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This is an in-depth Met Office UK Weather forecast for the next week and beyond. Many parts of England and Wales desperately need the rain. This week, the rain returns with a vengeance. But, whilst it will be welcome rain for many, for others it brings the risk of torrential downpours, flash flooding, lightning and hail. How has the atmosphere switched so dramatically? Bringing you this deep dive is Met Office meteorologist Aidan McGivern.
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00:00Many of us across England and Wales have been crying out for rain for what seems like weeks on end.
00:05And I know a lot of Met Heads who enjoy watching our YouTube videos have been asking,
00:10where are the thunderstorms?
00:12Both have been severely lacking, that is, until this, the final week of meteorological summer.
00:18Welcome to the Met Office Deep Dive.
00:20If you enjoy these regular, in-depth analyses of the UK's weather and beyond,
00:25please do follow us on YouTube, send us a like, recommend us to your friends and family,
00:31and you can always ask us a question in the comments.
00:33We try and answer a lot of these in our regular Weather Studio Live videos that we do on a
00:38Friday at lunchtime.
00:40But enough about that, let's get stuck in.
00:43This week's Deep Dive will be focused on the thunderstorms, the chance and the risk of thunderstorms,
00:51because they will cause some negative impacts as well as positive impacts during the rest of meteorological summer,
00:57which, of course, comes to an end next week on the 1st of September.
01:00But where have the thunderstorms been so far this summer?
01:04We've had the heat, we've had the humidity.
01:06Why hasn't all that energy at the surface sparked more thunderstorms?
01:11That's a question we've had quite a lot.
01:13So I'll briefly answer that before I get on to the weather of this week.
01:18And the answer is relatively simple.
01:20It's to do with the pressure at the surface, but also higher up.
01:25That pressure has been especially high throughout summer of 2026.
01:30Let's take a look at the average surface pressure for July, for example,
01:34just to make this nice comparison with this summer.
01:37On average, high pressure sits close to the Azores.
01:41It's called the Azores High and extends a little bit into Western Europe.
01:45You can see the pressure there across northern Scotland, 1,012 millibars.
01:50But if I switch on to the pressure that we've seen during this July,
01:56you'll see that has migrated.
01:59The high pressure has migrated much further north.
02:03This is the anomaly compared with average.
02:05We've had this extension of much higher pressure from the Azores across the UK.
02:10So we've had high pressure, not just through July, but throughout the second half of June,
02:15the first half of August, dominant at the surface over the UK, but not just at the surface.
02:20This shows the average position of the jet stream in a typical July 30-year average, 1991 to 2020.
02:27And the jet stream during that 30-year period took an average path coming out of North America,
02:32zooming across the Atlantic and then sort of cutting across the UK there.
02:36But if I flick on to what we saw during this July, and again, not just this July,
02:41also part of June and part of August, watch how it is much further north and it's much weaker.
02:47So I'll flick on to the next chart.
02:49There we go.
02:49It's going up across Iceland and leaving this ridge of high pressure at higher levels,
02:56at the height of the jet stream.
02:58I'm going to talk a lot about the height of the jet stream, 300 hectopascal pressure level
03:03or 25,000, 30,000 feet above the ground, 9,000, 10 kilometers, depending on what units you prefer.
03:11So at that level, we've had high pressure as well.
03:15High pressure at the higher level where the jet stream lies, high pressure at the surface.
03:19That's been suppressing storm development, no matter how high temperatures and humidities have got at the surface.
03:26Now, let's contrast that with what we're going to see this week.
03:31And I've showed these charts before in the deep dive, I think a few months ago during the winter.
03:36I've shown these sort of charts.
03:38It's a different way of looking at the jet stream.
03:40So here's the jet stream, how we normally view it, a streak of winds coming out of North America
03:47and, at the time of recording, diving south over the Azores into Iberia
03:52and leaving what we call an upper trough, this upper level low to the west of the UK.
03:58But we could put a bit more detail on that.
04:00This graphic just shows the weather wind speeds are above around 60 knots at that level in the atmosphere.
04:07But if we show all the winds and combine that with the temperature, the air temperature,
04:13at the height of the jet stream, so again, we're talking about 300 hectopascals pressure level
04:20or 25,000, 30,000 feet roughly up in the sky, this shows the winds and the temperature at that
04:29level.
04:30I also put a bit more detail on it.
04:32So what we can see here is that the warmer parts of the globe at that height are greens and
04:39close to a yellow colour
04:41and the bluer parts of the world are where we've got colder air at 300 hectopascals pressure level
04:50and colder air at that height typically means lower pressure at that level in the atmosphere
04:56and it can, when combined with warmer air at the surface, cause more rising air, more instability
05:02and I'll show you why in a moment.
05:04Why do we talk about 300 hectopascals rather than showing the temperature at 25,000 feet
05:10or picking, say, 30,000 feet above the ground level?
05:13Well, the reason is that when you get to that level in the atmosphere,
05:17the air interacts around the globe along levels of pressure rather than heights.
05:26I won't go into the nitty-gritty of that because that's another deep dive in itself,
05:30but it's more useful for meteorologists to look at pressure levels when you're talking about, say,
05:36the height of the jet stream or the temperature at 300 hectopascals or the thicknesses of the atmosphere
05:43and so on. It's more useful to talk about pressure levels than it is to talk about specific heights in
05:48the atmosphere.
05:49Heights are more useful for humans, pressure levels more useful for meteorology
05:54and how the air is moving around the globe.
05:57So, the important thing here is that if I move over to the middle of the Atlantic,
06:03we had this kind of air over us throughout much of summer.
06:07We've got these greens and yellows, higher temperatures at 300 hectopascals
06:11and a ridge of high pressure, higher pressure as well at that level.
06:15So, that indicates that we had quite a thick layer of atmosphere sitting over Western Europe.
06:21We had sinking air throughout that layer of atmosphere as well, suppressing storm development
06:28and a jet stream that was diverted further north.
06:32That's all been shunted west across the Atlantic.
06:35Now, the difference is for the final week of meteorological summer,
06:39we've got low pressure in the upper atmosphere to the west of the UK,
06:45jet stream diving south and these low temperatures now moving in over the next few days
06:52at 300 hectopascals over the UK.
06:55That's what's been lacking this summer.
06:58You need to consider the atmosphere in three dimensions.
07:01It's not just about the heat and humidity at the surface.
07:04It's about how quickly the air cools when you go from the surface upwards.
07:10And that's so important because that determines whether the air is stable or unstable.
07:15The faster the air cools down as it rises above the surface of the ground,
07:21the more unstable it is.
07:22And I'll demonstrate that with a couple of teffagrams in a moment.
07:25But suffice to say, this is a very different set up at 300 hectopascals,
07:31way up close to the tropopause, the top of the troposphere,
07:34compared with much of summer, basically.
07:37Jet stream diving south, this colder air coming in at higher levels from the west across the UK.
07:43Now, it's not just the UK where things are changing.
07:47You may have seen on the news some remarkable footage, I'll show it now,
07:52of a tornado in the south of France.
07:55This footage from the BBC, a number of people captured it.
08:00You'll see the credit up here on the right.
08:03This is the aftermath of the tornado.
08:05It's going to loop back to the beginning in a moment,
08:08show the remarkable footage of the tornado itself.
08:11And this is all associated with a very vigorous supercell thunderstorm back in,
08:17here it is, across southern France.
08:20Here is the tornado, really quite large.
08:23Not the sort of thing we often associate with somewhere like France.
08:27It's something you're more like to associate with the USA.
08:31But of course, these kinds of tornadoes can and do happen in many continents across the world,
08:37not just the USA and North America.
08:40And this is the aftermath of that really severe thunderstorm and tornado.
08:46Nearby town of Pomas recorded a wind gust of 62 miles an hour.
08:51But of course, that won't be under the tornado.
08:53It will be much higher wind speeds for the tornado because of, look at the damage,
08:57extensive damage, more than 40 people injured, sadly,
08:59and 300 homes or more affected by damage or loss of power.
09:04There it is playing again.
09:06It's an incredible thunderstorm, all part of a supercell system.
09:09That moved through the south of France.
09:11If we play back the lightning footage from Monday afternoon,
09:18you can see as the town Versailles, where the tornado struck.
09:23Let's go back to the beginning again.
09:25Here's the cluster of thunderstorms.
09:27These are the lightning strikes.
09:29Look how many there are across the south of France moving through there.
09:33Of course, France has had a truly remarkable summer in terms of heat and also dry conditions.
09:38But we're seeing this increased instability now across the whole of Western Europe.
09:43And we're expecting some very lively weather across much of Western Europe over the next few days.
09:49We've got this system being picked up by the trough of the jet stream there into Portugal.
09:54You can see how that develops into a deeper low.
09:57That's going to bring some very heavy rain and strong winds into western parts of Iberia.
10:02Overnight into the start of Wednesday, it's then going to start to track north eastwards,
10:08arriving into France.
10:09And eventually we'll see some lively weather, courtesy of this whole low-pressure system.
10:15Not just low pressure at the surface, but low pressure higher up as well.
10:19We're already seeing some heavy showers on the rainfall radar.
10:22Let's take a look at those and zoom in.
10:25Watch these showers develop.
10:28Very bright colours here.
10:30Moving into the southwest of England.
10:33This is overnight and the start of Tuesday.
10:37I'm going to play that through.
10:40Now, if you're in the south and southwest, you might have looked at the radar there.
10:45Look at that.
10:46And thought, wow, it should be raining really quite heavily outside because of the bright colours on the radar.
10:53But actually, most areas under that bright area of radar hardly got a drop.
11:01And the reason is, not because the radar system is faulty.
11:05The radar is picking up big drops of heavy rain falling out of the sky.
11:10But as that rain was leaving the cloud, it had quite a long way to drop through drier air closer
11:17to the surface.
11:18And I picked out what we call a tephigram here at the Met Office.
11:22Other people call them skew-t charts.
11:24These are where we send weather balloons up through the atmosphere from the surface.
11:29This is from the Brest Peninsula.
11:30It's from last night from the Brest Peninsula.
11:33And it shows how the temperature, and the wind on the right here, but the temperature in red and the
11:39dew point in blue changed through the atmosphere.
11:43And the temperatures are on the bottom here, but they're actually skewed, hence the skew-t name that's given to
11:49these diagrams.
11:50And the reason they're skewed is so that it's not a crazy wide graph showing all of this stuff way
11:57out to the left.
11:58It's easier for people to read.
11:59And what we're looking at here is there's the freezing level, there's the zero degree line.
12:04And so the air temperature obviously varies with height, generally decreases, etc., etc.
12:11The dew point also generally decreases with height.
12:13But where the air temperature and the dew point come together, that's where the air is more saturated.
12:18And that's where you like to have clouds.
12:20So these are the shower clouds here, this trunk of atmosphere.
12:24The bottom is about 6,000 feet, 2,000 meters or so, and the top goes up to about 15
12:34,000 feet or so.
12:35So quite a thick shower cloud, but underneath we've got this area, you can see, where the two lines are
12:43further apart.
12:43So it's drier air, the rain coming out of the cloud dries, and you don't get much at the surface.
12:49So it's what's called basically elevated showers.
12:52Because these showers are higher up, and therefore they're coming out of quite thick clouds, heavy downpours,
12:59but evaporating a lot of the time before they reach the surface.
13:02While we're on the subject of teffigrams, let's take a look at the forecast teffy.
13:08So that's from an actual balloon ascent that was sent up over the breast cancer overnight.
13:13But this is a forecast teffygram.
13:15It's not as detailed, because it's from a weather model with lower resolution than, well, reality.
13:20But this is for Wednesday at around midday.
13:25Again, the red line shows the air temperature as it decreases with height.
13:30The blue line shows the dew point.
13:32And what's important here is that we can imagine a parcel of air on the ground,
13:40say, because of solar heating around the middle of the day on Wednesday,
13:44and how much that is likely to rise through the atmosphere,
13:48and how quickly it's likely to rise,
13:50because we can compare it at all heights with the actual air temperature.
13:54So, what we've got in terms of West Oxfordshire,
13:59Wednesday lunchtime is a dew point in the mid-teens, so reservoir for humid air.
14:04Air temperature around the mid-20s, so warm air.
14:08And it starts off that that air temperature, it's been rising through the morning,
14:13gets to the point where that parcel of air is warmer than its surroundings,
14:17so it starts to rise.
14:18And initially, it decreases at a rate of 10 degrees per kilometre.
14:24That's known as the dry adiabatic lapse rate.
14:28Lapse rate means the cooling rate as it goes up,
14:30and adiabatic means without exchanging heat with its surroundings.
14:35So, why does it cool?
14:36It simply cools because it's rising from higher pressure at the surface
14:40to lower pressure higher up in the atmosphere.
14:43As that parcel of air rises, it always encounters lower pressure.
14:47There's less pressure squeezing down on it, so it expands.
14:50Expanding air cools down.
14:53It's similar to releasing the valve on your bike,
14:56and the air rushes out, and it feels cold
14:59because it's going from high pressure to low pressure.
15:01It cools down.
15:02So, this parcel of air, it's cooling,
15:05and that's what this straight line towards the bottom of the chart shows.
15:09It shows how quickly that air is cooling.
15:11At some point, it intersects the dew point,
15:14and at that point, the air becomes saturated.
15:16That's your base level of the cloud.
15:18So, it cools, cools, cools, becomes saturated.
15:21Cloud forms, I don't know, 4,000 or 5,000 feet up in the atmosphere.
15:26So, that's the base of cloud.
15:28Now, after that, the parcel continues rising
15:31as long as it's to the right of the air temperature,
15:34as long as it's warmer than the air temperature,
15:35but it cools down more slowly,
15:38and that's because it's saturated air.
15:41As it's cooling down, it must condense some of that moisture
15:47to continue to cool down.
15:49That condensation takes energy out of the surrounding air,
15:53and so it slows the rate.
15:57No, it adds energy.
15:58I beg your pardon.
15:59It adds energy, so it slows the rate of cooling
16:02because it's adding a bit of heat every time it condenses the air.
16:06So, it's a slower rate of cooling,
16:08and it's a more curved rate
16:09because it depends on how much moisture is in the atmosphere,
16:12and that decreases,
16:14that amount of moisture in the parcel of air
16:17decreases as you go higher up,
16:18so it's a curved rate.
16:19But as you can see, right, this is the important thing,
16:22that dotted line,
16:23that's what we call the saturated adiabatic lapse rate,
16:27the rate of cooling of a saturated air parcel,
16:31and it's to the right of that air temperature,
16:34all the way up,
16:35close to the 300 hectopascal level or just above it,
16:38and close to this where the air temperature rises again.
16:43That's what we think of as the top of the troposphere
16:46or the tropopause.
16:47So, we've got the stratosphere up here
16:49where the air actually starts to warm up again with height.
16:53But it's this we're interested in.
16:55It shows that we've got a base of the cloud at 4,000, 5,000 feet,
16:59and we've got this thunderstorm cloud
17:02extending all the way up to the top of the troposphere.
17:06So, we've got the cloud base,
17:07we've got the cloud height,
17:08and it's this gap in between the air temperature
17:11and the saturated lapse rate there
17:15that is important for the amount of potential energy
17:20that that thunderstorm has.
17:21The bigger the gap,
17:23the more energy the system has
17:26because it's got a faster rate of rising.
17:30The thermals are more energetic through the atmosphere,
17:34and the more energy they have,
17:36the more likely you are to get torrential rain, hail, lightning,
17:41all of those thunderstorm hazards.
17:44So, what we look for is bottom, top of the cloud,
17:48the area between the air temperature
17:51and the cooling rate of this bubble of air,
17:55and that indicates how much energy we've got available in the atmosphere.
18:01In fact, there's a term for it,
18:02convectively available potential energy.
18:05It's also known as CAPE.
18:07And there's a map here
18:08that shows the CAPE
18:10that we're expecting lunchtime Wednesday across the UK.
18:14I appreciate this is a very technical diagram,
18:16and it also isn't necessarily produced
18:20with people watching the deep dive in mind.
18:23This is a forecast tool for meteorologists here at the Met Office.
18:27But I'm just showing you it
18:28because I think it's interesting to show those areas
18:31that have the most convectively available potential energy,
18:34the most of that energy,
18:37thunderstorm energy in the atmosphere.
18:39And it's these pink areas through East Wales into the Midlands,
18:44across the home counties, the southeast of England,
18:47where the energy is exceeding 1,500 joules per kilogram.
18:53That just indicates that there's a lot of energy present
18:57and that there's a lot of potential with these thunderstorms
19:03as they develop across initially southern parts of the UK
19:07on Wednesday morning,
19:08pushing through central parts.
19:10And then this area of CAPE,
19:12these high values,
19:13does move north into parts of northern England.
19:15And eventually, we get higher levels into southern Scotland,
19:19parts of Northern Ireland as well, through the day.
19:21So, that means there's a greater risk of things like hail,
19:27large hail, lightning, heavy rainfall.
19:29This similarly shows on Wednesday afternoon
19:32the risk of lightning in any one area.
19:34But it shows a map here.
19:35And we've got parts of Wales, the Midlands, southeast England,
19:39greatest risk of seeing lightning.
19:42Now, the individual points within that area
19:45are still low risk of lightning,
19:47but it shows quite a broad area
19:50where there is the greater risk of lightning across the UK.
19:53So, what does all that look like when we consider the 300 hectopascal diagram once again?
20:03Essentially, we've got what we call this broad upper trough,
20:07this long wave upper trough, so it's quite long,
20:10extending south, just to the west of the UK.
20:13And then these little wriggles along the forward side of that,
20:16that indicates a number of what we call shortwave troughs.
20:21They increase the instability in the atmosphere.
20:24So, it's basically lines where you've got even colder air up at that level
20:28coming along and even lower pressure.
20:31So, these little shortwave troughs.
20:33You can see one, that's 8am, across southern parts of the UK.
20:38And, in addition to that, on the forward side of this trough,
20:42we've got this very strong jet stream to the west of the trough
20:45and less of a strong jet stream to the right of the trough
20:50or to the east of the trough.
20:51And we've got these arrows that are kind of diverging a little bit.
20:54So, there's a few things going on here.
20:56Here, you've got colder air at that level, 300 hectopascals,
21:01coming in from the west.
21:02So, the air is cooling down at that level and the pressure is lowering.
21:06So, if that's happening, the air, essentially, at that level,
21:12is disappearing as like a vacuum.
21:15The air has to leave 300 hectopascals and go elsewhere
21:20in order to lower the pressure.
21:22And so, if the air is escaping at 300 hectopascals way up there,
21:2625,000, 30,000 feet,
21:29then the air at the surface has to rush up to fill it.
21:32So, you've got this whole thing going on where the air at that level is escaping,
21:36it's moving away, it's diverging,
21:38and the air at the surface has to rush up
21:39because there's a vacuum of air at that higher level.
21:43That air at the surface, as I've already mentioned,
21:45it's mid-20s air temperature, it's mid-teens dew point.
21:48It has energy.
21:50It has the kind of energy that we saw at the surface throughout much of the summer,
21:53but this time, the difference is it's colder at the top
21:55and with lower pressure at the top.
21:57So, all these things are going on,
21:59and that essentially results in some heavy showers and thunderstorms.
22:06Now, I mentioned the showers that are not quite reaching the ground
22:10across the southwest as we've started Tuesday,
22:12but as we've got these shortwave upper troughs moving in increasingly from the south overnight
22:20and into the start of Wednesday, we're likely to see more activity taking place.
22:25So, there's this plume of heavy rain pushing into parts of Northern Ireland,
22:28this area of showers blossoming across Ireland, Northern Ireland,
22:31perhaps parts of southwest Scotland.
22:32Then, this other area of showers and potential thunderstorms moving into East Anglia.
22:39Here it is.
22:40Small area, yeah, but it actually expands a little bit.
22:43This is an occluded front,
22:46and it coincides with one of those shortwave upper troughs.
22:50So, that's the first area.
22:52Starts overnight in East Anglia in the southeast,
22:55moves north into Northern England,
22:56eventually pushing into southern Scotland.
22:59A chance of showers and thunderstorms.
23:01But what is even more lively than that
23:06are these showers and thunderstorms that are likely to develop
23:08as the air temperature rises through the day.
23:11And we've got humid air in this part of central UK,
23:15or central England, central parts of Wales,
23:18combining with the lowering pressure at higher levels.
23:21And you can see the speckled nature of these showers developing,
23:26but really quite lively downpours, as you can see.
23:33And again, they're going to be pushing north into southern Scotland,
23:37eventually western Scotland, like so.
23:41Fizzling out generally.
23:44So, yeah, Scotland, certainly central and northern Scotland,
23:47not seeing a great deal of activity.
23:49And then the next system comes along,
23:51and this is the emerging area of low pressure
23:54with its weather fronts that I mentioned that will affect Iberia.
23:58This is going into the start of Thursday as it moves up from the south.
24:01And there's more activity along with these fronts.
24:06And again, we've got interesting stuff happening higher up.
24:09And again, heavy downpours coming up from the south,
24:13Wednesday night into the start of Thursday.
24:16By Thursday itself, look at the angry rain across Wales,
24:19the Midlands, East Anglia.
24:22It really could be very heavy rain for a time
24:27through these central parts of the UK,
24:29with large hail and lightning as well.
24:32So, yeah, we've been crying out for rain, a lot of us,
24:35especially in these areas where we're likely to see some heavy rain.
24:38We don't want a huge amount in a short space of time.
24:41That's, despite the dry ground, still a big risk
24:45that could still cause localised flooding and other impacts.
24:49So we don't necessarily want that.
24:50We want a moderate spell of rain spread out over longer periods.
24:55But this is looking very possible into Thursday.
24:59How does that look on the Cape chart?
25:01Here's the convectively available potential energy again.
25:04And this is midday Thursday.
25:07It starts off with even higher values.
25:10This colour here across central parts of England.
25:14That then moves north through the afternoon
25:16into Midlands, northern England, parts of Wales.
25:20So really quite lively.
25:22And again, this risk of lightning across central areas.
25:26So, in terms of rainfall amounts,
25:31there could be some very large amounts of rain
25:34in a short space of time.
25:36And just to illustrate that, let's skip forward to tomorrow, 6 a.m.
25:39And this shows the accumulated rain between 3 and 6 a.m.
25:44Starting off across, say, Suffolk, into parts of Essex, London area.
25:49And then if I skip through to midday,
25:53you can see that area of 25 millimetres plus in three hours
25:58moves north into parts of the East Midlands, for example,
26:01Lincolnshire, and it continues to move north.
26:05By the time we get to the evening,
26:08into southern Scotland, some lively rainfall rates.
26:11Northern Ireland's seeing some showers, but not quite as heavy.
26:14But then there's this other area that I mentioned
26:17where we've got these very hit-and-miss popcorn-like showers
26:20developing and again becoming organised potentially
26:22into more organised systems.
26:26Again, with the risk of lightning, hail,
26:29and 25, 30 millimetres in a couple of hours
26:32or, you know, as much as 50 millimetres in three hours or so
26:36across parts of Wales, the Midlands,
26:38and eastern parts of south, well, central southern England.
26:44So, yeah, very lively rain.
26:47And then going forward again to Thursday,
26:50this is Thursday early afternoon,
26:53and this swayed across parts of Wales into northern England.
26:56Again, some really quite heavy rainfall
27:00in an hour to three hours, 25 millimetres.
27:03In some places, 50 millimetres.
27:06So we don't want that amount of rain in just a few hours.
27:08That's going to cause more harm than good
27:10if we get that intensity of rain despite the dry ground,
27:13despite the fact that we need rain and the lightning
27:16and the hail and so on.
27:19Not just that,
27:22but I'll move on to this graphic again.
27:27As we go into Friday,
27:29these systems are increasingly tracking north,
27:32so likely to bring heavy rain into the south
27:34and east of Scotland.
27:36And then we've got another system emerging
27:38out to the west in the Atlantic for the weekend.
27:42Again, this is likely to bring some heavy downpours,
27:46an organised area of thunderstorms perhaps,
27:50and some gusty winds in from the south west
27:52as we start off Saturday and go into Sunday.
27:55So, we've got the potential for quite a lot of rain to come,
27:59but highly localised over the next few days.
28:03Useful for many,
28:05but potential for significant impacts for others.
28:09That's why we have warnings in place.
28:13Here are the highest risk areas for Wednesday.
28:18Now, if you're outside the yellow warning area,
28:21it doesn't mean you won't get thunderstorms,
28:22you won't get heavy rain.
28:23This is the biggest risk area,
28:25but it's not the only risk area.
28:26This is the highest risk area, I should say,
28:29across the UK,
28:29and a similar risk area into Thursday.
28:32But by Thursday,
28:34there are increasing uncertainties
28:37in terms of where the heaviest rainfall will be.
28:41I think I've got a graphic that illustrates that.
28:44Maybe not.
28:46It was a graphic,
28:47if I move that on.
28:48Ah, here we are.
28:49That compares the last three runs
28:51of the high-res Met Office model.
28:55I appreciate it might not be the easiest thing to see,
28:57but you've got Western Scotland sticking out there.
28:59This is the 24-hour totals on Thursday.
29:02Western Scotland sticking out there
29:03as a dry area.
29:05But some pretty large rainfall rates.
29:07This is the most recent run
29:09across parts of Northern England
29:11into the North Midlands
29:12and other areas.
29:1450 to 100 millimetres
29:16in that 24-hour period.
29:18Hopefully, it won't be that much
29:21because whilst we need it,
29:22that amount of rain in 24 hours
29:24wouldn't be welcome.
29:25And there's a lot of variation.
29:27Those are the peak rainfall totals
29:29and the area in the most recent model run,
29:31but it's different areas
29:33and different rainfall totals
29:34in the model run before that.
29:37And again,
29:37different totals
29:38and different areas
29:40in the model run before that.
29:41So, we've got Eastern England here.
29:43We've got back into Northern England.
29:46Here is the highest risk area.
29:47So, increasingly through the next few days,
29:50as you'd expect,
29:51in this kind of situation
29:52where you've got thunderstorms developing
29:55and then blossoming into larger areas
29:57of more organised heavy rain
29:58and hail and lightning,
30:00there are big uncertainties
30:02in the finer detail.
30:04Where and when
30:05the heavier rain will affect,
30:07where and when we'll get lightning,
30:09all of that sort of thing.
30:10Suffice to say,
30:11is the ingredients are there.
30:13We've got the warmth
30:14and the humidity
30:15at the surface,
30:16mid to high 20s
30:17over the next few days
30:18in some places.
30:19And we've got dew points
30:21of the mid to high teens.
30:23Not only that,
30:24we've got lowering pressure
30:25way up where the jet stream sits,
30:28the jet stream diving to the south
30:29and then this trough
30:31moving across the UK.
30:32And we've got colder air
30:34at that level as well,
30:35increasing the instability
30:36through the atmosphere
30:37and increasing that potential energy
30:39throughout that layer of atmosphere
30:42from the surface
30:43up to the top of the troposphere.
30:45So all the ingredients are in place,
30:47but uncertainties in terms of
30:49where we're going to see
30:50the heaviest of the rain
30:51and whether it will be useful rain,
30:54which it will be for places,
30:56or whether it will be more impactful rain.
30:59And just to finish up,
31:01this graphic shows the total rain
31:06rolling from the time of recording
31:08out to the next few days.
31:09Let's press play
31:09and you can see how that rain builds up.
31:13Northern Ireland seeing some rain overnight,
31:16eastern Scotland as well.
31:18But the heaviest rain
31:19on Tuesday night into Wednesday,
31:21you can see these darker blues emerging
31:23initially east Anglia
31:24into the Midlands, parts of Wales.
31:26Very speckled amounts, as you can see.
31:30Some areas still dry for a time,
31:32but then we've got successive systems
31:34moving up from the south and southwest.
31:38Increasingly, brighter colours emerging
31:39across central parts of England
31:41into parts of Wales.
31:42That's where you've got rain totals
31:43of 100 millimetres building up
31:45next few days,
31:46but highly localised.
31:47And I wouldn't take these locations
31:50too literally
31:50because it is varying so much,
31:52model run to model run.
31:53It shows the potential that's there
31:55in the atmosphere
31:56over the next few days,
31:57not the guarantee that we'll see
31:59that amount of rain in those places.
32:00And it's running forward still.
32:02It's up to Saturday now.
32:04We've got this other system
32:05coming through from the southwest
32:06on Saturday.
32:07Further spells of rain.
32:09Eastern Scotland, southern Scotland,
32:11not immune from the heavier downpours
32:13and the chance of thunderstorms
32:15later this week.
32:16Some brighter colours here.
32:17But you can see,
32:18by the time we get to the weekend,
32:21huge variations place to place.
32:25Some areas in the south
32:27not seeing nearly as much
32:28as across these central areas.
32:30But as a general rule of thumb,
32:31it's these central areas
32:33where we've got the warnings
32:34Wednesday and Thursday
32:35because of the amount of rain
32:38and the other impacts
32:39from thunderstorms
32:40that we're likely to see
32:41over the next few days
32:43despite us needing the rain.
32:45Like I say,
32:45we don't need
32:47to see it all at once,
32:48do we?
32:49We'd quite like it spread out
32:50over a longer period of time.
32:52But, you know,
32:53when does that ever
32:54affect what the atmosphere does?
32:56And of course,
32:57it's a very different
32:58end to meteorological summer
32:59compared with
33:00how the season has been
33:01so far.
33:02Keeping us on our toes,
33:04that's for sure.
33:05That's all for me.
33:06I hope it made
33:09some sort of sense.
33:10But if any of it didn't,
33:12just send me a comment
33:13and I'll try and explain
33:15because it's not always
33:16explaining some of this stuff
33:18live and ad-libbed.
33:21But there we are.
33:22We try our best.
33:23Anyway, thanks again
33:24and I'll see you again soon.
33:26Bye-bye.
33:40Bye-bye.
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