms, but also pushing them towards us, on what can be thought of as an atmospheric superhighway.

Winds up to 80mph

The stormy weather is expected to affect north Wales, northern England, Scotland and Northern Ireland from late on storm_warning_MO_wpTuesday evening, until the early hours of Thursday morning.

Gusts of wind are widely expected to reach 60-70mph, with some coasts and hills in the north west having gusts of 80mph.

This strength of wind is enough to cause damage to trees and power lines, as well as travel disruption. Coastal parts of western and northern Scotland will also see large waves, which may give localised flooding.

In addition to the wind, there will also be spells of rain, with significant snow falling over the mountains of Scotland.

Whilst it will be windy further southwards, the winds at this stage are not as likely to be disruptive.

More strong winds Thursday into Friday

After the midweek storm moves away, there is the potential for another deep area of low pressure to sweep across the UK during Thursday night into Friday morning.

However, there is a huge amount of uncertainty over the strength of wind that this will deliver, as the weather computer models are giving varying messages about its position and intensity.

Nevertheless, there could be gusts of 50-60mph, locally 70mph for western coasts, across England, Wales, Northern Ireland and southern Scotland, along with heavy rain.

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

Tweets by @liamdutton

One reader comment

  1. Georgios says:

    Good afternoon Mr Dutton!
    My name isGeorge and i am weather enthousiast! I dont understand the mechanism that produce the lift of air in a trough. I do understand that there is a term that named positive vorticity but i dont understand how positive vorticity or in general vorticity creates upward motion. Also i dont understand the way the convergence/devergence is created in jet streaks.
    Please let me know or could you recommend me any info to read about
    Thank you for your time best regards

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