This is the Met Office UK Weather forecast for the next 10 days 25/09/2024. After a very wet few days more rain this week is expected to cause further flooding, but what happens next? Bringing you this 10 day weather forecast is Alex Deakin.
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00:00Thanks for joining me for this Met Office 10-day trend.
00:03If you're watching on YouTube and you like these longer form
00:05videos, then don't forget to hit subscribe,
00:08and you'll also be able to see our exclusive deep dive videos
00:12that we do every Tuesday.
00:13But this is the 10-day trend.
00:14Plenty going on, as always.
00:16Lots actually going on in the next four or five days.
00:19And we'll deal with the shorter term first of all.
00:22It's been a very wet week, and this kind of explains why.
00:25This is the jet stream, a fast-moving ribbon
00:28of air high up in the atmosphere that's
00:30been spinning up and pushing low-pressure systems our way.
00:33It's a south-shifted jet, and that's
00:36why we've seen a series of low-pressure systems.
00:38That's why it's been so wet.
00:40What's happening in the next couple of days,
00:41the jet's actually carrying another low up
00:43towards Scandinavia, but it leaves behind this one.
00:46And that only slowly meanders across the southern half
00:49of the UK over the next 48 hours,
00:51generating further heavy rain.
00:54And after such a wet start to the week,
00:56that is likely to cause some further problems.
00:58Let's look at the rainfall then in detail.
01:00This arm of rain spreads north and then
01:02pivots and sits across particularly north-east
01:05England during Wednesday night and into Thursday.
01:07We may also see what's called a standing wave,
01:10generating some heavier rain a bit further west.
01:13But the main focus, the main concern,
01:15is the rain feeding in from the North Sea
01:18across north-east England.
01:19Then in the south, some heavy showers generated.
01:22And then we see this band of rain sinking south,
01:25the colder air slipping south, hitting the warmer air.
01:27And that's likely to generate lines of heavy downpours
01:31during the course of Thursday night and into Friday,
01:33potentially affecting the already flooded areas
01:36and, again, likely to cause some further disruption.
01:40Let's take a look at the rainfall amounts
01:42we're expecting.
01:42The rain is spreading its way northwards.
01:44These are the 12-hour rainfall accumulations.
01:47And with the winds coming in from the North Sea,
01:49you can see those rainfall totals really building up,
01:51yes, over the hills, but also close to the coast there.
01:55So, again, we could see some further disruption,
01:58some further flooding is possible.
02:00And then the attention moves further south with the showers.
02:02Notice the spiky nature of the downpours
02:05and then potentially these lines of heavy showers
02:08sitting somewhere across England and Wales
02:10during Thursday night and into Friday.
02:13Some uncertainty about the exact location
02:15of those lines of heavy rain,
02:16but they could potentially affect
02:18the already flooded areas.
02:19So, Met Office, yellow warning in place
02:21through Wednesday night and Thursday
02:24for the northeast of England.
02:26We'd have to keep our eye on Northern Ireland as well.
02:28Some heavy rain is also possible here.
02:30And then for Thursday night and into Friday morning,
02:33a broader area across the south.
02:36Not everywhere in here is going to see
02:38torrential rain, far from it.
02:39But that's the risk area for those narrower
02:42bounds of heavy rain.
02:43And, of course, the previously flooded areas
02:46very susceptible to any further rain,
02:48which could cause further disruption.
02:50For the full details of the Met Office warnings,
02:52check our app and our website.
02:56Okay, that's the shorter term,
02:57that low pressure system,
02:58though starting to pull away during Friday morning,
03:01still bringing some heavy rain for a time.
03:04But as it pulls away,
03:05what happens is it opens the isobars up.
03:08The winds will be coming down from the north
03:11the next couple of days,
03:12pretty chilly across Northern Scotland.
03:13But come Friday, that colder air floods further south
03:16right across the UK.
03:18So, we'll all see that chill,
03:19particularly Friday night.
03:21The weekend is going to start fairly fresh
03:23with the cold air in place.
03:25But also coming in is a little ridge of high pressure.
03:29So, that should at least bring the south,
03:32which will see the heaviest rain over the next 48 hours,
03:35a dry spell through the weekend.
03:36There's low pressure nearby to the north.
03:38We will see some showers.
03:39And yes, look at this,
03:41waiting in the wings for Sunday night and Monday.
03:45More on that in a moment.
03:46But let's, first of all,
03:48kind of sum up the weekends
03:50because we know it's going to be a chillier start
03:51with those northerly winds bringing that fresher air,
03:54but it probably won't last too long.
03:56And with a ridge of high pressure across the south,
03:59the weekend, thankfully,
03:59looks a lot drier for England and Wales.
04:01There will be some showers
04:03across parts of Scotland and Northern Ireland,
04:05but nothing like the heavy downpours
04:06we're going to see across the south
04:08in the next 48 hours.
04:10However, as we go into next week,
04:12we are keeping our close eye on things in the Atlantic.
04:15Just showed you that area of low pressure that's moving in.
04:18Let's take a closer look at that now
04:19because that's the biggest uncertainty,
04:21I'd say, in the medium range forecast.
04:24The jet stream dipping to the south
04:26as we go through the rest of this week
04:27and then toppling up to the north,
04:29allowing that little ridge of high pressure to move in.
04:32But this little streak is quite interesting.
04:35That's the key player
04:36as we head into Sunday night and into Monday.
04:39If we rewind what the jet stream is doing
04:41and then put on what that means for the surface pressure,
04:44it's this dip in the jet stream,
04:46allowing that low to sit across the UK for the next few days.
04:49That clears away.
04:50Then we see that ridge of high pressure moving in.
04:53But then this little pulse of the jet streak
04:59is actually likely to spin up an area of low pressure
05:02somewhere out to the west of the UK.
05:04But it's a small little feature and this is five days ahead,
05:07but it could have quite a significant impact
05:09because it could turn this low
05:10into quite a substantial area of low pressure.
05:13It's likely to bring a spell of wet and windy weather
05:16across particularly Western parts
05:18as we head through Sunday night and into Monday.
05:20But there is quite a bit of uncertainty
05:22about the position and intensity of this low.
05:25And it's all to do with just how strong
05:27the jet stream is going to be.
05:28Now this is the Met Office model,
05:30what we've just been looking at really,
05:32but we've changed the colours around.
05:33Now the jet is in the yellow here
05:35and you can see there's the arm
05:37of the jet pushing to the north,
05:39allowing the ridge to build in for the weekend.
05:40But it's this little feature, this little jet streak,
05:43kind of breakaway small feature
05:44that's going to spin up that area of low pressure.
05:48That's the Met Office model.
05:49But if we look at what the European model is doing,
05:52it's similar, it's got that kind of ridging,
05:55the jet stream arching to the north,
05:58but it doesn't have the same little jet streak to the south.
06:01It's more one continuous jet,
06:04which means the low pressure system
06:06that's in amongst there won't become as intense,
06:11won't get spun up as much.
06:12And it's likely to be much more south shifted,
06:15which means there's quite a bit of uncertainty
06:18about what the rainfall will look like for Monday.
06:21And that's shown in this map here.
06:23This graphic is showing where the rainfall
06:26is likely to build up in the Met Office model
06:30and the European model shown side by side
06:32for the 36 hours from midday on Sunday
06:35all the way through to the end of Monday.
06:37You can see quite a difference.
06:39Many Western areas will be wet in both scenarios,
06:42but actually the heaviest rain, the red colours there,
06:45really focus across Western Scotland and Northern Ireland
06:47because that's the Met Office model
06:48which spins the low up and pushes it further north.
06:51Whereas the European model doesn't have
06:54such an intense air flow pressure
06:55in terms of its wind strength,
06:57and it's all a bit further south.
06:58So the heaviest rain is across South Wales
07:00and Southwest England.
07:01So quite a disparity there
07:03in the two main computer models that we look at.
07:05We also look at other models.
07:07This is the American computer model,
07:09which is a coarser resolution.
07:11So you don't get as much detail.
07:13It's somewhere in between,
07:14but it is closer to the European model
07:16with the heaviest rain close to South Wales there.
07:19So quite a bit of disparity there about Monday's rainfall.
07:23That's in the main deterministic weather models
07:28that we use when you just look
07:29at the main computer model run.
07:30But of course, if you watch the 10-day trend regularly,
07:33you'll know that we often look at ensembles.
07:35That's a better way of looking
07:37at these medium range forecasts
07:38when you run the model many, many times.
07:41And that's what we've got here.
07:42This is the Met Office ensemble
07:43showing the different potentials,
07:46the different members, each one,
07:47a different kind of future in a multiverse, if you like.
07:51And they're showing the disparity here.
07:53That's the main computer model run
07:54with that deep low up to the Northwest.
07:57Member number one is pretty similar.
07:58But if we take a look at some of the others,
08:01they're quite similar to the European model.
08:03For example, number 11 there has a weaker low
08:07and a further south.
08:08And number eight is also further south as well.
08:11So quite a spread, as we say, in the potential solutions.
08:14So for Monday, there's quite a bit of uncertainty,
08:17more so than usual about what's going to happen.
08:21And that's also shown here on this.
08:23I like to call this the confidence-o-meter, if you like,
08:26where we look at how confident we are in the forecast
08:28based on how similar the computer models
08:31and the ensemble members are.
08:33Dates going along the bottom.
08:35The average confidence is this line here.
08:39And the actual is represented by this solid line.
08:43And when the solid line is above the average,
08:45we have the green shading,
08:47suggesting we're more confident than usual.
08:49And the red is less confident.
08:52You can see that confidence really drops off there on Monday.
08:55So a big dip and actually stays in the red zone
08:58for much of next week,
09:00suggesting we don't have a lot of confidence
09:01or certainly less than normal
09:03in the longer range forecast into next week.
09:06We're pretty happy that a spell of wet and windy weather
09:09will hit the UK early next week,
09:10but the details remain fairly unsure.
09:13So do keep up to date with the forecast
09:16because that could be quite a lively spell of rain.
09:18But of course, any extra rain falling
09:20is potentially going to cause some problems
09:22after such a wet week.
09:25This is the pressure trend through next week.
09:28We've shown these before, of course, on the 10-day trend.
09:30Blue is lower pressure, more likely.
09:33Red is higher pressure, more likely.
09:35And I want to show this
09:35because it just gets very wishy-washy through next week.
09:39Actually, a couple of runs ago,
09:41the previous computer model runs, of course,
09:42going down the side here
09:44and the dates going forward along the top.
09:46A couple of model runs ago,
09:48there was more blue on the chart for next week,
09:50suggesting it was more likely
09:51to be low pressure and unsettled.
09:53But now in recent runs,
09:55we have higher pressure a little bit closer.
09:58So yeah, just adding to that uncertainty through next week.
10:01But this is the most likely pressure set up,
10:04certainly from Tuesday onwards
10:05once we've lost that low that's coming in on Monday
10:08with low pressure somewhere up to the Northwest,
10:10high pressure trying to build in from the South.
10:12But if this high is closer,
10:14then we'll have more settled weather.
10:15If the low is closer, then we call that more cyclonic
10:18and we're likely to have more showers.
10:19But either way, in this kind of pressure set up,
10:22the most likely is that the winds are going to be coming in
10:24from the Northwest,
10:25and that will generally mean temperatures
10:27are around or below average
10:30and generally leading to a fairly showery set up.
10:33So the second half of next week
10:35generally looks calmer than the next four or five days,
10:39generally a mixture of sunshine and showers
10:42with those temperatures, as I said,
10:43with a northwesterly wind likely to be close to
10:46or somewhat below average.
10:48Please do keep up to date with the forecast,
10:50particularly as developments towards Monday.
10:53And also do keep up to date with those Met Office
10:56weather warnings that are in place.
10:58The best way to do that, check our app
11:00or of course our website, as I said at the start.
11:02If you're watching on YouTube, hit subscribe.