This is an in-depth Met Office UK Weather forecast for the next week and beyond. High pressure is here and, while the heat won't last more than a couple of days, it looks like that the settled weather will. . Bringing you this deep dive is Met Office meteorologist Aidan McGivern.
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00:00Dry, sunny and hot. Is this a sign of things to come? I'm going to be talking about how the UK's
00:07weather patterns are likely to change or not to change during the next couple of weeks and
00:13for the rest of the century. That's right, I'm going to be joined a little bit later on by
00:18Met Office climate scientist James Pope who's going to be talking about a study in which he
00:23and other colleagues performed looking at how our weather patterns are likely to change as a result
00:28of global warming. So that's going to be a really interesting discussion and of course before we
00:33get on to that I'm going to be talking about how high temperatures are expected to get during the
00:38next few days in this remarkable, albeit relatively brief, hot spell. Thank you for joining me, this is
00:43the Met Office Deep Dive, an in-depth look at the UK's weather that we do every Tuesday. If you're
00:49new to this then why not hit subscribe on our YouTube channel because you'll then never miss
00:54one of these when they pop up on a Tuesday and don't forget to shout about it to your weather
00:59loving friends. Now as you can see on the screen behind me we've got a classic summertime scenario
01:06for the UK with high pressure sitting very close to the country and the jet stream pushed to the north.
01:14The jet stream across the Canaries, Madeira, the Azores is diving south and there's this area of low
01:21pressure which again is bringing some changeable weather to Iberia. This is a familiar pattern
01:25that we've seen repeat itself during the last few months and at the moment it is bringing higher
01:32temperatures. Each day warmer than the last. The reason is not because we're importing warm air from
01:38the south. There isn't much warm air to the south in fact. Parts of the Mediterranean are cooler than the
01:45UK at the moment. No what's happening is that cloud-free skies at the moment strong solar insulation
01:52means that day by day the air is warming up. The sun of course at this time of year is as strong as it
01:58is in August and under an area of high pressure the air tends to sink and that sinking air a bit like
02:06when you pump up your bike tires tends to get compressed and warm up. So that's what we're seeing
02:11at the moment. We're not importing warm air from anywhere else. This is homegrown warmth and
02:15temperatures are in fact expected to rise during Tuesday into Wednesday. That high pressure not
02:22moving far. It's always just to the east of the UK for the last day of April and the first day of May.
02:29But a subtle change then starts to take place through Thursday. As you can see a cold front begins to
02:33drift south across Scotland and Northern Ireland. It's of course running into high pressure so it's not
02:38going to bring much rainfall but it is going to bring a marked temperature downturn. And by Friday
02:45that front is introducing cooler air across many parts of the UK although not all. I'll come on to
02:53that in a moment. But you can see those cooler colours there into the north in particular. Still
02:57some warmth clinging on in the southeast. By the weekend we've got that cooler air slowly making
03:04in roads across the whole of the UK. Temperatures for most back to average and in fact by Sunday
03:11we've got a bit more of an easterly or northeasterly airflow for much of the UK particularly towards
03:18the east. So actually temperatures below average by this stage feeling much much cooler on that north
03:23sea coast warmer towards the west. However that's not the only story as we go into the bank holiday
03:29weekend. You might be thinking typical as we go into bank holiday weekend the weather
03:32deteriorates. But I wouldn't say it deteriorates because we've still got high pressure nearby.
03:38All that's happened is that the centre of gravity of that high has moved from just to the east of the UK
03:44and into Thursday and Friday it's going to be sitting more to the west. So we've got more of an
03:49Atlantic feed of air and in fact on later Saturday and into Sunday the ice bars are pointing more
03:55towards the north. So a change of wind direction but that high pressure then edges a bit closer in
04:01again during the weekend. So actually a lot of fine weather continuing and the main talking point
04:08over the next few days will be the temperatures. Not for everyone of course but certainly for much
04:14of the UK those temperatures are going to be remarkably high for the time of year. This is just a snapshot
04:19over the next few days of typical temperatures across the UK, typical maximum temperatures. But we can
04:25take a closer look. We can zoom in. Let's fast forward to Wednesday first of all. And if I zoom in here and are we showing the right?
04:40There we go. I think that's showing the right one. We'll soon find out. There we go.
04:44So I can draw on the map here most likely maximum temperatures. And as you can see Wednesday afternoon
04:52we're into the mid-20s fairly widely. 26, 27 in places. 28 is the most likely high temperature
05:01on Wednesday somewhere between London and Bristol. But even further north into northwest England you
05:10can see temperatures of 25, 26 or even 27 Celsius through the Vale of York there. 26, 25. So the warmth
05:18is fairly extensive. 22 Celsius there for Edinburgh. Southern Scotland fairly widely in the low 20s.
05:25Northern Ireland likewise. Interestingly I looked a little earlier on at Northern Ireland's temperatures
05:32last summer and I believe there was only one day in the whole summer in which temperatures in Northern
05:38Ireland exceeded 25 degrees. And we're getting close to that tomorrow on the last day of April.
05:43So yeah across much of southern Scotland high teens low 20s. But quite a bit cooler there for the north
05:52of Scotland we're talking about 13 and 12, 14 for Shetland. Now that's the last day of April. Headline
06:00maximum temperature 28 Celsius. There's always the possibility that the temperature will be a degree or so
06:06either side of that. And that's particularly remarkable because the actual record maximum
06:12temperature for April is 29.4 Celsius. So it wouldn't take much of an error in the forecast
06:19maximum temperature of a degree and a half or so for Wednesday to be the hottest day on record in April
06:27for the UK. But that's not what we're going for is the most likely scenario at the moment. We're talking
06:32about 27, 28 Celsius across southern parts of England into East Wales. Thursday though we are
06:40likely to see temperatures upwards up above that April all-time maximum 29.4 degrees. But of course
06:49Thursday is the first of May so it wouldn't be a record. The record for May, the highest temperature
06:55ever recorded in May in the UK is 32.8 Celsius. As you can see temperatures a degree or so higher
07:02across the board on the first day of May. 27 Celsius showing up there for London. But if I move the pen
07:10around here you can find a few spots that are showing 29 or 30 Celsius. Now we're a couple of days
07:18away and there's always going to be a little bit of uncertainty about how well the model is predicting
07:23the temperatures on Thursday two days time. Again there's going to be an error of a degree or so.
07:29The most likely temperatures that we're expecting is 29 Celsius somewhere like London or again somewhere
07:36like Bristol into southeast Wales for example or actually quite widely into the east of England,
07:45northwest England. We're talking about the mid to high 20s. So most likely maximum temperature on
07:52Thursday the 1st of May 29 Celsius. But there's the possibility, a smaller chance, 10-20% chance
07:58of 30 Celsius. That would be remarkable because if we saw 30 Celsius recorded
08:04on the 1st of May it would be the earliest 30 Celsius had ever been recorded in the UK.
08:11Top of my head, might be slightly wrong on this, top of my head I think the earliest
08:15is the 12th of May but the 1st of May would bring it forward significant if that happened. However,
08:22like I say, the most likely is 29 Celsius and as you can see 28-29 Celsius showing up there as a
08:30possible maximum temperature for Thursday. At the same time there's quite a significant temperature
08:36contrast because if we look further north we've got high single figures, low double figures across northern
08:42Scotland into central Scotland through the Cairngorms across the highlands into the central belt.
08:48We're talking about mid-teens. Northern Ireland also not as warm as Wednesday. And you can see that
08:56temperature contrast by the colours because I've got the fronts on here. There we go, there's the cold front
09:02position. A little bit of uncertainty, of course, on the position of that, the north-south
09:09position, but it looks likely that there'll be this significant temperature contrast across the UK.
09:15Now, by Friday those temperatures are lowering across the whole of the UK. Still the possibility
09:23of the mid-20s, even 27 Celsius perhaps in the far southeast of England, but it's significantly cooler
09:31further north and west. And then by the time we get to the weekend, we're talking about back towards
09:38average, certainly by Sunday. Those temperatures... Ah, I've got the wrong data on there. There we go.
09:49Look at that. Those temperatures are significantly down across eastern parts of the UK because of this brisk
09:57north-east wind. So interesting daytime temperatures, perhaps even more interesting overnight temperatures.
10:06Let's take a look at those
10:09before we get onto the further ahead outlook.
10:11Let's take a look. And this is Wednesday morning. So tonight, the temperatures are likely to be highly
10:19variable across the country. I'm just going to zoom in and show an example of that and then explain why.
10:25Tonight, you can see by the colours, in fact, where we're likely to see some of the warmer and colder
10:29spots. Now, typical temperatures overnight will be down into the mid to high single figures in sheltered
10:36spots away from urban centres. And that's because overnight temperatures get lower from the ground
10:43upwards. So the ground is cooling first. And so the temperature actually gets lower from the ground
10:48upwards. And that cooler air slowly gets or reaches a higher slice of atmosphere gradually
10:55through the night. That's what happens. And that's why under this kind of situation where you've
10:59got high pressure, you've got sinking air, at the same time you've got cooling air at the surface,
11:04you tend to get temperature inversion. So at the lowest layers, you get relatively cool conditions,
11:10six, seven, eight Celsius overnight as the ground cools. But you don't have to go that high up to find
11:16the warmer air, which has failed to cool down in time for the overnight period. And that's why
11:23I click on here, there are some higher parts of North Wales where temperatures remain in the double
11:31figures. And not just higher parts of North Wales, but some lower parts of North Wales,
11:37if they are benefiting from the wind coming over the mountain or the hills and then descending and
11:45mixing the air up. So that cooler layer at the surface gets mixed up with the warmer air above the
11:50temperature inversion. And that's why somewhere like Northwest Wales, not quite showing up on here, but
11:57somewhere like Northwest Wales could see 14 or 15 Celsius overnight tonight. Remarkably high for an April
12:07night. Manchester there showing 15 Celsius in fact. So highly variable temperatures overnight and even warmer
12:15night then as we go into the first morning of May, we're talking about temperatures of 16 or even 17
12:22Celsius. Again, always difficult to find an exact location because the temperatures will be so variable.
12:27In some places, it'll be three or four Celsius first thing Thursday. In other places, we're talking about
12:32mid-teens. So remarkably varied temperatures. Who knows whether one of those very warm spots will be
12:39picked up by an observation, but it'd be interesting to see what happens by the first of May. So yeah,
12:45very warm days and in some places, not everywhere, particularly over hills and just down wind of
12:50the hills, very warm nights as well before temperatures return back to average by the weekend.
12:57And finally, the only other piece of weather to talk about really are the showers. There are going to
13:03be a few showers around, but for the vast majority, just want to emphasize that for the vast majority,
13:09it is going to stay dry during the next few days until the end of the bank holiday weekend.
13:13Now, this is Wednesday and you can see some shower clouds bubbling up there across central and
13:21northern Scotland. I think there's always the chance of one or two showers developing across
13:26Northern Ireland and Northern Scotland on Wednesday. Into Thursday, there are more showers appearing by
13:33this stage across the UK and there's two reasons for that. One is the cold front that I mentioned that's
13:39coming south. And so along that, we've got this swathe of cloud and always a chance of some patchy
13:44cloud or patchy rain and a few showers or even the odd very beefy shower, thunderstorm. And then further
13:51south, we've got higher instability resulting from a slight change in wind direction and also the higher
14:00temperatures. And so really quite unstable air in the south by Thursday afternoon. But to compensate for
14:09that, we've got very dry air across the south. So that would suggest that there's the risk of a shower,
14:16but they'll be very isolated. However, where they do occur, it could be really quite lively with hail,
14:23thunder and lightning. Likewise, on Friday, a greater chance of showers across southern parts of the UK,
14:30some generally light showers in the north-west of the airflow across Northern Scotland. And into the
14:35weekend, I think southern counties of England, particularly to the south of the M4, likely to
14:41see some extra cloud and some showers coming along, likewise for north-eastern parts of the country with
14:46the wind coming from the North Sea. By Sunday, the showers in the south have disappeared and then most
14:52places are dry except for some of these north sea coasts. And the fine weather basically continues
14:57into the start of next week, which is what all of this output shows. And we talked about this
15:07decider output before here in the deep dive. I think the first deep dive that we did in January,
15:14or perhaps the second, I talked to Rob Neill here at the Met Office, who decided it would be a good idea
15:22to create these decider products. And what they basically do is they summarise more than 250 computer
15:30model simulations that look four, five, six weeks into the future and assign various weather patterns to
15:37each of those simulations. And then we can work out the probability of different weather patterns or
15:42different circulation types that affect the UK and Northern Europe and the Atlantic. And that's what
15:48this is showing essentially. So if I go to, let's see, I want to go to Monday, Bank Holiday Monday,
15:56and it's showing, skip today, edge back slightly, there we go, Bank Holiday Monday. And what this is
16:04essentially showing is the most likely top three weather patterns to affect the UK for Bank Holiday
16:10Monday. And what we're seeing is that trend in which higher pressure just moves to the west of the UK
16:17basically stays with us. So most likely high pressure just to the southwest of Ireland.
16:25The blue colours here indicate where we're most likely to see rain, Northern Scotland effectively,
16:29the rest of the UK, dry. And northwest to the airflow or an Atlantic feed of weather. So
16:35temperatures not far from average for the time of year, certainly not as hot as the next few days.
16:41And then this is the second most likely scenario. It's got high pressure just to the southwest,
16:46a little bit further south. And again, some rain for the north and northwest of Scotland,
16:51otherwise mostly dry. And this is the third scenario. So high pressure much closer to the UK,
16:56most places dry. In other words, although there is some uncertainty about exactly where that high is
17:01going to sit, it's high pressure that is most likely to be very close to the UK, maintaining
17:07settled weather. And for most this weekend, Saturday, Sunday, Monday is going to be fine. A couple of
17:13exceptions, those showers that mentioned in the south on Saturday, could be a thunderstorm or two as
17:18well. A few showers coming down the North Sea on Saturday and into Sunday as well. Feeling rather chilly,
17:26on that North Sea coast, particularly on Sunday. And more cloud, I think, this weekend because of
17:31that Atlantic feed of air. More cloud than we're seeing over the next few days and lower temperatures,
17:36back towards average. So yeah, not as hot, not as sunny, but mostly fine. Not bad at all for a bank
17:45holiday Monday. Now next week is interesting because if you were to ask me, in fact, a few people did ask me
17:53a few days ago, how's NetSuite looking? I'd have said, it's looking rather unsettled, low pressure
18:01returns. And the reason is because high pressure to the west drifts further west and allows low
18:08pressure to become centred close to the UK. But in the last few days, there's been a significant
18:14departure from that theme from the computer models, a significant trend towards that high pressure, not
18:19drifting to the west, but staying very close to the UK throughout next week. This is Thursday the 8th
18:27of May, and it shows very similar to bank holiday Monday. High pressure, most likely sitting to the
18:34west or northwest of the country and maintaining largely settled weather. Always the chance that areas
18:41of low pressure will drift close to the north of Scotland to give some rain at times, a bit more of
18:46a breeze at times as well. But for the vast majority, particularly towards the south and east of the
18:52country, it's looking largely fine. Temperatures through next week, not far from average. If we get
18:57some sunshine by the day, of course, it's probably going to be a bit above average, but not as hot as
19:01this week. Overnights, light winds, clear skies, it's probably going to be a little bit below average if
19:08that happens. So temperature's not remarkable, but as far as the dry spell is concerned with that high
19:15pressure nearby, and I know a lot of people are crying out for rain, doesn't look like away from the
19:19north of Scotland we're going to see an awful lot of it through next week because of that high pressure
19:24still in charge. And that is not going to do wonders for the rainfall totals that we're seeing across
19:33the UK this spring. Before we get into that actually, we've got the average temperature so far this
19:38spring. This shows the average temperature as it progresses through spring. That's the black line
19:44there. That's the average 1991 to 2020 average. The red line on top is the record temperature for up to
19:54that date, and we're bang on the record at the moment. This goes out to the 28th, I believe 28th of
20:02April, so yesterday, and we're right on the record. So wouldn't be surprised if it's the warmest May-April
20:09period on record. And as far as the rainfall is concerned, it also shows quite a significant
20:15departure from the average. There's the black line, the average, and we're languishing down there about
20:21half the amount of rain we should have received, or what we'd normally see in the UK at this point in
20:29spring. So half the amount of rain up to this point, and that means for the full period of spring, we're on about a
20:35third of the rainfall. It's not been dry everywhere. March's rainfall distribution shows average rain across
20:43northern Scotland, but very dry in the south, whilst April's rain up to this point shows very dry in the east, but actually
20:53rather wet, that's what the blues here show, Pembrokeshire, parts of south-west England, parts of Northern Ireland.
20:58So we have had some, certainly during the last couple of weeks, we've had some systems moving into western parts to
21:03bring some wet weather at times. But yeah, certainly here in the east, it's been remarkably dry this spring, and not just
21:10spring, a couple of months before that as well. So with the weather patterns remaining very static over the next few days, with high
21:20pressure, most likely to dominate, little sign of that rain that people are crying out for.
21:28And the big question is, is this kind of weather pattern, as we go through spring and into summer, where we've got high
21:34pressure arriving and persisting, giving us dry and very warm weather, is this likely to be more frequent in the future? Is it likely to
21:45stick around for longer in the future? Well, the man with all the answers on this is James Pope, climate
21:52scientist here at the Met Office. Welcome to the deep dive, James. Thank you, Aidan. Your full job title is
21:57science manager, the application... Ready data team. Ready data team. I wrote it down, and then I, for some
22:04reason, I wrote science manager, application manager. I think I was talking to you at the same time, can't multitask. So,
22:10this is all about the application of science, right? And the first time I worked with you, actually, was on the
22:202050 weather forecast. The weather forecast, if you've not seen it, we did this five years ago, believe it or not, in which we
22:30projected what a summer heat wave could look like in the year 2050, based on increased levels of carbon dioxide and other emissions and land use changes in the atmosphere and so on.
22:41And the work that was involved in that was UK climate projections, wasn't it?
22:47Yes. So, we built that forecast using what we call UKCP, the UK Climate Projections. It's a suite of different
22:55products. We have a statistical-based probabilistic set of projections built over many thousands of
23:01different calculations. We then also have a series of different global models that do
23:07to 28 different global climate model simulations from 1900 to 2100, and then a regional model that
23:13covers roughly this domain, actually, the North Atlantic European domain at 12 kilometers. That
23:19does 1980 to 2080. And then we have a British Isles-focused simulation at 2.2 kilometers, a really high
23:25resolution close to the weather forecasting model, again, 1980 to 2080. And these arrange different
23:31products along with some sea level analysis, and then some of the tools that we're going to talk
23:36about, such as the weather patterns. Yeah, back in 2020, when we did that 2050 forecast,
23:42we were looking at a heat wave that lasted a remarkably long period of time. And I remember,
23:48and temperatures were getting into the 40s, and this was before a temperature in the 40s had ever
23:54been recorded in the UK. Of course, it happened two years later, not 30 years later. But I remember
23:59thinking at the time, this is a remarkably long period for sunny skies and heat in the UK. And we were talking
24:08about how UK summers were projected to become hotter and drier, but at the same time, winters were projected
24:16to become wetter and milder. And one thing I was thinking about, and you must have been thinking
24:22about at the time was, is that because the weather patterns themselves are becoming hotter and drier in
24:28the summer or wetter and milder in the winter? Or are the weather patterns changing in the UK?
24:34Yeah, exactly. And that's where the research started. So I arrived at the Met Office in the summer of
24:392019. And the UK client projections have been released in 2018 with this headline message,
24:46warmer, wetter winters, hotter, drier summers. And exactly what you want to understand,
24:51was that just a climate change signal we're seeing? Or is there changes in the actual weather patterns?
24:55And because, you know, as you've been wonderfully showing here, and as you show every week's 10 day
25:00trend and videos like that, exactly where the high and low pressure sits has a real impact on the
25:06weather that different parts of the country has seen. As you highlighted just then, April,
25:10we've had a slightly damp, not damp, but close to average rainfall in sort of Cornwall, Devon,
25:16South Wales, but so dry over the east of England. And that sort of variation, those weather patterns,
25:22is really important for a range of people looking at sort of planning in future energy,
25:28water demand, but also agriculture, and a host of other sectors, even sort of transport,
25:32places like that. They're really interested in what our weather patterns do,
25:35as we go out towards 2100. Yeah, that's why it's really useful to look at these weather patterns
25:41that Rob Neil and his team developed, because they give us so much information, don't they?
25:47Yeah, and I think it's the, what's quite incredible is the model we were working with to generate these
25:53weather patterns has what we call a resolution of 60 kilometres, which means that we turn the entire
25:58surface of the world into grid boxes based around latitude and longitude. And on average, in our global
26:04models, those grid boxes were 60 degrees by 60, 60 kilometres by 60 kilometres. So they're very large,
26:11quite coarse areas, you maybe get sort of six or seven boxes over the British Isles.
26:16But we can work with the weather patterns, which work with some, you know, very large
26:20scale distribution of high and low pressure to take up a large area and take this quite relatively
26:25coarse information and distill it down into some surprisingly interesting regional variation.
26:31I've worked in the outer, with colleagues in the outer Hebrides, and we found differences between
26:36Stornoway and South East. They're about 50 miles apart, yet you can see for different weather patterns,
26:42really like interesting climatological signals already in our present day weather.
26:47Yeah, because when these weather patterns were put together, as Rob explained in the deep dive that we
26:55did back in January, the weather patterns were then fed into a reanalysis model and they could then
27:04determine in this kind of weather pattern, what kind of rainfall do you get in here and here and in this
27:10part of the UK and you get quite fine detail that other projections on lower resolution models fail
27:17to show you.
27:18Yeah, we would never be able to determine a signal like this from a global model. It'd be very,
27:23very hard. That's where the UKCP regional, the UKCP local come in because they can do that,
27:28but they're very expensive to run. Take an awful lot of time on the supercomputer
27:32and, you know, that's got a computational cost, as we talk about it, and very large data sets.
27:37The weather patterns are much more nimble. They're smaller and they allow us to work at this sort of
27:42still relatively fine scale, but with a much easier tool to work with. And you can see here,
27:47this is a great example that sort of Eastern Scotland, reasonably dry, but really quite wet in
27:53in parts of Western Scotland and over the outerities, just picking on that example.
27:57Yeah. And this is where your paper came about, isn't it? This is the paper, by the way,
28:03Pope et al. 2021 from Climate Dynamics, investigation of future climate change over
28:10the British Isles using weather patterns. It's open access. So if you type that into Google Scholar,
28:15you'll be able to find it and look at it yourselves if you fancy it. But yeah, this is where this research
28:22came about, isn't it?
28:23Yeah. And this was the output. About 18, 19 months or so we spent looking at this and analysing it and,
28:29you know, able to, really fortunate to be able to draw on some, you know, great, great people here
28:34at the Met Office. Obviously, Rob, with his sort of wonderful knowledge of the weather patterns,
28:39as you covered earlier this year. But then colleagues across different parts of applied science. And then
28:44at the end there, another, one of our other meteorologists is able to really give us that
28:48meteorological steer. So even though we're a group of climatologists looking into the future,
28:53this is a weather-based tool. So you want that sort of experience that a meteorologist has they
28:57can bring into the tool. And that's a real advantage of doing this work here at the Met Office.
29:01Yeah. And the way you use the tool, of course, is very similar to the way the tool is used
29:07on a daily basis for our weather forecasts, isn't it?
29:10Yeah. And so you were saying 250 simulations in the ensemble, run through the weather patterns,
29:16have a look at what's coming, get a percentage chance for the week ahead. And we did a very similar
29:21thing with the 28 models within UKCP. And we were able to run the model 28 times. But instead of
29:27looking at maybe a couple of weeks, a month or so into the future, we ran for 200 years. So 1900 to
29:342100. But what we were able to do is take each individual day for each of the 28 simulations and
29:41use exactly the same software, exactly the same piece of computer code that we're using
29:47today operationally to do decider weather forecasts, to do a climate projection from decider out into
29:53the future. Yeah. And there's a reason you look back, isn't there? You're not just interested in
30:00looking forward, you want to test the model as well. Exactly. To be able to look into the future,
30:06we need to be able to make sure that our model can actually do the real world currently. And that's
30:10exactly what's on this figure here. So there are two sets of boxes. These are box and whisker plots.
30:17And there's a red box, which represents what we call the PPE 15, which is 15 different versions of
30:22the Met Office model. We make small changes to the physics in the model and then run that simulation.
30:28So 15 of those, and we had 13 simulations from what we call CMIP 5. That's the coupled model into
30:35comparison project. A massive global climate modeling campaign. CMIP 7 is just in the process
30:41of spinning up and it supports IPCC reports and a lot of other climate science. So we've got those in
30:47purple. And the box and whiskers plot show the spread you'd see in the ensemble. We obviously got the
30:53winter months on the top and the summer months on the bottom. And you can see a distribution. So in our
30:58winter months here on the top, the lower number patterns are less common. We don't see those as
31:02frequently in the winter. And this is represented by a series of black dots, which you can hopefully
31:07make out. And they're from the era 5 reanalysis. So the black dots are the frequency we saw actually
31:13happen over this period. So of 1980 to 2010. And then the ensemble models, so the climate model
31:21simulations for the same period are then compared. And so you can sort of see that we're representing
31:26very low occurrence of these patterns in the winter. The higher numbers we're getting
31:31but we have more occurrence in the winter. So you're seeing that black dot, the vast majority
31:35of the simulation sitting inside the box, especially when it's inside the box, but within the box and
31:40whiskers plot itself. The ensemble range is capturing what's happening in the real world. That gives us
31:46confidence. And similarly, in the summer you get the opposite trend. So we can see that we have more of
31:52the lower number patterns in the summer. And the higher number patterns are much less frequent in the
31:57winter. Sorry, less frequent in the summer. And again, we get that trend and our dots, our black dots
32:04of what really happened is within the ensemble. Now, these climate models weren't running exact
32:09representations of those days through the real world. So for example, these black dots include
32:15the time when Mount Pinatuba erupted. It exerted a very large climate forcing for about 18 months.
32:21The climate model simulations didn't explicitly include that, but the black dots in the real world did.
32:26So we get those little bits of nuance that come out. But even with that, we're still able to capture
32:32the range of what we saw. And that gave us the confidence going forward that we could look at
32:36this as a tool. We also replicated this for the spring and for the autumn, got the same sort of
32:42result. And again, when you write a paper like this, you pick out your flagship results, but we provided
32:46all of that information in what we call a supplement. So if anyone does go and read it, they can find all
32:51that as well. It's all there and you can pour over it in detail like we did.
32:55So there's a 30 year period in which you ran 28 simulations and saw how often various weather
33:01patterns, 30 weather patterns occurred in those simulations and compared with how often those
33:07weather patterns occurred in the 30 year period. And it's remarkable how close the 30 year actual
33:15occurrences of those patterns occurred with the simulations. And like you say,
33:20these kind of stormier weather patterns occur more often in the winter in reality and in your
33:28simulations. Likewise, for the more settled summer like weather patterns more frequently in both the
33:34simulations and the actuals. And that gives you confidence then to look to the end of the century,
33:40doesn't it? Yes. But you're looking at two things at the end of the century because your analysis
33:46period was 2071 to 2099 and you're looking at two emission scenarios. Can you explain why you looked
33:54at two emission scenarios? Yeah. So we had the, we had two sorts of what you consider the end member
33:59and some emission scenarios that were available at this time. So the first one is called RCP 2.6,
34:05that's representative concentration pathway. It leads to a global warming by the end of the century
34:10of around 1.6, 1.7 degrees Celsius. So very close actually to the Paris Agreement target of 1.5 degrees
34:16Celsius. We then have another scenario, RCP 8.5, which is the very top end. It's about 4, 4.5 degrees
34:24of warming by the end of the century. It's probably worth clarifying that the current emissions gap
34:29report by the UN at the end of last year suggests that based on current pledges, we're looking at
34:34around 2.6 to 3.1 degrees of warming. So RCP 8.5 is higher than what is our current expected level of
34:42warming by the end of the century. But it's still useful to see the difference that those sorts of
34:47end members of the emission scenarios into the future mean. That gives us sort of a bracket. We can
34:52sort of think about what's our likely range, what sorts of changes will we see? So it gives us that
34:57ability to explore the uncertainty. Yeah. And the biggest uncertainty, of course, is human behaviour.
35:03How much we'll continue to emit and, you know, whether we'll be able to bring down emissions and
35:08so on. And so it's important to look at both scenarios. And coming on to the, well, the important
35:15results here. And like the previous chart, we've got winter months on the top, summer months on the
35:22bottom. And effectively, it shows this is the frequency, how the frequency of these weather patterns
35:28changes in the future, isn't it? Yeah. So what we calculate is what we call the percentage change.
35:32Right. Now, because the weather patterns have different individual small percentage
35:37change frequencies in the future, one weather pattern increasing by one percent might not be a
35:43massive change. But another weather pattern increasing by one percent of frequency would be a
35:46huge change. Okay. And that's what's represented here. So we do, we do the calculation of how much
35:51is the change divided by what was the original amount and then multiply that by a hundred. So
35:57that's why we're able to get this and why some of the changes are, you know, sort of much bigger,
36:02they look much bigger. And we're not saying that we're going to get a 40 percent occurrence of this
36:06weather pattern at this time. We're saying it's increasing by a 40 percent chance. That's its
36:11percentage change increase. And so for the winter, there's more of these down this end. These are
36:18the higher numbered weather patterns that are increasing, aren't there? Yeah. So now the blue
36:24bars are the low emission scenario, the RCP 2.6. The red is the high emission scenario, the RCP 8.5. So
36:31that's, you can already see, hopefully, as you look at these bars, that while there are some where the
36:36trend is in the same direction, not all of them are, so we do have some subtle differences into the future.
36:41What definitely comes out is that the blue bars are predominantly smaller than the red bars. So
36:48in a higher global warming world, we are seeing a stronger change to our weather patterns. And
36:54you can see that if we pick on our winter weather patterns, sort of 23, 26 and 30, all a series of low
37:03pressure, westerly conditions. So this is 23. I already had 23 picked. And this is a typical situation
37:14in which you've got high pressure near the Azores, low pressure near Iceland. This is what meteorologists
37:20call a positive North Atlantic oscillation. You typically have lower pressure near Iceland and higher
37:25pressure near the Azores. When you get even higher than normal pressure over Iceland, even lower over
37:31did I say Iceland? I meant the Azores. Even lower over Iceland, you get this enhanced westerly airflow.
37:37And that's what this is essentially showing, isn't it? Yeah. And you can sort of see that we see
37:42for this weather pattern 23, we've got this wetter conditions in Western Scotland.
37:47Um, not as wet over the rest of the country, but as you sort of, if you cycle through sort of 26,
37:53um, you can see how that distribution of rainfall starts to change. So the sort of the peak has now
37:58drifted into, uh, Southern Scotland towards the borders region. And then we're getting it also
38:03to see some in the Lake District, northwest of England. And then pattern 30, a bit more of a leaning
38:07towards the south, that low pressure has drifted from Iceland down closer to Scotland. And this is our
38:12sort of our stormiest weather pattern. This is, if we're going to see a named storm in a winter,
38:17a good number of those named storms probably originate in this sort of setup. And particularly,
38:21actually, when we have that transition through those weather patterns. And this is a common
38:25theme, isn't it? With all of the weather patterns that showed an increase in the future under both
38:29emission scenarios, westerlies. Yeah, exactly. So we're getting, and we're bringing that, so that's
38:34bringing us the wetter weather, but also because of it being a westerly flow coming off the Atlantic,
38:40we're also getting that warmer weather. So we're able to actually see in the weather patterns,
38:45this is the temperature anomaly now. So 30 is a bit less warm compared with others,
38:51still an anomaly there of 2.0, 26, likewise the southeast, 23, much warmer than average across
39:00the UK. So we're getting these warmer conditions, these wetter conditions, this westerly flow,
39:05and it's bringing the air this way. And this is what we sort of, you know, this is what, and as you said,
39:10this NAO positive setup. And that means that what we're seeing here in the winter weather patterns
39:17is exactly what we were getting from when we looked at it statistically. The statistics were
39:21saying warmer, wetter winters. And actually, even just from the weather patterns alone, not thinking
39:26about any change in the underlying climate change effect on our temperatures, on our rainfall,
39:31we would still get warmer and wetter conditions in the winter months with these sorts of weather
39:34patterns increasing.
39:35Yeah, so what you're saying is if global warming wasn't happening, but someone told us that we'd
39:43get more of these kinds of weather patterns in the future, our weather would get warmer in the winter
39:47and wetter anyway. And that's, then you're factoring in the fact that the climate is warming.
39:53Those winds coming from the Atlantic are likely to warm up as well and get wetter.
39:59Yeah, exactly. And while none of the weather patterns disappear into the future,
40:05so we could still throw up a weather pattern that brings us strong easterly conditions,
40:10and a flow from sort of Fenno-Scandinavia from Eastern Europe and those sort of, you know,
40:14maybe beasts from the east style conditions, none of those patterns disappear. The way I like to think
40:19about it is that we're changing the die. So now if I roll the die in our present day weather conditions,
40:25I've got a decent chance of rolling a one, some cold easterly conditions, or a six, wet westerly
40:31stormy conditions. What we're saying, particularly in that high emission scenario, what we're seeing
40:37is actually we're weighting the die, we're adding a sort of a bias, so I'm much more likely to roll a six.
40:42I can still roll a one, I can still get colder conditions, but just more likely. We're sort of,
40:47just loading the die, pushing it in a certain direction, and that's what we're seeing.
40:51The blue bars though, because those changes are much smaller, that actually evens out. So while
40:58some of the, while we still see little increases in sort of 23, for example, pattern 30 is a little
41:03bit decreased. And so what we can actually start to see is that when you look at them on average,
41:08you get net zero change in those, in that low emission scenario. So a bit of redistribution of where
41:14the rain, rain and the warmer temperatures occur, as you showed the nuance of the weather patterns,
41:19that's why the 30 is so powerful. We are generally seeing no real change in the overall scenario.
41:25Our climate is much closer to what we'd expect in the present day.
41:28And you've looked in even more detail, haven't you, with the, was it the Outer Hebrides that you looked at?
41:33Yep. So in the Outer Hebrides, on average, they would see our, their stormiest weather patterns,
41:38about 20, 22 days on average in winter. That obviously goes up and down each year.
41:47In an RCP 2.6 scenario, so the low emission scenario, there's no real change in that occurrence of those
41:53weather patterns in the future. In an RCP 8.5 world, they're looking at about nine days of additional
42:01stormy days just in winter. So the sort of 90 days of December, January, February, almost one in 10 of
42:06those days switches to become a stormier weather pattern. They're not all named storms, they're not
42:11all bringing dreadful weather, but they are all likely to bring clouds, they're all likely to bring
42:16rain. And you know, when you're up in the very north of Scotland in winter, there's not a lot of
42:21sunlight, not a lot of daylight at the best of times. So you can really imagine what that would do to you
42:26and people living on the islands. And we've been working with them so they can explore the sorts of
42:30changes they might need to make to their lives, so they can continue to, to thrive on the islands.
42:35Yeah, and just before we move on to summer, there are some here that show decreases like you were
42:40saying. So I just want to show some of these. This is 16, 17, 27, 28. We just flick those on and this
42:48shows the temperature anomalies. So 16, that's got higher pressure over Denmark, more of an easterly
42:54airflow. This is one of the easterly type of weather patterns that you were saying is likely to decrease.
42:59Very similar for pattern 17. These are the temperature anomalies in January, minus 2.5,
43:05and 27, blimey, that's a, that must be one of our coldest ones, minus 4.7, proper easterly,
43:13and 28 there. So it's these really cold weather patterns that are decreasing and you're likely to
43:19see less of them, right? Exactly. And so even if we didn't really change the, the underpinning climate,
43:26that shift away from these patterns would mean that our winters are, we're leaning towards those
43:31warmer winter conditions. Now, on top of this, we'll have a climate change signal. So I think as was,
43:35I think you possibly discussed earlier this winter, when we were thinking about this setup arriving in
43:39sort of in mid February time, because of the lack of snow this winter in sort of Eastern Europe,
43:45parts of Scandinavia, that air mass wasn't as cold as you would normally expect. We didn't really get
43:50as deep a cold when we did get the cold conditions. We can probably expect a situation like that,
43:54with the global warming impact on top of the weather pattern change as well. Yes, double whammy
44:00effect essentially. Now, moving on to summer, and it's actually even more stark, isn't it,
44:07the changes with some of these weather patterns? Yeah, we really see, and we've sort of seen the opposite
44:14happening in, in some of the conditions. So if we pick on five and six, for example, here,
44:19and I think we're around about pattern five this week at the moment, aren't we? Yeah. And you can
44:24see the pattern five, pattern six increase in the summer months in both, both scenarios actually,
44:29and decrease into the future. So that's right, in the winter. And so what we're seeing is that sort
44:35of opposite. Again, you can see it with pattern 30, decrease in the summer months, and increase in the
44:40winter months. So you're really getting that divergence in, in our climate. And we're seeing
44:46a sort of an enhancement of our seasonality. The winter weather patterns are warmer and wetter,
44:51the summer weather patterns are hotter and drier. And that really brings out differences between the
44:56two seasons. I'm going to click on July now and show what these weather patterns look like in July.
45:01So weather pattern five, above average temperatures. And we've got, I think that's higher, higher pressure
45:08near the Azores, I believe. There's no labels on there, but it's basically a rather settled
45:13weather pattern. Weather pattern six is very similar to what we've got at the moment. We've got higher
45:18pressure extending from the Azores. Again, very settled across the UK, above average temperatures,
45:24and below average rainfall. This shows below average rainfall across northwestern parts of the UK.
45:29What I found interesting, actually, we were talking about this earlier, weather pattern 19,
45:33and this is one of the ones that actually increases more than any other weather pattern in the summer.
45:39There it is. Particularly in that high emission scenario. And it's got high pressure to the west
45:45of the UK. Interesting, because this is what we're seeing next week. And it's got this north and Sunday,
45:49in fact, this is very similar, northeast to the airflow. But it's got below average temperatures. So in a way,
45:54this isn't showing that hot, dry kind of flavor. But there's some nuances here, isn't there?
46:02Yeah, so when we then look at the climatological difference, I've sort of been hinting on this a
46:07little bit. So as well as taking each day and assigning it to its weather pattern,
46:12I could go into the climate models and extract the temperature for that day.
46:18So what I did was I matched every single day in the 2071-2099 period, say for summer,
46:25for each of the weather patterns that occurs. Whenever that weather pattern occurred, what's
46:30its temperature? And I did the difference of how those temperatures have changed. And what we saw,
46:34weather pattern 19 actually has the biggest swing of temperature. So compared to the baseline period,
46:40that 1980 to 2010, it actually increases by six degrees in the summer. So it's six degrees warmer
46:46than we were sort of seeing in the present day. So that weather pattern, you know, we're sort of looking
46:52at changes here, three degrees below the current climatology. It's very similar to the climatology we're
46:56using in the model. What we're actually going to see is actually this weather pattern itself just
47:00becomes warmer because of the climate change signal within the model. So these minus threes end up
47:07being plus threes when you compare it with that 30-year period, 1980 to 2010. And I guess part of the
47:13reason for that is the Arctic is the fastest warming part of the planet. These winds are coming from the
47:18north. And so you've just got this enhanced difference, haven't you, with the pattern itself is
47:24becoming more frequent. But at the same time, when the pattern occurs, it's much warmer than it used
47:30to because the the air upstream is much warmer than it used to be. Yeah, and this is a, you know,
47:35in the high emission scenario, very end of the 21st century, we're having much less sea ice in the
47:40Arctic in the winter even. So even so our summer extent is much, it's retreating. So whereas, you know,
47:47sea ice levels up here and retreating much earlier into the spring and obviously high solar energy comes
47:53into the high latitude. So obviously northern hemisphere, spring and summer, we're getting
47:56lots of energy into that part of the world. And so the ocean absorbs that heat really well. So even
48:02though we're bringing that flow down the coast of Norway, and of course, less snow in winter over
48:08Norway and Finland and Sweden, and that sort of all adds into the signal to make it just warm up quicker
48:15and therefore be warmer into the summer, which is why we're getting this climatological swing.
48:19Now I hinted at it earlier, the fact that we've got high pressure in place this week,
48:23it's going to drift a little bit through the weekend and next week, but it's essentially sticking
48:27around. And that persistence of certain weather patterns is another thing that you looked at,
48:32isn't it? Yes, exactly. And the persistence of the weather pattern plays a really important role
48:39in our day-to-day weather. And what we can see is in the winter, pretty much all of the weather
48:44patterns decrease in persistence. So that means that they're lasting for longer. So they're lasting
48:53less longer, exactly. And so what happens is that the persistence was calculated by taking the weather
48:58pattern on a day and seeing if the weather pattern the next day was the same one or not. And if it was,
49:03it starts adding that up. And then we extract that and work out how often we had more than one day
49:09occurring. And what you're sort of seeing here is that decrease in that occurrence, which means that
49:13the weather pattern is changing more day-to-day than we see in the climatology, particularly in the
49:21winter months. So where we have our stormier conditions, not only are we seeing more days of
49:26patterns 26, 23, pattern 30, westerly stormy, windy conditions, they're going through quicker.
49:35So the storms are more, we say more mobile, which potentially brings the risk to potentially be more
49:40impactful because they just have that more. They're moving quicker. They can deepen quicker
49:44and the associated impacts that come from that. Conversely, in the summer, patterns like five and
49:49six, those high pressure patterns you just had up, they persist for longer. So their persistence actually
49:57increases, they last long. And that allows us to end up in these sorts of more blocked regimes
50:01where the air gets stuck, it gets trapped. We end up building up the heat within it, as you were
50:07sort of highlighting about with the high pressure, that air can sink, it can get warmer.
50:11But also associated risks in that, of course, air quality and things, depending on where the airflow
50:16is coming from. So you might have increase in air pollution, might increase in pollen and things
50:22like that. It all gets stuck because there's no real change in that air mass either, because it gets stuck
50:27because the persistence is increased. And you get higher temperatures because in the UK, when you get high
50:32pressure lasting day by day, temperatures rise, which was what we're seeing this week. And so you've got the
50:39higher temperatures because you've got the more frequent high pressure, you've got the more persistent
50:43high pressure, and as you said, the high pressure patterns are warming themselves as well. Yeah.
50:50Triple whammy. Exactly. Yeah. And you know, that sort of builds a nice build. And when we, when you
50:56mentioned the future weather forecast, well, one of the ways that we assess to design that, to find
51:02that wet, that is that example, which we use the weather patterns as a base template. And we found
51:08periods where we have that persistent weather patterns, five and six, to exactly as it happened
51:13in that forecast, build up that heat, get stuck in just day by day by day, finishing with the 42,
51:1943 degree Celsius heat wave we have at the peak of the video. Yeah. Really interesting. So just to
51:25summarise, 30 weather patterns that we talk about often in the deep dive, we've been looking, you've
51:32been looking at how they're likely to change in the future, they all still happen. They all still happen
51:38at the end of the century, in a high emission scenario, and in a less high emission scenario,
51:43they're still happening. But in the winter, the wetter, milder westerlies happen more often,
51:49the easterlies, sutherlies, northerlies happen less often. In the summer, high pressure happens more
51:54frequently. And when it happens, it's more likely to stick around. And on top of all of that, the
52:01winter weather patterns, as you were saying, are, on average, getting wetter and milder. Every single
52:07one of them is getting, even the easterlies, they're getting milder, they're getting wetter. And the
52:11summer weather patterns are getting hotter and drier, every single one of them, even the north,
52:15especially the northerlies, are getting hotter in the summer. So really interesting research
52:23that you've done into that, and really important, you know, when we're looking further ahead and
52:27planning for the future. So thank you very much, James Pope. I hope to you, I hope you enjoyed that
52:33and found it really interesting, like I did. But that's all we've got time for this week.
52:39Don't forget to hit subscribe, send us a comment, send us a question,
52:42and we'll try our best to answer. Thank you. Bye bye.