This is an in-depth Met Office UK Weather forecast for the next week and beyond. Taking an in depth look at tropical cyclones, with a special guest, and why Tropical Cyclone Alfred was so unusual. Plus it's turning colder in the UK but what are the chances of snow? Bringing you this deep dive is Met Office meteorologist Honor Criswick.
You may also enjoy:
– 10 Day trend forecast https://www.youtube.com/playlist?list=PLGVVqeJodR_ZDSHKqsgszMnk9d5IEF5UH
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You may also enjoy:
– 10 Day trend forecast https://www.youtube.com/playlist?list=PLGVVqeJodR_ZDSHKqsgszMnk9d5IEF5UH
– Podcasts exploring weather and climate https://www.youtube.com/playlist?list=PLGVVqeJodR_brL5mcfsqI4cu42ueHttv0
– Daily weather forecasts https://www.youtube.com/playlist?list=PLGVVqeJodR_Zew9xGAqYVtGjYHau-E2yL
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NewsTranscript
00:00We're well and truly into meteorological spring but this week is going to feel a little
00:05bit more like winter. But why is this? How long is it going to last? And does it have
00:10anything to do with sudden stratospheric warming? Hello there, welcome to this week's Deep
00:16Dive. My name's Anna Criswick and I'm a meteorologist and presenter here at the Met
00:21office. Now I've got a treat for you today. We're also going to be taking a look at
00:24some global weather. We're going to be taking a look at tropical cyclones, including tropical
00:29cyclone Alfred, which has affected eastern parts of Australia. And to do this, I've got
00:35a special guest in, Julian, who has been on Deep Dives before. Come on over, Julian. I
00:40don't have to hide him away anymore. Hello and welcome to this week's Deep Dive. So we're
00:45going to be talking about tropical cyclones. So to start us off, could you just give us
00:49a brief overview of what tropical cyclones are and how they're impacted by La Niña?
00:54Well, a tropical cyclone is an area of low pressure which forms in the tropical oceans
01:00primarily. And actually, this is a good place to start. This is a global map showing several
01:04decades' worth of tropical cyclone tracks. So basically, they're storms which derive
01:08their energy from the warm ocean surface in the tropics. So you can see they all kind
01:13of form in this zone either side of the equator. And these show the tracks which show they
01:17do actually move out in the direction of the poles eventually. But they're primarily driven
01:22by this high sea surface temperature around the tropical zones around the globe. OK, lovely.
01:30And what we've seen recently, haven't we, is that we've had a few more tropical cyclones
01:35this season, particularly in the Indian Ocean. Is that right? Yes, that's right. Actually,
01:41if we go back to that, I'll just show the Southern Hemisphere season. Because actually,
01:47it's nice to talk about the Southern Hemisphere season for a change. Actually, often when
01:49I come on here, I'm talking about the Atlantic in our summer. But this time of year, from
01:55November through to April, we get tropical cyclones in the Southern Hemisphere. And you
01:59can see the tracks here. There's not so many in the Southern Hemisphere as there is in
02:03the Northern Hemisphere. And we have these zones where we don't get many, like in the
02:07southeastern Pacific Ocean in the South Atlantic. That's primarily due to things like cold ocean
02:13currents and not enough organized bands of storm activity to cause it. But we do get
02:19them in this part of the southwestern Pacific around Australia and the South Indian Ocean.
02:24And as you were just saying, this season, in the South Indian Ocean in particular, it's
02:29been very active. We've had a large number of storms in that area and some which have
02:33caused some impacts. And of course, just recently, we've had a few more around Australia as well,
02:38which I think we'll go on to talk about. Yes. So a bit of a link with sea surface temperatures.
02:44Yes, there is. If we look at the sea surface temperatures, firstly, this is the Pacific
02:49zone. And the thing which jumps out, firstly, I should explain that the colors represent
02:54anomalies. So there are differences from normal. And so the brighter colors, yellows and reds,
03:00are where the sea surface temperature is higher than normal and the blues are below normal.
03:04And this blue zone along the equator tells us that we are in a La Niña situation, although
03:11actually we're starting to transition out of it because we're getting this zone of slightly
03:15warmer ocean closer to South America. It means that we might be coming out of it. We don't
03:21know yet. It might carry on, it might not. But we've had a La Niña for some time and
03:26that does have an impact on the southern hemisphere tropical cycling activity. So it tends to
03:31mean that we get less activity in this part of the South Pacific. But in the South Indian
03:37Ocean, we can get more activity. And actually, if we go to the sea surface temperature map
03:41for the Indian Ocean, you can see how warm it's been anyway in that region. And that
03:46is one of the reasons why we've had an active season in the South Indian Ocean. We've had
03:52these, see the orange and yellow colors showing that the sea temperatures have been quite
03:57a bit above normal. This map was from late February, but it's been much the same throughout
04:02the whole of the season. In particular, this area around Western Australia, we've had some
04:07damaging cyclones in that area, one of which came ashore some weeks ago. So that kind of
04:13sets the scene for the fact that we've had this higher activity in the South Indian Ocean.
04:18I think you can see that from the track map as well that we've got down here. So actually,
04:26this shows the South Pacific Ocean. I'll have to orientate you here. This is the coast of
04:32Australia. Yeah, so that's Alfred there, isn't it? These are the tracks of the storms we've
04:36had so far this season. And actually, there's not many. And the three main ones we've had
04:40are Alfred, Siru and Ray, all which occurred during one week towards the end of February.
04:47But apart from that, not much at all. But if we switch across to the South Indian Ocean,
04:52you can see this huge proliferation of tracks. So we've had these over near Australia. We
04:57had Zelia, which was a very intense storm which hit Australia. We've had some long-lived
05:01storms as well, which stayed out over the ocean. So we've had Talia and Vince. And then
05:06over the western part of the basin, we've had a lot of storms in this region, some of
05:11which have made landfall over Mozambique, Malawi earlier in the season. And another
05:16one, Guerin, which hit La Reunion, which is the French island there. So we've had a lot
05:21of activity. And this kind of culminated in a period in late February where we had multiple
05:27storms active at the same time across the whole Southern Hemisphere.
05:31Yes, I think we've got something to show that as well. So we had, what was it, five, almost
05:36six. It wasn't quite six, was it, at the same time?
05:38Yes, this satellite picture was from late February. And although we've labelled all
05:43the different storms on here, if we can orientate ourselves again, here's Africa, here's Australia.
05:48So we had Honda and Guerin near Madagascar, Bianca near Western Australia, Alfred across
05:56near Eastern Australia, and then across in the South Pacific, Siru. Ray at this time
06:00was just about going through the transition into what we call an extra-tropical system.
06:06So it was losing its tropical characteristics. So that wasn't technically a tropical cyclone
06:11at the time that Guerin's formed. So actually, there were five tropical cyclones active simultaneously
06:18in the Southern Hemisphere. And that equals the record for the number of simultaneous
06:24tropical cyclones in the Southern Hemisphere, which is five. And the last time we had that
06:28was back in 1992. So it shows what an active period it is. So as I said, that's because
06:34we've had a generally active South Indian Ocean. South Pacific wasn't particularly active,
06:39but we just had this one period where there was what we call a South Pacific convergence
06:43zone really developed, which is a zone of disturbed weather through this part of the
06:47ocean. And we had these three spun up quickly, but they were almost the only three that we've
06:51had all season in that region. So that's why we had this particularly active moment,
06:56if you like, in the Southern Hemisphere season. Wow, really interesting. And this image actually
07:00illustrates it really nicely. I love that you can see them all on the same satellite
07:05image. So let's focus a bit more on Alfred then, because, yeah, a little bit unusual
07:11for this part in Australia. Taking a look at the track, it's almost like it changed
07:16its mind and had its eye on Brisbane, excuse the pun. Did you want to talk a bit more about
07:21that? Well, you can see where it formed. So it formed up here in the northern part of
07:25the basin in the Coral Sea. And the storms which develop in this area, we do get them
07:30fairly frequently. And a lot of them do tend to either move in towards, make landfall over
07:36northern Queensland, so the zone down from Cairns through Townsville, Mackay, that sort
07:41of area. Or sometimes if the steering currents are different, they might just run parallel
07:45to the coast, keep out over sea, or maybe come down parallel to the coast here and weaken
07:50as they do. But in this case, Alfred, the reds here show when it was at its peak in
07:55terms of its intensity, and then it weakened as it came further south, but then hit an
07:59area where the steering currents, which is the kind of upper air which determines which
08:04direction storms go in, became very weak. And then it kind of reversed, and we had this
08:09movement in towards the Brisbane area, a Brisbane kind of gold coast, sunshine coast
08:15area, and making landfall there. Now I have to say, it came ashore as a relatively weak
08:21tropical storm. So for many other parts of the tropics, a landfall of a tropical storm
08:26of that intensity wouldn't have been very noteworthy. But of course, this is a really
08:30populous area, and also they're not very used to getting tropical storms. I think we can
08:35see that from the kind of map of the kind of history of storms hitting that region.
08:40Oh yes, here. So this is a real zoom in towards Brisbane, gold coast area, and looking at
08:47all the storms in the historical record which have passed through that zone, the green lines
08:53are of tropical storm strength. So not particularly strong, but this is all the storms that have
09:00ever done that, and there's not many, and the ones that do tend to come down from the
09:03north. And there's only really one in the historical record which came in from the east,
09:08and that was this one here, Cyclone Dora in 1971. So you can see how infrequent it is
09:15for them to get this kind of storm. So it hit Brisbane, and there's kind of two impacts
09:21it had. There was a lot of rain. I think we can see that from the rainfall map, can't
09:26we? We can, yes. Where did I pop that? It's hidden behind this one. Yeah, here we go.
09:31So this is the rainfall map over Australia for the last week, and you see the purple
09:37colours here around south-east Queensland and north-east New South Wales, and the purple
09:43colours mean they had three, four hundred millimetres plus of rain in just a few days.
09:48So that caused some flooding inland, some of the river basins in that region. But the
09:53other thing is because the storm was coming in from the east, and fairly slowly, there
09:58was a constant wave-pounding action along that part of the coast. And that part of the
10:03coast has some lovely stretches of sandy beaches, which generally tend to slope gently down
10:10to the sea. But the pictures that we've seen from that area since the storm hit are remarkable.
10:16You get the beach, and it's gently moving out to sea, and then you get a new kind of
10:21cliff edge of two or three metres, where the sand has just been completely eroded from
10:27the beach area. So there's now these new cliffs, if you like, all along the seafront
10:32there, where there used to be kind of gently sloping sandy beaches. Yeah, some quite sad
10:36images actually. I'm sure many of our audience have seen quite a lot across social media
10:40and the news of these beaches basically disappeared as a result of this storm. So yeah, quite
10:46an unusual event for this part of Australia. Anything else you want to talk about, Alfred?
10:52I think that's about it for Alfred, yeah. So we're coming up to date now with what's
10:56happening at the moment. Yes, so it's largely weakened now, that storm. Yes, it's moved
11:01inland and it's weakened, and there is some remnant rainfall, but yeah, most of the effects
11:05have gone now. Okay. So another tropical cyclone that we're just going to briefly talk about
11:11is Jude, affecting more kind of Mozambique. Yes, that's right. I mean, the only storms
11:17active now at the moment, we have two more in the South Indian Ocean. I was saying that
11:22we've had a very active season there and it's continuing. So we've got these two storms
11:26there. The first one, Avon, probably won't cause any problems. It's fairly weak. It's
11:31sitting out in the central part of the South Indian Ocean. And this is the current forecast
11:36from the regional forecast agency there, and they're predicting that it'll gently drift
11:42southwards, so shouldn't bother any land areas. But we've got Jude, which is over near the
11:47coast of Africa. And in fact, it started up here and tracked across the north of Madagascar,
11:54reached the equivalent of hurricane strength before it made landfall over Mozambique. It's
12:00now inland near Malawi, and it's weakened right down to tropical depression. So the
12:06winds aren't very strong at all now, which is typically what happens with a tropical
12:09cyclone. It loses its source of moisture and energy as it moves inland. So the winds died
12:15down. But there's still a lot of remnant rainfall from that storm, or depression as
12:20it is now, producing a lot of heavy rain in northern Mozambique and in Malawi. And we
12:26expect that to cause some flooding. There could be 300 or 400 millimetres of rain in
12:30that zone. But the thing you'll notice as well from the forecast chart is that it's
12:35not just going to move inland and dissipate, but we expect it to turn back out to sea.
12:40And so probably by Thursday, it'll be back out over the Mozambique Channel. And once
12:44it comes back out over the warm ocean surface, it's got the potential to re-strengthen. Probably
12:49not to as strong as it was previously, because it won't have the time, because it's going
12:53to cross the Mozambique Channel. It'll bring some heavy rain to southern Madagascar, and
12:58then we expect it to move out over the open ocean and will probably dissipate at some
13:02point in the future there. So there's still more impacts likely to come from Jude, both
13:07from rainfall over Mozambique, Malawi, and also it's going to move back out across Madagascar
13:12as well. And this was the third one of the season for this area? To hit Mozambique, yes,
13:18we had two earlier in the season. We had Chido, which was a little bit further north. In fact,
13:23you can see it marked on the map here, Mayotte. There's a French island called Mayotte there.
13:28And in December, Cyclone Chido, very strong cyclone, hit Mayotte. And there was some real
13:34severe damage and devastation in that island because it had a direct hit. And there's another
13:40one a little bit later called Dikoledi, which moved across here and across Madagascar, just
13:45grazed the coast and then moved back out again, a little bit like Jude is doing. So yeah,
13:50all in all, it's been a busy season in the southern hemisphere. And I say we're in March,
13:54so it's quite possible there could be more in the remainder of the season. Typically,
13:58the season lasts from November to April, but it's not unheard of to get storms in this
14:03season as late as May or even early June. So there could be more to come. Okay, well,
14:08we'll have to get back on if there's any more exciting ones. I think it's really interesting
14:12as well, two storms that we've kind of focused on today, more kind of impacts from rainfall rather
14:17than strong winds. I think people always think of tropical cyclone storms, you know, strong winds,
14:22heavy rain, but actually, in both these cases, it was more kind of the rain that was causing.
14:26Yes, it's often the case that inland flooding can be one of the biggest impacts from tropical
14:30cyclones, any part of the world, rather than the wind. Although often we hear about the wind,
14:35because you can see the impact of it very clearly when it makes the landform.
14:39Yeah. Okay, lovely. Anything else you want to add?
14:42I think that's about it. We've brought everything up to date.
14:45We have, yeah. That was a really good summary.
14:47Yeah, thank you so much for that, Julian. That was super, super interesting. I've been
14:51looking forward to this chat all day. Yeah, thank you so much. And yeah, obviously, I'm sure we've
14:57seen quite a lot on social media about particularly tropical storm Alfred. So it was really great to
15:03a bit of an understanding as to why and what occurred. But now we're going to move on to UK
15:09weather and figure out why it has been so cold. So now let's bring it back to some UK weather.
15:18Now, you might have noticed already today that it's felt a little bit cooler, particularly if
15:23you compare it to the weekend, where we had lots of sunshine, and it really felt warm in that
15:27sunshine too. We just about made it to a rounded 20 degrees. So nice warm spring sunshine, but
15:34feeling a little bit chillier today. And I'm afraid to say through the rest of the week,
15:39it's going to get even colder. Temperatures are slightly below average, I suppose,
15:44but what's really making it chilly is the brisk north to north easterly winds.
15:50So where are they coming from? What's the reason for this change? Well, it's all thanks to this
15:55area of high pressure just to the southwest of Iceland. Now, this area of high pressure eventually
16:01actually bringing us something a bit drier as we head towards the weekend. But before we take a look
16:07at that, I'm just going to add on the kind of the air mass temperature. So you can see already this
16:12northerly flow. If we follow these isobars down, we can see that northerly flow across the country
16:18bringing in that colder air, all thanks to this area of high pressure, turning the winds kind of
16:23clockwise. And if we zoom out, we can see actually these winds kind of already originating all the
16:29way up from the Arctic Sea. So bringing in some really quite cold air across parts of the UK and
16:34some brisk winds at times, which is really adding on to the wind chill through the course of the
16:39week, particularly if you find yourself in any exposed spots around North Sea coast. But through
16:44the week, even if you're away from those areas, it is going to be feeling chilly. Now, as we head
16:50through the evening, if I just play this through, we can see this frontal feature moving its way,
16:56or the centre of it, I suppose, moving its way southwards down through the North Sea, bringing in
17:01this cold front. What we'll find behind this cold front is actually a lowering of the freezing level,
17:06but along the front itself bringing in a bit more cloud, perhaps some light outbreaks of rain. But
17:11there's going to be plenty of showers through the course of the week as a result of this kind of
17:17northeasterly flow of air. And you notice we still find ourselves in that kind of cold plume all
17:22through the coming days, so still Thursday and into Friday. But keeping your eye on that area
17:29of high pressure as we head into Saturday and also Sunday, it's kind of shifted its way eastwards.
17:37So by the time we reach Saturday and Sunday, if you get a bit sick of the showers towards the end
17:42of the week, that high pressure is going to build with the centre of it across the country. So that's
17:47going to ease away any showers, largely kill them off. So Saturday and Sunday actually look like
17:52quite decent days. Probably going to see quite a lot of blue skies around. Still going to be cold
17:57though, some frosty, possibly icy starts. Notice we're still in that colder plume of air for
18:03Saturday and also Sunday as well. So still on the chilly side, but if you're not a fan of the rain,
18:09then the weekend does look a lot drier. But earlier in the week, what does this kind of
18:15northeasterly flow of air mean for the weather? Showers, showers and more showers. Sunshine and
18:22showers. You're going to be sick of us saying that by the time we reach the end of the week.
18:26All through the week, you can see all the way through to Friday, there's a risk of sunshine and
18:31showers. Now some of us are going to see more showers than others. Obviously with our winds
18:36coming from a north to northeasterly directions, that means the bulk of the showers are going to
18:40be across northeastern areas, North Sea coasts, East Anglia, even some feeding through into parts
18:46of the southeast, Sussex and Kent, for example. But even still some showers moving inland at time.
18:52So a little bit drier in the west. Yes, west is best this week, but it's not necessarily going to
18:59be completely dry. There's still a chance of those showers and that brisk flow being moved into
19:03western areas because at times, particularly on Wednesday, for example, Northern Ireland,
19:07western parts of Scotland, probably once again seeing quite a decent day, but still, as I say,
19:12on the chilly side. And then it's as we reach into the weekend, we can see a gradual decline
19:18in those showers. There are still some about can't totally rule out the odd shower or two,
19:23but for most it's going to be a dry day. Few more blue skies around, but still feeling cold.
19:29So focusing on the showers you might have seen already, we've mentioned a risk of some sleet and
19:35snow. So I want to just show you the the freezing level. So the temperature at which of any
19:40precipitate at the height at which sorry, if any precipitation falls through, that's where we're
19:45going to see any precipitation largely fall asleep, possibly snow. Now we can see on Tuesday
19:53where we're starting freezing level largely between 400, 800 metres. But notice as I move
20:02through into this evening, tomorrow morning, we can see a lowering of that freezing level. Remember
20:09that cold front shifting its way southwards behind that we're seeing our zero degree isotherm
20:14lower and obviously plenty of showers moving specifically into these areas. So it's likely
20:20we probably are going to see some snow, mainly high ground, the Scottish Highlands, the Pennines,
20:26the North York Moors, for example, likely to see some snow across hills, higher ground. But
20:30as we see this freezing level lower, possibly even seeing some snow flurries to lower levels
20:36to is it going to be impactful snow? Probably not. Most of it melting away as the sun comes up
20:42during the during the course of the morning. But the main risk is going to be ice for the first
20:48part of the morning. Obviously, plenty of showers. That's going to make quite a lot of surfaces quite
20:53wet, particularly across higher ground. That's probably where the main ice risk is going to be.
20:57So a chance of some slippery surfaces during the morning through the course of the week. So
21:02keep an eye out for warnings. A low risk we could see some ice warnings and obviously just take
21:07care throughout about during the early morning. And where we see any clear skies overnight,
21:11it's likely that we're going to see some some frosty conditions, too. But through the course
21:15of the week, anywhere we see those sort of grey colours, so whether the kind of freezing levels
21:20dropping to around 200 metres, that's definitely where we see those showers move through. There is
21:24a risk possibly of of seeing some snow to lower levels as we head through into tomorrow morning.
21:31But nothing, nothing impactful. But yes, snow on the card. So it doesn't really feel like spring
21:35weather, does it? Now, the question is, is the cold snap anything to do with sudden stratospheric
21:43warming or the SSW for short? Well, it has been confirmed that the stratosphere polar vortex
21:51has collapsed. And if you're not sure what I'm talking about, well, this is when the winds
21:55in the mid stratosphere change from westerly to easterly. But what does that actually mean
22:00for the weather? Usually about 70 percent of SSW events lead to colder weather in places like
22:08northern Europe and the UK with easterly winds. The forecast is showing hints of this happening.
22:15So there's a higher than normal chance of a cold snap. But later in the month. But not every SSW
22:21event leads to extreme weather. So we'll have to wait and see if that one plays out. But we'll get
22:27more details on how this could affect the weather as it gets closer. But the polar vortex actually
22:32collapses every couple of years during midwinter. So it's not something that happens all the time.
22:38But the current cold weather is not directly related to this. So just in case there were any
22:44questions around that. So not directly linked this week to the SSW, but a thing, something we're
22:49keeping an eye on for later on as we head into March. Speaking of later on into March, shall we
22:56see if this cold spell is going to stick around? So what we can kind of see, here's a
23:04stacked probability chart of whether we're going to see more high pressure dominating. So more of
23:10these reds, oranges and yellow colours. Or if we're going to see more low pressure dominating
23:14some more of the more of the blue colours. And this is the timeline along the bottom here. So
23:19moving further into March. So we can see mainly red colours to start. That's where we're under
23:23the influence of that high pressure moving its way eastwards towards the UK, moving its way in
23:28from the southwest of Iceland. But notice how we get into the middle of March, further into March,
23:34see a few more of these bluer colours. So an indication that perhaps some kind of low pressure
23:39is going to start to dominate. And what we're going to see is that high pressure obviously
23:43shifting its way towards the country over the weekend. But then it continues to move its way
23:47eastwards into parts of Europe. And that kind of sets us up into something we're a bit more familiar
23:54with. So, for example, as we see that high pressure drift its way more towards Europe,
24:05that allows a bit more of a low pressure set up to set up into the Atlantic. That means notice a
24:11change in our wind direction. So rather than a cold north northeasterly, we're going to see
24:16something a little bit milder start to move in from the from the northwest. So this is for the
24:21end of next week. So Friday the 21st of March, a kind of idea of what potentially the weather
24:26could look like. And notice the temperatures returning a bit more towards average, perhaps
24:30slightly milder. So it looks like it's going to be quite a brief cold spell for now, mainly this
24:35week. And as we head into next week, something a bit milder coming along. But as we know, milder
24:40doesn't always mean better. If we're getting more of a wind flow from the west southwest,
24:46that means a chance of some frontal systems coming in more cloud, possibly some outbreaks
24:51of rain, mainly for the west, perhaps slightly drier to towards eastern areas at times. So
24:58it changes on its way if you're not a fan of the cold and you want spring to return,
25:02but it might just mean that there's a return of some more cloud and of some more rain. So
25:08it depends. It depends what you like more, I suppose. But that's pretty much it for UK weather.
25:14Doesn't seem quite as exciting as what we've spoken to Julian about towards Australia and
25:19other parts of the world. Another big thanks to Julian for joining me today. I really enjoyed
25:24that chat about tropical cyclones, and I hope you did too. Let us know in the comments if you did
25:29enjoy it. And if you have any further questions, drop them in the comments as well. I always do
25:35try and take a look at the comments in my deep dives because, of course, we'll have our weather
25:40studio live on Friday, 12.15, so I can try and answer some of them then. It will be me and Alex
25:47Birkhill. And if you haven't had enough of our content already, we do actually have a new video
25:52on our YouTube channel around climate change. It's a really good video that I was able to take part
25:57of. We've got an experiment. I got to wear a lab coat. It's really, really interesting. So make
26:02sure you go check that out as well and give it a like while you're there. And obviously give this
26:06video a like if you enjoyed it too. But yeah, I hope you have a great week. I hope you don't
26:11mind the cold so much, and I'll catch you again soon. Bye-bye.