This is an in-depth Met Office UK Weather forecast for the next week and beyond. After the storm the weather is calming down but there is still rain in the forecast as well as some frosty mornings and lingering fog. Bringing you this deep dive is Met Office meteorologist Honor Criswick.
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NewsTranscript
00:00Hello there and welcome to this week's Deep Dive. My name's Onna Criswick, I'm a
00:06meteorologist and presenter here at the Met Office. This is a very special Deep
00:11Dive, it's actually my first one, so what could go wrong? I've finally been let
00:16loose on the touchscreen and we've got plenty of weather to talk about this
00:21week from the snow and the ice that we saw last week and then we went straight
00:26into a named storm over the weekend, Storm Burt, which brought quite
00:29widespread strong winds, some heavy outbreaks of rain and some snow for a
00:33time over the weekend too, so it was a multi-hazard event, plenty for us to
00:38talk about. Now the weather is calming down this week, we've got high
00:43pressure building but there are a couple things we need to keep our eye on. There
00:46is going to be some heavy rain at times in the south and with high pressure
00:50building across the country that's leading to some clear skies, so some
00:53chilly and frosty nights on their way and also a risk of fog and towards the
00:58end we are going to have a quick look at how we do forecast fog too, so don't
01:03forget to watch until the end, don't forget to like and subscribe if you're a
01:08fan of this video and you can leave comments as well, I'll try and take a
01:12look through the comments if you do have any questions. So let's get started
01:17then. So what I'm going to talk about to start off with is the weather that we
01:21saw last week and over the weekend. Obviously the main talking point was our
01:25named storm, Storm Burt, which we can see nicely on this satellite image, we can
01:30see it, here we go, if we start from Thursday into Friday we can see it
01:33building out here into the Atlantic, moving frontal systems across the
01:37country, then we eventually see it swirling around on the weekend just to
01:41the northwest of the country before it eventually cleared its way over to
01:45Scandinavia. So obviously this brought plenty of heavy rain across the country
01:52So what we can see here is the view from space, this is satellite imagery and I've
01:56just overlaid the radar onto this as well, so we can see from Friday night
02:00into Saturday we can see that rain sweeping its way across the country,
02:04those brighter colours showing the heavy rain in places as well. What this doesn't
02:07show is the snow falling as well, obviously we started off in that really
02:11cold air mass, so as the rain fell into the colder air it fell as snow at first
02:15and then eventually as that frontal system brought in some slightly milder
02:19where more and more the precipitation fell as rain rather than snow, and it
02:24also brought in some pretty strong winds across parts of the country too, and the
02:28winds were actually quite widely spread strong too. So what we're going to do
02:33first, we're going to take a look at some stats around storm Burt, so I'm going to
02:37start off here with the maximum gust speeds that we saw, this is from the 23rd
02:43through to the 25th as that storm was with us for around two to three days. So
02:48the top one here, we can see the date on the very far left, the site name, what
02:53area that the site is in, how high that site is, as well as the maximum speed in
02:58knots and on the far right in miles per hour. So the top maximum gust wind speed
03:03that we did see as a result of storm Burt, that was in Capel Currig in Gwynedd
03:09and the top speed that we got to was 82 miles per hour, so obviously very strong
03:16winds, it's not the strongest we've seen with a storm moving through the UK, but
03:19obviously pretty strong winds here across parts of Wales. But what's
03:23interesting here is what we can see, is if we take a look through just down the
03:27area column here, we can see we had strong winds in Wales, we also had
03:32some strong winds down to the south in parts of Devon, the Isle of Wight, and
03:35also we had strong winds to the far north of the country in parts of Cumbria
03:39and also Shetland too. So what's interesting about this storm as it moved
03:44through is that we did see some strong winds but quite widespread across the
03:48country, they weren't really localised in one particular area. Many of us saw quite
03:53a blustery day with the top speed being around 82 miles per hour in Wales, but
03:58many areas across the south reached mid to high 70s miles per hour and even
04:03across Scotland we saw the high 60s, so particularly blustery conditions as
04:08storm Burt moved its way through, particularly around any exposed spots. A
04:15few more stats here for you as well, this is once again from the 23rd to the 25th,
04:20what else did we see? Well we also saw some snow, we saw some snow towards the
04:24end of the week, we were in that colder air mass and as the storm moved its way
04:29through, that rain falling into the colder air mass, so it fell as snow for a
04:32time, but also as a result of the snow that we had towards the end of the
04:37week as well. So the top snow depth, this is from the 23rd to the 25th, that was in
04:43Loch Glaskanok, hopefully I've pronounced that correctly in Ross and
04:47Cometry there, so they saw 25 centimetres of snow, so that's the highest snow depth
04:52that we saw accumulating from the 23rd to the 25th. A slight
04:58word of caution around these snow depth figures is that across the Met Office we
05:04have a network of observation sites that collects this kind of data for us,
05:09but in terms of snow depth measurements across the UK, it's generally
05:14quite sparse, so there's probably a few more locations that
05:18probably reached this kind of snow depth, a few more than what's this showing on
05:22this table here. So this just gives an overall summary of the kind of snow
05:27depths that we were looking at as that storm moved through, but there were
05:30probably a few other places where we didn't quite get measurements that had
05:33similar sorts of snow depths, but at the moment it looks like the top snow
05:38depth that we saw from the 23rd to the 25th was around 25 centimetres, but even
05:42in parts of Durham we got to 21 centimetres, in parts of Derbyshire we
05:47got 18 centimetres, so a significant amount of snow and that definitely did
05:51cause some impacts over the weekend. Now a few more stats just to finish off,
05:59these are rainfall totals from the 23rd to the 25th, these are provisional
06:04figures at the moment and it's also worth bearing in mind that some of these
06:08figures could also be as a result of the snowmelt that we saw, so these figures
06:13may change, so once again just kind of giving you a rough idea of the kind of
06:16impacts that we saw over the weekend. So in the number one spot, that's White
06:21Barrow in parts of Devon, where at the moment we're looking at around 175.7
06:27millimetres of rain, so obviously that is a lot of rain over two to three days as
06:32a result of the storm and obviously we saw some of the impacts to homes and
06:36infrastructure, we saw some flooding impacts in places too, but once again
06:40fairly widespread across parts of Wales, parts of Devon, we saw very high
06:46rainfall totals, widely kind of above sort of between 140 to 175 millimetres
06:53of rain, so a lot of rain over the weekend. Now in general it looks like
07:00next week, or this week I should say, the weather is calming down but there is
07:05also some rain in the forecast which could cause further impacts, particularly
07:09where we have seen flooding already. So let's move over then to the weather this
07:15week. So here we go then, this is quite a good chart actually, shows the
07:20different kind of weather elements split into four, so over on the far, far
07:25right, the far right from me, we have the synoptic pattern where we see the
07:30frontal system, the isobars and then just to the right or just to the left of this
07:35we also have rainfall, then we have winds and then we have temperatures. So as I
07:41mentioned already, there is generally high pressure is building but we do have
07:46some slight caveats to that, as you can see on my far right, making sure I get my
07:53left and right right, we do have low pressure that's moving through Tuesday
07:57night, so tonight, through into Wednesday morning and that is going to bring some
08:01outbreaks of rain, this could be heavy and persistent at times and there is a
08:04chance it could affect areas that have already seen quite a lot of rain this
08:07weekend and areas where we have seen some flooding too. So this is generally
08:13moving across the south from Thursday, Tuesday night sorry, through into
08:18Wednesday morning, could be heavy and persistent at times before that high
08:22pressure really builds across the country bringing a slight calm as well.
08:26What we can see, we do have high pressure to the very far north of this, so it is
08:30on its way. So a thing to note about this is when we forecast here at the Met
08:35Office, we use a range of different models to give us an idea of what the
08:40weather's doing and from time to time all those models agree and then we can
08:44kind of forecast with high kind of certainty, high levels of
08:49confidence but there are times where we forecast when certain models say
08:53something slightly differently to what the other models are saying and this can
08:56happen, it does happen quite a lot actually in longer lead times but it can
09:00also happen in shorter lead times as well. And we've had a little bit of this
09:05this week, some models have had this area of rain slightly further north impacting
09:09more across central and northern areas but most models at this time in
09:14particular are keeping this rain to the far south. So that's the story that we're
09:19sticking with through Wednesday night into Thursday but it's always worth
09:22keeping an eye on the forecast just in case this does change. Most models now do
09:27have this rain running just to the far south but it's always worth keeping an
09:31eye on the weather forecast just in case it does change and those few model runs
09:34that have it slightly further north are in fact correct. But at the moment it
09:38generally looks like it's low pressure sweeping in these frontal systems to the
09:42south. Heavy and persistent rain at times and there are a couple of rain warnings
09:45issued from the Met Office so keep an eye on those if you are in this area. But to
09:49the far north a slightly different story, it's shown quite well here by the
09:53temperatures actually. Temperatures ranging more from 3 to 4 degrees, we've got
09:58high pressure, clear skies, those temperatures are really going to drop
10:01off Tuesday night through into Wednesday morning. But slightly further south where
10:05we see those cloudier skies where that rain starts to move in, we're looking at
10:08more between sort of 10 to 8 degrees or 8 to 10 degrees I should say. So a
10:12slightly milder night here, temperatures not dropping quite as low under the
10:15cloud and rain but those temperatures really dropping under those clear skies
10:19to the far north. If I drag this through, if we head to, oh here we go, just drag
10:28this through to Wednesday morning, kind of around rush hour time just in case
10:36you're on your way to work Wednesday morning, you can see the rain generally
10:39has cleared the far southwest. It's looking likely there'll be some cloud
10:42perhaps some rain and drizzle lingering on. Some heavy outbreaks of rain we could
10:45see around sort of the Sussex, Essex and Sussex area and then some outbreaks of
10:50rain across parts of Wales, central areas and parts of East Anglia too. Not only
10:55this but you can see that the Isle of Bards slightly closer together, the wind
11:00speeds are picking up a little bit too. So it's not only going to be quite a wet
11:02start across parts of the south on Wednesday, it's going to be a little bit
11:05blustery too with winds really picking up particularly around kind of coasts,
11:10exposed coasts for example. So quite a wet start across the south on Wednesday,
11:16do keep an eye on our forecast for that one and as I say we do have some Met
11:20Office weather warnings issued here. Eventually though it's quite slow moving
11:25but it will eventually clear its way off to the North Sea and this then allows
11:29high pressure to build later on Wednesday and into Thursday. So Wednesday
11:35night that high pressure is sitting quite nicely across parts of the UK. Now
11:41what does this mean? Well with clear skies and you can see with the spread of
11:46the Isle of Bards as well, generally light winds, that can lead us into well firstly
11:51actually staying in a slightly cold air mass as well. Those temperatures are going
11:54to drop away so it's likely we're going to see quite a sharp widespread frost
11:58particularly across Scotland, northern England, parts of Northern Ireland likely
12:02to see a sharp frost here, perhaps even some icy stretches. So take care once
12:06again Thursday morning if you are out and about, particularly for the
12:09morning rush hour. Still slightly milder to the south but those temperatures
12:12dropping away compared to tonight. But high pressure with clearer skies and
12:17light winds that also leads us into the risk of some fog and with temperatures
12:21below zero as well that also leads us into the risk of some freezing fog
12:24patches as well. So a chance of more disruptive weather by the time we reach
12:29Thursday morning too with some fog patches, perhaps some frost and some icy
12:34stretches as that high pressure builds. But it's also coming to the time of year
12:39as well, end of November some of that fog may be thick enough to stick around
12:42for a time too, so a chance we could see some further fog warnings in the
12:46forecast this week too, so don't forget to stay updated on our website for those.
12:49Then high pressure is dominating the weather quite a lot for the rest of the
12:53week and into the weekend. But you can see it's sitting slightly further to the
12:57east as well, so that does allow some frontal systems to move in at times.
13:00Notice once again a squeeze in the Isle of Bards in the west too. So from later
13:05Thursday into Friday through into the weekend that high pressure as it sits
13:08just slightly more to the east, that's allowing some rain, some stronger winds
13:12just moving into the west, so it's not going to be completely settled and then
13:15eventually but sort of the driest and brightest of the weather going to be
13:18across the far southeast and then eventually that high pressure slipping
13:22away allowing a bit more rain to move through on Wednesday and as we head into
13:26the weekend too. Another thing you'll notice about into the weekend, look at
13:34these temperatures, these are looking much much milder for the time of year
13:38compared to the kind of cold dip that we've had in temperatures
13:41sort of last weekend, this week really. Looking at more by the time we reach
13:45Saturday between sort of 12 to 13 degrees, a significant change particularly
13:50across parts of Scotland as well. So what I'm going to do is to show this nicely,
13:57I'm going to get up, oh there we go first time and it works, I'm going to get up
14:03some temperature graphs just to kind of show. So this is max temperature here at
14:09the top and then we've got minimum temperature here on the bottom. This is
14:14in Brinington, so just near Manchester, so north of England, northern parts of
14:18England. So notice temperatures Tuesday roughly around about average for the
14:23time of year, we start to see that slight dip as we head into Wednesday and
14:27Thursday, that high-pressure building, plenty of clear skies particularly
14:30overnight, so seeing that drop in temperature. But by the time we reach the
14:34weekend, temperatures a bit milder for the time of year, so around 12 to 13
14:39degrees and this kind of trend in temperatures where we go from kind of
14:43average, we see that slight dip and then an increase onto the weekend, perfect
14:47timing really, that trend is kind of, we can see that across much of the country.
14:52So here we go in Uddingston, close to Glasgow, we can see once again that dip
14:57in temperatures on Wednesday, starting to improve towards the end of the week
15:00and then by the weekend something slightly milder on the cards and if we
15:03move our way to the far south as well, Southampton, once again that dip and that
15:08trend to those slightly milder temperatures for the weekend. So that's
15:13the general gist of the weather this week, there are a couple of things to
15:16keep an eye on, the rain in the south potentially being slightly further north
15:20as we reach Wednesday morning, high-pressure building, bring lots of
15:24settled conditions, there's probably going to be lots of sunshine around,
15:27obviously those cold nights, those frosty nights, a risk of some ice and also that
15:32risk of fog and in some places that fog could linger for a time, just where we're
15:37starting to move our way towards meteorological winter, we're moving our
15:41way towards the winter solstice, so the days are getting shorter, which doesn't
15:45help in terms of fog clearance. So let's take a look at that now, we'll take a
15:49look at some fog forecasting. Now as a rule of thumb, if you didn't have
15:55anything at all, what you can do is you can take a wild guess at what time fog
16:01is going to clear. So for example, we're in November, that is the 11th month, so
16:06you could roughly say as a rule of thumb that the fog is going to clear at around
16:1111 a.m. This is true for the kind of second six months of the year, but for
16:16the first six months you take the number 13 and you take away the month of the
16:21year, so for example in March 13 take away 3, March is the
16:27third month, 13 take away 3 is 10 and you could roughly guesstimate that the fog
16:32is going to clear around 10 a.m. Obviously here at the Met Office with us
16:37as forecasters that's probably not quite good enough, particularly if you're
16:41working for example in the aviation sector. So something that we like to use
16:45as forecasters is what we call a tephagram, which looks something like
16:52this. Now don't be scared, they're not as complicated as they look, once you know
16:57what all the lines mean they're generally pretty easy to interpret, but
17:01these are great forecasting tools that we use here at the Met Office. We can
17:06really tell a lot from using one of these tephagrams as a forecaster. We can
17:11take a look at temperature, we can take a look at wind, we can take a look at
17:15cloud, whether it's layer cloud, so frontal cloud moving through, whether
17:19it's convective cloud and from that we can tell how heavy precipitation is
17:23going to be, whether it's going to fall as rain or whether it's going to fall as
17:26snow. So they're really great forecasting tools, you'll look at them multiple times
17:31a day as a forecaster, every day in fact, and you really get used to them as well.
17:35So don't be afraid, I'm going to explain what this all means. So below the bottom
17:40here we've got temperature, so as I move my way to the left temperature is
17:44decreasing, and then as we move our way up the y-axis this is an increase with
17:50height, so we've got temperature decreasing as you move to the left and
17:53as we increase upwards that is temperature increasing high up in the
17:59atmosphere. So what this generally is showing us is temperature in the
18:03atmosphere as we move our way upwards. So these diagonal lines here, these
18:12are called isotherms, so these are constant temperature with height if
18:17you follow them upwards, if you follow the isotherm upwards. So they move
18:22in a more slightly diagonal kind of direction and that just
18:26accounts for temperature generally decreasing as we move up higher in the
18:30atmosphere, so that's why they're on a slight slant. And this dashed line here,
18:35this red dashed line, this is the zero degree isotherm. So this is constantly
18:40zero degrees as we move up in the atmosphere and you follow this diagonal
18:43line. So anything to the left of this is below zero and anything to the right is
18:48above zero, so colder, warmer. Then we have this solid blue line, so this shows us as
18:56we decrease, as we increase the height of the atmosphere this is what our
19:01temperature is going to be. So if I wanted to know the temperature at this
19:04height I'd follow this isotherm downwards and this gives me minus seven
19:10so at this height, which is about 9,000 foot, I know that temperature is going to
19:14be minus nine. So this is temperature as you increase with height, so the
19:19temperature of the air. This blue dashed line, this is what we call dew point
19:24temperature. So this is the temperature that the air would have to cool to in
19:29order to become saturated. Therefore the further apart these lines are, the drier
19:37the air. So here we can see the air is very dry loft, so probably blue skies
19:41looking at this. Towards the surface of the earth the lines are
19:48very close together, in fact they're overlapping towards the surface of the
19:52UK, towards the surface of the, towards the ground sorry. So this is very moist
19:58air, so the lines further apart that's dry air and to the south that's very
20:02moist air where the lines are very close together if not touching. So this shows
20:07us that the ground around the surface is very moist, it's very saturated. We
20:12already know we have clear skies and light winds replenishing the kind of
20:17moisture in the air. So this gives an indication that there is cloud and this
20:21could be anywhere on the Teffy ground. If the lines were closer together near the
20:24top we know we were going to get some high level cloud or sort of towards the
20:28middle of the Teffy ground, some medium level cloud. But the lines are together
20:31towards the surface, so low level cloud touching the ground, in other words
20:36fog. So straight away as a forecaster when you look at this Teffy ground you can see
20:40that there is a fog risk. We've got moisture at the surface, we've got clear
20:44skies where the temperature is going to drop. So this means here where the
20:50temperatures are touching, this means that the air is saturated here. So
20:54temperature and dew point temperature are roughly similar, so that means dew is
20:58going to deposit onto the ground. We've got light winds constantly replenishing
21:03that air and the water vapour becomes suspended in the air and that's how we
21:09start to get cloud formation right here at the surface. So this is where the fog
21:13is beginning to form. Not only this actually, I've just noticed it's just to
21:18the left of the zero degree isotherm, so there is a chance actually a risk that
21:21this could be freezing fog. This is one of our model Teffy grounds from our
21:25global model. This is Thursday morning in the Midlands, so already this is a very
21:30good indication that we are expecting some fog Thursday morning in the
21:35Midlands as a result of this moisture low to the surface. Another thing
21:41we can do with these Teffy grounds is that we can work out the temperature
21:45that the air needs to be in order for fog formation and this is called a fog
21:51point, which we can see here in the pink line. So our fog point is minus 0.9, our
21:58dew point temperature is minus 0.8 and the temperature, if our air
22:05temperature is 1.9 then our fog point is going to be minus 0.9. So we can see
22:11here from the solid blue line that our temperature is probably roughly, it just
22:15cuts off, it's probably around minus 0.1, 0.2, so very close to the fog point
22:22temperature and therefore is likely that we're going to get fog in the Midlands
22:27by the time we reach Thursday morning. Not only that but a chance of some
22:31freezing fog as well. So rather than just going over the rule of thumb that I
22:36mentioned earlier, we can use instruments such as a Teffy ground in order to help
22:41us forecast fog. We know what temperature we need to get to in order for fog
22:46formation but even with a best guess with the clear skies, light winds, we're
22:51always thinking about that we're going to get a chance of radiation fog and
22:54this kind of solidifies that forecast for you. Now there's loads of
23:00different ways to forecast fog, there's loads of different things that we can
23:03use with these Teffy grounds, so that's quite a brief introduction to fog
23:07forecasting. So if you want us or me to go into more detail, feel free to leave
23:11some comments and some questions and we can perhaps revisit it in another video.
23:17But it does mean that we could end up with scenes similar to this by the time
23:22we reach Wednesday morning and in particular Thursday morning. And as I
23:25mentioned as the days are getting shorter, we're getting very close to
23:29meteorological winter, so a chance we could see some quite dense fog patches
23:33that are really going to struggle to clear. And obviously where we're getting
23:37quite cold in those northern areas as well, temperatures widely dropping below
23:40zero, a chance we could see some freezing fog patches too. Now not much of a hazard
23:45in general, walking around actually makes for some quite nice pictures, but for
23:49certain services such as the aviation sector that is a really big hazard for
23:53aircraft, so freezing fog. So definitely a lot to play for in
23:59the forecast this week, the heavy rain in the south, the frost, the risk of ice and
24:04also the risk of fog. So as always stay updated on our website in case there are
24:10any warnings this week and obviously take care if you're out and about,
24:13particularly in the morning where we could see some quite dense fog patches
24:16that struggle to clear. But otherwise that's it from me, there we go, we did it,
24:21we got through the first deep dive. Don't forget you can like and subscribe, leave
24:27any comments if you have any further comments or questions about fog
24:30forecasting, leave them below and I'll try and take a look and answer as many
24:34as I can. Not only that, but we do have our live on Friday 12.15, so stay tuned
24:40for that one and if you have any questions or any general questions about
24:44the weather this week then we'll be there to answer them too. Otherwise I
24:48hope you enjoyed and that's it from me, bye bye.