Published on 3 Dec 2013

Gales, a brief chill, then milder – but nothing unusual

The British weather is going to live up to its reputation for being very changeable later this week, with a variety of things to keep an eye on.

However, it is December and it’s a time of year when we would expect the weather to throw everything at us apart from the kitchen sink.

The reason for the active weather in the coming days is cold Arctic air colliding with milder sub-tropical air in the mid-Atlantic, giving a strong temperature contrast over a relatively short distance.

hillsnow_bluesky_g_wp

As the speed of the jet stream is driven by temperature contrasts in the atmosphere, this will give it a boost – hitting 190mph five miles up in the sky on Thursday.

This will spawn a deep area of low pressure that will first of all bring us some very windy weather on Thursday, followed by a burst of Arctic air on its backside as it pulls away into Friday.

Strong wind

As the deep area of low pressure passes just to the north of Scotland during Thursday, there’s going to be a spell of very windy weather – especially for the northern half of the UK.

stormy_lighthouse_g_wpScotland, Northern Ireland, as well as northern parts of England and Wales, will see gusts as high as 70mph coinciding with the morning rush hour. Exposed coasts and hills in northern Scotland could see gusts a little stronger at 80-90mph.

This strength of wind will have the potential to cause some problems, with a risk of a few trees and power lines being blown down, as well as some disruption to transport. The gales will also generate some large waves which could give localised coastal flooding.

For the rest of the UK, it’ll be windy, but not as windy as further north, with gusts of 40-60mph.

Cold air and snow

As the area low pressure pulls away later on Thursday, the wind will change to come from a northerly direction, allowing very cold Arctic air to flood southwards into Friday.

This will give some snow showers to coasts and hills exposed to the wind, however, significant snow fall is likely to be confined to northern Scotland. Here, 2-5cm could accumulate on low ground, with 10-20cm over the higher hills and mountains.

For most of us, though, there won’t be any snow at all – just sunshine and a raw wind accentuating the chill.

Temperatures on Friday will be around 0-3C for Scotland and northern England, with 3-8C elsewhere.

Milder this weekend

Despite some of the recent Daily Express headlines claiming that the UK is in for 100 days of heavy snow, the cold weather is only going to stay with us for a day before temperatures pick up to average this weekend.

winter_sunshine_g_wpLooking further ahead, the key to what happens later in December depends on where a big area of high pressure grinds to a halt.

At the moment, there’s a split in its potential position, with some weather models bringing the cold weather back mid-month, whereas others keep it mild.

In the meantime, 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

5 reader comments

  1. Paul Weaver says:

    I am glad I was directed to your blog Liam. It is refreshing to get an educated and balanced forecast opposed to the hysterical, scare-mongering, front page headlines I keep reading and am quite sick of. News of your blog is spreading fast, we cannot change the weather that is coming our way but it does help to have a level-head when reporting it – many thanks

  2. George Marsh says:

    Thanks Liam for a constructive forecast. I check what you have to say most nights.

  3. ashley haworth-roberts says:

    My recent thoughts about the Daily Express can in fact be read here:
    http://www.bbc.co.uk/blogs/paulhudson/posts/A-look-back-at-autumn-and-forward-into-early-winter#dna-comments

    Whilst the Met Office generally do better than the private self-appointed forecasters (and I believe Channel 4 like the BBC largely relies on them) they sometimes either get it wrong or change their initial forecast (this week the Met Office and/or the BBC have downgraded the cold air/snow showers warning for the UK on Friday but also upgraded their wind warning for Scotland on Thursday).
    It does look like a nasty storm is on the way for areas to the east of the UK Thursday into Friday eg Denmark. A low of around 963 mb over Sweden according to current charts on the Met Office website.

  4. Linda Joy says:

    Many thanks as usual for an informative blog. I just wish more professionals would mention the jet stream as it gives such a logical background to your forecast!

  5. Jeff Killicoat says:

    Totally agree with other posts,keep up the good work !

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