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This is an in-depth Met Office UK Weather forecast for the next week and beyond. Where and when will we see showers during the next few days? And why? Bringing you this deep dive is Met Office meteorologist Aidan McGivern.
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00:00Slow-moving summer downpours. We've seen enough of them during the last few days and we're going to see more of them during the next few days.
00:08But when will they occur? Where will they occur? And because this is the Metalfiz Deep Dive, why will they occur?
00:15This week I'm going to be taking an in-depth look at the kinds of tools that meteorologists here at the Met Office use for predicting these kinds of slow-moving summer thunderstorms and downpours
00:25that helps to explain why they occur and why they occur in certain places and not in other places.
00:31I'm going to be taking a look at the showers we're expecting on Wednesday as a little case study.
00:36This is the Metalfiz Deep Dive. It's an in-depth look at the weather across the UK and we do this every Tuesday on our YouTube channel.
00:44We also do it for our Spotify channel. If you're not already following us on Spotify, I do encourage you to start doing so.
00:51And, of course, keep hitting like, sending us comments on YouTube and tell your friends to subscribe to our YouTube channel
00:58if they, like hopefully you, enjoy these in-depth discussions of the UK's weather.
01:05Now, we've seen a lot of showers and thunderstorms over the past few days.
01:10This is the radar imagery from the last 24 hours and you can see the speckled nature of the showers across much of the country
01:18but also some longer spells of wet weather. We started the week with some particularly nasty rainfall
01:24across parts of Northern Ireland. An amber warning was issued for Sunday night into the start of Monday
01:28because of the signal for some very heavy rain across parts of Northern Ireland.
01:33And for the 24 hours of Monday itself, Kilowen in Northern Ireland saw 72 millimetres of rain,
01:40bearing in mind that the average July rainfall for Northern Ireland is 88 millimetres.
01:44So, not far off a month's worth of rain on Monday in Kilowen, for example.
01:50Other spots across Northern Ireland recorded similar amounts.
01:56And we also saw that weather move into western and northwestern Scotland.
02:00And in these regions, northern and northwest Scotland, Northern Ireland,
02:04we saw impacts from that heavy rain, localised flooding and travel disruption.
02:09Elsewhere across the UK on Monday, we saw a lot of heavy showers across central and eastern parts of the country.
02:14Further showers are now starting to develop at the time of recording across central and eastern and southern parts of the UK.
02:24But what I want to focus on are the showers we're expecting to happen on Wednesday
02:29because that is a particularly interesting setup and helps to explain why these summer downpours happen,
02:35how they can become slow moving and how they can cause big impacts in some places and very few impacts in others.
02:41And first, I want to take a look at something that we don't often look at in our forecasts,
02:48which is the temperature at 300 hectopascals in the atmosphere.
02:54We're often looking at the winds at 300 hectopascals in the atmosphere, otherwise known as the jet stream.
03:01Here's the jet stream on a more familiar chart with the surface pressure laid out, the weather fronts.
03:07And the jet stream there is a circulation of winds at 300 hectopascals in the atmosphere.
03:13What does that even mean, 300 hectopascals in the atmosphere?
03:17It's basically a pressure level and the height of which varies across the globe.
03:23Now, at the surface, at sea level, the pressure is more typically about 1,000 hectopascals.
03:29The average surface pressure is 1,013, so when you get up to 1,020, 1,025, it's higher pressure like this.
03:37When you get down to the 990s, it's lower pressure like these features.
03:42And so we're used to talking about these highs and lows because they determine our weather.
03:47We also have highs and lows in the upper atmosphere,
03:49but the way that we look at those is not how high or how low the pressure is at a certain height,
03:56say 5,000 feet or 30,000 feet.
04:00We look at the height of pressure levels, so it's the other way around,
04:04the height of pressure surfaces, pressure levels above the surface.
04:09And so the 300 hectopascal pressure level, that's typically about 30,000 feet or 10 kilometers above sea level.
04:21But it varies.
04:22Above the equator, it's higher because the air above the equator is on average warmer than the poles
04:29and warmer air expands.
04:31And so that pushes the 300 hectopascal pressure level up higher than it would be over the poles,
04:38where it's lower because the air is colder and more dense.
04:43It's basically lower down in the atmosphere.
04:47So say 11 kilometers, 12 kilometers above the equator, and then 8, 9 kilometers above the poles.
04:55So what I'm going to show you now is the temperature at that pressure level,
05:04the actual air temperature at 300 hectopascals,
05:07bearing in mind that this is the temperature at around 30,000 feet above the surface,
05:13but the level of that temperature will be lower towards the north, higher towards the south.
05:19Why don't we look at the height rather than the pressure level?
05:23We humans think about heights, but the weather actually behaves along pressure levels.
05:29And so it's the temperature contrast at a pressure level that will determine things like the jet stream.
05:36It's the temperature contrast at 300 hectopascals that causes the winds at 300 hectopascals,
05:42which basically is the jet stream.
05:46And so, yeah, the stronger that temperature contrast at this pressure level,
05:51the stronger the jet stream.
05:53Hope that made sense.
05:54And what we're seeing here is the temperature at 300 hectopascals.
05:59We've got warm areas, for example, over the Middle East there,
06:03into India, the Tibetan plateau, the Iranian plateau.
06:10This is actually the warmest place on the planet for this pressure level, 300 hectopascals,
06:16but it's still about minus 20 degrees up there, so it's relatively warm.
06:22It's more like minus 60 where it's coldest, and I'll show you that in a moment.
06:26But why is it so warm in this region?
06:29This is the warmest part of the world.
06:31First of all, the Tibetan plateau, Iranian plateau, over across the Middle East, parts of the Sahara,
06:37you've got high pressure, so you've got all this air coming in and sinking and compressing.
06:42So that leads to some warming.
06:44Also, you've got a lot of sunshine, cloud-free skies, high pressure in these areas at this time of year
06:49leads to a lot of warming in the atmosphere.
06:51So the whole atmosphere warms.
06:54But also, India and Pakistan are right in the midst of their monsoon summer or their wet season.
07:03And all that heavy rainfall, these enormous showers and thunderstorms that are constantly happening,
07:10put on the rainfall, through the day, they're basically rising through the atmosphere.
07:18You've got all these showers and thunderstorms developing through the atmosphere.
07:22What happens is that the water vapour in the atmosphere rises, cools, and condenses near the top of the troposphere,
07:33the weather part of the atmosphere.
07:35And that condensation releases heat.
07:38It's the opposite of what happens when you get out of the shower, you've got water droplets on you,
07:42you feel cold, because the water, when it's evaporating from your skin, extracts heat in order to give it energy to evaporate.
07:52And it takes that heat from your skin, you feel colder.
07:54This is the opposite.
07:55This is condensational heating.
07:57And you've got this condensation happening throughout the atmosphere, all the way up to the top of the troposphere,
08:03that releases heat into the atmosphere and causes this warming at the top of the 300 hectopascals above the sky in India and Pakistan
08:14because of the monsoon rains.
08:17Meanwhile, on the other side of the planet, that's where the coldest air is at 300 hectopascals,
08:23minus 60 or below across Antarctica.
08:26But what you'll notice here, you can just spin it around in the right place.
08:32What you'll notice is a big temperature contrast, not just one, but two across the southern hemisphere.
08:42And that significant temperature contrast, it is winter, of course, you've got particularly cold air there,
08:48that fuels powerful jet stream, not just one, but two.
08:52You've got these two temperature contrasts and you can see this powerful jet stream across the southern hemisphere.
08:58And that powerful jet stream needs deep lows, lots of lows at this time of year.
09:06So it's winter, they've got a powerful jet stream, they've got these deep lows.
09:11And the lows have a lot of weather fronts wrapped around them because the main cause of rain in the winter,
09:20in the southern hemisphere and in the winter in the northern hemisphere, is from fronts.
09:25These temperature contrasts, you've got this significant temperature contrast causing the powerful jet stream
09:30and causing these weather fronts and you get this frontal rain.
09:33Very different to the northern hemisphere where it's not as cold at this time of year at 300 hectopascals above the North Pole.
09:43The temperature contrasts aren't as significant, so the jet stream is much weaker.
09:47Look at the difference between what you saw there in the southern hemisphere and what you've got across the northern hemisphere.
09:52So as a result, the low pressure systems, which are created by powerful jet streams, are not quite as deep.
10:01They're quite shallow.
10:03There's still some weather fronts because there are still some temperature contrasts, but the weather fronts aren't quite as active.
10:08And what's more common in the summer is warmer land surfaces.
10:13And that means that when these shallow lows end up over the land, you've got warmth at the bottom on the ground surface
10:21that leads to rising air and a lot of shower reactivity.
10:27And that is indeed what we're going to see over the next few days.
10:29And this is why I want to highlight the temperature at 300 hectopascals,
10:34because what you can see here is this dark blue turning up as we go through Tuesday night across the UK,
10:44specifically towards the southwest of the UK.
10:48And this is what we call an upper cold pool.
10:51Now, of course, if you've got a warm land surface at this time of year,
10:55well, we haven't got the heat waves at the moment, but it's still relatively warm.
10:59We've still got some moisture, some humidity in the atmosphere and some relative warmth on the surface.
11:05Then you introduce cold air way up high, 30,000 feet above you.
11:10You've got an enhanced temperature gradient.
11:12So the temperature decreases more rapidly as you go up.
11:16And that means that any air at the surface will rise more quickly
11:20because it's always going to be significantly warmer than the surrounding air.
11:24And that's why you get stronger thermals, stronger thermal uplift.
11:29And as a result, shower clouds, thunderstorms and so on.
11:33So that's the key ingredient.
11:35We're looking here at the 300 hectopascal temperature,
11:38this cold pool turning up from the end of Tuesday.
11:42So there it is.
11:43It extends from Iceland, pushes into Ireland during Tuesday afternoon,
11:48and then it swings into southwest England and, well, I'd say Brittany, for example,
11:56on Wednesday morning, early hours.
11:59And that's going to be the key driver.
12:01But it's not the only thing.
12:02We also look at the jet stream.
12:03Now, I showed the jet stream earlier, and it's dipping to the south of the UK.
12:08So we're on this cold side, hence the cold pool.
12:10But if I just turn on a different way of visualising the jet stream,
12:16a much more detailed way of visualising it,
12:20so that you can see every single arrow on the map.
12:24And what you can see, rewind it back to the beginning,
12:29is that this, what we call upper trough, extends towards Ireland
12:33and then becomes so elongated, it becomes its own closed circulation
12:38as we go into Wednesday across southern parts of the UK.
12:43So we've got this cold pool, this air, 30,000 feet-ish,
12:49that's particularly cold.
12:51I think it's about minus 45, minus 50 degrees
12:54by the time we go into Wednesday afternoon.
12:57And you've got this enclosed circulation,
13:01this cut-off upper vortex, that's what we call it,
13:04that circulates around.
13:05So it's basically an upper area of low pressure.
13:08And because you've got lower pressure, way up high,
13:12you've got a vacuum effect.
13:14The air at the surface wants to rush up and fill that.
13:16So you've got this vacuum, a lack of air at 30,000 feet,
13:20air at the surface rushing up to come and replace that air.
13:25So two things going on there.
13:26You've got the fact that you've got this big temperature contrast
13:30between the surface and way up high,
13:33and you've got this vacuum effect
13:34where the air is being sucked up as well.
13:36And so as a result, those two factors combine to force,
13:40it's called forced ascent, force the air to ascend,
13:45cool, condense into showers and thunderstorms,
13:49particularly across southern parts of the UK,
13:51because that's where it's all centred
13:53as we go into Wednesday afternoon.
13:55Not only that, but there are things happening at the surface
13:59that will help with shower and thunderstorm development
14:02and help explain why these showers and thunderstorms
14:06will be slow moving.
14:07So just turning off those layers for a moment
14:11and zooming right in.
14:14And the first thing to point out
14:16is that if we start off Wednesday
14:18and not the right one,
14:23I'm putting the surface winds on.
14:25We'd normally show it like this.
14:27The winds are quite light.
14:28Tomorrow, they're not going to be
14:30a particularly important impact of the weather,
14:35but they will,
14:38if we put it on in a lot more detail,
14:41they will help to determine where the showers happen.
14:43Now, this is 8am, and what you can see,
14:46I've put loads of winds on,
14:49a lot of high-density arrows.
14:52It looks like it's going to be really windy,
14:53but this is just emphasising
14:56how the winds are going to be converging together
15:01and where they're going to be occurring,
15:03because how we'd normally present it like that
15:07won't quite cut it in this situation.
15:09So, by showing the winds in this way,
15:14we can see where those wind arrows are pinching together
15:17in great detail, and that's really important.
15:19We start off Wednesday with a few showers around
15:22because of the upper cold pool and the upper vortex.
15:26So, that's typically where the showers will be,
15:31but those winds are going to be pinching together
15:35in places, and increasingly so
15:39as we go through into the afternoon.
15:42So, that by 4 o'clock,
15:44we're going to see what we call convergence zones.
15:46Now, convergence zones often happen in the summer
15:50where you get winds coming in from one direction
15:53and then a sea breeze setting up from another direction.
15:57And so, as temperatures rise through the morning
15:59into the early afternoon,
16:01along the south coast,
16:02although the main wind direction is coming from the northwest,
16:06along the south coast,
16:07a little bit of a sea breeze will develop.
16:09That's where the air warms up close to the coast.
16:13It rises and you get this inflow of winds from the sea.
16:18And, of course, that's coming in at an opposite direction
16:20compared with the north-northwestities
16:23that are prevailing through the day.
16:25And, as a result, by the afternoon,
16:27you get the winds converging right along the coast.
16:30Not just there, but across East Anglia.
16:32A little bit of convergence there.
16:33Wherever these wind arrows are pinching together,
16:37the winds collide, they force the air upwards.
16:40So, that's a mechanism for forcing the air to rise
16:43from the surface.
16:45You've got the two mechanisms from way up high,
16:48but now a helping hand from the surface,
16:50the winds coming together in the afternoon, colliding.
16:53And, this is why you can get, in these situations,
16:57slow-moving or stationary showers occurring in lines close to the coast.
17:02Not quite on the coast, but a few miles inland,
17:05you can see winds pinching together there
17:07across parts of South Devon,
17:10and then more especially along that south coast
17:13from Dorset through to Hampshire,
17:16into Sussex, Kent, and so on.
17:17And, then also across East Anglia.
17:20So, you've got the convergence zones,
17:22and where they occur, showers will basically
17:24start happening and stay
17:27wherever that convergence zone
17:29continues.
17:32But, also,
17:33you've got air coming in
17:35in different directions
17:37at different heights.
17:39And, this is a significant factor of the weather
17:41for tomorrow as well.
17:42This is the surface wind direction,
17:44and, if we pay attention to East Anglia,
17:46the wind's coming in at the surface
17:48from the north-north-west.
17:50But, if I put the jet stream back on,
17:53you can see the wind's coming in
17:56from an opposite direction,
17:58from the south-southeast.
17:59That's the surface.
18:04That's the jet stream.
18:05And, we can show that
18:06Holograph is a tool
18:11that we look at as meteorologists
18:12for determining wind shear.
18:15So, that's the difference
18:16in the wind speed or direction,
18:18or both,
18:20as you go from the surface
18:21up to the top of the troposphere.
18:24And, that wind difference
18:26is important when identifying
18:27how things like showers and thunderstorms
18:30will move,
18:31and how they might rotate,
18:33and how they might become sustained
18:36by their own updrafts
18:38and downdrafts, and so on.
18:39We covered a bit of this
18:41when we talked about supercells
18:42a few weeks ago
18:44with Dan Holley,
18:45one of our chiefs here
18:47at the Met Office.
18:48And, what we're going to look at now
18:52is how these holographs
18:55can help tell us
18:56how fast or how slow
18:58these showers during Wednesday
19:00are likely to happen.
19:02Holograph, by the way,
19:04comes from the Greek
19:05for hodos,
19:06which means the path or the way,
19:09and graph to draw.
19:10So, it's effectively drawing
19:12the path of different wind directions.
19:15And, it's quite tricky
19:17to get your head around
19:18the first time you see one,
19:20but I'll try my best to explain it.
19:21Basically, you plot
19:24the wind direction
19:25and the wind speed
19:26on this graph,
19:29and then connect,
19:30well, the wind direction
19:31and the wind speed
19:32for each level in the atmosphere,
19:34and then join each of those up,
19:37like join the dots.
19:38So, the first plot here
19:41is the surface.
19:43So, that's where the surface winds are.
19:45And, zero,
19:47right in the middle there,
19:48that means the winds are flat calm.
19:50And then, the further away
19:52you go from that centre,
19:54the stronger the winds are.
19:55So, out here, it's 50 knots.
19:57So, if there's a wind of 50 knots
19:59at the surface,
20:01you'd plot it
20:01on that circle
20:03that surrounds it.
20:05Where do you plot it
20:06on the circle?
20:07Well, that depends on
20:08where the wind is blowing to.
20:11So, if the wind is northerly,
20:13then you'd basically draw an arrow
20:15from the centre,
20:17which is zero knots,
20:19and then you'd go
20:20all the way down here
20:20and plot it there,
20:22because it's blowing
20:22from there to there,
20:24and it's 50 knots.
20:25It's not that strong.
20:27Tomorrow, it's pretty light,
20:29so it's basically
20:30plotting that dot
20:32from the surface,
20:34from the centre,
20:35to this dot here,
20:37and then saying,
20:38yeah, that's where
20:38my surface wind is.
20:39It's a light wind,
20:40but it's coming from the north.
20:41So, imagine an arrow
20:42going that way.
20:44Then, you've got, say,
20:45halfway up,
20:46say 10,000 feet
20:48above the surface,
20:49you've got a wind
20:49that's pointing
20:51from the west,
20:54and it's very light,
20:56and so you point an arrow there.
20:57You start to join
20:58these dots up,
20:59and then the wind's
21:00way up at 300 hectopascals,
21:0330,000 feet or so,
21:05are plotted here.
21:06That's the black dot
21:07up here,
21:08and that's coming,
21:09like I said,
21:09it's coming from the southeast,
21:11so you draw an arrow
21:12up here,
21:13and that's where that is,
21:14and then for each
21:15of these dots,
21:15you draw a line,
21:18and what that tells us
21:19is how much
21:21the wind direction
21:22is varying
21:23as you go from the surface
21:24up to the top
21:25of the atmosphere.
21:26If the wind,
21:28if the line here
21:30is curved,
21:31then it means
21:32the winds
21:33are changing direction
21:34with height,
21:35and that's important,
21:36because if that happens,
21:38then the storm
21:39can start rotating
21:40and become more powerful.
21:43It can be a supercell,
21:44for example,
21:44that's what we look out for.
21:46If the line
21:48doesn't curve,
21:49but it's more
21:49of a straight line,
21:51so it starts there,
21:52and then it goes there,
21:54and then it goes there,
21:55then it's directional shear.
21:56It means that
21:57it's the same direction,
21:58keeps pointing that way,
22:00but the wind speed
22:02gets higher
22:02as you go up
22:03in the atmosphere.
22:04What this shows us
22:06for Wattersham
22:07in Suffolk
22:08for Wednesday,
22:09and this is showing
22:114pm on Wednesday,
22:14is that the winds
22:16start off
22:17coming from the north,
22:19then they curve round
22:20and go more
22:22coming up
22:23from the south-southeast.
22:26And basically,
22:28if you pick somewhere
22:29in the middle,
22:31that's effectively
22:32a good estimate
22:33of where the storm
22:35will move,
22:36how fast it will move,
22:37and in which direction.
22:38And the middle of this
22:39is slap-bang
22:40in the middle
22:40of the holograph,
22:41and so that effectively
22:43suggests that
22:44the surface winds
22:46are going to
22:47cancel out
22:48the upper winds
22:49and the storm
22:49will stay
22:51more or less stationary.
22:53So that's what
22:53we're looking at here.
22:54We're looking at
22:55the winds at the surface,
22:56the winds higher up,
22:58picking somewhere
22:58in the middle,
22:59and saying,
23:00that's where the
23:01storm will move,
23:03and it's right in the middle
23:04of the holograph.
23:05It's at the zero point,
23:06so it's not particularly
23:07going to move anywhere.
23:08And even these winds
23:10at the surface
23:10and higher up
23:11are pretty light as well.
23:12So, yeah,
23:14some wind shear,
23:15but it's all
23:16quite light wind shear,
23:18and the steering level,
23:20that mid-level wind,
23:22is right on the middle
23:23of the graph.
23:24So that indicates,
23:26looking at that,
23:26that the storms
23:27across East Anglia,
23:29where they develop,
23:30are going to be
23:30very slow moving.
23:32And we look at,
23:35say,
23:36somewhere else in the country,
23:38you get a different
23:39profile on the holograph.
23:41This is Dartmoor.
23:43And what this shows
23:44is that winds
23:45start off quite light,
23:47so that's the surface,
23:49that red bit there
23:50at the start,
23:52and they're coming in
23:52from the north-west,
23:54and then the winds
23:55stay generally
23:56north-north-west
23:57as you go up
23:58in the atmosphere,
23:59because the jet stream
24:00is coming in
24:01from the north-north-west
24:02across Dartmoor,
24:03as opposed to Suffolk,
24:05where it's coming in
24:05from the south-south-east,
24:06because the jet stream
24:07is kind of doing
24:08that circular thing
24:09over the south of the UK.
24:10So what we've got here
24:12is directional shear,
24:13where the winds get stronger
24:14as you go up
24:15in the atmosphere,
24:16and some good steering levels.
24:18So if you pick somewhere
24:19in the middle,
24:20you can actually see
24:21that the storm
24:22will move
24:23from the north-north-west
24:24to the south-south-east
24:26at a reasonable pace.
24:29But the difference
24:31with Dartmoor
24:32is that, of course,
24:35it's elevated ground.
24:37And so this is another
24:38factor we look for
24:38when we're talking
24:39about shower development
24:41in the summer
24:42is any elevated surfaces
24:45of warmth.
24:47And, you know,
24:47you've got some heating
24:48over Dartmoor.
24:49It's higher up
24:50than its surroundings,
24:51and so the air,
24:52as it's heated
24:53during the day,
24:54will be warmer
24:55than the air surrounding it.
24:58And that will help
24:59to aid convection,
25:02help to aid that rising air
25:04over Dartmoor.
25:05And so you get
25:06shower development
25:07after shower development
25:08over Dartmoor.
25:09They might be moving off,
25:10they might be moving
25:11to the south,
25:13but they're going
25:15to keep reforming.
25:16So,
25:19by putting on,
25:20let's put the streamlines
25:22back on,
25:23and this needs
25:26to go to Wednesday afternoon
25:28for the peak development.
25:29and what you can see here
25:32is this cluster
25:35of heavy showers
25:36and thunderstorms
25:37that start over Dartmoor,
25:39get pushed
25:40to the south,
25:40south east,
25:41and then just become
25:43aligned with the coast
25:44all along the south coast
25:46there,
25:47and then up
25:47as you go into East Anglia,
25:49this pinching together
25:50of the winds
25:50and you've got
25:51some heavy showers
25:52developing across
25:53parts of Essex,
25:54into Kent,
25:55near London,
25:56and it's this whole
25:58zone across
25:59the south,
26:00south west,
26:01and south east
26:02where these showers
26:04will develop
26:05and they'll be slow moving.
26:06They'll be slow moving
26:07because the winds
26:09are coming together,
26:11convergent zones
26:12because of sea breezes
26:13and other effects.
26:14They'll also be slow moving
26:15because as I mentioned
26:16across East Anglia,
26:17you've got
26:18the winds at the surface
26:20going in the opposite direction
26:21of the winds higher up.
26:22Both those winds
26:24are relatively light
26:25and so the storms
26:26will basically form
26:27and just sit there.
26:29And they'll be slow moving
26:31across Dartmoor
26:31because they'll just keep
26:32popping up through the day
26:33across Dartmoor
26:34because it's higher up
26:36than its surroundings.
26:37So all of these factors,
26:39you've got the cold air
26:41way up at 300 hectopascals
26:43or 30,000 feet
26:44that sits over the south
26:46of the UK.
26:47You've got the circulation,
26:48this closed upper vortex.
26:50You've got the sea breezes,
26:52you've got the winds
26:52coming together,
26:53you've got the winds
26:54going in different directions
26:55at different levels
26:56and you've got the elevated ground
26:58over Dartmoor, for example.
26:59All those reasons
27:01will lead to some very heavy downpours,
27:04perhaps some thunderstorms,
27:05that will stay in the same places
27:08through the afternoon
27:09and lead to perhaps some impacts
27:12because where these occur,
27:14they're not going to shift
27:15very quickly.
27:16But of course,
27:17that means that other places,
27:18even in the areas
27:20I've just mentioned,
27:21won't see any at all.
27:23And this is highlighted
27:24by this graphic.
27:27We look at Wednesday
27:30through to 6pm
27:31and you can see
27:35some very speckled forecast rain
27:37across East Anglia
27:38into the east
27:40and southeast of England
27:41all along the southwest.
27:43Some areas,
27:4530, 40 millimetres of rain
27:47in a few hours,
27:48other areas,
27:49very little
27:50because where these showers occur
27:52and become slow moving,
27:53of course,
27:55in other places,
27:56they will not occur at all.
27:59Some places,
27:59avoiding them entirely
28:00and staying dry.
28:02There will be other showers occurring
28:03across the UK.
28:05The Pennines, for example,
28:06are focused for showers.
28:07Southeast Scotland,
28:09once again,
28:11a focal point
28:12for some heavy showers.
28:15More scattered showers
28:16across Northern Ireland,
28:17Western Scotland,
28:18not quite as heavy
28:20or as slow moving.
28:21But yeah,
28:22you can see the impact
28:23of all those factors
28:24coming together
28:24across the southeast,
28:25not just across
28:26the south of the UK
28:27but across northern France
28:28as well,
28:29interestingly.
28:31Now,
28:32that's Wednesday.
28:34As we go into Thursday,
28:36things start to change.
28:39We've still got some showers around,
28:41this time across central,
28:43the central spine of England
28:44into the east of England,
28:45for example,
28:46the heaviest downpours
28:47across East Anglia
28:48as that upper vortex
28:51moves away to the east.
28:53But meanwhile,
28:55things are changing
28:56out to the west.
28:58Let's take a look
28:59at what that looks like
28:59on the 300 hectopascal temperature.
29:05As I suspected it would do,
29:07it looks like warmer air
29:10is coming in
29:11at that level
29:12to western parts of the UK.
29:13So here's that cold pool.
29:15It's moving into central Europe.
29:17Warmer air is starting
29:18to appear
29:19towards the southwest.
29:21Actually,
29:21that cold pool moves away
29:24but it persists.
29:27That's the wrong one.
29:28It persists
29:29for quite a few days
29:31across central Europe.
29:32Here it is,
29:33moving into the Alps.
29:34Oh,
29:36I don't want that on there.
29:37And into Sunday,
29:38it's over Italy.
29:39So yeah,
29:40that could cause
29:40some lively thunderstorms.
29:42That upper cold pool
29:43pushing south
29:45over some very hot ground.
29:47And if I put the rainfall on,
29:49you can probably see
29:49some wet weather there
29:51across Croatia
29:52into northern Italy.
29:54But aside from that,
29:55across the UK,
29:55we've got higher temperatures
29:57moving in from the southwest
29:58and a ridge of high pressure
30:00building in at this point.
30:03And that is going to lead
30:05to a significant change
30:06once again
30:06across the UK
30:09as we go into the weekend.
30:10So,
30:11by Friday,
30:14many places
30:15drier.
30:17Best of the sunshine on Friday
30:19towards the east
30:20and southeast,
30:2027 degrees possible.
30:22Still some cloud
30:23coming to the west
30:24and northwest.
30:24And by Saturday,
30:27this is Saturday early hours,
30:29we've got showers
30:30across Scotland
30:31and Northern Ireland.
30:32Fairly brisk moving showers,
30:35not particularly heavy
30:36in between some bright spells.
30:38And you can see
30:38across much of England
30:39and Wales,
30:39plenty of sunshine
30:40on Saturday,
30:41feeling warm,
30:42temperatures in the low
30:43to mid-twenties.
30:44Some question marks
30:45about Sunday.
30:46This area of low pressure
30:48moves in.
30:49But how far north
30:50and south it will be,
30:52that is a source
30:53of uncertainty
30:54the European model
30:56has it much further north
30:57and so much of the UK
30:58avoids it.
30:59But the Met Office model,
31:01as you can see,
31:02pushes the rain
31:02into many parts
31:04of the UK
31:05by Sunday.
31:06We'll take a look
31:06at that in a bit more detail
31:08in tomorrow's 10-day trend
31:09with Greg Dewhurst.
31:11Then,
31:12into next week,
31:13well,
31:13it's a fairly
31:14what we call
31:15climatological setup.
31:17We've got
31:18still a lot of blues
31:23on the graphic here.
31:24This is the most likely
31:25weather pattern
31:25for each day
31:27and the blues
31:28represent low pressure
31:29close to the UK.
31:30But,
31:31as you can see,
31:31by the time we get
31:32into next week,
31:33it's more of these
31:35lighter blues
31:36that are appearing
31:37and that indicates
31:38higher pressure
31:42extending from the southwest
31:45in some shape or form
31:47and the more unsettled weather
31:48towards the north
31:49and east of the UK.
31:53This shows the kind of
31:55rainfall anomaly
31:56we'd expect
31:57in this kind of situation.
32:00As you can see,
32:01fairly average over the UK.
32:02some wet weather
32:04across the near continent
32:06and the average pressure
32:09through next week
32:10is quite interesting.
32:12Got quite low pressure
32:13over the near continent
32:17over Germany and Denmark
32:19with a build
32:20of higher pressure.
32:21This is the average pressure
32:22anomaly through next week.
32:24Well, actually,
32:24through the rest of this week
32:26and then into next week
32:30an even stronger build
32:32of pressure
32:32towards the southwest,
32:33lower pressure
32:34to the east of the UK.
32:36And that trend
32:36tends to continue
32:38into the second week of August.
32:40This is the 4th of August
32:41to the 11th of August
32:43and we've got a higher pressure
32:44becoming more prevalent
32:45over the UK.
32:46So what I suspect
32:47will happen
32:47is that
32:49through next week
32:51the UK
32:51will be subject
32:52to the jet stream
32:53lying across the north
32:55of the UK.
32:55It will stay fairly changeable
32:56for Scotland
32:57and Northern Ireland
32:58mostly dry
32:59for England and Wales
33:01with higher pressure,
33:03a ridge of higher pressure
33:04coming and going
33:05at times.
33:06No sign of a heat wave
33:07next week.
33:08Mostly it's cool,
33:09changeable westerly winds.
33:12But then as we go
33:12into August
33:13the signs are
33:15that pressure
33:16will begin to build
33:17a bit more
33:17towards the west
33:18and the southwest
33:19of the UK
33:20perhaps bringing
33:21more widespread
33:22settled weather
33:23and higher temperatures
33:25as a result.
33:26But of course
33:26that's a long way off
33:27and we'll be covering it
33:29much more closer
33:30to the time
33:31and I'm sure
33:32we'll be covering it
33:32in the deep dive again
33:33so make sure
33:34you'll be tuning in
33:35next week
33:36for the Men's Office
33:37deep dive
33:38but otherwise
33:38that's all from me.
33:39Bye bye.
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