10 Day Trend – Changes on the way but any sign of snow?
After a fairly sedate start to the year the weather wakes up a bit in the coming days, but snow fans shouldn’t get too excited as westerly winds are most likely to dominate next week. Alex Deakin has the details.
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00:00Welcome along to the Met Office 10-day trend that takes us into February, and the weather
00:05is looking livelier, more changeable over the next week or so. However, if you're a
00:10fan of the white stuff, if you're a snowmantic, I'll be honest, there isn't a lot to get excited
00:15about. Our weather is kind of on a repeat pattern at the moment. High pressure has been
00:21dominating certainly across the southern half of the UK for most of January. Further north,
00:26we have had lows and weather fronts, and we're going to see another one drifting south during
00:29Thursday, bumping into the high pressure and fizzling out. The high builds in behind,
00:35and so we're going to see a repeat through the weekend with weakening weather fronts
00:38drifting southwards, hitting that area of high pressure. However, we could see something
00:44of a mix-up, a change to that pattern come Sunday as this area of low pressure looks
00:50to develop. We'll have more on that in just a moment, but first of all, let's get back
00:54to the rest of this week and that repeating pattern, because even within that, there's
00:58some really quite interesting features to pick out, and quite notably, the isobars really
01:03squeezing together there behind this area of low pressure across northern Scotland on
01:08Thursday morning. Through Wednesday night, the early hours of Thursday, some very strong
01:13winds across northern Scotland, especially Orkney, and we do have a Met Office yellow
01:17warning in place. This weather front will then swing southwards and move away a lot
01:23of the clouds, so offering some brighter skies for most on Thursday before we see
01:28that next weather front drifting southwards during Friday and Saturday. Again, the isobars
01:32pretty close together across the north. For the rest of this week, we are going to see
01:36some windy spells, particularly across the northern half of the UK, something a bit brighter
01:41certainly for most of us on Thursday, but the weather generally a bit more changeable,
01:45but also it is going to be milder. Then we have to look at Sunday. I said a minute ago,
01:52let's focus in on this area of low pressure because moving in towards the UK looks like
01:57quite a deep affair, doesn't it? Lots of isobars on the chart. There's weather fronts likely
02:01to bring a spell of heavy rain as well, so some wet and windy weather is likely, but
02:06exactly where and exactly when, that's open to quite a bit of doubt. This is the projection
02:12from the Met Office main computer run, but obviously, we look at other computer models
02:17and the European model has a deep area of low pressure, but in quite a different position,
02:23a fair bit further north and west. In this scenario, yes, wet and windy weather across
02:29maybe Northern Ireland and parts of Scotland, but a good part of England and Wales on Sunday
02:33in this scenario will be largely dry and fine. That's the deterministic or the main run from
02:39the European computer model run, but if you're a fan of the 10-day trend, you'll know that
02:44for medium and long-term weather forecasts, we often run the computer models several times.
02:50We call these ensemble forecasts and this is an example of that. The Met Office projection,
02:56the ensemble forecast where we run the model lots of times and this is just a handful of
03:01those models for that same time for that midday picture on Sunday and you can see the control
03:06there has the low to the northwest. Other examples, number 9 and 10 here have something
03:10similar with a deep area of low pressure to the northwest, but others like number 6 and 7
03:15barely have a low pressure at all and that just signifies quite a bit of uncertainty
03:21about Sunday's forecast. Let's look at why there's uncertainty now and for that, we need to
03:27rewind and head back to Saturday and watch this area of low pressure actually kind of form way
03:33out in the Atlantic. It's going to interact with the jet stream, that's what picks it up,
03:38that's what intensifies this low and it moves it from a fairly weak area of low pressure on the
03:45warm side of the jet. As this arm of the jet dips down, we call this little trough, it picks up the
03:51low, intensifies it as it moves across to the cold side of the jets, but those interactions are very
03:58subtle and a slight shift or slight change in the position of the jet stream will move that area of
04:05low pressure quite a bit. And what's happening on the other side of the Atlantic is actually
04:09influencing the shape of the jet stream. This area of low pressure, set to bring some very
04:15wintry conditions to parts of eastern Canada at the weekend, may well interact with the jet and
04:19affect how far north that jet stream goes and therefore how it interacts exactly with our area
04:27of low pressure. So there's lots going on, that's why there's quite a bit of uncertainty about Sunday
04:33for the moment. It's best to say there is a possibility of quite a wet and windy spell, so
04:39stay tuned to the forecast as things develop over the next several days. What happens beyond that
04:46and looking at next week? Well, we know we're going to start with the jet stream in this kind
04:49of position, this kind of amplified arching down across the UK and in here that's where the high
04:56pressure is likely to then build back in. So that's the broad picture through next week, but
05:02as that low clears away it is likely to leave the winds coming down from the north or northwest
05:08on Monday. So Monday is likely to bring quite a cold day depending on exactly where that low
05:13pressure shifts through. We're likely to be in the wake of it bringing a cold feel with a mixture of
05:18sunshine and showers. And then beyond that, well it looks like this kind of pressure pattern will
05:23dominate. Low pressure through next week will continue to push up towards Iceland and high
05:29pressure instead of sitting close to the UK looks like controlling things but from further afield,
05:35from further down to the southwest. So this is the broad picture, the broadly expected pressure
05:40pattern for much of next week and if this is the case then the winds are obviously going to
05:45mostly be coming in from the west. Quite brisk winds at times, particularly close to the low
05:50across the north, but westerly winds always coming in from the Atlantic are never going to bring
05:56particularly cold weather. Now this is the probabilistic pressure trend through next
06:01week from the European model. We've shown these before on the 10-day trend and throughout January
06:06we've shown them because they've been entirely red suggesting that high pressure has been
06:11going to dominate as it has been. But you can see a change here through the dates next week,
06:17the colours changing there, hints of low pressure, high pressure, no real strong signal but
06:23just indicating that things are going to be more changeable through next week.
06:28However there is a strong signal if we look at the flow where the winds are most likely to be
06:33coming from. Blue is westerly winds and you can see an awful lot of blue on that chart right
06:39throughout next week going down here the previous computer model run. So we've got a lot of confidence
06:44that westerly winds will be the dominant feature through next week. As I said that's going to bring
06:50mild air off the Atlantic and that's shown here with the temperature projections. This one's for
06:55Hull but I could have picked almost anywhere across the UK. The red box and whiskers plots
07:02showing the maximum temperatures and you see that rise over the next few days so it is getting mild
07:06at this week. A bit of a dip into the weekend but also notice the plots get bigger suggesting
07:12there's more uncertainty and that's as we get to Sunday with the position of that low. But even
07:17though there's a bit more uncertainty throughout next week those box and whiskers plots tend to be
07:22above that red line which is the average line. So suggesting that temperatures will remain around or
07:28above average through next week as westerly winds will dominate. So that's the main themes for next
07:33week. As I said not too much if you're a snow fan to get excited about at this stage. Westerly winds
07:38dominating temperatures mostly above average. There will be showers around particularly across
07:43the north something a little drier further south. Make sure you stay up to date with the very latest
07:48particularly with Sunday in mind and subscribe to our YouTube channels. You'll never miss a forecast.