This is an in-depth Met Office UK Weather forecast for the next week and beyond. Southerly winds during the next few days will continue to bring a lot of grey skies, mist, fog and drizzle to the UK. Why does it get so gloomy under high pressure at this time of year? Bringing you this deep dive is Met Office meteorologist Aidan McGivern.
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00:00Anticyclonic gloom. What is it? Why does it happen at this time of year and how long will it last?
00:08I'm going to try and answer those questions in this week's Met Office Deep Dive,
00:12including an explanation of the weather pattern we've got at the moment
00:16and why it would give us warm sunshine in the summer rather than dreary cloud in November,
00:22and I'll try and explain the fern effect.
00:26All that to come. But before I get started, in last week's Deep Dive,
00:31I promised that this week, if you tune in, I would have a special announcement.
00:36So without further ado, take a look at this.
00:56Head between your knees like that. Try and touch as little of the ground as possible, basically.
01:08Stop laughing. That's a demonstration, a live demonstration on YouTube.
01:13Yes, the Met Office Weather Studio Live is coming back this Friday, the 8th of November at 12.15.
01:20Now, those of you who aren't aware, we used to do these regular Tuesday lives in 2020 and before,
01:27and we're bringing them back. They're similar to the Deep Dive, but the main difference is that they will be live.
01:34So if you tune in at 12.15 on a Friday, it will be your opportunity to ask us questions.
01:40We won't necessarily be coming up with the topics ourselves like we do in the Deep Dive.
01:45So please hit subscribe if you're following us on YouTube and you won't miss one of those when they pop up in your feed.
01:52Now, we've had this high pressure system with us for just over a week now,
01:59and it's brought mostly grey skies across the UK and some drizzle.
02:04It's not brought entirely dry and sunny weather, and that's primarily because of the time of year.
02:10And I'm going to be explaining why that's the case in just a moment.
02:13But before I do, just in case you're about to head out to a bonfire display,
02:19I thought I'd give you a quick rundown of conditions on Tuesday nights.
02:24And because of the high pressure, well, we're not expecting anything particularly unsettled,
02:30nothing particularly wet or windy, so mostly fine for bonfire night and plenty of dry weather.
02:38Although there will again be some drizzle, most notably southwest Scotland, northwest England, parts of West Wales and Northern Ireland.
02:46That's where we've got this southerly wind coming through and a lot of low cloud pushed against these hills and coasts in the west, giving some drizzle.
02:55The brighter whites here show areas of hill fog.
02:58And if we do get some cloud breaks during the day into the evening,
03:02well, those clearer spells will get filled in by fog as well.
03:06And that will be helped along by, of course, the bonfire smoke in the atmosphere.
03:11So all in all, a gloomy but mostly settled bonfire night.
03:17And into the start of Wednesday, there's likely to be, as a result of the gloom, widespread fog across many parts of the UK,
03:27particularly towards the south where winds are generally light, poor visibility first thing.
03:32So watch out if you're on the roads during Wednesday morning.
03:35Some of that fog, I suspect, could last all day.
03:38The sun is particularly weak at the moment, but it's a mild start to the day.
03:43These are the kinds of temperatures at 11 a.m.
03:46So generally double figures, whether you've got the cloud or some sunny skies that will be a little more prevalent across northern Scotland.
03:56And to explain why it's mild and to explain why we're most likely to see clear skies towards the north of the UK, northern Scotland in particular,
04:07let's take a look at the bigger picture. Now, at the moment.
04:13The UK is sitting in between low pressure in the Atlantic and higher pressure over the continent.
04:20That higher pressure is just edging a little further east over the next few days.
04:26And that allows this southerly airflow, particularly for northern and western parts of the UK.
04:32Now, as I mentioned, if this was in the summer, we'd be experiencing very, very different conditions.
04:38You see the warm colours on the map there. We've got a southerly wind.
04:42We've got high pressure in place. All the ingredients there, if this was August, for some very warm and sunny weather.
04:49So why isn't that the case at the start of November?
04:53The primary reason is the sun is weak and these colours represent the temperature at 5000 feet.
05:00The reason we use the temperatures at 5000 feet in that kind of map is to show air masses, areas of similar weather characteristics.
05:14And of course, where you've got a stark difference between different air masses, you get weather fronts and you get bands of rain or snow and so on.
05:23This, again, is showing the temperature at 5000 feet or 1500 metres.
05:28And typically, certainly in the summer, it correlates very well with the kinds of weather that we experience at the surface.
05:39And that's still the case for some parts of the globe.
05:42So if we look at Africa, we've got the very warm or hot colours there.
05:45And if I switch to the surface temperature, very warm or hot weather over Africa at the moment, indicated by temperatures in the mid to high 30s.
05:57Those are the surface temperatures. Just clicking onto the 5000 feet temperatures or 1500 metres.
06:05And the temperature at that height is in the low 20s. The temperature at the surface is in the mid 30s.
06:12And so there's a difference there of about 10 to 15 degrees.
06:16The temperature typically decreases with height and that typically decreases at a rate of about a degree every hundred metres.
06:25So if that was in a perfect scenario where the temperature decreased uniformly with heights from the surface up to 1500 metres,
06:34you'd expect it to be 15 degrees colder at 1500 metres.
06:39And that's roughly the case for, say, West Africa there. But it's not the case for parts of Europe.
06:47Now, this is the surface temperature again. You can see some quite cold air there across central parts of Europe.
06:53Temperatures in the mid single figures or so. I'm going to skip forward to Wednesday, actually.
06:58Wednesday shows it even more clearly. This is five o'clock on Wednesday. Temperatures in the low to mid single figures across central Europe.
07:06But putting the temperature at 1500 metres on. And it's actually higher.
07:1410 degrees, 8 degrees, 7 degrees. As you can see. And it's the same for the UK.
07:23So this is the temperature at 1500 metres. Wednesday afternoon, 8 to 11 degrees.
07:31The temperature at the surface. 5 degrees, 9 degrees, 14 there over Ireland.
07:39So in many places across Europe at the moment, the temperature at 1500 metres is actually higher than the temperature at the surface.
07:49And that's because we've got high pressure in charge and higher pressure in the winter half of the year often leads to colder air at the surface than at 1500 metres.
08:02And that's because the nights are much longer than the days. And under higher pressure, you get a longer period of cooling during the day during the night and a shorter period of warming during the day.
08:15The opposite happens in the summer. In this situation, the summer, the temperatures would be rising considerably during the day, not cooling too much during the night.
08:25And just to illustrate this, I've got what we call a tephagram. Tephagram simply stands for temperature. That's the T. Phi.
08:35That means energy or entropy. And it's a gram. So it's a diagram.
08:42And a tephagram is a diagram that shows the temperature and the energy of the atmosphere as you go up through it vertically.
08:53And this is an actual reading from a weather balloon that was sent up from Albemarle in northern England midnight last night.
09:02And I appreciate it might be difficult to see it, but there is a thin red line that goes up through the top there and it corresponds to a cooling.
09:14So the temperature there is on the X axis. There's minus 50 where I'm pointing there, minus 100 over here.
09:23And then the height is going up on the Y axis here all the way up to 13 kilometres at the top.
09:30And a couple of things to point out here. Mostly the temperature is decreasing with height.
09:37So as you get higher in the atmosphere, the temperature is going down. That's the red line.
09:42But there's a point up here where the temperature increases with height.
09:48And that is the top of the troposphere. The troposphere is that part of the atmosphere where most of our weather takes place.
09:55And the troposphere is marked by, on average, the temperature decreasing with height.
10:00And the reason is because you get the sun warming the land or the sea below.
10:05That warmth rises and cools through the atmosphere. And this continuous cooling, on average, takes place up to this point, which is the top of the troposphere.
10:14And then it starts to rise. And the reason it starts to rise as it goes into the stratosphere is because in the stratosphere,
10:21you've got something taking place called photolysis where the sun breaks apart molecules of ozone and that causes a reaction.
10:30It causes a release of heat. And so in the stratosphere, the higher you go, the warmer it gets again.
10:36But the air is really thin in the stratosphere. The pressure, remember, goes down as you go higher up in the atmosphere because you've got less air coming down on top of you.
10:45And so it probably doesn't feel that warm, even if temperatures are rising.
10:49This, by the way, is something like minus 60 up here at the top of the troposphere.
10:53Anyway, there's another bit way down here where also you've got the red line increasing rather than decreasing with height.
11:03And it's quite a sudden increase over just a matter of tens of feet, really, or tens of metres.
11:10And it suddenly goes up to about 13, 14 degrees. So it drops away from the surface up to, I think, about 1000 metres.
11:21So a kilometre above us. And then the temperature rises and that's called an inversion.
11:26It's more clearly seen if we skip to the next image, which is the same weather balloon reading.
11:34But all that's happened going from this one to this one is that it's been tilted.
11:40This is often called a skew T diagram. It's skewed. So now the temperature is the temperature lines are at 45 degrees, essentially.
11:49So minus 20 here and then that isotherm, that line of equal temperature goes up this way rather than up straight vertically.
11:58So minus 20 is here and it points to that bit there on the line.
12:03And you can see this is the point at which the stratosphere begins.
12:07And you can follow that line down here. And it's about minus 60 degrees.
12:12The other thing to point out on this is the blue line and that's the dew point temperature.
12:16So it takes readings of the wind and the pressure and so on.
12:20But it also takes a reading as well as the air temperature, the dew point temperature.
12:24The dew point temperature is the temperature at which the air must cool to, to become saturated.
12:30If the air temperature and the dew point temperature are the same, you get fog.
12:34If you're at the surface or higher up, you get cloud forming.
12:38So where these lines, the red and the blue, are close together, you get cloud.
12:42And where they're far apart, you get very little cloud, you get very dry air.
12:46And you can see at higher altitudes, the blue line goes quite far to the left.
12:53And there's this big gap that indicates very dry air, no cloud if you're flying through it.
12:58Some cloud, perhaps at this kind of height up here, that's probably about, let's see, three to five thousand metres high.
13:10But towards the surface, the two lines meet.
13:14And let's zoom in on that bit, because this is the bit we're interested in.
13:20This slice of atmosphere here, the two lines are touching.
13:24And that means there's this layer of cloud that goes from about 700 metres up to that inversion that I mentioned at 1000 metres.
13:35So there's this layer, what we call stratus, 700 metres up to about 1000 metres, marked out by the two lines touching.
13:46And the air cools at a slower rate where you've got that cloud.
13:53There's two different rates in which the air can cool.
13:56And this is significant for the Fern effect. This will come clear in a moment.
14:02There's something called the dry adiabatic lapse rate. Lapse rate means the rate at which the temperature cools or lapses with height.
14:11Adiabatic basically means you take a parcel of air, lift it into the atmosphere and it warms up or cools down only because it's encountering air with lower pressure or higher pressure.
14:23And that's what causes it to warm up or cool down.
14:26Adiabatic basically means there's no added heat except for the fact that the pressure is changing as the air is rising.
14:35So when you take air from the surface and lift it through the atmosphere, it encounters lower pressure.
14:42That means that the air parcel expands and the molecules have got more space to basically fly about in.
14:51And so they slow down and the air cools.
14:54Likewise, if the air descends through the atmosphere, it compresses and gets warmer.
14:59The same thing happens when you pump up your bike tyres.
15:01When you pump up your bike tyres, then the pump or at least the inlet valve gets really hot because you're compressing that air.
15:10You're adding pressure and that increases the temperature.
15:14So rising air through the atmosphere, lower pressure, lower temperature.
15:19And the rate at which that happens is, as I mentioned before, one degree roughly per hundred metres.
15:26That's the dry adiabatic lapse rate. That's the rate at which the temperature decreases for dry air, air that isn't saturated, air that isn't in a cloud basically.
15:37But at the same time, you've got the dew point that starts off on the surface at a certain value and that also decreases, but at a slower rate.
15:46So that decreases at about two degrees per kilometre as opposed to 10 degrees per kilometre.
15:54So at some point, the air temperature decreases enough so that it meets the dew point temperature at a certain height.
16:02And you can figure out the base of the cloud by doing that kind of calculation.
16:05And in this case, you've got the air temperature decreasing one degree per hundred metres.
16:11And then at this point, it meets the dew point temperature, a cloud forms.
16:17Then it decreases in temperature at a slower rate. And the reason is because it's saturated.
16:24And so in order to continue decreasing, then it must release water vapour.
16:33And that's because lower temperature air contains less water vapour.
16:39So as it continues to cool, as it rises through the atmosphere, it must release water vapour.
16:44That's called condensation. Basically, that's why you get a cloud.
16:47The water vapour turns to water droplets, but that at the same time releases energy.
16:51It's called latent heat energy. And so that release of energy means that you've got energy added and it slows the rate of cooling.
17:00That's called the saturated adiabatic lapse rate. And that cools at a rate of five degrees per kilometre.
17:06So it's about half. And it cools at an even slower rate, even higher in the atmosphere because you've got even less water.
17:12Or it cools at a faster rate, I should say, higher up in the atmosphere because you've got less water vapour.
17:17But the important thing to remember is when the air is dry, it cools at a rate of 10 degrees per kilometre.
17:25When it's saturated, when you've got clouds, they cool at a rate of five degrees per kilometre.
17:31Why is that important? Let's take a look at the situation across the UK Wednesday afternoon.
17:40It's quite an interesting one. What we've got is this marked contrast across Scotland.
17:46Zooming right in. And I just want to highlight three areas here.
17:56Stirling, Braemar, Lossiemouth. Lots of cloud over the Highlands and Grampians here.
18:02And some blue spots there as well, giving some drizzle.
18:05Lots of low cloud, the brighter whites indicating hill fog as well.
18:09So Stirling's cloudy, mostly dry. Then Braemar, fairly foggy, some drizzle about.
18:15Lossiemouth, no clouds whatsoever.
18:19And this is because of the difference in the dry adiabatic lapse rate, the saturated adiabatic lapse rate,
18:27and the progression of the air over the hills, leading to a fern effect.
18:33What on earth am I talking about? Let's draw a diagram to try and explain.
18:40This is how the fern effect works. OK, so we've got the surface of the ground here.
18:49This is sea level. And then I'm going to draw the y-axes up here.
18:54This is the height. That's 1,500 metres, 1,000 metres, 500, and zero.
19:11And then imagine there's a mountain range across Scotland, for example, that goes up to about 500 metres.
19:23Fairly modest when you consider other mountain ranges around the world.
19:28Obviously there are higher mountains in Scotland, but there are large parts of central Scotland,
19:32the Highlands and the Grampians, that are around 500 metres.
19:36So imagine that's the case. It makes it easier for calculations as well.
19:41So that's the mountain range. At the same time, there's an inversion.
19:50As there is with the current weather situation, there's this inversion at 1,000 metres.
19:58And above that inversion, you've got this high pressure.
20:07So the air is slowly sinking, slowly descending. And the air up here is dry and it's warm. It's 10 degrees.
20:20At the surface, before the air goes over the mountain, the temperature might be 10 degrees and the dew point might be 8 degrees.
20:37Then the air is pushed over the mountain. It's forced to rise. So it starts to climb.
20:48Just taking into account the air temperature, if that went all the way up to 500 degrees, it would cool by 5 degrees.
20:54So it would be 5 degrees at 500 metres. The dew point would cool by 1 degree. So that would be 7.
21:03So we've got 5 and 7. But you can't have the air temperature being lower than the dew point.
21:13At some point, they're meeting. And that looks to be halfway. So halfway at about 250 metres, they are both 7.5.
21:29I've forgotten how to draw. At 250 metres, the dew point and the air temperature are both 7.5.
21:35It's at this point that you get a cloud forming on the way up to the mountain.
21:41The cloud bottom is 250 metres. And it goes up to that inversion where all of a sudden the air gets dry.
21:52As the air continues to climb over the mountain, the bottom of the cloud runs over the mountain, is forced to rise and releases its moisture with drizzle and hill fog and so on.
22:08So it loses some of that moisture. But you've still got a lot of cloud over the mountain.
22:15At the same time, the top of this cloud, this bit, is forced because this whole chunk gets moved up, not just the surface.
22:27All of the air gets shoved up. The top of the cloud is forced into the dry air above.
22:33Then, when you remove the hill again on the other side, because you've got high pressure, the air is generally sinking above the inversion.
22:43All of it sinks back down again. It's like jelly. Push some jelly and it wobbles.
22:50It doesn't stay in the same place that you pushed it. It wobbles back because jelly is very stable.
22:55It's the same with this kind of weather setup where you've got high pressure.
22:58If you force it up, then eventually when the obstacle gets out of the way, it comes back down again.
23:05As the bottom of the cloud reaches the top of the mountain, it's continuing to cool.
23:11It's about six degrees or 6.25 degrees by this stage, both in terms of air temperature and dew point.
23:20But as the surface of the cloud comes back down again, it warms up at the rate of the dry adiabatic lapse rate, the dry air, because it's lost a lot of that moisture.
23:33It's started its ascent over the mountain at a slower rate of cooling because it's saturated.
23:40Then it begins its descent on the other side of the mountain at a faster rate of cooling because it's no longer saturated.
23:47So the dew point stays roughly the same. It probably goes up to about seven, but it's going down 500 metres.
23:54That means it warms by five degrees. The air temperature at the bottom ends up about 11.5.
24:01So it's a modest rise in temperature from 10 degrees to 11.5. That's the fern effect.
24:07It's also drier. So the cloud at the bottom of the cloud has dried out.
24:14But at the same time, this drier air up here is mixing with the top of the cloud and then forced back down again.
24:22So not only have you got the air dumping a lot of its moisture over the hill and coming back down the other side warmer and drier,
24:31but you've got all this dry air up here mixing now with the slice of atmosphere that was forced above the inversion.
24:41And in fact, this continues to oscillate because it normally overshoots.
24:46So when it's forced back down the other side of the mountain, it normally overshoots and then it rebounds back up again.
24:52Again, like poking a jelly, it wobbles. It doesn't just go one way and back again.
24:58It continues to wobble and that wobbling will take the air back up into the dry bit once again.
25:04Less so, but still a little bit back up into the dry bit.
25:08And so you've got this continued mixing then, which you didn't have before the air climbed the mountain because this air here was so stable.
25:18It was slowly sinking and this air didn't have enough buoyancy to push itself into the dry air above until it was forced to rise over the mountain.
25:31And that caused it to mix with the dryer air above and to dump a lot of its moisture over the hill.
25:37So for those two reasons, the air on the other side of the mountain is a lot drier and it's generally cloud free.
25:44So that hopefully explains the Fern effect, why you have clear skies and higher temperatures on the other side of the mountain range.
25:53Of course, 500 metres is a relatively modest height.
25:56In other parts of the world, the Alps, the Rockies and so on, much greater mountain ranges.
26:03And you can have much higher extremes of temperature rise and so on.
26:08And some remarkable extremes like temperature going from minus 20 up to plus 10 degrees.
26:15And there's a well-known name for the Fern effect in North America, the Chinook.
26:20And it is also colloquially named the Snow Eater because, of course, when you get the change in wind direction and this warm Fern effect coming down a mountain, it can eat the snow.
26:34It can melt the snow very, very quickly. It happens in the Alps as well.
26:38And in the summer, it can cause bursts of heat and wildfires as well.
26:42So it can be quite a dangerous wind.
26:45In the UK, not so dangerous. The extremes that you get out of it aren't quite as wild, but it has led to some extreme temperatures.
26:56The November temperature record was set in Ceredigion in West Wales.
27:01That was a Fern effect wind that resulted from the wind going over the Welsh mountains.
27:07And also Sutherland, Agfari, in December and in January, both months, that location in Sutherland, northern Scotland, set the UK's maximum temperature record.
27:21Again, Fern effect wind.
27:23So, of course, in those months of the year, November, December, January, the sun is so weak in the UK that it needs a bit of assistance from the Fern effect.
27:31In other parts of the year and other times of the year, that's not necessarily the case.
27:37Just going back to this and this. As I mentioned, this area of high pressure, you've got sinking air throughout it, apart from in the lowest thousand metres or so.
27:52And it's within this area where you've got this layer of cloud.
27:55That layer of cloud is sticking around in November because the sun isn't strong enough at this time of year to heat up the air at the bottom and give it enough buoyancy to push the cloud up into the drier air above and then lead to sunny skies and even more heating.
28:16And I think I worked out that the temperature at the moment, if the sun was strong enough to lift that low cloud into the drier air above and continue heating, several hours of heating through the day, then you'd end up with mid to high 20s in this kind of weather situation.
28:33If the sun was stronger, if it was the kind of strength you get in July, August and so on.
28:39As it is, it's November. You get only a limited amount of solar heating through the day, not enough to lift, to give enough buoyancy to lift that low cloud into the drier air above and lead to clear skies.
28:52That's why you basically need to force it up. And the only way that the weather manages to do that is to push it over mountains.
29:01And in northern Scotland, of course, you have got mountains to push over. As I mentioned, just taking a look at this again on Wednesday.
29:15And to remove that, this highlights some of those mountain ranges I was talking about.
29:24The coloured in area here is everywhere above 500 metres. So that's why I chose 500 metres.
29:31Quite extensive areas across central Scotland through the Grampians and the Highlands where the land is above 500 metres.
29:38So you can imagine air that's moving from Stirling to Braemar to Lossiemouth, starting off cloudy, ending up drizzly and low over Braemar and then ending up clear over Lossiemouth.
29:53You don't have to take my word for it. I've got a nice little diagram that shows it here.
29:59This is another one of those tephigrams, another one of those vertical profiles of the atmosphere.
30:05This one in particular is for Stirling. And it shows the predicted vertical profile.
30:12So this isn't taking a weather balloon. This is predicting what a weather balloon would experience if it was flying from Stirling up through the atmosphere on Wednesday afternoon.
30:21Wednesday is a great example because you've got southerly winds across Scotland. You've got relatively moist air.
30:28And you've got a marked fern effect because you've got higher pressure, this descending air through here.
30:34So it's a similar sort of look to the diagram I showed before of the actual vertical profile across northern England.
30:40This is Stirling. And what you can see, the two lines, the dew point and the air temperature, very far apart, above 1,000 metres.
30:51So dry air up here. But then in the lowest 1,000 metres, they're right next to each other.
30:56So you've got that thick cloud, that thick low stratus for Stirling.
31:02Now, pay attention to this bit here. And I'm going to flick on to what it looks like for Braemar.
31:08So it's the same thing, but it's shown Braemar at the same time.
31:12What you can see is it went up a bit because Braemar is 335 metres. Stirling's 26 metres above sea level.
31:18So Stirling starts off close to sea level. Then the air, as it moves over those mountains, it's forced up.
31:27Braemar's 335. As you can see, the lowest part jumps up.
31:34You've still got those lines close together. In fact, you've just got hill fog, maybe some drizzle for Braemar.
31:40And then you've still got this area not far above Braemar, a few hundred metres, where it's clear skies.
31:47So if you were to shoot up a weather balloon or show a drone up through the atmosphere in Braemar,
31:55you'd have cloudless skies just a few hundred metres above, but very dreary conditions for Braemar itself.
32:01Then as that air descends on the other side, watch this change take place in these bits here.
32:09This is Lossiemouth at the same time. Lossiemouth's at a lower height. It's virtually sea level.
32:15So again, these lines come back down again. But what happens is that they're quite far apart at the surface.
32:22You've lost that low cloud. But at the same time, the dew point rises above that.
32:29In fact, there's not really evidence for an inversion above Lossiemouth.
32:34The two lines are virtually parallel as they go up. So just skipping back to Braemar.
32:42These lines very far apart at about 3000 metres, for example, they're much closer together at 3000 metres.
32:49The opposite happens close to the surface. Braemar, Lossiemouth, Braemar, Lossiemouth.
32:56And it's almost as if you can imagine all this air in this part of the atmosphere,
33:03the lowest five kilometres or whatever, just mixes together like that.
33:10So the really dry and much warmer air above the clouds mixes with the cloudy area for Lossiemouth
33:17to result in generally clear skies and warmer air at the surface, but also higher up as well.
33:26Hope that makes sense. Probably quite a long, rambling explanation of the Fern effect, but it is the deep dive after all.
33:34Right. Quick look at the rest of this week. There isn't much to talk about, I'll be honest.
33:39And it is all about those areas of cloud and cloud breaks.
33:44Effectively, as I mentioned, rest of Tuesday, some drizzly showers for western parts of the UK,
33:49mostly hills and coasts, but otherwise a mostly fine bonfire night for many places.
33:55Any cloud breaks are likely to fill in with fog, although northeast Scotland, again,
34:00must be seeing some decent cloud breaks developing through Tuesday and continuing into Wednesday morning.
34:05So that's where the lowest temperatures will be first thing Wednesday.
34:08Otherwise, it's a mild, a very mild start to the day. Temperatures of 12, 13, 14 Celsius.
34:14It's more of the same really through Wednesday. A chance of some cloud breaks there for north Wales, parts of northern England.
34:22Same mechanism as northern Scotland, Fern effect, but yeah, they'll come and go.
34:28I don't think they're going to be as reliable, perhaps, as parts of northern Scotland.
34:33Over on the left here, we've got the jet stream just coming into view.
34:36Some weather fronts waiting out in the Atlantic to come in and the isobars tightening.
34:41So later Wednesday and into Thursday, the winds strengthen. This is a southerly wind,
34:47so it does mean it's going to be very mild over the next few days.
34:49We had some colder air with us over the weekend at the start of this week,
34:53but overnight temperatures remarkably above average, actually, both by day and night.
34:58Double figures generally. Once again, northern Scotland seeing some decent sunshine on Thursday.
35:03Otherwise, most of the UK again under low clouds, some drizzle in the west and some strong winds.
35:11Perhaps 40, 45 miles an hour across western Scotland, so blustery in the west.
35:16And we're likely to see some thicker cloud and some outbreaks of rain turning up with this weather front.
35:22It's just trying to move in from the Atlantic and coming up against the high pressure.
35:26So weakening. And that nevertheless will bring some damp weather to parts of Northern Ireland
35:30and western Scotland during later Thursday and into Friday.
35:34But again, some cloud breaks there for northern Scotland.
35:37Hit and miss cloud breaks elsewhere. You wouldn't rule out cloud breaks just about anywhere
35:41because you could have some patches of drier air originating over the continent
35:45and drifting north into southern parts of the UK over the next few days.
35:48They're not going to be that reliable, though. They'll come and go.
35:52Friday, you can see some rain edging into the southwest.
35:56And the weekend sees a front crossing the country.
36:01This is Saturday and bringing some showery rain.
36:05No huge totals, certainly, and with all the dry air at the moment.
36:10Nothing to be too concerned about. But yes, some showery rain crossing the country on Saturday west to east.
36:16However, behind that front later Saturday, a better chance of some sunshine breaking out for western parts of Britain.
36:23Then another front comes along, and this is likely to bring some wetter weather once again
36:30into northwestern parts of the UK, basically as we start off Sunday.
36:35And that's going to cross the country. This is a more active area of low pressure, actually.
36:41I'll show you on the bigger picture. Here it is. It's being picked up by the jet stream.
36:47And it's moving in. A little bit of uncertainty at the moment on the track and the depth of that low as it arrives.
36:56It's going to swing to the north of the UK because we're still going to have the jet stream directing systems to the north of the UK.
37:02But it's likely to bring some strong winds to the northwest.
37:05So for western Scotland and for Northern Ireland and some outbreaks of rain.
37:10The general theme is that the front as it crosses the UK will weaken, likely to bring some cloud and some showery rain for a time on Sunday.
37:18But once it clears through, watch this. High pressure returns.
37:24However, this high pressure comes in from the Atlantic behind the cold front.
37:33Some uncertainty about this, but that means there's a good chance that it will build into clearer air.
37:40What does that mean? A better chance of some sunshine at the start of next week.
37:45This is the most likely weather pattern for Monday, the 11th of October.
37:49It's got high pressure to the southwest of the UK, dominating things across the country.
37:54Just some patchy rain for the northwest of Scotland.
37:56But with that high building in after a cold front's cleared, there is the good chance for some clearer spells, some sunshine with the high pressure at the start of next week.
38:06A bit of uncertainty, though, about the clearance of the front.
38:09It's not guaranteed that the front will completely clear and that we'll be completely free of the cloud associated with that front that goes through on Sunday.
38:18Either way, once we've got high pressure at the start of next week, it's likely to stick around once again throughout next week.
38:26High confidence on this. High pressure sticking around for another period of time.
38:32This is Wednesday. This is Saturday.
38:35Now, as the week progresses, it looks increasingly likely that more cloud will be mixed in with the high.
38:42So even if it starts off sunny, well, there's an increased chance later in the week that that low cloud will return because it will just start to rotate around the area of high pressure.
38:52It will suck itself in from the Atlantic, for example, as the week progresses.
38:57This is Saturday and this is when there are some hints that some subtle changes might start to take place.
39:05This is the most likely weather pattern for Saturday. High pressure still nearby.
39:09This is the second most likely weather pattern. High pressure to the south, but weather front starting to move into the north.
39:17So wet weather starting to arrive into the north and northwest of Scotland.
39:22So next week, if we start off with clear spells, chance of frost and fog at night, but then increasingly cloudy again.
39:29So mostly mild, most of the kinds of temperatures that we're seeing this week, 9, 10, 11, 12 and so on.
39:37However, around the middle of the week, and this has been signaled for a while, 17th, 18th, 19th of November,
39:44these systems are likely to start to increasingly affect the UK.
39:49And this is shown quite clearly, actually from the European model pressure anomalies.
39:56And this is the summary for next week. So this is the average pressure anomaly throughout next week.
40:02High pressure slap bang over the UK. But fast forward another week and this is the middle of November.
40:11And it's got higher pressure to the south of the UK. So the driest weather most likely hanging on to the south with systems starting to come into the north.
40:20So if it turns unsettled through the middle of the month, it's most likely to start to turn unsettled from the north.
40:27And just a final graphic here to show that in a different way. This is the next two weeks of weather patterns.
40:34Weather patterns illustrated by various colours here. Blues typically mean low pressure.
40:40Now, it's got this light blue for the last few days. That's kind of because the high pressure that's been dominating things has been quite far to the east.
40:48And we've had this southerly airflow with low pressure to the west. But effectively, we've had high pressure influencing our weather for the last week.
40:55And these reds and oranges indicate that's going to continue for the next week or so.
41:00But these blues, which indicate lower pressure most likely dominating, start to take charge around the middle of the month.
41:08But uncertainty about exactly when and how that takes place. We will, of course, keep you updated right here at the Met Office.
41:15Please do stay tuned for all those updates. And don't forget the Weather Studio Live is back this Friday, 12.15.
41:22So I hope to see you there. Bye bye.