This is an in-depth Met Office UK Weather forecast for the next week and beyond.
It’s been mild and wet so far this autumn but things are about to change... Bringing you this deep dive is Met Office meteorologist Aidan McGivern.
It’s been mild and wet so far this autumn but things are about to change... Bringing you this deep dive is Met Office meteorologist Aidan McGivern.
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00:00 High pressure, lower temperatures and less rainfall.
00:04 We've got it all covered in this week's Deep Dive.
00:07 Hit subscribe if you like these in-depth forecasts that we do every Tuesday.
00:12 And if you comment and hit like and so on, share the love with your friends and family,
00:19 then it may well encourage us to do more things like this in the coming months.
00:25 But before I go into detail about the upcoming weather, let's take a look at the autumn
00:29 so far and paint the picture.
00:34 Because this is showing the mean temperature anomaly, so the difference from average for
00:40 autumn across the UK up to the 20th of November.
00:44 So of course we've still got the coldest part of autumn still to come, but nevertheless
00:48 the 1st of September to the 20th of November, compared with the average autumn, has been
00:53 remarkably warm, especially for England and Wales.
00:57 Southern England has seen a temperature anomaly so far of +2.5 Celsius, so 2.5 degrees up
01:03 to this point, warmer than a typical autumn.
01:07 Less of an anomaly across Scotland, but still warmer than average here.
01:12 Not only has it been warm, it's been wet.
01:15 This shows the rainfall anomaly.
01:17 Now at this point in the season you'd normally expect 89% of the average autumn rainfall,
01:23 so that would be a colour approximating white, I imagine there.
01:27 And some places have the white colour, so for example parts of central and western Scotland,
01:32 some parts of northern and western Northern Ireland.
01:35 But actually you can see the blues are much more widespread on the map, and overall for
01:40 the UK we've had 116% of the typical autumn rainfall.
01:46 But that difference has been particularly marked across parts of southern and eastern
01:51 England, eastern Scotland.
01:52 Some areas have had 1.3 times their average autumn rainfall up to this point.
01:57 Of course we've still got 9-10 days to go.
02:00 Western Scotland has been drier than average, so less rainfall here.
02:04 And that's because of the way that areas of low pressure have been moving in through the
02:09 autumn so far.
02:10 We've had quite a strong jet stream, but a south-shifted jet stream, especially through
02:16 October and the first part of November.
02:18 And that's sent the low pressure systems in on a more southerly track.
02:23 So rather than bringing their wet and windy weather to western Scotland, which is more
02:27 typical for autumn in the UK, they've been pushing wind and rain into southern parts
02:32 of the UK, bringing a lot of wet weather to England, Wales and then Northern Ireland as
02:37 well.
02:38 And then as those systems moved up, most notably of course with storm Babette, as those systems
02:43 moved up and squeezed up against high pressure that has been sitting over Scandinavia, they've
02:49 stalled and brought a lot of wet weather to eastern Scotland.
02:52 So storm Babette, a key example of that.
02:55 But actually we've seen that kind of situation a number of times during the last few weeks.
03:00 So a wet and warm autumn so far.
03:05 But that is about to change for the rest of the season.
03:09 I think the remaining 9-10 days of the season looking quite different to autumn so far.
03:15 Why is that the case?
03:16 Well it's the case because of high pressure.
03:19 Let's take a look at the bigger picture.
03:23 You can see high pressure there at the time of recording, nicely situated to the south-west
03:28 of the UK.
03:29 It's a fine day actually for many of us.
03:30 We have got some showery rain clearing from the south-east of England.
03:34 But for most we've got this ridge of high pressure.
03:36 That's led to a cold start, a frost across parts of Scotland for example this morning.
03:41 But plenty of bright skies around.
03:43 Now it's not all plain sailing over the next few days.
03:47 That high pressure now setting up across or close to the UK.
03:53 But it's not going to be entirely slap bang over the UK.
03:57 So one complication is that the high pressure is now shifting the jet stream to the north.
04:02 But it's a powerful jet stream.
04:04 And over the next 24 hours or so that jet stream is going to reach speeds in excess
04:08 of 200 miles an hour.
04:09 So 200, 220 miles an hour.
04:13 And if I play that forward actually you can see this streak of very powerful winds high
04:18 up in the atmosphere.
04:19 The jet stream deepening areas of low pressure up near Iceland and Greenland.
04:26 And although we've got high pressure close to the UK, specifically during Wednesday towards
04:32 the south west of the UK, that jet stream is still influencing our weather, especially
04:37 in the north.
04:38 And sending this weather front into northern Scotland.
04:41 So increasingly wet through Wednesday across much of Scotland.
04:45 And that rain also extending further south as the day progresses.
04:49 But not only that, let's just remove the jet stream for a moment.
04:53 You can see these tightly packed isobars.
04:55 In fact, as the jet stream, as that powerful jet stream deepens these areas of low pressure
04:59 near Iceland, we've got high pressure close to the south west of the UK.
05:03 Those isobars will tighten further.
05:06 And it's going to turn increasingly windy.
05:09 Zooming in a touch there.
05:12 Increasingly windy across the far north of Scotland.
05:15 More on that in a moment.
05:17 But yeah, although we've got higher pressure closer to the UK than we have had through
05:21 much of autumn so far, it's also leading to this marked pressure gradient.
05:27 Tightly packed isobars, in other words, especially for northern Scotland.
05:30 What you can see there as well, well, if I zoom in a bit further, you might be able to
05:35 see it, is what we call troughing in the isobars.
05:39 So this waviness.
05:41 That's caused by the topography of the UK, so the hills and mountains.
05:45 And what's interesting is that as the wind comes in on a relatively straight line, so
05:50 straight lines here, and then the wind is forced to rise over the mountains, but then
05:58 it starts bouncing.
05:59 So on the other side of the mountain, to the lee of the higher ground, the wind goes back
06:05 down again and then it continues bouncing.
06:08 It's got some buoyancy and it starts to rise again.
06:11 And that rise in the air leads to some lower pressure.
06:15 And so you've got this troughing of the isobars just here.
06:19 North-East England, Eastern Scotland.
06:21 What that also indicates when you see that pattern in the isobars is that the winds will
06:25 be particularly gusty around North-East England, Eastern Scotland.
06:30 And so those winds are just forced to move over the mountains.
06:34 They're pushed up, then they fall back down again, then they continue bouncing.
06:37 And you can continue to see that effect some significant miles to the east of higher ground
06:43 in this kind of situation.
06:45 But that just indicates those tightly packed isobars and the troughing, this bumpiness
06:49 in the isobars, indicates some gusty conditions.
06:52 Through the second half of Wednesday in particular and into Thursday.
06:54 So running out forward, you've got the front there bringing some heavier rain for a time
06:59 on Thursday.
07:01 And the strong winds as well.
07:02 Some very lively winds on Thursday.
07:06 Peaking, I think, early morning on Thursday.
07:10 Chills of severe gales in the far north of Scotland before that cold front pushes south.
07:16 Then, zooming out once again, as that front pushes south, the winds, still strong, but
07:24 not as strong.
07:26 They're going to start to come from a different direction.
07:28 They're going to come from the north.
07:30 Playing that forward, you can see by the start of Friday, as that cold front shifts south,
07:39 chilly winds.
07:40 And pausing it there, this is the very start of Friday, all the way from the Arctic.
07:45 So cold air arriving.
07:49 Those blue colours on the chart.
07:50 We've got mild air out towards the southwest.
07:53 Still quite mild at the start of Friday in the far southwest, but the cold air arriving
07:58 behind the cold front.
08:00 And these winds also coming down straight from the Arctic.
08:05 Which, as you can see, isn't as cold as it can get in the winter, of course.
08:09 We're still in the late autumn period.
08:12 But nevertheless, winds from the Arctic, always cold.
08:15 But they would be particularly cold at the end of winter.
08:19 So it's turning colder later this week.
08:22 Winds from the north.
08:24 But how long will it last?
08:26 That's the question.
08:27 Before I answer that, I want to take a look at the forecast over the next few days.
08:31 Where's it going to rain?
08:32 Where's it going to be sunny?
08:34 How strong those winds will be on Thursday.
08:35 So let's take a look at the maps in detail then.
08:38 And this is the rest of Tuesday.
08:39 Rest of Tuesday, we've got some showers clearing from East Anglia and the southeast.
08:45 They are fading away.
08:46 And then we've got this window of fine, crisp autumn sunshine crossing the country.
08:51 That's the ridge of high pressure.
08:52 But already cloud thickening out towards the north and west of Scotland.
08:56 Northern Ireland also seeing increasingly cloudy skies, increasingly hazy or milky sunshine
09:00 arriving.
09:02 Winds picking up in the far northwest of Scotland.
09:04 Skipping forward to Wednesday morning and those outbreaks of rain then developing across
09:08 Scotland.
09:09 Fairly persistent wet weather.
09:11 It's light to moderate rain generally through Wednesday across Scotland.
09:16 Mostly, mostly it's affecting the central and western hills.
09:21 So you can see there.
09:22 But some drifts and drafts of rain elsewhere.
09:23 Northern Ireland, into parts of northern England at times.
09:26 Wales as well.
09:28 Very little rainfall sinking further south at this stage.
09:31 So we're going to start off with a chilly start in, let's start there.
09:37 A chilly but bright start in the southeast on Wednesday.
09:40 Turns increasingly cloudy.
09:42 A bit breezier later but actually a fine day for much of England and Wales if rather cloudy.
09:47 And then those little spots of rain by Wednesday evening start to push southwards.
09:52 But no significant wet weather.
09:53 So real contrast compared with the very soggy weather that we've seen so much of during
09:58 the recent weeks.
09:59 The more unsettled weather this time now across northern and western Scotland.
10:03 That's not been the case during recent weeks.
10:06 Remember it's been drier than average across western Scotland.
10:09 But into late Wednesday and early Thursday we've got the cold front.
10:13 You can see it here.
10:14 This band of blue with some yellowy brighter colours there indicating some heavier bursts.
10:20 So a brief spell of heavier rain as that cold front sinks south.
10:24 And the winds really strengthening especially behind the cold front along with some blustery
10:29 showers.
10:30 If I pause it mid-morning Thursday you can see that really strong wind coming from the
10:35 north-northwest.
10:37 Heavy showers following into the north and central part of Scotland as well.
10:41 Most of these are going to be rain at this stage but some sleet and snow over the hills
10:45 I should think.
10:47 The rain Thursday morning pushing into Northern Ireland, Northern England.
10:51 A bright start for southern parts of the UK but we have got that rain sinking south.
10:56 So that by the afternoon it's into parts of North Wales, into the Midlands.
11:00 It's weakening.
11:01 It's coming into contact with that high pressure so it really fizzles out.
11:04 Very little rainfall indeed by the time it reaches southern parts of the UK.
11:08 We've got the cloudy mild weather there in the far south-west.
11:11 Some spots of rain but the cold wind following.
11:15 And as I mentioned that wind's going to be strong so let's take a look at the wind gusts
11:18 on let's see Thursday morning.
11:22 Ah perfect.
11:23 I'm going to actually just rewind it a little bit because it's going to be about 5, 6 in
11:28 the morning that the winds are peaking across the north of Scotland.
11:31 Here's the key.
11:32 50 mph plus coloured in and we've got the darker shade there.
11:36 60 to 69 mph.
11:38 So yeah touching 70 mph for Shetland, for Orkney, perhaps far north of Caithness, Sutherland,
11:45 Lewes.
11:46 Now very, very much business as usual in terms of those kinds of winds.
11:52 It's not going to be pleasant at all.
11:53 It could disrupt ferries and so on but I know that in the far north of Scotland those kinds
11:58 of winds are certainly not uncommon at this time of year.
12:03 Likewise we're going to see very strong wind gusts affecting parts of upland Scotland and
12:09 just to the east of the higher ground increasingly so.
12:12 Imagine through Thursday you can see the colours there.
12:16 Just over the Pennines 50, 60, perhaps approaching 70 mph wind gusts for a time during Thursday.
12:22 So very blustery conditions over the hills of northern England and Scotland and just
12:25 downwind of the hills as well.
12:28 So yeah winds, a particular issue on Thursday and then those winds peaking during the morning
12:34 before staying strong into the weekend but not quite as strong.
12:39 And you can see that as the winds change direction we've still got 50 mph wind gusts, perhaps
12:43 a touch more for Shetland and those wind gusts again pretty strong down that North Sea coast
12:49 down the east of England for example as the winds change direction to the north of the
12:53 east.
12:54 And that could cause some sea surge, so some big waves, some tropical conditions around
12:57 the coast.
12:58 Lighter winds further west but I'd say for most parts it's going to be a breezy day and
13:03 you're going to feel the cold air in that wind.
13:05 In fact, let's take a look at the wind chill on Thursday.
13:09 Is it day four?
13:11 Good guess.
13:12 So these are the wind chill temperatures.
13:15 If I switch on the actual temperatures, so this is what a thermometer would read, actual
13:20 temperatures 6 to 8 degrees, 9 Celsius perhaps in the far south west, 4 or 5 in the north.
13:26 Switch on the wind chill temperatures, it's more like low single figures so it's going
13:30 to feel raw in that wind and it will be bringing air that is cold enough for snow.
13:39 This doesn't quite go far enough ahead, this data only goes out to the next two days but
13:44 if I just play it forward, this is Wednesday and what this is showing, let's pause it there,
13:51 is the height of the zero degree isotherm, of the zero degree level in the atmosphere.
13:58 So the height that you have to go to to get to zero degrees.
14:02 Normally the air cools as you go up in the atmosphere unless you've got what's called
14:06 an inversion but normally the air cools and at some point you get to zero degrees.
14:12 And this is a really important thing for looking at to determine whether it's going to snow
14:15 or not.
14:16 Now the key here indicates that everywhere virtually across the UK you'd have to go up
14:22 above 1400 metres, the height of Ben Nevis or so, to get to that zero degrees at the
14:27 start of Thursday.
14:28 But playing it forward and you can see this big gradient in that data there so quite quickly
14:36 as the northerlies arrive we get into the blues, 400 to 800 metres.
14:41 And then by the end of this and into Friday we've got into the greys and dark blues here,
14:47 200 to 400 metres.
14:48 And a general rule of thumb, it does depend on the stability of the air, the kind of rainfall,
14:53 the kind of heaviness of the precipitation, but a general rule of thumb is 200 metres
14:59 for the height of the zero degree isotherm and you'd be looking at snow at sea level.
15:04 And then you can subtract 200 metres to determine the height over just about anywhere.
15:10 So you'd be looking at, with these blue colours, 400 metres, perhaps 600 metres for some of
15:19 northern Scotland at this stage.
15:20 So certainly we're getting to, by Friday, a situation where the far north of Scotland
15:28 could see snow down to lower levels, snow falling that is.
15:32 But for much of Scotland it's over hills a few hundred metres above the ground.
15:38 And for any settling snow at this stage, we're talking about hills really, not really at
15:42 sea levels.
15:43 But having said that, it will be cold enough by night for any showers that are falling,
15:49 even around coastal areas during Friday, as sky's clear then on Friday night, it'll be
15:54 cold enough for some icy patches to form.
15:56 So widespread snow, nope.
15:59 Snow over some hilltops of Scotland, some mountains of Scotland, yeah, very possible,
16:05 no huge amounts.
16:07 Snow at sea level for Scotland, less likely.
16:11 Falling snow perhaps, but lying snow less likely.
16:14 However, ice probably the main issue as we start the weekend then with freezing temperatures.
16:19 Because actually we'll see quite a widespread frost at the start of the weekend.
16:23 Where's it gone there?
16:26 Temperatures, there we are.
16:28 Minimum temperatures, so this is Tuesday morning, generally frost free, although it was chilly
16:34 in the far south.
16:37 Actually that's not quite, yeah, it was chilly in Scotland Tuesday morning, getting my days
16:40 mixed up.
16:41 Wednesday's chilly in the south, not so much elsewhere.
16:44 And then into Friday, you can see it's getting colder, low single figures, but certainly
16:50 in shelter spots, a frost.
16:53 And by Saturday, a much more widespread frost across the country.
16:57 These urban temperatures at the start of Saturday probably a little too high.
17:02 I'd say quite widely we're looking at in urban areas 1 to 3 Celsius, and in the countryside
17:08 a degree or several degrees below freezing.
17:11 So a fairly widespread frost across the UK as we start off Saturday.
17:14 And as I mentioned, those showers across much of Scotland and a few coming further south
17:18 into parts of northern and eastern England could lead to some icy patches first thing
17:22 this weekend.
17:23 So, yeah, increasingly cold, but overnight frost the main issue, icy patches the main
17:29 issue rather than widespread snow.
17:32 Snow showers mostly northern and central Scotland and any lying snow, upland parts of Scotland
17:39 generally heading into the weekend.
17:40 And then really it settles down.
17:43 So we're looking at, there we go, Saturday, beautiful start to the day.
17:49 Snow showers are mostly in the North Sea, one or two across eastern parts of England,
17:53 mostly rain showers.
17:54 But actually for most of the UK, it's a beautiful crisp start to the weekend.
17:58 Plenty of blue skies, it's going to be cold out there, but light winds, dry and bright.
18:03 Not the kind of autumn weather we've seen a lot of recently, but I'm sure lots of people
18:08 will appreciate the break in the rain, the break in the blustery weather that we've seen
18:12 recently.
18:13 It's just going to be a nice November day.
18:16 Back to the West, we've got this front.
18:19 It's a very weak front because it's running into that area of high pressure, so it's weakening
18:23 all the while.
18:25 But it does indicate milder air just to the West of it.
18:28 This is the Atlantic air trying to feed back in again.
18:31 So this is the Arctic air, here's the Atlantic air trying to feed back in again.
18:34 And in fact, playing it forward just a touch, we've got those showers feeding into East
18:38 Anglia through Saturday.
18:40 Most places dry and bright, plenty of sunshine.
18:43 Midlands, much of Scotland, barely a cloud in the sky.
18:45 But then by the end of Saturday, cloud thickens, dribs and drabs of rainfall into Scotland,
18:50 Northern Ireland, West Wales, Western England.
18:53 But this computer model run is showing the weather front about here at this stage.
19:00 However, other computer model runs are showing very different things.
19:04 So let's take a look at that variability in computer model runs by showing a spaghetti
19:09 chart.
19:10 We've shown these before.
19:11 It might take a minute or two to get your head around it.
19:14 The left image here, the left image on the graphic is showing the UK in the middle.
19:20 I think you can just about make out the UK in the middle.
19:22 And this is midday Friday, the position of the cold front as it pushes South across the
19:26 UK.
19:27 So the blue there, that's the cold front.
19:29 And most computer model runs have that cold front sitting somewhere over Cornwall or just
19:34 to the southwest of Cornwall.
19:35 That means most of the UK is in the cold rare.
19:39 Then fast forward 24 hours, we've got the warm front to the West.
19:43 Now there's the UK in the middle again of the graphic.
19:47 Increasingly difficult to see the UK, admittedly, because it's covered by fronts.
19:52 But just to the West of Ireland, we've got this green colour which shows what the operational
19:58 model run of the European model is suggesting for that frontal position.
20:02 So it's to the West of Ireland.
20:03 There it is, to the West of Ireland.
20:05 Just ahead of that, we've got the position from 50 odd computer model runs of the warm
20:11 front that's coming back in.
20:13 One of those model runs has it over Eastern England, midday Saturday.
20:17 Most of them have it near the operational run or just behind the operational run.
20:21 So most have that front slower to come in.
20:24 Then this is midday Saturday on the right.
20:28 Really difficult to see the UK here, admittedly, and that's simply because all these different
20:32 computer model runs are suggesting different positions for the weather front.
20:37 But most of them have it somewhere across north-western parts of the UK, suggesting
20:41 - there it is - that's the operational run there.
20:45 And then many of them have it to the north-west, so sitting over western Scotland, sitting
20:49 over northern Ireland.
20:50 Now it's not going to be a particularly rainy front.
20:52 It's going to bring an area of cloud in, some drizzle and so on.
20:55 But the most important thing is how cold, how mild that weather becomes as that front
21:00 moves in.
21:02 And this just shows you 50 computer model runs and the difference by midnight, that
21:08 Sunday going into Monday, how far the mild air comes in and how much the cold air holds
21:15 on.
21:16 So I know it's very, very difficult to see all these different postage stamps in detail.
21:21 I'll just have to take my word for it.
21:23 But this one here is showing mild air widely across the UK.
21:26 This one's showing cold air widely across the UK.
21:30 It's a bit of a mess by this stage.
21:34 It becomes increasingly difficult for the computer models to agree on whether the mild
21:39 air from the west covers the whole of the UK or whether the cold air from the north
21:44 holds on.
21:45 That's basically what I'm getting at by showing you all these different images and different
21:49 computer model runs.
21:51 So start of the weekend, crisp, frosty autumn weather.
21:54 Through the weekend, the most likely situation is we've got milder, cloudier, more drizzly
22:00 weather coming in from the Atlantic with an uptick in temperatures.
22:04 But that is not guaranteed.
22:06 A lot of computer model runs keep the cold air in place.
22:09 So just quickly, beyond that, what are the signals?
22:14 Well, this is for the middle of next week and the most likely weather patterns.
22:19 And most likely, one common theme here is that we've got high pressure close to the
22:24 UK again.
22:25 So for many places it's mostly dry, especially towards the south and southwest.
22:30 Again, a welcome respite from all the wet weather we've seen in the south recently.
22:35 But there's a difference emerging in terms of whether that high pressure is centred over
22:39 the UK, keeping virtually everywhere dry, crisp, frosty and so on, or whether it just
22:45 sinks to the south and allows more of a westerly airflow.
22:48 And again, this is probably related to that difference in the frontal position that comes
22:53 in later in the weekend and how far the mild air mix inroads across the UK and how much
22:57 the cold air holds on.
22:59 So it's all about the position of this high pressure.
23:00 Is it over the UK in the middle of next week?
23:03 Has it sunk to the south, allowing more changeable stuff to come in from the Atlantic?
23:07 Milder weather, wetter weather, especially in the northwest.
23:11 And finally, as we go into later next week, these are the two most likely weather patterns.
23:16 Again, the prevailing theme is high pressure close to the UK, somewhere to the west or
23:20 southwest and so a lot of fine weather.
23:23 It can be quite cold at times, frosty nights, yes, widespread snow, quite unlikely I imagine.
23:29 But there is an indication there of a northwesterly airflow in this pattern, which has about the
23:35 same probability as this weather pattern.
23:37 So high pressure generally continuing to influence our weather through the rest of November,
23:42 mostly dry, colder than it has been.
23:46 And beyond that, well, all the signs are that as we go into December, the different teleconnections,
23:54 that is the different influences from elsewhere in the globe that we've talked about occasionally
23:59 in the deep dive and the 10-day trend.
24:00 I won't go in depth about those this week, but there's El Niño at the moment, a strong
24:05 El Niño taking place in the Pacific.
24:07 And there's the Indian Ocean Dipole, which is another strong event that's taking place
24:12 in the Indian Ocean.
24:14 Now both of those are oscillations in pressure patterns and sea surface temperatures in those
24:18 big oceans.
24:20 And at the moment, El Niño and positive Indian Ocean Dipole both lead to similar effects
24:27 on the UK's weather.
24:28 They both influence more cyclonic, more unsettled, more wet, windy, mild weather, which we've
24:37 seen a lot of recently.
24:39 But they both favour those kinds of weather patterns affecting the UK at this time of
24:44 year, late autumn, early winter.
24:46 And so as we go into December, it seems most likely because of those global influences
24:53 that we'll see a return to low pressure, to wind and rain.
24:58 But perhaps not as south shifted as it's been so much during the last few weeks.
25:04 It looks more likely to be typical for the UK, the most unsettled weather towards the
25:09 northwest, less unsettled weather towards the southeast.
25:11 That's what some of the computer models are suggesting.
25:14 And that is indeed what we'd expect with El Niño and Indian Ocean Dipole.
25:18 But I'm sure we'll cover that a bit more in the coming weeks and months, because it's
25:22 a very interesting topic all on its own.
25:24 But that's all I've got for you this week.
25:26 Thank you for joining me.
25:27 Don't forget to hit subscribe if you enjoy seeing these.
25:29 It will help us out when we try and justify doing more of these in the future.
25:33 And goodbye for now.
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