 Okay, I think we'll make a start Gary. Can you hear me? Yeah, loud and clear. Great stuff. Likewise. Welcome everyone. Thank you for joining us this evening. We are obviously live so we're happy to take your questions throughout the evening. And if you'd like to, if you're on zoom and you'd like to post any questions then please do use the Q&A function. We'll ask Gary questions as he goes along. I'm sure lots of you will have lots of questions. So we'll try and get through as many as possible. If you're watching on Facebook because we're live on Facebook tonight as well, then use the comments function below and place your questions on there and I'll be monitoring as many as possible. So there we go. So it's a great privilege to introduce Gary. We, other spring and we've just started working with MWIS and I'd encourage you to go and check out the website. There's loads of useful information on there after this evening's talk. So it's a, we've just got this partnership going with them and back in January. So hopefully it'll come in handy when we're allowed to go back into the hills and start wandering again, which hopefully won't be too soon. Too, too long or too far away. So quick introduction to Gary. He's, he's worked for MWIS for seven years now. And he's, he's highly qualified. He's a degree in meteorology. He's a background geography and he's one of a small team at MWIS who work 365 days a year to bring you forecasting and all the information around sort of the hills and mountains around the UK. So, like I said, go and go and check them out. It's a really good resource. So please give them your support and I will, I will hand over to Gary. Thank you very much. Thank you very much, Mark. Thank you to Ellis Brigham for hosting the event this evening and everyone out there watching and hopefully it gives you something entertaining on another one of these lockdown evenings. Hopefully we've got a sense of improving times ahead. It might be a while till we're properly getting the mountains back where we'd want them to be in terms of getting there. Hopefully something entertaining, something interesting for you throughout here, a whistle stop tour if you like, of all things mountain weather, as Mark said, my background has come up meteorology through a geographical background and for the job of doing mountain forecasting in all intents and purposes, the concepts of pattern recognition, local patterns, understanding of just that small scale situations across British weather is all critical. So I think hopefully that will come through in this talk tonight as to just how localised and how varied our weather very much can be. And what I want to do, have it relatively interactive as we go through this evening for you. We'll take a few questions as we go along basically just see how things that pan out, Mark will chip in with your questions as we as we take things through. We will dive in and basically these statements, I guess, sum up the basic goal of forecasting through and through that if you can get all this lot together, you're not a million miles away from a total weather forecast in many respects for the British Isles it can just come down to as simple as this but the complexity that all this then brings on a day to day weather. So many variables come together basically any day any days weather forecasting if you know the way you are, which way the wind is blowing the basic direction and then when the where that air itself has come from. So the story that we can build and hopefully at the end of tonight's these statements will ring loud and clear in your idea of what British weather can do will as I say a fairly whistle stop tour of various things and we'll divert as we go along basically I thought interesting to start with a chart like this which is the wind chill values basically and something that was all too notable in the forecasts. Through the early part of February at least obviously it's become a bit milder in recent times, but we were having some very severe wind chill values very commonly for a number of days altogether. We refer to a chart such as this for wind speed and temperature to calculate wind chill that you often see in our forecast it's all been calculated scientifically over the years. And it just shows how quickly I think conditions can become very severe indeed on the mountains even what could be considered a fairly modest temperature, zero Celsius at a 30 mile an hour wind on that that's not necessarily a gale day, it's already getting to a wind chill real feel factor at around minus 11 so any exposure to that, if you have an accident on the hills, you know you're very quickly getting into serious conditions and once you're just going down the temperature speed, the whole thing just escalates and we were very much commonly in early February seeing wind chill values that we were putting in our forecasts below minus 20 minus 25 and wouldn't have been far off minus 30 on the other day I think certainly in the big beast from the east pattern that came in back in 2018, I certainly remember writing a minus 30 wind chill value across the Cairngorms, we have been seeing temperatures down at minus 11 or 12 on the recordings from Cairngorm Summit in early February. So yeah just an idea of how cold really things were earlier earlier on this month. So that's sort of wet your appetite for being on the hills as soon as you can consider just where those low temperatures go to when you add on just that exposure to the wind. A chart like this, just to try and begin really with where the concept of our forecasting goes and sometimes I throw some charts a bit like this on the on the video that we put out on YouTube. This is essentially just trying to give you a feel for where the big weather patterns go. We're at the mercy of whether that can come from any point on the compass really at any point in time. It's all affected by what's going on all around the hemisphere in many respects this is a forecast chart this is for this week this is essentially showing pressure anomalies over a week as a whole it shows where higher or lower than average pressure patterns exist and there's always this anomalous situation going on the atmosphere is working very much like a fluid in many respects the whole thing is just rotating around and weather regimes are moving around the hemisphere all the time. Essentially, it's broad areas of air that have different temperatures in many respects it's a constant cycling round of temperature across the hemisphere, our weather, we look to the Atlantic for where it's coming in from. What goes on over the Atlantic is dictated to what goes on over North America, and that is dictated to what by what happens over the Pacific and to some extent that is influenced by what goes on around Southeast Asia all goes around the sequence more or less, in terms of producing the overall weather patterns, what goes on over the North Pole as well, cyclical variations of weather patterns there all do have a role in just what comes in our direction. And what we're seeing at this point in time is a broad zone of high pressure effectively which is an existence across much of Europe into Scandinavia to polar regions, and a broad zone of low pressure that exists this week out over the North Pacific and we're thinking about the jet stream. I mean the jet stream in many respects is a bit of a chicken and egg situation in that they talk on the, the TV weather about all the jet stream is coming back across us and that is driving the weather well yes it does, but the jet stream itself is driven by the contrast of temperature across portions of the hemisphere so that essentially where you have the greatest temperature gradient if you like and at the moment this zone across the North Atlantic here, that's about where the jet stream exists coming in towards Britain, it's turning the airflow basically as a south by southwesterly. Some of that airflow as well is coming around out of southern parts of Europe towards us right now so it's a mild pattern. At any point where this pattern just shuffles itself round we effectively get a different side of the weather story it just depends on all these various pieces move around and they do so over weeks and months and they vary over years and that is all part and parcel of what the weather on a broad scale that gets thrown towards us. If we just for interest and what's been happening in recent times across North America because some very severe conditions existed as you've probably seen on the news in recent times, particularly in Texas. Now this was a chart which again the same concept as of a chart that we've just looked at its pressure anomalies showing where lower and higher pressure patterns existed. This was in the period up until 20th of February it's a five day average and just have a look at the bottom of this chart and what's happening over North America at this point in time we've got a what we call a broad upper level trough in existence. And that was essentially a large zone of very cold air that was in existence over North America effectively being drawn in out of polar regions, all squashed in between a couple of zones of higher pressure which existed out over the Pacific and out of the Atlantic and and that trough was what just drew a very cold air mass down into the far south of the USA through that period and that's what effectively triggered that very very cold pattern, quite anomalous really but these things do have their variability over many many years and all just is how meandering this upper level weather pattern is in terms of any weather that we get when things are very loopy if you like in terms of these high and low pressure systems, then you can get these great anomalies of warm and cold air that move as north or south relative to what would be considered normal and it's all that meandering nature of the weather that just dictates what we will get anytime when it's a little bit more what we call zonal which is west to east flowing. Then we get a more sort of average conditions coming in on westerly winds toward Britain, for example, but if we get something that's a little bit more of this sort of more meridional we call it pattern. This is where things are flowing more north to south, then we can get these extremes of warm and cold and that's sort of what happened for us recently and what happened over North America as well, just to contrast that that is a actual temperature chart for again the period up until the 20th of February when North America was seeing its deep cold you can see the temperatures way way below long term averages across that sway that North America at this point in time as well there was a broad zone of cold that existed across Eastern Europe across much of Russia. At that point we just about finished our worst of our cold spell and we were already getting back into milder weather patterns to see again how there are variations all the way around the hemisphere in terms of essentially very large bubbles of warm and cold air masses that exist and it's just where those move around to as to the weather patterns in play. We think about climate change and well dwell too far into that because that can go down a completely different subject this evening but in terms of long term changes. What we call me and during patterns, the suggestion being that maybe they are becoming a bit more common partly connected to changing in temperature gradients between polar regions as they warm and tropical regions warming quite as quickly. That may be an effect as a broad scale view of a knock on effect on the jet stream is just maybe slowing down the general intensity of jet stream on an average scale. The suggestion that that maybe is contributing towards maybe greater extremes of weather that are occurring, you bear in mind though that there's plenty of other factors natural variability at play as well, on top of any signal of changing climate and day to day is not just the patterns that play when we deal with analyzing climate change we really look at what's going on in the longer term. So, to bring that a little bit closer to home and any good meteorological textbook will show you something much like this in terms of what comes toward the British Isles in weather patterns, and what we call air masses, essentially. So the compass are very much covered here, and each one of these named air masses essentially has different characteristics and as that moves towards us, we are then affected by those differing characteristics of whether it's just bringing the air from wherever it's and modifying it as it comes toward the British Isles so anything that comes in from the Southwest as they are tropical maritime that started out life way out over the mid-Atlantic has got greater amounts of moisture greater amounts of temperature. It just moves its way towards us that encounters a cooler environment and the end result can just tend to be yes mild, but very damp air that comes in so if you end up in a situation where your western hills and mountains are clagged in with very low cloud. The tropical maritime has probably got your name on it because that just brings a lot of moisture towards our shores. Now contrast the polar maritime has come from a cooler source region now that exists, say over the North Atlantic it can have started out life over northern Canada and Greenland as well, which starting out in a very cold environment again that air will move out over moderately warmer and come towards us into a slightly warmer environment now this produces unstable conditions it produces showers essentially as anything comes in from a cooler source. The air tends to be a little bit clearer you tend to get higher cloud bases. Anything that comes around from the west or northwest isn't quite as filled in with moisture, but it can still produce very showery and unsettled weather. The one in between which is the interesting one is one that we get all too often the so called returning polar maritime pattern. This is a bit of a combination a hybrid of both really the sense that any air that starts out life quite commonly towards way towards our northwest, often around low pressure which exists just to the west of Britain that air gets drawn away towards the Azores even sometimes air that essentially is cool and fairly unstable and has the ability to produce showers, gets some added moisture some added temperature, and that just invigorates the whole pattern even more and the whole thing then just throws the kitchen sink at us basically which again is a very common pattern in terms of some heavy rain that comes in from the Atlantic that any air that you know can be coming in from the southwest, some of that kind of starts to lie further northwest so the subtle variations that's where you really just starting to think of where the air has come from. In terms of the weather that is going on, no two southwesterly winds are necessarily exactly the same in that respect, just to briefly fill the circle round basically if you go around further to the north and Arctic maritime some air comes from essentially an environment that has lower humidity so this doesn't bring a great deal of moisture in total it brings with that much clearer conditions so when we sometimes talk about super visibility in our mountain forecasts, it's probably got an Arctic maritime flavor to it, a pure northerly regime that comes down from the North Pole can bring showers, snow and some hail mixed in but also can bring some very clear conditions the low humidity with that is really what's king in terms of that clarity of the air and the greater chance of cloud bases being higher. You turn all of that round and you look at a polar continental air mass and that comes in from a dry source essentially with a lot of land mass that the air has originated from. Just pick up a bit of moisture over the North Sea and sometimes that can result in low cloud and fog as all of that to air that passes across the North Sea can then just create a bit of flag down the eastern side of the country now it varies between between winter and summer in terms of air that comes in from any easterly sources in the winter time as we've seen recently a polar continental air mass is a very cold one can produce snow showers as that picks up the moisture over the North Sea but again in terms of total precipitation tends not to be huge amounts and just to briefly fill that round to the south tropical continental does what it says. It's essentially a very warm air mass or mild air mass anytime of year that something comes in effectively from the Mediterranean, it's going to bring something mild for the time of year, so to speak and that that's maybe the concept of all of this that my pet peeve I suppose if you like in weather forecasting speak is any reference to what things should be for any time of year. It all depends which way the air is coming from in so many respects in that you look at what we're seeing this week in the temperatures for the later part of February. Well, we're seeing an airflow that's coming up on the south or south westerly. Naturally, that's going to bring some very mild or warm conditions so if you think what the February temperatures should be with the wind coming from the south southwest it's pretty much what it is at the moment the long term average of course is everything in weather and you look at going to look at what has happened in February 2021 chances are the month is going to come out somewhere near to average in its overall temperature, but you can find the very cold start with the very mild finish and you all end up averaging things out but day to day weather in terms of what it should be all just depends which way the wind is coming from. I don't want to dive in with anything on air masses before we rattle on any further allow. Sorry, Gary, there's a couple of questions coming. Just on the, not sure which slide it was I think it's the slide before this one someone was asking what the colors mean. The temperature chart was at this one. Yeah, yeah. Now that is a temperature anomaly so it's difference from long term average is what we're seeing on on that chart so the way you've got the blues and pinks and purples temperatures are well below long term averages so it's it's comparing what is happening through that particular five day window which is up until the 20th of February with what the long term average temperatures would be so if you look at North America. You were dealing with well below 10 degrees below seasonal averages and through that sort of spell so it's it's looking at temperatures by contrast to what would be average for that time of year so yeah when you're into the issue you're seeing below average temperatures if you're in the oranges and reds. You're seeing above average temperatures and again it's all part and parcel of just where the big scale, whether patterns around the hemisphere are going. Great thanks go there's just two more questions of my the Richard asked, do you MWIS and Met Office forecasters use the same base information to create their forecasts. So any differences advanced interpretation of the data by the respective forecasts. The answer to that maybe you'd have to ask them I mean we we don't have any direct link with the Met Office I mean what we do our job really is interpreting charts we're looking at a wealth of data from put out essentially from meteorological centres all around the world. There's a wealth of computer modeling that we study on a day to day basis so I mean through our own experience of forecasting we will sort of almost pick and choose the forecast model of the moment if you like that we understand maybe got the best handle on what's going on so we will analyze a whole wealth of data, maybe that Met Office forecasters do the same sort of thing they may use their own Met Office data a little bit more. Directly I suppose because that's their centre that they're working with all forecasters will analyze a wealth of data from different sources. I mean, in terms of which forecasting model may or may not be the best over a long enough period of time that they've all got their good merits that the day where they're all slightly different is where we have our headaches basically because that's where we're trying to figure out what's going on and ends up with low confidence in the forecast. We through experience I guess have come to know which of the forecasting models have the best diagnostic tools, if you like to give us the best information, putting our mountain forecast together, maybe it's the best way of looking at it. Chances are we're also looking at something similar, but it's just how that's being interpreted and that's what we're doing. Thanks Gary. I'll say the rest. Yeah, we'll rattle on hope might be that as we go along things. Any other questions get answered along the way we will get gradually more and more in depth to specific mountain events as we go on to the session. Now, classic fronts that we see on TV weather and we'll see them on our videos as well. These are essentially just the boundaries between those big scale air masses so we were talking about those tropical maritime versus polar maritime. Well they do meet somewhere over the North Atlantic and where they do. So this is where fronts form and essentially this is the life cycle of a frontal system that comes in from the Atlantic. Basically things start out life where you have, let's say somewhere off Newfoundland, cold air to the north, warmer air to the south. You're on a front which is more or less in a straight line. There's a lot of processes of air that sort of moves against itself really you have warmer air and colder air warmer air tends to sort of being less dense ride over colder air so it does tend to rise. You will just sort of shuffle the whole thing around. Things to circulate eventually is as one body of air rides over another, and you go through the stages of developing depression, essentially as we call it mid latitude cyclone, mid latitude depression. It forms an area of low pressure essentially and that's what all too often is moving in across the British Isles and it does tend to just follow in sequence through. As you can see here from top to bottom more or less and once the system has become what we call occluded. That really is where the warmer air that was within a warm sector which is between the warm and the cold fronts gets lifted off the surface really so it becomes lifted higher up there isn't really the sense of seeing the temperature difference across the front at the surface all is starting to get towards its latter part of its life cycle of the weather system the thing that's driving it which is the temperature and humidity contrasts has done its job it's produced the cloud bearing rain bearing system that then spins its way across the British Isles so that's. It's all just air that's moving around against itself that generates our weather these are the dynamic weather systems basically these are the things that are real weather makers, in terms of what comes in off the Atlantic and it's not constant imbalance between warmer and colder air masses just constantly trying to balance itself out between warm and cold across the mid latitudes and that's just the ongoing sequence of weather that comes in our direction. Very briefly again it's out of a textbook essentially what you would see of warm and cold fronts I won't dwell on this too far. It gives you a sense of section if you like or what you would see of a frontal system that comes through. It gives maybe the sense that the warm air does tend to ride up over cooler air, and as you get a weather system coming in from the Atlantic basically brings rain on and then you tend to get the milder air that follows a cold front that eventually comes in from the West, as that begins to cut in as colder air arrives it creates instability it creates heavier rain bearing clouds and showers which then follow. So won't maybe get too in depth on that hoping that just gives you maybe a schematic of what's going on within a weather system like that. Now all that weather gets thrown at us from the Atlantic on a regular basis the prevailing West Southwest that's the most common weather so for all those air masses for all those wind directions we still have something that is more frequent and that is the West by Southwest and that maybe is told by a chart like this this is the rainfall annual average over a 30 year period. This maybe starts to just tell a tale a little bit about the fact that the mountains modify and enhance and make their own weather. You could be forgiven looking at a chart like this for thinking it was a terrain map of the British Isles that this is actually showing the landscape and the hills because it almost matches like for like in terms of where the rainfall occurs over a calendar year with maybe just the exception of the area around the Cairngorms which being somewhat sheltered from the West Highlands doesn't quite pick up on the same volume of rainfall as it would out west but it really does highlight just how the mountains do enhance rainfall that comes in. Our western coast would already be wetter than the east simply because that's where the weather comes from, but the fact that the hills and the mountains are there, it does just enhance that story. And that is a process more or less like this, this is what we call or a graphic enhancement complicated phrase for simply the mountains making heavier rainfall. Now, essentially, the air that comes in from the Atlantic on those west or southwesterly winds comes up against the hills and mountains that exist across much of western Britain. And as it does so that air has got to go somewhere it is forced to rise basically as it comes up against the hills. As the air rises, as it does it cools it condenses that then forms cloud and that cloud then leads to rain, and you end up with a situation where yeah there's already weather coming in there's already rain going on, but this enhanced lifting of air over the hills just creates extra rainfall as that process unfolds. If the hills weren't there, that extra lift of the air, that extra kick that it gets by being forced upwards wouldn't occur. So the hills and the mountains on the western side of Britain in existence make more rainfall across those parts from Snowdonia to the Lake District to western Scotland. By contrast to that on the lee side, the downwind side of the mountains, we get a situation where we call it a rain shadow, where all of that extra moisture that has rained itself out across the mountains in the west. That's been lost from the system basically, and the air that then moves further towards the east it comes downslope off the mountains, various physical processes are taking place, and that air ends up drier than it started basically it's lost its moisture by raining it out and all those processes sometimes and quite often can lead to what we call the phone effect, which is quite simply the fact that point E on this chart ends up even warmer than point a simply just through processes of losing moisture, air rising and falling as air descends. It's compressed a little bit and warming takes place and those lee areas, you're thinking in the south westerly wind of places for example on the Moray coast maybe down the eastern side of the pen islands you can get extra mild air that exists just simply because the air itself has crossed the hills and lost its moisture. Sometimes this is quite a marked situation it doesn't even have to be particularly wet weather that creates this if you've got a very damp atmosphere that's producing a lot of drizzle and low cloud out towards the west or the southwest say. And even you've just lost that relative moisture, you can create these very localized warm spots in the wintertime particularly you can get places, say on a southerly wind, with this effect taking off where you way up into the middle even high teens somewhere in the north of Scotland that I think the record for January is somewhere like leg in the north of the Highlands, which would have got to about 18 degrees in January and it's these processes of the air crossing the hills, and then descending and warming as it does so that creates those local warm spots. Now then, everybody's favorite scene on the hills the good old inversion and just explain a little bit about that because there's something the real holy grail of being on the hills that you want to experience that delightful moment where you come up through the cloud you've been in the murk and the damp and you appear out of the top of that and you get a sea of fog below you and it's maybe all the better. If you guess the cloud is halfway up the hill where you thought you just going to go into a great big fog bank and all of a sudden, a few more hundred meters you come right out of the top of it all together, and you look down on that cloud bank so it doesn't necessarily have to be a fog that's in the valleys or the Glens, it can be a bank and a sheet of low cloud that exists sort of say halfway up and this was a situation. There were some really classic inversions, which were around in August last year, and that was a view just looking down on Glencoe. Over a few days in fact there was some absolute classic inversion conditions where some very damp air was just trapped, lower down and meanwhile, drier and warmer air was an existence higher up on the mountain so what's going on to create that situation we talked about it here at And we're quite a bit in some of the videos and the blogs over the past months. It's a situation like this now we suddenly throw you in with some very technical charts there it must be said but look at the chart on the left. This is a vertical profile of the atmosphere, which is taking you up from eventually sea level at the bottom, right way up to more or less the top of the troposphere which is up around 300 millibars you're up at this part of 30,000 feet in that respect so you're looking way way up in the atmosphere in that situation but we're concentrating on the bottom part of what's going on here and it's the sense that the temperature inversion exists is where we have generally a zone of high pressure under high pressure air is just very slowly descending as it descends zone of compression takes place it creates some warming. And it can just trap the cooler denser air below that zone, which just tends to hang about below an inversion so it's that air that's happening higher up in the atmosphere just higher for the hills. It just gradually descends underneath higher pressure environments that leads to a drying out a warming of the air higher up. And it leaves a cooler damper layer lower down and that's essentially the inversion where normal circumstances would be that temperature would fall with height but plenty of times it doesn't. That gradual lowering of temperature with height reverses itself and you end up in a situation where the temperature with added height suddenly goes a bit higher than you would have been under so called normal circumstances it's typically all seen under these more stable weather environments. As we call it where high pressure is in charge the air itself then is not wanting to rise it's just gradually descending in a quiet weather regime and that can just leave that fog layer to be trapped beneath it. And I'll have a look at the chart on the right in a moment I'll just show you a satellite picture because that was what we had in the middle of August last year and this situation is happening. Have a look across northern Britain we've got sheets of very low stratus cloud, we'd had a very humid atmosphere that had come up from the south, leading up to this which had left a lot of moisture available. So some of that had condensed over the North Sea and that's North Sea, low cloud half red, whatever you want to call it, had lapped well inland across northeast England, Central Scotland, did more or less sort of wrapped itself around Scotland as a whole but just notice the gaps in that cloud and that's the zones of much higher rain across Kanghams, the Western Highlands that were poking through above that fog layer and that's a classic satellite picture for seeing that. Again, Lake District Northwest England, the barrier of the Pennines to all intents and purposes was stopping that North Sea clag from getting further westwards the whole idea of that cooler moist air being trapped just below the inversion. So if you get westwards across the Pennines, it was all held down at lower levels in northeast England so it's very easy in metrological sense to get air, not to go where you might think it would want to go it, a bit like the tide coming in if you like that it will keep itself where it wants to be. If you don't want in these certain situations that air and the damp air can just quite easily be trapped in place in that sense. Now we just, I'll just finish the counter thoughts of that which is the concept of an unstable atmosphere which is the chart on the right hand side here. That is a completely different weather situation realistically that's the situation where there is a very marked fall of temperature with height basically is the simple sense of this. When temperature is falling dramatically with height, it can rise buoyantly and as soon as it can rise buoyantly. You can create big shower clouds basically the air itself is rising cooling condensing, and you end up in a situation where big cumulus and cumulonimbus clouds can frost themselves up you can sometimes see them growing in front of your eyes that sort of a cloud will just grow vertically when the air is very unstable. It can rise rise and create big shower clouds and that can create hail, it can create thunderstorms as well. And the satellite picture would look completely different so we'd have a situation where you've got big clumpy shower clouds that are affecting Britain with some good downpours thrown in for good measure. So it's a fairly technical chart to follow that thought all the way through. This is a chart that's at a middle levels in the atmosphere about five kilometers up at this level. Now that would correspond to the previous satellite picture. We've got a zone of cold air essentially that's moved across northern Britain within an upper level trough, as we call it. And that body of cold air that's come in, probably come in as a polar maritime air mass. That is the trigger for producing those big showers that air can just rise buoyantly to produce showers so on that day in history, you would have been finding lots of heavy showers probably some hail coming in across western Britain it was all on a westerly flow. It's that instability that produces showery weather so that's a different situation. Let's get to what we mentioned earlier on where we're talking about weather fronts that are dynamic processes where it's contrasting air warm and cold air bumping into each other effectively producing frontal systems and rain bearing cloud. This is a different situation this is convective processes this is just a body of air, creating the weather in terms of showers that it's not a contrast of air as such the surface that's producing the weather. The contrast is vertical in many respects it's the change of temperature from surface to higher levels that's producing weather in that sense. So yeah that chart on the right as seen there anything where the air drop of temperature with height is very rapid, that is what produces the showers it's instability in the atmosphere. So if you pause there, whether there's any any feedback or any questions going along just at the moment on that, plenty to take in we could spend hours trying to explain what's going on with some of that it must be said. There are a few questions Gary. Here we go. One second. Lots of people asking if there's any good books that you'd recommend on this topic. But there's various. I won. I've got a few just nothing that we've got that we could directly be endorsing ourselves, but I've got one just to hand, and maybe just to give you a, nothing to do with us which one I quite like it's one that's called 30 second meteorology, which has got a lot of concepts in there and broken down into fairly simple digestible bite size moments if that's not direct endorsement. I'm not involved with that book but I do quite like it if someone wants to just get into meteorology and the concepts of forecasting that's quite a nice one. But I found that we've often been asked, are we going to write our own forecasting book I think we should get around to doing something like that one day. I'm sorry, Jill, Jill Baker asked how far ahead can you accurately predict air mass movements. Again, it will vary to some extent depending on just how mobile the weather pattern is I think we're a pretty good, good up to about a week and maybe a bit more in terms of where these large bodies of air move to I still think that once we get beyond. Maybe a week to 10 days, the forecasting simulation still leave a little bit to be desired they're getting a lot better, and sometimes we can get good trends out of those broad scale patterns. You know, over several weeks ahead. So, thinking back to a chart like that, we can start to see the trends and especially if we're watching the trends build up over a number of days. We can sort of get the rough feel for a few weeks ahead as to where these big players get to but yeah I think in terms of sensible sort of day to day forecasting. And then once you're beyond about a week, you're starting to maybe getting to the realms of is what you're saying, better than just almost a chance sort of 5050 would it go that way or the other. You get to a point where you've got maybe a 20% chance of any one of five variables happening eventually so that that becomes maybe a, you know, the further ahead you go, you sort of into the realms of no better than just a chance outcome. Fiona asks, why don't air masses get named in weather forecast very often. It maybe goes beyond. I don't know that the, the technical capabilities of what they want to show and describe really once or twice I've seen even on the BBC forecast a little bit more on their in depth stuff occasionally they'll refer to it but not, not often, I mean they don't often throw it in that occasionally and if something quite marked is happening they will. But yeah these broad scale bodies of air that they do stick out in forecasting textbooks but yeah not so much on the day to day weather as I say that they, maybe the, they should sometimes explain things a little bit better in terms of where the air has actually come from some of the forecasters do a reasonable job but they're not not that often in terms of describing these. That's a good question for you carry on you go. Graham asks, as I understand it cool air falls and creates high pressure which brings a sustained period of stable weather with blue skies and warm sunshine. If that's the case though why doesn't that warm weather actually create low pressure. Very complicated description. Just go back on the on the lot of that I'll try and explain that. He says, as he understands it cool air falls and creates high pressure, which brings a sustained period of stable weather with blue skies and warm sunshine. If that's the case, why doesn't that warm weather actually create low pressure. I suppose over a. That's a difficult one to explain it in a simple term I suppose. In any. I'm trying to think the best way to try and explain any of that really that you, the whole air that's rising and falling is starting to generate the weather pattern in place so if you've got sort of a generally sort of a coolish body of air. As I said it as it as it descends it does tend to warm which stabilizes things it's it's that maybe concept of stability that is what sort of going on some to some extent any any air that begins on mass to descend is creating a stable situation. Perhaps not an easy one to explain directly without having to divert down a very long, long way but I think anytime it's a. It's looking at the what's going on in terms of surface weather versus what's going on higher up I suppose it's contrast between sort of the sea level temperature or ground level temperature versus the air a lot so if you think about maybe in the summertime. If you get a warm air surface if you get a slightly cooler body of air come across that destabilizes everything and some extent that enhances the development of low pressure. Whereas if you've got a sort of a cool body of air coming over a fairly warm. A warmer body of air let's say coming over a cooler surface it just destabilize things probably hopefully some of what we've said maybe answers some of that already but not not easy to dwell to heavily and what I'll do. Just to sort of drift along and we'll have a look at what's going on at the moment in terms of some weather patterns are recently as well as we close just to follow on that showery situation. I'll show you a couple of charts here just contrasting what's going on on a, on a south westerly. Weather pattern, comparing if you like between winter and summer winter and left summer on the right and this is under sort of generally showery weather patterns or where precipitation is frequent and it's just giving that sort of localized effects of where the weather is and no great surprise that in the winter at least it's the western regions that are picking up on the greatest amounts of rainfall, first in the firing line to a southwest wind in many respects what's maybe worth noting on that is just how relatively the far north of Scotland is the area around some sky and torrid and if the wind is from a south westerly direction you go a little bit further north naturally some of those west coastal mountains are sheltered very well on a pure wind, compared to areas around mall, the West Highlands further southwards which just get hit by the first weather that's coming in just off the Atlantic. Yeah, Northern Ireland has a bit of a sheltering effect but not enough to stop Western Scotland getting particularly wet. So just sort of comparing if anything between winter and summer is where showers exist basically because in the wintertime showers get triggered off over the sea. The contrast of the relatively warm sea with cooler air that moves across the warm sea. That produces showers in the wintertime so showers will rattle their way in from the Atlantic and come in from the coast basically in the summertime the opposite is maybe true, where showers form over the heat of the land so the daytime heating where you get some effects coming up in the heat of the summer sun. It's the land based convection that drives showers through the summer part of the year. Add to that, you get some effects from coastal sea breezes. So, you think that around all the coasts in the summertime, we get a situation where the nice wind patterns get themselves set up the sea breezes just tend to blow inland towards the coast now the shape of our coastline in the southwest like say and all around Wales as well. Those peninsulas end up with some localized convergence going on so the air to the meets in the middle, it can only go one place which is rising. The southwesterly wind will create bands of showers that form across the southwest peninsula and run away inland the same often happens across the mid and south Wales showers run away into the midlands or happen over Snowdonia. And interestingly we get some hotspots that pop up across northeastern hills and mountains as well now this is partly because of the sea breeze effect that kicks in off the North Sea you've got a prevailing southwesterly. You've got a gentle local sea breeze effect coming in off the North Sea, and that tends to mean that air just meets in the middle and you get little zones of more likely shower formation again it's where the air is forced to rise as those sort of wind patterns meet each other so you've got a generally big southwesterly wind in place doesn't have to be a windy day, but that's the prevailing wind, meeting some localized winds around the coast and that creates just one or two hotspots. It can mean on the fairly slack southwesterly that there's the risk of a thunderstorm if all the atmospheric patterns are in there. The risk of thunderstorm around the Cairngorms for example that can be quite common on a summertime southwesterly so we really start to look at the effect of the coastline. In terms of showers and thunderstorms in the summertime for where they do form and that's your local weather variations and we change that wind direction slightly prevailing wind direction, you'll get quite a variation just where those showers can occur. So we trust that briefly with a northerly situation. Again, just think about the summer first of all you're going to have an idea of some coastal effects but there's also a little bit of a thermaling that can go up over the hills that the bit of land based heating can create some showers across the West Highlands a few bands of showers run down the coastlines again a little bit of coastal convergence by the sea breezes around the western coast around the Irish sea can add to that somewhat on the north of the wind. But some of that is the daytime thermaling that goes off just locally in around the hills. Now contrast that to the wintertime because again we're back to showers that form over the sea in the wintertime so we have a situation where it's a direct convection relative warmth to see is what drives the showers and they will rattle themselves into the northern side of the Highlands you get the snow showers for example that come in from North Sea into North East England. And we get these little local effects these bands that run in down the Irish sea now that's being manipulated by the fact that the air has to squeeze itself. The gap of Northern Ireland and Southwest Scotland around Stranraer are low level air is forced between those land masses and as that gets squeezed in between. It is forced to rise and that produces convection and showers and those showers that start out life there had their way southwards, and they can cause what is infamously known as the Pembrokeshire dangler, which is a band of showers that quite commonly on the south of the wind, just intersects the west coast of Pembrokeshire and runs in for locally very frequent showers and the same just tip that wind north north west of the slightly, and some of those showers can run straight in across Snowdonia. It can be a situation where shower after shower after shower comes in in one location, you go five or 10 miles up the road, and they've hardly ever seen a shower all day so these localised effects local manipulation around the coasts, and exactly when the wind is blowing can just give you your local day to day variations and again if you just tip the wind from any slight direction, you'll just change the emphasis of who is going to see what in this existence. Some of those showers as well can get themselves all the way down to Bodminmore, some of the infamous snowy events across the A30 or the A38 can all be triggered by this sort of wintertime shower activity all starting out life just by the fact that you can get between Northern Ireland and Scotland. So that's just maybe a snapshot of some localised patterns which occur under, under showery situations it's not weather fronts it's not dynamic weather, but it's local showery situations they often say on the TV forecast for example oh showers are pretty random they occur almost well they can do, but there is also some pattern recognition in terms of different wind directions and where these showers will form. So that's always comes in some of our local forecasting, and it says much to do with the sea breezes in the summer and also coastal geography in the wintertime. And thinking of showers and downpours, we just look at the opposite side, which is the southerly airflow, but actually this would be a tropical continental pattern. And this then was a chart from the warmest day recorded in Britain, which was a couple of years ago when it got to 38.7 at Cambridge. Now that day in history had a very strong southerly airflow of real Spanish plume effect that was in existence, and all being driven again by large scale atmospheric processes that was creating a very meridional north, south, south to north weather pattern, something like that we'd have got a big zone of high pressure in existence somewhere across Central Europe. There was a developing low out over the Atlantic, you can see that there's a trail of cloud, which was associated with the front, which lies through there that was a cold front out there. This is your real classic three hot days in a thunderstorm situation really it's the thing that makes that heat that makes the pattern is also what breaks it in the end because it says that front moves in from the Atlantic. And that creates the instability already coming in ahead of that through some land based convection over Europe. And as it did on that day in history, very hot conditions but already destabilizing into big thunderstorms that were developing. And eventually the front that comes in from the West brings a cooler and fresher air mass, essentially what then happened of course is that that all started to spin around and it led to some significant flooding issues. As we got into the end of July 2019, and just to the start of August in that month around my part of the world and the peak district was hit badly by some big rainfall events that the reservoir at Whaley Bridge was the new story of course a bit later on, all following that sort of pattern. And that was a synoptic chart from that particular day so that's the show where that front existed. It shows that zone of lower pressure that was around over the Atlantic, and the idea. It's not easy to see on a chart like this but the whole body of air that was coming in on a on a strong, I'll draw it, strong southerly airflow, coming in ahead of that system before eventually we then have the change of air mass coming in So a very marked airflow, big tropical continental and that produced that very hot weather at that point in the in the year. What I want to do now and I'm just going in the final stages just to skip through what has happened recently and then where we're going. Next, basically just to sort of give you a field and some of these synoptic charts now some of you may understand what's going on with these better than others, but hopefully we can get something out of the story, just to sort of explain where we've been and where we're going in recent and ongoing times this was a chart from the beginning or the early part of February this is when all the snow was falling across the highlands at that point and we got a low pressure system was in charge. We'd got a cold air must that was coming in from the east so we were, we were dragging in some of the air off Central Eastern Europe some of it was coming around the high over Scandinavia so it was all dragging in colder air. There was a slow moving front that laid toward the south, and that was the thing that really hit the snow on that south easterly flow that came into the highlands. At that point in time, the contrast between colder air that was in existence and the moisture brought by a front that was producing all of that snow. Now as time went on in the early part of February, we then turned into a very cold easterly flow and that was where we were by the 9th of February. The whole sequence of weather coming in off the continent off Scandinavia that easterly flow that was in existence high pressure late to the north. Now this produced some local again coastal effects around the south of Scandinavia, where there was a little bit of convergence lines these lines that are coming in here. That's where the air sort of come together around Denmark and Norway, and that banded together some of the constant snowfall that ran in, even to the central belt of Scotland where it snowed consistently over a few days and that was traced back to what's going on. Just with the air coming in off Scandinavia on that easterly flow, all the maybe normal British weather at this point was running in Spain and Portugal. The low pressure systems were further to the south, we've got high pressure to the north. It's what we call quite a blocked pattern where we basically see high pressure just stuck in position around into the north of us and stops the Atlantic weather patterns getting any foothold at that point at least across things did then change as we went further onwards quick chart there that shows you that terrain was completely frozen that was a freezing level charts from that spell earlier in February when practically all terrain was muddled as being frozen. So things changed as we went on towards the middle of this month. We were still in under very cold conditions around the weekend of the 13th 14th high pressure was over the continent the air was still coming towards us from Scandinavia around the Baltic, coming in across a cold heart of Europe, and then around towards us on the southeast flow that all was that very cold day that Saturday from a week or so ago, before things then began to change and we could already see the chart like this that there's already a lot of mild air over the Atlantic and various fronts coming in that's knocking on the door and not too far away and it won't take much from that situation. You tip the scales like very cold air that was in existence was replaced by the very mild air that was not too far away on a chart like that, which of course if you then take things on for another day forwards. It was that mild Atlantic air that then began to win coming in on on that strong south to south westerly sequence, pushing the colder air back towards Eastern Europe the front's coming in, and the mild air swept through. In quite a dramatic fashion you went from having temperatures in the minus 23 is the very low temperature in Braemar under optimum conditions and then you were climbing back to double figures for many places in the days that followed and yeah quite a shift of air masses one very cold Baltic air mass to one very mild Azores type of air mass basically and quite a marked shift of weather pattern is not absolutely unprecedented but still quite dramatic nevertheless. I think even in the weather history of going back to the classic winter in 1947, maybe not quite as marked but there was when that winter did end. There was a sudden lift of temperature which then brought about a huge amount of flooding in that weather history so these things can happen these things can go from very cold to very mild in a fairly short space of time just to change the wind direction, basically through through time. And then we've just got stuck with mild south to south westerlies ever since basically this is where we've just been with that mild air coming up on that big southerly flow. And to show you where we are that's where we are at the moment we've got low pressure out to the northwest high pressure out over the continent still a mile south westerly through the middle of this week. That's the broad scale weather patterns going on. Now, just as a snapshot of what we look at imagine our forecasting day I've got about 20 or 30 tabs of weather open to try and work out what's going on in terms of the weather story across the mountains this is a snapshot, we're looking at things like this you've got a general a bit of a synoptic chart a frontal chart with some weather front son to understand what's going on. This is all for tomorrow, it must be said. This is Tuesday's forecast. Yep. I suppose close together is a windy day, the chart top right is the wind speed at what we call 900 millibars Hector Pascal's it's the same thing. a sense for what's going on higher up in the atmosphere well at levels corresponding to the mountains basically we have to look above the surface to to get that. So we're gauging the wind speed at height and how things are going for speed so we're looking at those sorts of charts we're looking at a temperature chart for example bottom left where you're looking at again a temperature at a specific height in the atmosphere to try and give us a feel and the first guess for where temperatures are on the mountains and the chart on the bottom right is one which projects cloud and where the cloud base comes in and again it's a first good guess for us as to where we write our cloud base forecasts and once you're into the oranges and reds you're practically filling everything in from almost the lowest hill slopes upwards which is what the forecast pretty much is for tomorrow across the western mountains of Britain it's a day tomorrow actually where you've got a very marked increase of wind speed with height as just within the broad warm sector coming in off the Atlantic things it creates the stability of the air I won't dwell on this too much maybe but it's the sense that there is a bit of an inversion in play it's not as good as you'd want in a stable weather situation for cloud inversions but nevertheless it creates a situation where the temperature fall with height is marginal and that forces the air over the hills it enhances the wind flow and just means that there's a very dramatic increase of wind speed with height so it might not be a gale at the surface at sea level but if you get up onto the hills tomorrow it is absolutely going to be a howling of a wind with any increase of height I won't dwell on that too much I think we're probably already good for time so what the whole mush all of that together and you end up with our classic forecast the traditional PDFs that MWIS is known and loved for maybe sometimes hated for if there's words like this on it if you were trying to go out on the hills where when there's a lot of words there's a lot of weather happening and tomorrow is one of those days where you've got words like ferocious gusts may blow you over which I think tells you everything you need to know about tomorrow's weather and all of that low cloud to boot so that's the standard forecast for a bad day on the hills maybe it's a good day to be in lockdown I don't know but yeah it's a complicated sequence and maybe to rattle things through in an hour that's not easy to get everything in but hopefully that's given you some insights into what we look at just in terms of our forecasting thank you Gary and anything to offer Mark we um we've had quite a few questions come through as you might let's say I think if we can just grab five minutes because we are sort of running over over time a little bit but um quick quick easy one the book that you mentioned was that 30 second meteorology yeah that was the book okay great yeah so some people were asking about that they didn't quite catch it yeah I think nothing to do with us directly but it's just a nice one that's a nice little sort of coffee table books we're dabbling into so yeah great stuff thank you um Gavin asks do MWIS have historical synoptic charts available to the public we don't but there is a website that's very good for past synoptic charts it's one that's um I think it comes from a German website it's wetter3.de so that's wetter w e t t e r three number three dot d e if you could do a google search for that you can find archive met office charts and things like that and you can go back quite a long way so that's that's quite a good site we don't have the archive charts ourselves but we if we want to look back that's quite a good site wetter3.de um have a have a browse great thank you Aaron asks where in the UK would you choose to live if it was purely based on weather throughout the year um depends what weather you want I mean if you want good weather and drier weather you'd want to be to the lee side of the the big hill groups if you want generally good dry conditions I suppose you'd sort of want to be around northeastern regions if you want to be to be somewhere near to the hills but maybe not being bombarded with the weather coming in from the Atlantic all the time so you yeah I think interestingly I've occasionally been been through the area and stayed in the area even even around the Cheviots and places like that once you're in the lee of the lake district you can actually get as long as you've not got the north sea clang coming in on the south westerly though those areas in north east england south west scotland actually do very well for a surprising amount of good weather um on the right wind direction thank you Adam asks and this is a this is a good um question to me as a visitor to north wales what is the difference for the marked difference in rain sorry what is the reason for the marked difference in rainfall frequency on angle c in winter compared to say the clean peninsula is it a sheltering effective island between angle c and was it that particular way and no necessarily no but uh yeah I I suppose so you you've got a degree of um it might be if we're thinking of that chart on the left for example it might just be that chart wasn't coloured in but so be it but there will there will be uh an effect I suppose where you are just yeah you are just in the lee a little bit more of the Wicklow mountains for example which can have an effect on on producing fewer showers there um maybe that answers that a little bit but but uh yeah I think again it comes down to very subtle variations in in wind direction you you just change any of those wind flows very slightly uh and and you can get um some of those some of those local spots even even as far as between angle c and the clean peninsula as I say I I must be honest with that I I half wonder whether that just didn't get coloured in but there you go I think there'd be some I think you'd still be getting some showers on the south westerly to be honest but there you go great sir thank you uh iris asks any recommended apps for weather forecasting to download um there's various ones I'd always be a little bit cautious with with apps because they only are as good as the data that goes into them straight off the model and if you want I suppose the human interpretation you're always going to want to be looking at what we put out ourselves I mean we're we're going to want to try and evolve our um app-based content a little bit but it would only be to have our own um written forecasts out there there's one I think there's an app called windy which is quite a good one um which gives quite a lot of graphics um as I say the one thing we'd always be a little bit cautious with in promoting app-based material especially if mountain weather is that it's trying it might you might think you're getting a sort of a location specific thing but you bear in mind that the um the topography the detail that the forecast models have is not absolutely pinpoint it doesn't pick out every single hill so any app-based content which is getting very very good in terms of what it will do is only going to be as good as the data that goes into it and sometimes that data will chop and change quite dramatically so I don't always think we probably want to be promoting the the human factor in that but so there's a there's a few nice ones for graphics I'll say I think there's windy there's there's even one off the Norwegian quite a few people look at the YR NO that Norwegian Met Service I think is quite good always always check out our human forecasts as well. Few people asking if uh you guys MWIS are going to launch your own app. Yeah as I said well there's one that uh is on Android at the moment but so we're wanting to develop our own app-based content just to make sure you've got stuff that's on devices you know keeping up with modern technology there's there's various things we've got in the in the pipeline and the planning and hopefully we'll have some new new bits and pieces there for you so yeah it's it will carry all the content that we put out basically so yeah watch this space as lockdown ends no matter a few new toys to play with. Great so Paul asks how do you decide what words to use on your forecasts such as arduous buffeting and ferocious? Experience what we you know we maybe have our own mental both at the scale of how to describe things you know we've got experience of being out on the hills and it's trying to tell it like it is for just what um what you will feel because it's surprising actually you don't need to get actually that much speed of wind to really start to feel it sometimes you can be on a day on the hill and if you with somebody who's not as experienced they say oh that was absolutely awful that was absolutely howling we couldn't put up with that and he said well it's only 30 miles an hour and it's like you you really know the difference between if you're on like a just a windy day which is unpleasant between a day when you're on the hills I'm sure many of you do where if you were there and trying to do it on a day when it was 50 60 miles an hour you're hardly able to walk and anything more than that I mean depends on how experienced you are walking in in the hills and the wind but but yeah arduous is the first level difficult it's just where you can hardly get walking and it's just unpleasant um but yeah buffeting I think is a very good description for walking in the wind I think that's it does it's our favorite phrase I think it comes in quite a bit yeah it's our own little mental both at scale from being negligible right up to the fold you may be blown over brilliant thanks Gary one more question is that okay yeah okay um Ben asked to what extent do the computational models you use account local mountain terrain and how much detail gets added in based on personal judgment um I mean personal judgment that we put in we're always using our experience of things there are some models that are getting very good they're getting you know right down to you know a kilometer's worth or less of detail in terms of how they're resolving the topography but they're only a simulation they're only a model um sometimes the newer models that have come on board in recent years you know they try and resolve detail but sometimes they still don't quite grasp all the fundamentals of the meteorology that's going on um so I think for the time being at least there's plenty of room for still needing the human element that there's a lot of the you know the more technical forecast models that we use that are doing very very well in terms of resolving topography one or two that the picking out the detail of freezing level across the highlands around the Great Glen and places like that that they they're getting very detailed they're getting very good at what they can do um but I think there's always it's always for us it's balancing the stuff that we can see with just our own interpretation of what's going on there's still plenty of room for experience at the hills especially you know dealing with our our side of forecasting great stuff thanks Gary and thanks very much for this evening that's um guess all we have time for I'm sorry for everyone who asked questions and we didn't get time to answer those but um Gary the the website has it carries weekly sort of summary forecasts and things like that it's a good resource from that point of view do you want to talk a bit more just one minute sort of plug for NWIS why ever check it yeah I hope that you know you all know and enjoy the content that we put out there we know we've got the daily um three day pdf forecasts that go out on the website they're the ones that get printed out and all the notice boards that you see all over the place they've got the website content that we do as well so that's updated every single day um we give the the planning summary within our forecasts as well that the video content that we're doing um hopefully we're going to do quite a bit more of as well as we go onwards we've got the the long-range planning content out there twice a week at the moment on the video forecast use both basically you've got your local 10 areas that we have as our our forecasts for the mountain areas locally it gives you your local details use that hand in hand with the videos I'll say we want to do a bit more with the video content in in the near future to try and give you that all-round picture of what's going on with with all the mountain forecasts that we that we put out if you have got any sort of questions if we didn't get to any um you know I'll try and respond on social media if you want to drop any questions if there's anything particularly technical that give me a chance to have a look at and have a think about there was one or two technical questions that were in there if you do want to just drop those in try and have a a discussion at some point on social media and get time so though as if if we can as far as we can do. Thanks very much Gary I'm really impressed that you managed to squeeze that into an hour so I was looking at your your presentation earlier I was thinking I think this is more like two or three hours. Yeah well that's it's it's a tricky one I mean you're trying to get through as much as we can just to try and give you a snapshot of everything we do but I'll say there's six months or two year course in that somewhere and then we we hopefully as times get better we'll get back to doing our day with emwis sessions if you've not heard of those just check out the emwis website and where you can come and spend a day with us and talk all about weather and we can get you to have a go at some forecasting as well so as times get better hopefully we don't just have to do them virtually hopefully we can be out and about and see you in person if you want to to book on one of those courses we'll announce the dates as soon as we can maybe the summer maybe the autumn but yeah it would be a very enjoyable day to to go more in depth than than just the the flash of an hour. Thank you everyone for joining this evening just if you we've got a couple of a couple more talks happening another one on Thursday evening and then another one week after so keep your eyes peeled on Facebook for that and yeah thanks thanks everyone for joining us this evening and thank you again to Gary really good evening thank you bye bye thank you