10 Day Trend 18/09/2024 – Storms on the way
This is the Met Office UK Weather forecast for the next 10 days 18/09/2024.
After a fine week the weather is changing with thunderstorms n places this weekend.
Bringing you this 10 day weather forecast is Alex Deakin.
After a fine week the weather is changing with thunderstorms n places this weekend.
Bringing you this 10 day weather forecast is Alex Deakin.
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NewsTranscript
00:00Hello. A couple of big changes in our weather patterns likely over the next 10 days or so.
00:05And yes, that does mean we are likely to see some wet weather.
00:09The bigger picture, though, showing the settled conditions we have at the moment.
00:13The reason why we've got the jet stream way up to the north,
00:16taking low pressure systems up across Iceland and to the south of it,
00:20allowing this high to dominate.
00:21It's been with us all week and it will continue to stick around.
00:26But some slow changes will introduce some significant changes as we head towards Friday and Saturday in particular.
00:34Notice this kind of arm of the jet stream develops a bit of an easterly high up in the sky,
00:39and that will start to change things a little.
00:42And then we'll see a bigger change as introduces low pressure coming up from the south and the high kind of waddles away up to the north and the east.
00:52And this low pressure heading in is going to introduce much more in the way of showers,
00:56some heavy ones likely this weekend across the south, although much of the north will still stay dry.
01:02Let's rewind the clock and look at the next couple of days, because with the high pressure in control, we've still got an easterly breeze.
01:08So just like on Wednesday morning, we'll see the cloud coming back in to start Thursday and then it should melt back to the coast.
01:15Parts of the east coast may stay a bit grey and then that easterly wind will blow that cloud back inland overnight.
01:22Generating another fairly cloudy starts to Friday.
01:25Notice all the while with an easterly wind, it's Northern Ireland or Western Scotland favoured for clearer skies.
01:32So generally speaking, the weather patterns are kind of stuck for the next few days.
01:36This is the chart for Friday.
01:37So it's similar to Wednesday in that the high pressure is up to the north and east.
01:42The low is not really with us at this stage.
01:44We've got an easterly wind, but this is what's going on at the surface.
01:48There's something stirring higher up.
01:51We're starting to see that little arm of the jet stream develop.
01:54And this chart shows that actually colder air is moving in high up.
01:59This is the temperature profile, but not at the surface at 500 hectopascals, around five and a half kilometres up in the sky.
02:08And you can see the blues here.
02:10That's a cold pool that's moving in across southern Britain, high in the sky.
02:16And what that does, it allows the air to rush up more readily.
02:21We know that warm air rises.
02:22But if you introduce colder air higher up, then that warmer air is going to rise more quickly.
02:28And faster rising air generates more in the way of showers.
02:32And this is what we call a cold pool.
02:35And that is going to generate, say, some pretty heavy showers during Friday.
02:38So it generally starts dry.
02:40But as that colder air moves in higher up, look at these showers getting going across the Midlands, South Wales and southern England.
02:48Now, it's going to be showery, so it's going to be hit and miss.
02:50But some heavy downpours are likely, rumbles of thunder, even a few hailstones.
02:55Further north, the weather is generally set fair.
02:57We've still got the easterly wind, so parts of the east coast likely to stay a bit grey.
03:01But it'll be western Scotland and parts of Northern Ireland that stay fine and dry.
03:06Not quite as warm as earlier in the week, but temperatures could still get into the high teens or low 20s here.
03:11By the time we get to the weekend, it's not just what's going on high up that's destabilising things.
03:17But low pressure, even at the surface, is moving in.
03:20And that's going to bring some further heavy downpours, increasing risk of thunderstorms on Saturday.
03:25And then this weather front may well bring some more persistent rain by the time we get to Sunday.
03:29Details of exactly where these weather fronts lie and where this low pressure sits still open to a little bit of doubt.
03:36This is the ensemble, the postage stamps, as they're known, when we run the computer model many, many times.
03:43This is showing the rainfall building up throughout the 24 hours of Saturday.
03:48Now, you probably can't pick out much detail there.
03:50But if we zoom in, we can see that they're all telling a similar story with the brighter colours, the reds and the pinks,
03:56indicating some heavy rain likely close to or across the southwest.
04:00But notice there are a couple of members, a couple of these postage stamps where the rain isn't across the UK.
04:07It's further south, number 23 there and behind me, number 11 as well.
04:10But most of them do have some heavy rain across parts of Wales and southwest England in particular.
04:16So a bit of uncertainty about the detail, but we are likely to see some heavy and thundery showers across the south into the weekend.
04:23All the while, likely to stay pretty good across western Scotland, dry and bright with sunny spells and much of Northern Ireland, too.
04:30And all the while, that easterly wind will continue to bring some mist and low cloud along parts of the east coast.
04:37So that's the weather set up through the weekends.
04:40Could we see a bigger change as we go into next week?
04:43The jet stream still in evidence way to the north of the UK, but weakening.
04:47It's what's going on out in the Atlantic.
04:49That's likely to mix things up as we go through next week.
04:53We're getting a more of a classic jet stream, if you like, picking up.
04:56These are the winds high up in the sky.
04:58Remember where the jet planes fly and the jet stream tends to steer low pressure systems.
05:04It's getting more lively and it's getting more south shifted.
05:08So that's likely to bring low pressure systems our way.
05:11And this is the pressure pattern from the European model for next Tuesday, showing quite a potent looking area of low pressure down to the south and west of the UK.
05:20Likely to be developing out in the Atlantic, but still could bring us a spell of wet and windy weather at some point through the early to middle part of next week.
05:29Now, the low pressure that's bringing us the rain and the showers in the south this weekend, that's likely to be clearing away at this stage.
05:34So actually, there may be a window on Tuesday where much of the UK is fine before this weather system arrives.
05:40But it's likely that low pressure will then continue to dominate our weather through much of next week.
05:46This is the most likely set up for Wednesday of next week, with low pressure sitting pretty much slap bang over the UK, showing some pretty heavy rain likely.
05:55And again, this is a more south shifted low pressure.
05:58So the south more susceptible in this set up to wet and windy spells.
06:02And even the most likely pressure pattern pressure anomaly, I should say, on this chart for Thursday shows low pressure sitting to the east of the UK.
06:11Now, maybe it's just one area of low pressure.
06:13It may be a number when the jet streams that active.
06:15We could see more of them spinning up.
06:17But all in all, low pressure is this close to the UK.
06:20It is likely to generate spells of wet and windy weather.
06:24And this chart is showing that strong flip in wind directions that we're going to see with the high pressure nearby.
06:31We've got easterly winds at the moment.
06:33Now, this isn't the high low pressure that we often show in the 10 day trend.
06:37This is the zonal trend.
06:39This is basically telling us what flavour the weather is in terms of easterly or westerly winds, where red is easterly and blue is westerly.
06:48These are the dates going forward along the top.
06:51These are the previous computer model runs.
06:53And look at that solid red for the easterly winds that we're pretty confident going to be the big feature of our weather for the next few days.
07:00And then we see that flip into the early part of next week, Monday, Tuesday.
07:04And then for the second half of next week, we're into the blues.
07:07So westerly winds much more likely through the second half of next week.
07:11So we're going to see that change.
07:12We've got westerly winds.
07:14We're much more likely to see spells of wet weather coming in from the Atlantic.
07:18So certainly from Monday onwards, much more changeable look to next week.
07:23There may be some fine spells, but generally speaking, low pressure nearby.
07:27Some heavy rain is likely and some gusty winds are also possible to for the day to day details.
07:34As you go through next week, please do stay up to date with the latest forecast.
07:39And of course, as we see those heavy showers developing across the south over the next few days, keep up to date with that as well through our app and our websites.
07:47And of course, watching this on YouTube, don't forget to hit subscribe.