00:00More severe weather is heading for the United Kingdom particularly on Friday
00:03and into the weekend. I'm going to be joined by Chief Meteorologist Steve
00:07Ramsdale in just a moment to talk about some of the potential impacts but let's
00:11just break down the warnings first of all deal with the rain initially the
00:15rain warning in force covering large parts of the UK during Friday but
00:19actually that rain is starting to come in during Thursday evening spreading in
00:24across the southwest. If we run through the sequence you can see this band of
00:28rain tracks northwards probably only lasting for an hour or so in some areas
00:32but look at the colors on there the bright colors showing some really
00:35intense rain as that band moves north and it's followed them by lots of
00:39showers and again some of those showers are likely to be very heavy indeed so
00:43some places are going to see quite a bit of rain during Friday. So that's the
00:47rainfall warning let's move on now and talk about the winds because actually the
00:50winds will start to pick up in the southwest later on on Friday but the
00:56wind warning really kicks in through Friday night and into Saturday as this
01:00area of low pressure moves northwards and the isobars start to squeeze
01:03together so the winds really picking up initially in the southwest but during
01:07Saturday strong winds likely across the bulk of England and Wales and then the
01:13next warning is for thunderstorms and that's in this zone close to the low
01:17pressure system where the winds are lighter and that's because that means
01:21the thunderstorms are likely to be slow moving so we have another warning for
01:25thunderstorms covering large swathes of northern Britain because as I say
01:30they'll be slow moving the thunderstorms here so they could drop a lot of rain
01:33just because of their slow moving nature meanwhile across the south we're going
01:37to see lots of blustery showers with the strength of the wind. So that's the
01:41warnings broken down let's talk a little bit more about the impacts let's bring
01:44Steve on thanks for joining me Steve you're a chief meteorologist one of
01:48you one of the parts of your job is to issue these warnings so let's talk about
01:53the rain warning first of all why do we have a rain warning in force for Friday
01:57across the UK? As we've seen we've got that band of rain pushing northwards and
02:01again followed by the showers on Friday and with those you could be seeing some
02:05quite large rainfall totals falling in quite a short period of time with the
02:08frontal rainfall itself we could be seeing sort of 10 to 15 mils quite
02:11widely falling along that band as it pushes northwards but the more
02:15concerning aspect is where we could see a 30 mils or so in only a few hours that
02:20kind of level of rainfall can often overwhelm just local drainage systems
02:24leading to you know ponding of water or even some localized flooding as well as
02:28well as that at least some spray and standing water just elsewhere so it
02:31means some difficult travel conditions but with that level of rainfall you
02:34could be seeing some localized flooding leading to disruption both on the roads
02:37but also to people's homes and businesses as well. So yeah as you
02:40mentioned there's some of the impacts that those those rainfall totals could
02:43bring there's gonna be a lot of surface water and spray on the roads and that's
02:45gonna have a big impact because it's Friday it's the middle of August there'll
02:48be a lot of people on the roads. That's right there's a lot of people traveling
02:51and you know well we we hope that summers are quite nice and dry and so
02:55when there's a lot of rain around sometimes it catches people out but with
02:58that as well again with it falling in such a short period of time that means
03:01conditions can change very quickly on the roads particularly when you're
03:04talking about showers which are a bit hit and miss in places so you could be
03:07that you're driving on quite a dry road you know quite happy really and then
03:10suddenly you're in a very heavy shower the roads suddenly becoming very wet
03:13your visibility is reduced it changes how you drive and it can lead to
03:17accidents and you know difficult driving conditions. Okay so that's the
03:20rainfall warning now the the wind warning across England and Wales as gusts
03:24picking up on Friday night but particularly during Saturday because a
03:27large chunk of England and Wales those winds are going to be unusually strong
03:31for the time of year. That's right and it's very important to say for the time
03:34of year as you do. We are looking at a potential for 40 to 50 mile an hour
03:38gusts inland by day particularly on Saturday but also very locally so 60
03:43miles an hour possible along coastlines as well. What that means is that you know
03:47during the winter we might not be worried about that people are used to
03:50that sort of level of wind during the winter is what kind of expect you know
03:53wet and windy weather. During the summer and believe it or not this is supposed
03:56to be peak summer this sort of level of wind people aren't necessarily prepared
04:00for. As you say there's a lot of people traveling but there's also children on
04:04holidays a lot of people traveling to different parts of the country a lot of
04:06people want to go on holiday there's caravans there's tents and things like
04:10that and they are susceptible to those strong winds. There's also a lot of
04:13outdoor events as well so there's a lot of outdoor and temporary structures
04:17being put up which are not necessarily able to withstand levels of wind at that
04:20level. One of the really important messages to get across is the impact so
04:23it's one of the things you deal with as a chief meteorologist because you issue
04:27these warnings based on impact so as you said in November December this kind of
04:31level of wind would not necessarily be causing the impacts that it's going to
04:35in August so that's one of the reasons why we have a warning in force. That's
04:38right yes it's all about what the impact on people could be as you say in November
04:42people we might have had a few events like this already people are used to
04:46them people are understanding they might put away the things that are going to
04:48blow around before that but during August when it hasn't been particularly
04:52windy recently suddenly getting something like this means people aren't
04:55prepared they're not prepared to change their you know way of driving way of
04:59preparing for things so it's important that we get that message out there to
05:02let people know it is going to be a pretty windy day. So it's a blustery day
05:05on Saturday in particular across England Wales just means the showers across
05:08England Wales move through quite quickly but the other aspect then those
05:11thunderstorms possibly across parts of Scotland Northern Ireland the winds
05:16there are that much lighter which means the storms are slow moving so they could
05:19drop a lot of rain. That's right and it's important there it's a bit hit and miss
05:23with thunderstorms where there's you know fairly slack flow it means that
05:26some areas will see very little rainfall you could get away with a dry day if
05:29you're lucky but where they do fall that means you could see some large amounts
05:33of rainfall falling in a short period of time and again like with the rainfall
05:37the day before where that does happen that means you could lead to some
05:40localized flooding and also difficult driving conditions again it's important
05:43people are aware that that potential for some heavy rain in a short period of
05:46time and quite locally is possible. Brilliant thanks for the summary of the
05:50warnings there Steve now let's take a look at the bigger picture let's people
05:53are asking why why is this happening so let's deal with the the bigger picture
05:58and maybe take a look at what's what's been developing out in the Atlantic over
06:02the past sort of 12 or so hours this is the satellite image so here's the UK
06:07here and it's this blob out in the Atlantic that's really been developing
06:10have we run through the sequence through last night just in here just talk us
06:13through that. That's right you can see the cloud before and you can see the way
06:16that this area of cloud is wrapping around and you get the sense that it's
06:20circulating around this area here and that's true that's what's happening
06:23that's where our low-pressure area is you've got this cloud being wrapped in
06:27through here now this sort of cloud signature we see on the satellite
06:30pictures with this type of low is often indicative of a low that's at it's
06:33almost as its lowest central pressure what we would call that is something
06:38going into its mature phase that means that it's not like to deepen anymore the
06:41winds around it are not likely to get any worse however that system itself
06:45will be coming northeastwards towards the UK so you can see the isobars around
06:49it representing those. Let's show that so here comes that low again and it's
06:53moving up towards the UK and if we just zoom in there the isobars squeezing
06:56together so really picking up across the southwest on Friday evening and then
07:00those tightly packed isobars throughout much of the day across the south on
07:04Saturday. Yeah that's right so with that level of wind strength across the UK
07:10you've got pretty strong winds throughout the atmosphere really and you
07:14can get those communicated down to the surface particularly around the showers
07:17what you often see in these sort of events is that the strongest winds are
07:21around the coast or up over hills that's partly because when they're coming in
07:25off the sea for example what we consider is the sea is a smoother surface there's
07:29less friction between the air and the surface whereas in land there's a bit
07:32more friction because what we call the roughness of the surface is a lot
07:36greater so you tend to get less strong winds in land however in this situation
07:40because there's potentially quite strong vertical motions associated with showers
07:44through the day that means some of that higher what we call momentum air or
07:47stronger winds can be pulled down from just above the surface to give you those
07:51strong gusts in land. So the potential for some the winds just suddenly whipping up
07:54all of a sudden. That's right it's going to be an appreciably windy day but
07:57particularly in and around showers that's where you could see some very
07:59strong winds for a shorter period of time but then back to sort of the
08:02standard windy day. Now speaking of standards we talked a little bit earlier
08:06about it I mean if you saw this weather chart in November or December you just
08:10think oh that's quite a deep low it just be a wet and windy weekend but this is
08:13unusual for this time of year. How rare is it to get these kind of gusts in
08:18August? Well we do often see one or two periods where we get the odd gust getting
08:23up to these sort of levels but mostly as I said before it's around coast or
08:27it's over high ground in land. So the idea of getting that to low levels and
08:31quite widely in land across the UK is quite unusual. You can see stronger winds
08:36in this if we go back to the 80s and early 90s there were periods where you
08:40could see 60 mile an hour winds quite widely in land. We're not expecting
08:43anything quite up to that level though there could be the odd 60 mile an hour
08:46gust through Saturday but it is still going to be unseasonably windy and again
08:51given the idea that there's a lot of people traveling there's a lot of
08:53events going on that's why considering the impact of this we feel it's
08:57necessary to have that warning out there. Brilliant fascinating stuff Steve thank
09:00you very much for joining me I know it's a very busy day. Please make sure you
09:04keep up to date with the very latest from the Met Office and the easiest way
09:08to do that is to follow us on social media.
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