This is an in-depth Met Office UK Weather forecast for the next week and beyond. The heat comes to an end but what happens next? Back to more typical UK summer weather? Bringing you this deep dive is Met Office meteorologist Aidan McGivern.
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00:00What a June it's been so far, a cold start, and now this brief hot spell.
00:07How long will it last? And will it end in a bang or a whimper?
00:12And what's next for this rollercoaster ride that is the Great British Summer?
00:16No matter what happens next, we will have you covered right here in the Met Office Deep Dive,
00:21our regular Tuesday treat for subscribers or non-subscribers of our YouTube channel.
00:27Although I do encourage you to subscribe because it will encourage us to do more of these sorts of things.
00:33Now, before the comments start rolling in, I want to emphasize that, yes, we know it's not been hot everywhere.
00:41And I'm starting with the exceptions to the heat just to make sure we've got those covered.
00:46Starting with Monday morning. Now, this is the satellite image, the visible image.
00:516 a.m. Monday or 7 a.m. And it shows quite extensive cloud across Wales and the southwest of England.
00:59A continuation of the cloudy conditions that we saw on Sunday.
01:03And I can tell you firsthand experience here in Devon of the grey leaden skies we've had over the last couple of days that have suppressed temperatures.
01:12Stratocumulus that has been persisting.
01:15That is now breaking up. But you can see the impact that had on temperatures on Monday.
01:21Now, this shows the maximum temperature on Monday. I appreciate the boxes might be a bit too small to see.
01:26So I'll just read out a few notable ones. It was on Monday, the warmest day of the year so far for England, certainly, and for the UK.
01:35Twenty eight point three Celsius there for Surrey.
01:37But a marked contrast for the coasts of West Wales, Devon and Cornwall, where we saw 18s and 19s under that relatively low cloud sheet.
01:48Looking at Scotland and Northern Ireland, again, relatively warm across many areas, but not everyone saw that warmth.
01:57Western Scotland, for example, again, cloudy skies here, more of a breeze, 18s, 17, 14 Celsius in parts of the West Coast.
02:07And so certainly a notable difference from Western Scotland to eastern Scotland and twenty seven point three Celsius there for a boy.
02:15Warmest day of the year so far for Scotland. Also the warmest day of the year so far for Northern Ireland with, I believe, twenty five point nine Celsius at McGilligan.
02:25So marked contrast across the UK on Monday and the same sort of thing on Tuesday.
02:31I just had a message through to say that it is now Tuesday is England's and Wales's and the UK's warmest day of the year so far.
02:41But I'm recording this just before two o'clock. So I imagine over the next few hours those temperatures will increase.
02:47But it's unlikely to be Scotland's warmest day of the year so far or indeed Northern Ireland's, because through Monday we started to see this thick area of cloud arrive across northwestern parts of the UK.
03:00And as we've started Tuesday, as you can see, that area of cloud associated with a weak frontal system has brought some patchy rain.
03:08Let's put the radar on some patchy rain into western Scotland and fast forward to the start of Tuesday.
03:15So that patchy rain and drizzle there and then that started to move its way slowly eastwards to affect central and southern parts of Scotland.
03:23Much of Northern Ireland under the cloud and the drizzly outbreaks of rain.
03:28Actually, we could see some heavier rain for a time during Tuesday afternoon.
03:31I won't dwell on that because I know this is going to go out after most of that has happened.
03:35But let's take a look at a few more exceptions over the next couple of days.
03:40And starting with Wednesday, I'm going to show Wednesday, pause it there.
03:45And what we've got on Wednesday on the cloud layer is just the hint there of some patchy cloud.
03:52Rewind a little bit. It's more extensive actually on Wednesday morning.
03:56And so we've got the frontal cloud across Scotland.
04:01This is the start of Wednesday. Eastern and southern Scotland, the far north of England, seeing that frontal cloud and some rain clearing first thing.
04:08But at the same time, there's some overnight low cloud affecting parts of eastern England, eastern Scotland and some mist in places.
04:16There's a bit of uncertainty about that aspect of the forecast.
04:19The reason there's uncertainty in the North Sea is that there's a lot more low cloud in the computer models than is there in reality.
04:27And so it's likely that that will be fairly patchy to start things on Wednesday.
04:32However, it could limit the increase in temperatures during the morning.
04:36And that's quite obvious when you look at let's switch to the temperatures here.
04:42When you look at the temperatures.
04:47Compared with average for Wednesday. And what this is showing is how the temperatures, maximum temperatures on Wednesday compare with the June average.
04:57And the red colours there show that in many places across central, northern, southern England, east Wales, for example, six degrees or nine degrees above the June average.
05:09And for Scotland, certainly north of the central belt, Northern Ireland back closer to average.
05:14But look at that slither down the east coast temperatures closer to average, not quite as hot because of that early mist.
05:22Now, compare that with the start of Thursday. That's Friday and Thursday.
05:28It shows much higher temperatures again down the east coast.
05:31And that's because of a change in wind direction, which I'll go on to in a moment.
05:34But looking at the actual temperatures and the kinds of highs that we're likely to see on Wednesday and extensive across England and Wales, mid to high 20s expected.
05:46But on that North Sea coast, just limited compared with the rest of inland England and Wales with temperatures closer to the low 20s, perhaps high teens.
05:56If we see some of that mist and low cloud last through the day.
05:59Likewise, Scotland and Northern Ireland, not as warm as Monday, but perhaps a little bit warmer in places compared with Tuesday because we're going to start to see sunnier skies once again, certainly for Northern Ireland and Western Scotland.
06:11Then watch this change. Click the wrong one again.
06:16Into Thursday, much fresher conditions into western parts.
06:20We keep some of that warmth in the east of England, but not as hot with temperatures here more likely to be 26 to 28 Celsius.
06:30So there's this cooling trend during Thursday and it happens during the day.
06:35Now, Scotland and Northern Ireland already closer to average temperatures, but turning even cooler later this week.
06:41Whilst England and Wales, this brief hot spell does come to an end.
06:45And the reason is. Taking a look at the bigger picture, and this is Tuesday.
06:50At the moment, we've got the jet stream to the north of the UK, high pressure to the east, so we're drawing up this warmth across the UK.
06:57But there's a bit of a pulse in the jet stream that picks up an area of low pressure.
07:03And actually, this is a relatively deep area of low pressure for the time of year.
07:09I think the central pressure by Thursday is 980 hectopascals, which is fairly unusual close to the UK in the middle of June.
07:19So that low pressure comes along. Now, the centre of the low stays away from mainland UK, but it does swing this frontal system in this occluded front.
07:30I'm just removing the jet stream and putting the temperatures colours on.
07:34And you can see this much fresher air arriving through Wednesday night and then into Thursday as that low moves in.
07:43Not only will it be turning cooler from the west with those temperatures returning closer to average widely on Thursday away from the east and across the whole of the UK by Friday.
07:53We're also going to see some heavy rain. Not everyone will experience the heavy rain.
07:57It will be more limited and it's most likely to affect northern parts of the UK.
08:02So day three, the start of Thursday, there's the low pressure, the swirl of cloud and outbreaks of rain.
08:11There's the front that's ahead of the low.
08:15And at the start of Thursday, it's a relatively weak feature across Western England and Wales.
08:20You can see it's both a narrow feature, but also nothing particularly heavy.
08:26However, a bit of a contrast there for the north east of Scotland, some heavier showers develop on that low for a time.
08:34And it's going to turn increasingly windy across northwestern parts of the UK with gusts into the mid to high 40s miles an hour.
08:43So increasingly unsettled. But the majority of the UK will just experience a few spots of rain and unlikely to experience a thundery breakdown.
08:54Although you couldn't necessarily rule that out over the next few days because we've got the heat in place.
08:58So there's always a chance of an isolated thunderstorm during Wednesday, Thursday and into the start of Friday.
09:04Most especially on Wednesday across some of these western and northern hills, the Pennines, the Welsh mountains.
09:10On Thursday then towards the southeast. And then there's always that threat that thunderstorms over the continent could reappear beyond that heading into the weekend into the far southeast.
09:21But it is a low risk for the vast majority. This heat wave or hot spell, I should say, because most places aren't experiencing a technical heat wave is going to end in a whimper.
09:31A band, a weak band of rain comes through a few spots of rain and then much cooler air.
09:36But that one exception, northeast Scotland. And let's just take a look at that, because it's likely that we'll see.
09:46Skip to Thursday. So this is. Thursday morning and the six hour rainfall total.
09:53So really, it's the overnight rain and the early morning rain and what it's coming up with across eastern parts of Aberdeenshire into the far north of Scotland.
10:01Orkney, for example, is 25, 30, 40 millimetres of rain falling during that period, during about six hours with some heavier showers moving through.
10:11A bit of uncertainty because these are narrow features that are moving through and relatively small parts of the UK as in Orkney and Shetland.
10:21So you'd have to have the two coincide to see the greatest amount of rainfall.
10:26But there is that threat of some heavier rain for a time in the far north of Scotland.
10:30Meanwhile, it's turning cooler across the rest of the UK.
10:33It's turning a bit more blustery and into the weekend things become more westerly dominated.
10:41So let's take a look at the big picture once again. And what I mean by that is we've got the jet stream back in charge of the UK's weather.
10:49Having been sitting to the north during the last few days. Here's the picture on Thursday.
10:54The first pulse of the jet pushing that low pressure to the north of the UK.
10:59Then interesting developments on the other side of the Atlantic and some rather uncertain developments on the other side of the Atlantic as well.
11:08Because we've got two branches of the jet stream that are coming out of North America.
11:16And one of them just picks up this relatively innocuous feature and starts to move it across the Atlantic.
11:24Meanwhile, this area of high pressure is beginning to build north of the Atlantic.
11:28So the whole pattern becomes more amplified, more wavy once again.
11:32And that means that the jet stream moves to the north as this high builds.
11:37And that allows the jet to just dive under that high pressure, picking up this area of low pressure during Friday.
11:49Here it comes. There's the jet extending north as the high builds and then diving south, picking up this area of low pressure.
11:56Not a particularly deep or active low at this stage, as to be said.
12:01And then late Friday, it looks like that's just going to come in to southern parts of the UK.
12:06But this is an uncertain aspect of the forecast. It depends on developments upstream coming out of North America over the next couple of days.
12:14And those elements, small changes in the jet stream and how they interact with areas of low pressure and so on can make a big difference.
12:21Yesterday's computer models had that low just pushing to the west of the UK,
12:26not really affecting us with a ridge of higher pressure, more likely for southern parts.
12:31Today, the models are suggesting that low pressure is going to become more centred over southern parts,
12:37but as a relatively flat feature, an area of cloud and outbreaks of rain.
12:43So the most likely scenario for that low, we have a look at the forecast for.
12:51Saturday, for example, this is the start of Saturday and you can see this area of cloud extending from parts of the Midlands,
12:59northern England into Wales and Ireland and outbreaks of rain, mostly these blue colours rather than the brighter colours.
13:06So light outbreaks of rain and just playing that forward.
13:10We've still got showers going across northern and western Scotland, by the way.
13:13That's going to be the main feature here during Friday and into the weekend.
13:17But this weak frontal zone then just sort of meanders across central and southern parts of England and Wales and fizzles out.
13:28So, yeah, it's likely to be a relatively cloudy picture in many of these areas,
13:33although there could be some sunshine coming through across the southeast and then later towards north Wales, northwest England.
13:39But rainfall amounts, not exceptional. Outbreaks of mostly light to moderate rain.
13:45Later on, there is the small chance that it becomes more showery.
13:49It could break out to some heavy showers by Sunday in the southeast.
13:52But what that means is through the weekend, generally cloudy skies, a few light to moderate showers associated with that frontal system.
14:01That's a 70 percent likelihood for the weekend.
14:06But speaking to my colleague Dan Harris, who's the expert looking at the medium range today,
14:12he was suggesting that there's a 20 percent chance that that low just dives to the south, out to the west of the UK and doesn't really affect us very much.
14:22And then there's a 10 percent chance that the jet stream, that small filament of extra energy in the jet stream,
14:27spins it up into a deeper feature to bring more extensive cloud, wind and rain across southern areas.
14:32So that's a 10 percent chance. But this is a 70 percent chance what you see on the screen here.
14:36So, yeah, expect a bit more cloud there across southern parts of the UK as we go into the weekend.
14:41It's going to feel cooler results because, of course, less sunshine around.
14:45And some outbreaks of mostly light to moderate rain just meandering,
14:50piddling their way southwards through Saturday and into Sunday.
14:55But like I say, no signs of heat in the forecast for the weekend, no signs of anything particularly wet either.
15:03Just back to relatively nondescript, westerly influenced summer weather.
15:07And speaking of relatively nondescript, westerly influenced summer weather, that is how things are looking for the start of July.
15:16This graphic here shows the most likely weather pattern for Monday, the 1st of July.
15:22This is a 35 percent probability. And what the models do, we run the computer model many, many times.
15:31Not only the Met Office model, but the European model, the American model as well.
15:34So there's dozens and dozens of computer model runs.
15:37And then here at the Met Office, we analyse all of that output and come up with the most likely weather patterns
15:44and the percentage chance of these happening.
15:46So this is Monday, the 1st of July, looking at all those different computer model runs and 35 percent chance that it will look something like this.
15:54There's the UK in the middle. We've got higher pressure over the Azores, lower pressure over Iceland.
15:59And the chance of that higher pressure could just ridge into southern parts to bring mostly fine weather to southern and southwestern parts.
16:07The chance of that low over Iceland will bring some cloud and some outbreaks of rain to the northwest of the UK with mostly westerly winds.
16:16And so temperatures close to average, perhaps a little bit above if that high pressure influence extends a bit closer to the UK.
16:23This is what we call a positive North Atlantic oscillation.
16:27Just very quickly, a North Atlantic oscillation is the oscillation between the pressure over Iceland and the pressure over the Azores.
16:34When the pressure is lower than normal over Iceland, because on average it is low, when it's even lower,
16:40and when it's higher than normal pressure over the Azores, because on average you get higher pressure over the Azores,
16:47but when it's even higher, then you get what we call a positive North Atlantic oscillation.
16:52It's this oscillation between the pressure over Iceland and the pressure over the Azores.
16:57When the pressure is higher than average over Iceland and lower than average over the Azores, it's called a negative North Atlantic oscillation.
17:04This though, like I say, lower than normal over Iceland, higher than normal over the Azores, positive North Atlantic oscillation.
17:11What does that mean for the UK?
17:13Well, in the winter you get this strong jet stream and you get strong westerly winds.
17:18You get stormier weather often, and it's often milder as well because of the increase in winds and rain and so on.
17:25In the summer, because you typically get a weaker jet stream and a more north-shifted jet stream,
17:30what this often means is that you still get some mixed weather towards the northwest of the UK,
17:35but you can have a bit more of a high-pressure influence into the south,
17:38and it can bring slightly above-average temperatures and mostly fine conditions in the south.
17:43That's what this is showing, 1st July.
17:46But small shifts in that pattern, north to south, can make a big difference in terms of how the weather feels for us in the UK.
17:56This is the second most likely weather pattern for the 1st July, and this is a 29% chance,
18:04so it's a pretty similar chance, 1 in 3 more or less compared to the other one.
18:09This shows a slightly south-shifted pattern, less influence from the high pressure over the Azores,
18:15a bit more of an influence from low pressure to the north, negative temperature anomalies,
18:20although not particularly far from average, a bit more rain into northwestern parts of the UK,
18:25a bit more of a northwesterly breeze, so cooler on the whole.
18:30And just to show you one possibility for the middle of next week,
18:36this is coming out as a possibility for the middle of next week,
18:41a 20% to 25% chance that it will be shifted even further south with low pressure closer to Scotland
18:47and more unsettled weather across the UK.
18:50So all that's happening here is there's a bit of variation in the output between how far north and south that pattern is shifted,
18:58how far away the low pressure is from the north of the UK, how close the high pressure is to the southwest.
19:04Either way, it's west-to-west-northwesterlies and fairly mixed weather across the UK.
19:11But always the chance, when you look at the whole week next week, that it will just oscillate up and down.
19:19So sometimes the jet will be a bit further north, sometimes it will be a bit further south,
19:23relatively changeable, westerly-dominated weather.
19:27And this shows the average pressure anomaly through next week, through the first week of July from the European model.
19:36And this tends to agree with the rest of the output.
19:38We've got this higher pressure just to the north of the Azores there,
19:43and that's showing a kind of west-to-west-northwesterly airflow across the UK.
19:48But I've got to emphasise this.
19:51There's always the possibility that that higher pressure could build in from time to time to bring more widely settled and warmer weather.
19:58In this kind of situation, you can get a build of heat to the south of the UK,
20:02so it wouldn't take much for the jet stream to perhaps be slightly buckled from, for example,
20:07developments over North America that we don't have a grasp on just yet,
20:12or a tropical storm that comes along in the tropics that could just buckle that very weak and meandering jet stream enough
20:20to push to the north of the UK and allow hotter weather to develop.
20:24So just to summarise, first week of July, yeah, we're back to cool, more changeable weather across the UK,
20:31nothing particularly cold or hot signalled at first, with more changeable weather across northern parts of the UK,
20:38more settled the further south you are.
20:41But it all hinges on how far north-south that pattern is shifted,
20:47whether we get the more unsettled influence coming in from the north or the more settled influence coming in from the south.
20:52And what I suspect will happen is we'll see a bit of both from day to day through the first week of July.
20:59And we'll keep you updated right here at the Met Office.
21:01Thank you for joining me this week.
21:03Let us know in the comments if you've got any questions, any ideas for any other topics.
21:08But otherwise, we'll be seeing you right here again next Tuesday. Bye bye.